A 3700‘! OF m3 AVMWS'U‘TY O? NATIVE AND ADDED fiHQSMORU! 5N SWEML MiCMGAN sums M MMSURED M Ct'iEMéCAé. ANALYEES Am} MART GROWfii iESPQNSE Thesis fan-3° {rims Denna (:5 .351. D. animam 5mm CGLLEGE E‘iwd Wi’iééam 3mm W49. IlernLMznijm rullllllllflfllfllfllll 10504 893 MSU LIBRARIES ”- MN) 27 2007 ©324~W RETURNING MATERIALS: P1ace in book drop to remove this checkout from your record. FINES wil] be charged if book is returned after the date stamped be1ow. A STUDY OF THE AVAILABILITY OF NATIVE AND ADDED PHOSPHORUS IN SEVERAL MICHIGAN SOILS AS MEASUHEU BY CHEMICAL ANALYSES AND PLANT GROWTH RESPONSE by FLOYD WILLIAM SEITH A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Soil Science 1949 THES‘S’ ACKNOWLEDGEMENT The author wishes to express his appreciation to Dr. R. L. Cook for his guidance and assistance throughout the course of this investigation and in the preparation of the manuscript. The photographs included in the manuscript were also taken by Dr. Cook. Acknowledgement is also due Dr. L. M. Turk for his helpful assistance in the preparation of the final manuscript. ldfldGV'SJn nottslcsrvqs atn a;91.xu Li .3: 9053131235 may can-si:. 3- x: n: has ac:osgiazvV.1 ._ I .a an incaractonq new .Swlcenan-- c, yd HSXBJ OSIH 313% I'!%“ ‘10: nmuT .u .5 .1" one (213 1 ad: to ncIJaxsqot- 53 ans TABLE OF CONTENTS I. INTRODUCTION II. METHODS OF EXPERIMENTATION III RESULTS AND DISCUSSION A. The Chemical Availability of Phosphorus B. Plant Growth Response 1. The Influence of Added Phosphorus on the Number of Wheat Heads Produced. 2. The Influence of Added Phosphorus on Yield of Plant Material. a. Yield of Wheat Straw b. Yield of Wheat Heads 0. Total Yield of Wheat Plant Material d. Tomato Yields 0. Chemical Analyses of Plant Material for Phosphorus l. The Phosphorus Content and Total Phos— phorus Removed by Wheat Plants from the Various Soils. 2. The Phosphorus Content and Total Phos- phorus Removed by Tomato Plants from the Various Soils. D. The Yield of a Second Crop of Tomatoes on the Same Scils Previously Utilized for Tomato Production. 80 92 96 E. The Yield of Tomatoes Following the Production of Wheat. 106 F. Relationship of Plant Growth Response to Avail- able Phosphorus as Measured by Various Chemical Means. IV. SUMMARY and CONCLUSIONS V. LITERATURE CITED 118 140 115 A STUDY OF THE AVAILABILITY OF NATIVE AND ADDED PHOSPHORUS IN SEVERAL MICHIGAN SOILS AS MEASURED BY CHEMICAL ANALYSES AND PLANT GROWTH RESPONSE INTRODUCTION It is a well established fact that various soils dif. fer considerably in their ability to render available to plants both the native and added phosphorus. It was ob- served that in the case of several of the soils included in this investigation a great variation did exist in connection with the growth of certain floriculture crops. Furthermore, it was not easy to explain these variations with the avail- able data relative to the chemically available forms of phosphorus in these soils. Watson (18) made extensive use of Spurway's (1“) active soil extracting solution in the establishment and mainten- ance of various levels of nutrients in connection with tomato production. This method is widely used in measuring the availability of nutrients, including phosphorus, espec- ially for greenhouse soils. Recently Bray (6) has made an extensive study of the availability of potassium in the soils of Illinois. This investigator has found a very close correlation between the exchangeable potassium content of a soil and plant growth response, provided that the latter is considered in terms of percentage yield rather than absolute yield. These cor- relations have been presented in several scientific ".’ JP" .- 'a. o AV~.‘.‘.--¢.. A -2£b silos auclrsv that deal cenqlicsat ct eldsllsvs refiner c: vdlsiss tier: —do sew 3T .euvodcsznc asbra our av. a: bohufcnl altos ed: to 'sxevsa 1c sear noitoencoo n1 :sixe bib KLI3PI1HV !~31. carelxeddzui .socxa exudlscIIOlt alerts: -Iisvs ed: n31: excl:-:zxv §9=u3 hir1cx! to enrol eidnlisVs vIEnolaegg ..3 “ evlros \“IJ a‘stqua 2o 9;: avianeixs e —ns3nism has tnenflaiidsiwa ed: at holes ddiw ncitoennoo u: sinexzvun lo :’ guirusnem at [can v:stlw a! -331 “g“, —ceqae ‘astoncaan garbcisn; t3311311:an .EILLa 9‘3 '10 Vii-.3338 971811932”)- 119 94?? r; aid? .aicaIIII 1c silo- e ‘... t . _ any .“J. rial a. an: neewted noirslsrioo sable ¢1av s be deora table can Ilsa v 'xoxuco mr‘ sated ni beratinnoo a: racial an: .;n ~1cc seed: .clelv easiesss can: I” sillshsica Iszeves n1 5833”"91 u,_ -2- presentations (6, 10). Bray (5) has spent considerable time in evaluating the various methods for measuring the chemical availability of phosphorus in the soil. This author has pointed out that in the past such methods have been based on an acid extrac- tion of the phosphorus. Recently much time has been devoted by this investigator to the development of a satisfactory method for the measurement of the adsorbed forms of phos- phorus in the soil. As a result of this research Dichman and Bray (11) and Bray and Dickman (3, u) have made an ex- tensive study of the use of the fluoride ion for the re- placement of adsorbed phosphorus from the anion exchange complex of the soil. A.proposed method involving these considerations has been published by Bray (5). Workers at the Illinois Station have spent consider- able time in develcping photometric methods for measuring the amount of phosphorus and potassium in soil extracts. Arnold and Eurtz (l) have perfected a.photometer method for this particular purpose. Similarly Bray (7) has published a method for measuring available potassium in the extract by photometric means. As mentioned previously Bray has published data relap tive to the correlation‘between exchangeable potassium and plant growth response. Subsequently this author (9) pub- lished additional work relative to correlations between available forms of phosphorus and plant growth response. to taillosLIsvs Isoimeoo or: anTUQBEJ t\1 38.13 3:10 hetero "5r. TD.!J"7’ -'.-L .3 .f.‘«:: s Asians £108 4.6 Leas} .:-',-~... -:t'r‘ ,:.cn‘.‘:9m bedovst need sea salt dour t:322:6£ ‘83-“J. vactosisiiss s to Jncnctifivs- a“: c: 222 ~aodq to ammo! neuroses 9.1,.c anemexuase sequoia dorssser 2:3: is :fuoe1 . 2- .4b -xe an sham evrn (# ,{) asvacl- :ufl 1528 h «or add 101 HLI estroull a“: :u ecu so: emsn‘cxe tit-ins 8:13 4:431- .1201“; ' haiku: esedi gnivicvai bonsai Eeaoccz~ I .‘3? .Qi‘) 28:5 ‘le -~;.5I.‘:'~'. need '1." «rebianoo inecs evra ncjasaa slonliil an: Bargugiisa‘ 1:01 Elf-4135’ C-J‘IJSDOO’OIIQ 31110015 .adcsrexe £108 of muiseekm arm eaten-1:: rot bcdtem raremcrcnv p Losoeixsq even \i} bedalic'uo as? g‘ t! $37.8 tlumga .Ocoq'um tcsxsxe en: rl mutsssroc sldsitrv" 1nixr~* .'..:e'.'.‘ -sIet 3339 bedaIIOUn aid roia viahcivsxn b has muiaas30q alcsegnndsxa neewéeo nnl:niw ~due (Q) tendon sin: 1-:aeupesdue .saHOu hearted asoissiexxoo o: evlrslsx htcw l .ssnooaax Ciwoxm :nsiq our suxoacscuq to -3— The published data were considerably less comprehensive in the case of phosphorus than in the case of potassium but nevertheless an apparently satisfactory relationship was found and thus the same principles are being applied in actual practical application in the Illinois Soils Exten- sion program. Lawton, et a1. (12) attempted to correlate the response of legume hay to both phosphorus and potassium fertiliza— tion with the chemically measured available forms of these two elements. These investigators used the methods of Spurway (14), Bray (5) and Peach and English (13). They were unable to find any high degree of linear correlation between crap response and soil test value with either phos- phorus or potassium. S1milarly the correlation‘between plant growth response as measured upon a percentage basis and exchangeable potassium did not appear to be significant. In light of the preceeding more or less confusing picture which has'been presented with regard to the corre- lation or lack of ccrrelation'between chemically measured phosphorus availability and plant growth response, a detail- ed investigation of the phosphorus fertility of a number of Michigan soils was undertaken‘by the author. Presented in the succeeding pages is a detailed discussion of this study. V'"‘l" -ne3x3 silos sfrziigl as: r: '7- eeacqasx ed: erslerzoo a: bsfcxarin 1 AJ'I ('3'. E -aailldte1 03198830u Luz 080$? 10 enrol eldeilrrs heru'nsr 7.;13 lo abodtem on: sea- etc -." ‘_. ved'r .(517 4&1):ng am noiselerxcu resell is 95125: -aodq saddle drip euisv tee: r» a ' .3Q} seaward neisrlewroc ,u. .. aissd sgsdneoxeq a noes messages .3asoitin31a 9d 03 .gnC’s gob Llo m aslsutncc ??u to s~om gains- ‘ r. -er:cc ed: 0: Diego: nax— mw.nus- bexuasem 21ier:.wno resarec n01: .-!Is$eb a ,oanoqaav dtuorfi :nuiq fin to assume 5 to 13111313: auxtdrgi” mi betnsaetq .xocshs ed: to has: .vhues sin: to notaauoslb tellers; The various soils used in this experiment were collected ~4- METHODS OF EEERIMENTATION during the fall of 1948 from various areas in lower Michigan as described in Table 1. Table 1. ability Studies. Identification of Soils Used in.Phosphorus Avail- 8011 Soil Type No. County Legal Description Brookston silt loam Brookston silt loam Brookston loam Brookston,1cam Brookston loam Brookston loam Brookston loam Brookston loam Miami loam Miami loam Isabella loam Isabella sandy loam Conover loam Maccmb Maccmb Saginaw Kent Gratiot Gratiot Clinton Tuscola Clinton Tuscola Kent Isabella Clinton Conover clay loam Macomb Napanee loam Kent silt loam Macomb Kent Clyde clay loam Macamb Oshtemo loamy sand Met sandy loam Leelanau Muck Clinton Eaton NWé m} NW4- NW NW NW sw s ehI NE 8:: N NWT Sec.5-T2NAR1#E Sec.lO—TlN-R13E Sec.33—T9N—R3E Sec.29-T8N—R12W Sec.26—T12N-R2W Sec.26-T12N-R2W Sec.21-T6N-R2W Sec.28-T14N-RSE Sec.21-T6H;R2W 866.31-T14N¥R11E 800.20-T8N5R12W Sec. 4-T1 311-3“ Sec.21-T6N—R2W Sec. 5-TlN-Rl E 800.31-T3N-R1 E Seo.3l-T3N-R14E Sec.27-T5N-R1W Sec. S-TBIN-Rllw North west of Baton Rapids .41st amo.lf:EL-o.§ 111 Lost: : ”1.11 .'. l .i 9. .1‘1" . f .' ' 3‘. .‘.'.'1 r‘ noizqgrcsa; AWJQI “:nu.a A: .x«. chr J 3411r.-9!ST—r.'\sr; 3-3 3 p I O f. l .1 VJ H 3E£H-KIT-UI.59¢ “nu 3€R~K€Ti§. 09L tn... sets. 3‘:ch a: ; WSIE—EST—QS.oeF ,EK : «A .rc; .::e;-n s a fimJSfl<fiba.Jfl :11- .m:.'amcj‘ E fiSEuHSIT-us.oea ,hfi it Hi: *F’ e' ..2 -J tanner-13.2.92; . z .‘ -‘."I:_' L'u’k - In .9 00". T S&1-H+‘I"-8.‘T.OEE git ‘v'tvsu'l met- ‘ _ era: a. - - «‘1 ‘SH-KOT-ID.JJC "'a- :1. 31;; I. u .‘s. ; it. “in Q 3ILfi-KPI1—IE.O;. ,.--01 ”IL? E) l i J" «Sm CI USIE-EBT-Os.eea 33a inch x J! "l--;eaI [I H¥£4fiEITJ .085 33-1: 51-..‘1 1?; v." '- ‘1 .-u-33I 7-; Hm I “SH—ad .-IS .caa :58 nccni . -cI :evoucT ‘1 lglflrfllT-Q Tfic fzrt dmcoz" are; ya}: invent: 5! ' Cl lbw-21’ T»I{.oeb J23! :imoan‘- mac! 3%!!3052’.‘ g; 3112 -uV?~§E.cse run 3353 use: 31:1 fuel a: Evin-'13:? 'Ii 0°95 vhf. 333?" -.~ riff. ’_. ..a 3mm VI ILL-328743.096 {.L’" 17' :5! {r'av'cg 0:393:18: ;! suns ‘JIE-MI{T~E .OSe r.h horn; to 39:3 asucf a .110." mm 15%.. .-- ' .. ”Ge 39 .'-".n . -'. : T‘JM' [OH -5- Veatch (17) has provided the following descriptions of the various soil series utilized in this investigation: grookstonz Soils of this series are predominantly loams and clay loams with dark colored plow soil, under- lain'by wet mottled gritty clay to depths of several feet. The organic matter content and fertility of such soils is high. The clay is highly retentive of mois- ture and is generally found moist or wet. The tOpography is that of level plains and valleys and the soil is wet or semi-swampy in character. Orig- inally such soils were covered with hardwood forest such as elm, soft maple, ash, shag bark hickory,‘base wood, swamp white oak, etc. These soils are regarded as of high value for hay, corn, small grains, beets, beans and alfalfa when artificially drained. giggg; These soils are light brownish loans and silt loans over brownish, compact and retentive but granué lar gritty clay. A clay substratum extends to depths of several feet. These soils are moist but not ex- cessively wet and the surface is acid but changes to a limy condition at shallow depths. In general these soils are of relatively high fertility. The tapography is that of rolling upland clay plains, associated swales of wet darker colored clay -6- land, lakes and muck.swamps. Locally the slopes are steep. The original vegetation was dense forest of sugar maple and beech with variable preportions of oaks and hickory. This soil is of high value for agricultural use and extensively used for general farming purposes. Gonover: Soils of this series are comprised of dark colored loams and silt loams underlain by yellowish and mottled gray massive, gritty clay to depths of several feet. The soils are generally nonpacid or only slightly acid.' These soils are of high fertility. The tOpography of this series of soils is that of smooth upland and swales which are intermediate in drainage between Miami and Brookston series. The original vegetation was hardwood forest consisting of large individual tree growth, mainly of elm, hickory, ash and basswood. Agriculturally these soils are suitable for hay, grain,‘beets, alfalfa and pasture and return medium to high yields. Napanee: These soils consist of grayish and light ‘brown silt and clay loam surface soils over very com- pact yellowish clay. The surface soil is lighter colored and.more compact and plastic clay than that under the Miami series. ' can Isratiuoiias 101 eulsv 4514 2c 21 J a -:a; .sesoqauq animus} IsisnS; Tu: WEED ~;-'Iz:v?v sash To oesirqmso 925 39130; 81:: 3c »_:-; :15 flatworiev‘vo aisixehav arse; :Iie ans sneer be To adqub 03 Yale 13:11; ,9 I.4fim 23:3 toftdc Io bios-sen [liszsreg 8:3 gifts ”JT .fwsl 7* .vtilitmel said in 37- 9;; a bang? .bsoa ariagirs to and: at alias is seizes aid: .0 vdqsrgnqo: 3H1 ‘ at eSsibsmiezni ear :dw sniswn has ans-q; n sdT .asirea £038£0035 va£ Lufll‘ assured use to snivstancs 3332s: 3“uwbE/1 sew,aoi¢s:egev inn ,vroioin ,rze to {Lazar .dtworg sex: Isuojvttai .i;’L'»-‘-3. _ .2 ,23d 10} archaan ems altos 536d: viistu3£uoizad o: mu:oem nausea has Clutsaq has etislxs ‘ates_ . t V II I.‘ 35311 4nc dsixsxa to reissue silos 52:34 -moo vrev :svo altos ez~tmca unci talc arr ails zssngii at 1:03 aosltua a”? .221: varwc'fs_ tad: nsdt talc o;3ssiq bx: tosqmuo stem “up we .seitse insiu on: -7- These soils consist of level and rolling uplands, clay plains and level strips adjacent to streams in association with the Brookston series. Locally, the topography may be of steep s10pes and bluffs. These soils are utilized agriculturally for hay and small grain production. Tillage operations are more difficult than for the Miami soils. lent: These soils are comprised of light brownish and grayish heavy silt and clay surface soils underlain by plastic compact and relatively impervious pale and reddish clay. Soils of this series are medium or low in organic matter but relatively high in other ele- ments of fertility. The topography of areas occupied by the Kent soil series consists of level, upland clay plains and these‘ are generally associated with swales of wet clay land and some muck. These soils are regarded as first class agricul- tural land for hay and small grains and are largely in cultivation. £1193: The soils of this series are generally of loam or clay loam texture and are underlain by plastic highly retentive bluish gray and mottled clay. These soils contain a very high percentage of organic matter -8- and may be mucky at the surface. Such soils are of high fertility and are limy at shallow depths but not in the surface layer. ‘ These soils occur in swampy and marsh land. The native vegetation consists of hardwoods, elm, ash, maple, and in part open land with grasses and sedges. These soils are of high agricultural value when drained for hay, beets, beans and grain. Qghtemo: This soil material is a light brown sand and is underlain by pervious sand with small admixtures of clay and gravel. This soil is characteristically dry, low in nitrogen.and intermediate to low in fertility. This material occurs on level or pitted dry sandy plains and terraces. The native vegetation is Open ‘type of forest consisting mainly of cake and hickory. The general agricultural value is low; The soil included in this investigation is so nearly pure sand in nature that it is not utilized for agricultural purposes. Egggg; These soils are deep, penetrable sandy soils, characterized by a light gray leached sand at the surb face and brown to umber brown sand or sandy loam at 6 to 12 inches. The surface layers are acid, but soil is limy at depths of about three feet. ,das ,mle 'JLCUW 4»: LC e:¢f-aw .seghes can sezssrfi as! «as; rue. nedw euiav stuiinzit_ " Ln .- :1 has an.s sword Jfigii a 5i .filf'fd lo aezuvximhs {isms hair bass aec1v1° ,yxb viisoiaairatosxenc a; ll;= -1": .231113191 mi «of a: essluemzavn‘ .. these gab nestle mo savei a. a.JCLu ueqo a: uciJssegev svi::n an: .. .vxoiold has also To g-nrs; ,,13323. 1108 edT ass! at sulsv lizUSIL"IZ“ hues stun 212695 Ca 31 muiJV.I?;a:x 13:;11n0i133 1c: :ssi.ita zen .1 ,31103 {sass elésrseaea ,ue u ‘10 .1”; ed: is cuss ledcnej ;‘t final. 3 ts maul {buss ur unur.;u-~u using at Iioa :uo ,blss are sxcg'- unvlrua .3563 card: tucas -9- The topography of such areas as are occupied by soils of this series is that of hilly uplands, includ- ing smooth crests and steep slapes of ridges. Both dry and swampy valleys are associated. The native vegetation consists of hardwood forest, sugar maple, beech, yellow birch, hemlock and white pine. The smoother land of this series may be regarded as first class for potatoes and of fair value for hay, oats, sweet clover and alfalfa. The steeper slapes are of small agricultural value. 222;; This sample of soil material (Soil 20) was not a truly representative muck in the usual sense. This material was obtained from a low lying area northwest of Eaton Rapids, Michigan. The material was of a de- finite red color and had a much higher volume weight than ordinary muck material. The surrounding upland mineral soil carried a considerable number of iron can- cretions and apparently much of this iron in the oxide form had found its way into the muck deposit. This particular area was apparently quite produc- tive. The material was used in this experiment'because it was felt that perhaps there would be evidence of exp treme phosphorus deficiency due to the presence of such a large amount of iron. ~10- In general, the various soils used in this study can ‘be regarded as representative of the various series des- criptions as presented above. Several distinguishing features of soils were noted and are summarized briefly as follows. Sample a, the Brookston silt loam from Kent county, can be regarded as of characteristic of that series only insofar as surface topography and texture are concerned. The color is not the same dark color as prevailed in the other members of this series which were included in this study. The soil possessed a distinct reddish cast both in the surface soil and in the subsoil layers. In this respect it was somewhat similar to sample 11, the Isabella loam also from a nearby location in Kent county. . Samples 7, 9 and 13 which are respectively members of the Brookston, Miami, and Gonover series were collected from a single farm in Clinton county and are, therefore, reprog- sentatives of a catena frequently found in southern Michigan. Samples 5 and 6 were collected from the same farm and are essentially identical except that number 5 was taken from a field used for general agricultural purposes whereas sample 6 was collected from an adjoining fence row which was under grass vegetation and had no history of recent cultiva- tion. The remainder of the samples were taken from fields used for the production of cultivated crops except for the -11- following. The oshtemo sand, sample 18, was not being ‘utilized for any agricultural purpose. The Kent silt loam, sample 16, was collected from a grassed area near Grand Rapids and from all Observations of the surrounding land it appeared unlikely that this land had ever been cultivated, at least not for a number of years. The Clyde clay loam, sample 17, was taken from a small wood lot and apparently this area had never been cultivated due to its low lying position and accompanying very poor drainage. The initial laboratory phases of this investigation consisted of the establishment of various levels of chemi- cally available phosphorus in the soil of each series. This was accomplished by adding to each of the soils four specified amounts of Oa(Hg P0h)2°fi20 and allowing this added phosphorus to come to a state of equilibrium with the soil during a three week interval in which the soil was maintained at cptimum moisture. After this interval of time the various experimental samples were dried to an air dry state and extracted by chemical means so that the available phosphorus could be measured colorimetrically in an aliquot of the soil extract by means of the Evelyn photoelectric calorimeter, using the Corning No. 660 filter in this in- strument. In.addition to the various samples of soil to which an addition of Ca(HgP04)2'HQO had been made, a sample of each soil was taken through the same procedure except for the addition.of no phosphorus compound. The amounts of hasxn xsen sear !333513 5 mail asses} has! saihnUC1rva Sat to saoiinvregcc ' ,bedsvitlun need revs ban bflui six: inj: 2. ,maci talc ebvlc ant, .etzex to 104:;n YItabTSQQB One :0! 500m fizzy s MCI; at saivl no! 8:! of syn beisvltiuo need 1 .sasnicrh xccq 218v gaixnsr acitsgitasvni am: '10 sea-“Hi.- amines: -imedo to slave! azcimsv IL Jasmd.liJ93£ aid? .891193 dose 10 {ins and a: avian;ac Tue} alias 3d: 10 does a: iainns‘ ‘ aid: anlwolis Q73 Usfi'gflJOi‘gd}sf is ad: dflw muimdiliups To $1332 a c: emoo 4 saw Iica ed: doinw n! invresni 399' s amid To IBV193fli sin? rail; .aiute‘sa mu' was :is as o: beitb exaw selrnae [;3a9: aidslfsvs ed: can: cs sneer lacimedb yd . douplis as at viiaoitaemlzcioo neruaaam ' otitoeleoton’uvievE 6LT ZL team j”; —ai aid: nl,1531£3 0cm .'_ 431$:(Z an: 0: line To 3910m3< eucrxzv 9:: e: an: , . sIQmBa n ,ensm 03%: .3; yafl'rigfiigi)'- - :01 Square axsnessie a mz L3 haunts: 3-; to sinu2mr enf ..nncmmoc aurci~2L.n -12. phosphorus added to each soil were according to the sche- dule indicated in Table 2. Table 2. The Amounts of 03(32 ENDS, 820 Added to 150 Grams of Air Dry Soil for th Establishment of Various Levels of Chemically Available Phosphorus. Phosphorus added to soil as Equivalent amount of e emental E superphosphate ppm ‘ Grams/150 grams (pounds/acre of 0-20-0) of soil 0 0 0 20 .0030 450 #0 .0060 900 80 .0120 1800 160 .oeuo 3600 The 150 gram quantity of soil for each sample was placed in a glass tumbler and maintained in such throughout the course of the investigation, The added phosphorus was weighed individually for each sample of soil on an analyti- cal balance and added dry to the soil in which it was care- fully mixed by hand manipulation. Following the return to the air dry condition each sample of soil was crushed by gentle rolling so as to facilitate more accurate sampling and to eliminate large aggregates of soil. A total of 8 extraction procedures was employed during the course of the laboratory investigations. The procedures may'be summarized as follows: 83810 031 03 Dasha C3395 “3qu SH) )10 '16. sinuorm an? .12 sl’rm‘r suolxsv lo enemas: .£:s§ d: 101 £t«c 215 :1; 70 .auxonqacdfia -Ideiisvn Vilflatre.l I: 51312 L.‘ To tauoms'tneisvinpa ' an 1; 3 a: “a a dtjnfiqgnfiQ‘ Msdqeodqrequs _ 1: Erifienele . (0-03-0 lo excs\snutcr) ‘ fl . Tfi—r-~—j dm‘it 08‘ .3145» MC k I105 .310 I 0 Co 0 03"! 0200 . or; i 00 . 0-00. 3n cos; ‘ care. ‘ a: 003‘; ‘ W50 . ' (‘61 ' sew elqmea dose 101 I103 10 vtltnnrp max; 011 sf? #mdguont done at Mandates mus 'iel'dmxfi 2119;” g -,} 559le new sxnodcscdq bebns eaT .noftsaicleV~i and 1c servos an: -itviaim as no Ilsa lo 312 was dose 2:: girauLIVIbnE heaping -erss asp 31 acids at Ilsa an: 03 21b nabns has sunrisfi g=c or a: u.ex ed: gaiwollol .noitsfnqlasm been yd L“(:V v'lnt vd badaume esw’ffoa lo efqmsa ache n :3iunco git-31' afif aniiqmss evsruooe atom esrciiiu~ % n: as on an!’;rv Iroe 1c 31.3. 1-11.151. eats: -" 3-x," - '3 Ci“. antrgb hevciqme saw serubaeomc b0f$0fi1$1£ 4 g; 1930: : sevaeooxq ed? .sac ~1i23:issvn£ vacxsxt J on: t: raiuoo ed: :swclicl a: hesitermua ad 3?: (I) (2) (3) (4) -13. Spurwayis Active Extraction: This extracting solup tion consists of .OISN acetic acid. Five grams Of soil were extracted with 20 ml. of the solution by means of shaking the suspension for exactly one minute after which the suspension was placed on a filter and the clear aliquot Obtained was used for phosphorus measurement. This method is exactly as outlined by Spurway (14), except for the use of the calorimeter. Spurway's Active Extraction (1:10 extractign gatio): The extracting solution used was the same as for method 1 above. However, 5 grams Of soil were extracted with 50 ml. of extracting solution. The suspension was shaken for exactly one minute. Spurway‘s Active Extraction (Qne hour shaking): This extracting solution was also the same as for method 1 and the ratio of soil to extracting solup tion was likewise the same. However, the suspen- sion was subjected to 1 hour of end over and shaking on a mechanical shaker. Spurway's Reserve Extraction: In this procedure 5 grams of soil were shaken for exactly one minute in .135N 301 as outlined by Spurway (1“) for the re- moval of the sO-called “reserve" portion of avail- able phosphorus. to amass evil .nir- .Jsani ”big. 1» a::!anoc L -. Yd nolfnlbs ed: 3L .Im 02 hits .s. e 7-2 .mu- 1; sac afforrs 1:: utiannqana en? _.};ria In enucr 8 no hassle sew aciscaocu» an; “2.. '-:_ :t-nin 101 beau asw boniavdo Joe f‘r {p.i: e». _' 153;: as vfrssxs el sadism aij .zrswsvnaael sure; and 10 38” ed: 101 3C957. ,\“I) gm ixfi; Yr snt-f:; ’ .‘I.’ inu'iuioz m! I _- If». .’TQ_)_\;1§.V:3 0-13} ,___£13 3. :j.::-u:jl:__‘,.._-5_ ;,.-_. 2:qu [3' ease and as .esu noiaiica _p;.- “J's an. 3i£3§-3 lies lo smaxa E ,mevewch .vve-fi I ucndez a .moietIOa 33130523xs 1O .1; 0? .riw made. ' - .eCunim sac vitcsx" ':1 vegan“ 3w untanuzhhe 1 :(23219L11“M‘§£E;-:Eé£ui?§té_§' =-i.3'13 -e;_ as! as case and eels :“r nc13n169 :i'~:~$ve 23.. «Ufa: ignitsa‘ztxe :3 11.3 Etc 513;. ..3 . , access: ~a'eqeue ed? ,zevewci-z' .ams 91w s‘aiwsilf am chi antisds has 1970 hue To rues I 03 55399,».2 Him Hti‘ sun-us 121' Reva-.351 6‘. It" a exubeoqu sin: nI :flfigCtlgfg_.:il_finai a' A.- nI 83116111! one Yidcsxe '10“: 39.12.13 grew 'l’ts ‘u '1 -61 9d! 16% aux) tnxnvqe {0 .snirsuo as 15? L&3-. ~Iisvs to acisxou “571.991“ 3:;ao—ca an: IQ Isvzm .BL’ICJCBOu 5 .LGE (5) (6) (7) -14— ngy:s Total Available Phosphorug: This procedure is according to that of Bray (5) and other Illinois associates (1). The extracting solution consists of .03 N H34F in .10 N HCl. Five grams of soil were shaken 40 seconds with the solution and then poured upon a filter. ggay's Adsorbed Phosphorug: This procedure is like- wise according to the methods outlined by Bray (5) and others (1). The extracting solution consists Of .03 N N34? in .025 N H01. Five grams of soil were shaken 40 seconds with the extracting solution and then the suspension was filtered. B521:s Total Available Phosphorus (1150 ratio): This method of extraction was identical with method 5 above except that a ratio of 1 part of soil to 50 parts of extracting solution was used. Bray (5) has recommended this ratio as being more desirable for certain research purposes in the calibration Of plant growth response than method 5 and for this reason this ratio was employed. (8) Bray's Adsorbed Phosphorus (1:50 ratio); This method or extraction was identical with method 6 above except that a ratio of 1 part of soil to 50 parts of extracting solution was employed. This ratio was suggested by Bray (5) as being better suited for research purposes than method 6. 10 a:slsnooguo!:hlta 53:1:stsxe adI .LI) 2939109293 crew lies :0 that; evil .103 X (I. n: zgxu H {0. betuoq and: one uni:nrca an: fistm :nncas; J» census .zathl': .r‘ rem! -e:1£ sl sinneooxq 31a? :33g5155g; L:3:3ff€fi_§llfizfl (a) 1818 2d heniituu 3h::::c an: 03 Lyleuo;s nary 10 83810503 ncituios 30230r13;e an? . ’7 ="nd: nrs exew lies to :mvuJ evie .iufi u ; -. ._ sash 1 ad. has aeitnioa laltosvae an: “3!? annnrea Du mehude $3183-11 arm. m- .rgn-w-uu. up: nan}: nudism dtiw Isoirnahi ?rw Jiflzdtitfi ‘ oLts _ 5:3? 08 08 £209 :0 sung I is 6.:91 .An: 3 95:9 avoaa and (e) 2515 .hsau haw u'Itzic- inrtcowtxe lo 3*:nq to! ardazieeb etc: ;n:vh -3 r.:-; 2.52 henne'ncoex '10 HOIJSZOIIBC to: x' aHeOGTUn nox59,57 ulstxeo _ aid: to! has - bench red: asnoqaex acacia 3031“ .bevoiome an: exit 7;..3‘ neans'r 315T :Lciva: Ofi;i)_gggca:ewnl «Suicans a‘t218 a DOL39W iIRw Inclineii as» n:1foax:xe to bodtsm OE 03 £103 2: 3130 I 1c oitvr s :53: 309953 avodr ath .hevofqme anw uoi!uI:u acidostixs lo 531» tetson :miso as (g) 232E yo hotesggua 85w 0132: .c ioztom had: asaoqxuo 5013583: vol 003108 -15. The various soils described.in Table l were also used 'in.the greenhouse for the measurement of actual growth re- ) spouse of wheat and tomato plants. Soil samples 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, l3, l6, 17, 18 and 20 were utilized for the production of Henry Spring wheat. The various cul- tures were established exactly in‘accordance with the addi- tion of phosphorus as outlined in Table 2 for the labor- atory investigations. The quantity of each soil used was 1l>,000 grams in a one gallon jar and thus the amount of phosphorus addediwas according to the schedule in Table 3. Table 3. The Amounts of 0a(H2POq_) -H 0 Added to "000 Grams of Air Dry Soil for the Establishment of Various Levels of Available Phosphorus for Greenhouse Experiment Involving the Growth of Henry Spring Wheat. Phosphorus added to soil a Equivalent amount of ta P .5 superphosphate (Pounds/acre of 0-20-0) ppm Grams/4000 grams 1 of soil 0 O O 20 .08 #50 no .16 900 80 .22 1600 160 . 4 3600 In addition to the above phosphate treatments each one gallon pot of soil was provided with 1.6 gms. of NHuN03 and 1.0 gram of 101 so as to insure a uniform abundance of both nitrogen and potassium in every culture. Each treatment was established in duplicate. M3!- benv 05:2 923m 1 3169: 31 ialflvfinl alira .V. o .. . ',-LJ'C~.:- '31.: -e': dtwc'u Inuit.“ lc :r'anozuaom. mi: '1'". aux'murvc: ads at ‘4‘ ,E ,5 ,I 3831:;ng [I08 .‘3:‘..' It‘. can“? 41:: beefiitu 519* :; uLF :1 .3 4 O. Ibo n D. a .. -i'uo euoi'mv erg! Juana-s Jul? ; ‘.-:;:si. L“ .c. .Ith sat ffiw ecaaiicocs 31 w, re L.;-j‘ -1003I ed: to} 5 9I "I .- ua:1;:;g 9: ;u._ 88w been lies .cna 1c 171:u3:r “a: .=h:; to :anome on: 25d; an» 19: .y - tn: a~ kc aanoqa ~ - v ; a e- t‘ t” d. - v. .- Us “~“".- "e.U 1°- -‘ V .- V“ 4551‘}: ."nvl' ‘0 3:13 2"“vn: vzuie ‘mu‘s'xfl (‘1‘ ,4." .E 91052 31 of node: an: a: Mr; a; n 163 uehfs zuucdaefidq auto 0W 0: l4SD’lI. vr‘a' (,“L :~:£‘1,‘." {—1‘3‘." fiat .; 91037 l. euotxev lo ineonaiionsr; vn$ ,c' I'll V" :JA EC eauoflnssra to! amoncemifi ;.7 5. - ,-. die-:3- gauge use}! ’10 Liv-wot". m; at}? -J, I ”2935,9013 .frenn _ ---_.,- - a lo 3nuoms :noieviugq k: 7 :1 n; fi.ia g;-. paodq Mahmoud-(aqua g, *5, _ ‘ {5:1 .-~ « -« (C-OS-O 20 9193\shnuofi) - U Y- ~ ; r . :m: J: - In v--‘s» -1- .—7—~»-.——.—v- ._.+_- l Cw . I o 03,; .. -A... we ! :1. v ooh: ; “1. r, 0066 g ~- . :1 -1 ano done affl5fl3EETI 9:9. 4;. o'cur no: -* ; -:.- ' .1 has ECHgHX it .ew .- “:1 -2erc1w A; _: ; is -.* hazing die: to nt-W'4aud..a,-,-;h . chi;.: L- '-n an - .i - d5? 3".I an 3HSJ:&31: “:4 . 04‘ d’..-': ’_.-I "9 ' f'jflrt'. “9 viii. “190,131“ .tiaflds‘ae -16- The pots were planted to wheat on April 7 and by Apr11 10 the seedlings had emerged. These were thinned to a uni- form stand of 11 plants per jar on April 16 and eventually to a stand of only 10 plants per Jar on April 24. Growth was quite rapid, especially on the pots which received the greater amounts of added phosphorus. No visual symptoms of either nitrogen or potassium deficiency become apparent during the course of the investigation. The wheat plants were harvested on June 18 at which time nearly all of the plants were at an advanced state of maturity. The heads of the grain were separated from the straw and separate weighp ings were made of each. No attempt was made to thrash the grain as it was badly shriveled and therefore it did not appear advisable to separate the grain from the chaff. The two portions of the plant material were ground separately and analyzed for total phosphorus content according to the method outlined by Ulrich (15, 16). The ten following soils were utilized for a greenhouse experiment involving the use of only 1000 grams each of soil in one quart jars: Soils 4, 5, 6, 8, ll, 12, 14, 15, 18 and 19, The amounts of Ca(HaP0h)2-320 added to these were as presented below in Table 4. to amotr‘xs Inezlv at .aiaonu;a 3E51£QU£ amcc-: (wholriied adusic 3298. in. .1?’ 1 lies? ed: :0 Ire qtttyn 5-;7 no-3; a '10 ahead 99."? .{3i’IL13fir lo -".‘ (‘3 —dg£ew etntnces and «5:33 :53 M ed: dastfi: of Shsm aux t~mu:; ton bl; 3i 5:015:53; .ne .~1 sdT .llsdc an: utxi 2.37. H; fle3sisqaa unmet; 52:“ l1}: 4. ed: 0: gnlnxccc thatuo. a'iChG .KCI , , asuodnssrx e 10} 09211135 azsw a 1103 lo dbea smart 6001 {Inc 1o 9 has 81 .61 ,41 ,SI .11 ,6 1s ,v , 88 Stan been: c3 heaps \gu-stJ -17- Table 4. The Amounts of Ca(H2POu) ~H20 Added to 1000 Grams of Air Dry Soil for the Establishment of Various Levels of Available Phosphorus for Greenhouse Experiment Involving the Growth of Gloriana Tomatoes. 1 Phosphorus added to the soil as Equivalent amount of elemental P superphosphate (Pounds/acre of 0-20-0 ppm. Grams/1600 Grams of soil 0 0 0 4O .04 900 80 .08 1800 160 .16 3600 320 .32 7200 These cultures were established in duplicate for each of the indicated levels of phosphorus. Additionally, .8 gm. of FHhHO3 and .5 gm. of K01 were added to each Jar to in— sure an adequacy of nitrogen and potassium on each soil. The jars were planted to tomatoes of the Gloriana variety on April 24, 1949. A single plant was allowed to remain until June 1 at which time the plants in all Jars were harvested. These plants were subsequently dried, weighed and ground in the Wiley mill in preparation for the (determination of total phosphorus as outlined by Ulrich (15, 16). The Jars involved in this experiment were replanted to tomatoes on June 6, 1949, so as to obtain a second growth -13- of this plant. The excess seedlings of this planting were utilized for planting the one gallon Jars utilized in the wheat experiment so as to make observations relative to the response of residual phosphorus remaining after the re- moval of the wheat crOp. The second planting of tomatoes on all Jars was har- vested on July 19 and the plants were dried and weighed. RESULTS AND DISCUSSION The Chemical Availability of Phosphorus The various amounts of available phosphorus extracted by each of the techniques already described are presented in Table 5. Graphic presentation of the results of four extraction procedures(K1) Spurway's Active extraction, (4) Spurway's reserve extraction, (7) Bray's total available phosphorus (1:50 ratio), and (8) Bray's adsorbed phos— phorus (1:50 ratio)) are presented for each of the twenty soils in Figures 1 to 20 inclusive. -19. HNH mmH om am am o.oH om N.OH ooa am mm H: mm om a.h m m.m ow «apesoo an we mm mm NH m.m m 0.: o: peoav om mm om mm m m.: a.m om aeoa pane ma ma ma ma 0 o.m m o.m o nepmxoonmai moa oma Ho mma mmH o.mH mm e.oa ooa mm mma mm mas an o.oa ma m.a ow “apesoo mm mHH mm am on a.a 0H m.m o: sesamemv mm moa Hm mm mm a.m m m.: om sooH mm mm ma mm a: w.h a H.e o copmMOOHmflmy mmH mom mm mum cad o.mH am m.mm ooh mu m: mm 2: 3H 0.? am 0.3 om «mango a: maa m moa mma o.m om w.» o: hsooeav o omH mm mm 0H :.m ma o.a om aaoH pane m MHH mm mm m e.a ma 0.0 o eohmAOOHmfimv mm mmm on wma caa m.hH mm o.ma oma we omH mm «Ha aha h.HH ma m.m om «aposoo mm man mm mm mm w.m m o.m o: oaooosv m: 00H mm om am m.~ a m.m om aeoa «Ham mm mma mm ma mm o.m m 3.: o nonmaoohmflay ~o .Ha oHos ammuaqrqdaqaa Aomuav Iaambd Iaampd obsommm mbapod o>Hpo< chapo4 ponnomud Hence connomca Hence m.>me m.>mk m.hme m.>me add m.mmnm m.>mnm m.hmnm m.>mnm Inddm Inddm Iasdm Indnm cocc< mm” m m N H ufinonfl . mlmmmmmmmmmhMWIaflmuhqwna oh on n a» .oohm Haom .coapmmspxo Handsome no memos econommau an enhances mm mHaom unease» on» a” msnondmona mannaambm no penance any .m canes -20- oafl com mm mmm mma m.ma Hm «.m: ooa mm cam mm omH mma o.mm m o.mm om «apnoea oa mom mm mma mag m.:H m o.ma o: oHoomoav mm maa mm :HH can :.ma ma :.HH om shod mm mas ma mm mm m.oa ea :.m o nonmAOOHm Ame moa oma ma NNH mag m.am mm :.mm own mm moa mm om ma m.~H ma m.HH om “Apogee mm om mm am mm m.oa ma m.~ o: nopehaov am am an mm om a.m a m.m om such on an HH an an m.a m N.m o qohthOHm “a: mma cam mm mmH ama :.m we o.a: oma we mmH om oma dos m.mm or m.~m ow “apesoo mm OHH am ea mm m.mH ma o.ma o: behpahov a we ma mm mm m.w ma 5.5 om seoa am am HH m: m m.m an o.m o nonmaooum Amv o H mwa mm owa z.aefl can a .mm omfl om MHH mm eon - w a.mw Mm W.MH om “Apnoea mm mm m mm m :.oa am m.m o: ponhahav pm mu N am am o.m ma o.~ om seoa mm am NH om m: m.~ ma :.m o oopmaoohm Amy sad vogue va “av Amv Amy Aav any Amv AHV oehono Imonm Haom eooehpeoo .m manna -21- omH oaH aoH onH mm . .mm o H ma mm a mm m “.ma m w.~H ow Aaaeooo am mm a me a o.: nH o.m o: uHHohuoHv 0 Ha mm HH m.H m ~.m om such begun om om oH mm m o.H :.~ o aHHohooH.mH mmH omH moH H on m.m m.~ o H as om am mu mm ~.n -m m.H om Hahqsoo Mm m mm am mH m.m ..m :.H o: peony on n :~ m 0H a.~ m.m ~.H om anon mH om 3 am m we ma «H o uHHohooHHJl mMH maH m mmH «H .on an a. o H mm EH m mm m» “.1: mm m .miHH om a a. m m 3 am a mum a raw”? mm mm mm m: mm m.» ”H ~.m o smog HaoH=.oH mmH mom mnH mmH oHH «.mm a: m.mm omH so mHH me mm mm a.o~ em m.mH on mm ma m mm mm o.HH oH m.~ o: Hapoooo am am m m om m.m m m.m om eoaeHHov m cm mm m mH a. a m.: o soon HaoH:.m :1 age eoeoa 3523 “my Hay Amy Amy “av «my «my AHV noohm HHom auauaaqma_.m «Hana _ -22- o H H ma oMH mm .Hm . m o H m H mm .aa an m m.m~ mm .MLMH om Hapqsoo am mm am mm m m.m aH M.~ o: peony mm Mm mm Hm Hm m.m «H .m om auoH ma mH :: mm m.m 0H m.: o pHHu paou.mH mmH osH a «H mm o.MH mm .HH 0 H ma oHH m we . m a.» MH m.m ow Haaasoo .. a a h . a . a a He mm m: mH Mm mm m.m w w.m o oohha¢~.mH mu mmH mm H mHH :.mH mm «.mH o H mm mNH an w? m aoH NH 9m om mm ooH Hm on a N.“ cam o: Hapoooo NH on :H m mm .m m a.m om psoooav «H mm 0H m Hm v.0 a m.: o Hop88th H maH aHH omH mH a.~a mm m.mm o H a mmH o mm ma chum mm o.mH ow Haaoooo am an m m mm «.mH mH m.HH o: oopoHHov m me an o m m.m HH o.~ om anon o um NH mm mm n.m oH n.m o nooohoo.nH nan noea< mahonn H8 «C 3v 3v 2; R. 3; A5 1.23 . :8 cosqucoo .m loaa -23- omH omH ONH odd OOH m: on om mm omn omm omm 0mm com RH an 8H om rnn¥§=rox ”mam-IN HI-I d’d’mNN O\O\O\NN #Wmd’o \OKON=I‘O Shane 83 #MI‘EIS mm Nut-4510‘ HI-h-I H O O 0 0 PIN d’NNNd’ onnoom NNN'QW ital-11"): d'LONN NNNLDI‘ cud-what mono I-l omH cm 03 ON 0 omH on 3 ON 0 omH on 0: ON 0 omH on cm H 358 noon: nos. . cm H 358 saccaooqv 133 human posse . H H 358 8323 B8 28 23.3 H 358 2.035 smog keno ouhao.ua AB At 3v “my Hi HS 3v 3v ...f .3”!wa .4}. .. , E 3 3. Te. E .. )2 , .t v . .H a 3 :v A,v.\ L“ (m ”Def ). v .I. ..e. . x C. r, ( ., . -J .. . .. ‘1 CH. , . .L . ., r . 2H. . .7 .... .. a x a y _. . \. a , .. y i . . . CY. l I . v . v . t t. - .b x V. . .1 _. . . v . a. ... . . . . . i .J ... , , .. a... u. . . u H r . v . . t . L . . . L . A t .f r r . 1n, _ T . .. a. . ... a. . _ A .. 7.5 z , v u I.” . o o . J .. H“ - 1, H .. _.. 9 o .\ f ‘i O. lillllilvt‘iill.| .own I c to . n. o . -. oi .o o . pan 0. at o ,h. < ., .o.< .-C .1 . i r‘x _. ., ' I ,. s‘ «x‘ [,. P‘! 6-- . l H a . E...” 1 a .. J. I ‘... ~_H . t .. H .h .i as x. of o : a. l , c. .1. . _. 11v... .- v. .. >n. L a.>., _. l .55.... .ll‘:1\!||vi} ‘. . 220~ 200- 18C 160 Available phosphorus (pm) 1 i no Figuri‘l. (7) (4) '(8) .. (1) 160 O l 40 {g _ Added 1: osphorus (ppm) tween added phosphorus _ horus .- in Brookston silt loam (1). ____________ and ohmi cally Relationship be available phosp Avaiiaole phosphorus (ppm.) 240, £fl30+ °(7) 180i ' (4) 2160, (8) 20- ”’fififl”fl’fl’;;rapfiflyfl,‘e C1) m ‘ -I-ilgo Added phosphorus (ppm) Figure 2. Relationship between added phosphorus and chemi call available phosphorus in Brookston silt loam (2). y 240 ,— -26- 220 I. 200.. (7) 18C! 16k) 14K) 120 ;.(4) 100 . (8) '80 60 20 J (1) l L l 20 1 80 - 160 Added phosphorus (ppm) Figure 3. Relationship between added phosphorus and chemically available phosphorus in Brookston loam (3). nvuiiuUAO yuvqyuvaud (ppm) 240 available phosphorus in Brookston 10a. (4). r -27- 220 . 200 . 18C) e 160 - 14o . (7 g 120 a -(8 1001.. 80 - 6o . (a) 40 _ . 20 . " ‘ 4(1) - : a we? L Added phosphorus (ppm) Figure u. Relationship between added phosphorus and chemically in ("H‘- ta.) 240 --28- 220 . 200 . (7) L80 160 140 120 100 80 (1) , l - I ‘26 71?) so 160 Added phosphorus (ppm) l'18ure 5. Relationship between added phosphorus and chemically available phosphorus in Brookston loam (5). F ,.L ‘J M ll! II.) )1 . 240, 220 200 180 160 140 3120 '100 80 60 20 (7) -29- (4) ’ (8) db 0 3 20 ho so 160 Added phosphorus (ppm) Figure 6. Relationship between added phosphorus and chemically available phosphorus in Brookston loam (6). 0“ ‘IA “4 A—an.‘ no 20 200 .80 L60 140 120 100 80 60 40. 20 (7) (4) (8) (1) l o 35 160 Added phosphorus (ppm) 20 Figure 7. Relationship between added phosphorus and chemically available phosphorus in Brookston loam (7). *31- 3 _ . (7) a . O b . (1*) (8) (1). 20 _ £0 1.50 480 ‘ 160 Added phosphorus (Ppm) Figure 8. Relationship between added phosphorus and chemically availahle phosphorus in Brookston loam (8). 240 22C) 20C) 180 160 '140 120 ‘ 100 80 60 40 20 -32- L 0 / a ./o (1) u / l) O C l I I I 20 40 ‘ so 180 Added phosphorus (ppm) Figure 9. Relationship between added phosphorus and chemically available phosphorus in Miami 1081:: (9). IF"! L60 140 120 100 80 60 40 20 O 20 Figure 10. (7) ‘ (s) .1304) (1) 13’ L 1 l ‘W 80w 160 Added phosphorus (ppm) Relationship between added phosphorus and chemically available phosphorus in Miami loam (10). -34- 200 .. 180 b 160 (7) 140 . (8) 120 100; 80- 60b (4) no 20 ‘~® ‘60) 20 80 T60 Added phosphorus (ppm) Figure 11. Relationship between added phosphorus and chemically available phosphorus in Isabella loam (ll). 240 220 200 - 180 .. 160 140 \I’M“! H N 0 § --o---u~-\l yéov ”91“-- «c O\ OH O O 40 20 I 1 1 . 20 40 go Added phosphorus (ppm) Figure 12. Relationship between added phosphorus and chemically available phosphorus in Isabella sandy loam (12) 160 fif“ . C I O 5 U a '|~v '. 0“ J) DO- ' (7) (4) (8) __JB (1) __G__ 1 o 20 40 80' ‘ 160 Added phosphorus (ppm) Figure 14. Relationship between added phosphorus and chemically available phosphorus in Conover clay loam (14). (7) .(8) ‘ (’4) 30, 45(1) W + 20 :40 80 160 Added phoqahorus (ppm) Figure 15. Relationship between added phosphorus and chemically available phosphorus in lapanee loan (15). (7) (8) (4) ' I _l l ‘20 4O 80 160 Added phosphorus (ppm) Eigure 16. Relationship between added phOSPhOTUS RUd ChEPiCVlly available phosphorus in Kent silt loam (16) )o. F 20 J (1) w l 50 40 6‘5 150 Added phosphorus (ppm) mSure 17. Relationship between added phosphorus and chemically available phosphorus in Clyde clay loan (17). E33 «- 1w '1‘) W‘ 0.. .r. adv VJ ‘A ‘o euo ,. (5) -41... 220 200 130 in) 120 100 80 60 E fl __9, 45(1) ‘? 20 40 . . 80 160 Added phosphorus (ppm) figure 18. Relationship between added phosphorus and chemically available phosphorus in Oshtemo loamy sand (18). 0 ~42— (7) (8) (4) (1) if i i l 80 160 ,3 Added phosphorus (ppm) Figure 19. Relationship between added phosphorus and chemically " available phosphorus in Enumet sandy loan: (19). -43- (7) (8) 80L- 0 40 . ____._...._.._.-..,._ mum-43(4) a t! n _...._._.. 20 In #9 1) W .e, ( L_ 1 . . l , 20 4o 80 160 Added phosphorus (ppm) Figure 20. Relationship between added phosphorus and chemically available phosphorus in luck (20). -44— In general the amount of phosphorus removed by the active extracting solution of Spurway (14) was quite low in comparison to that removed by the stronger acid extractants used in the reserve method of Spurway or in the techniques of Bray (5). This method of extraction did, nevertheless, tend to reflect an increasing amount of available phos- phorus in the soils as the increment of added phosphorus became greater. In some cases the rise was not great, suggesting perhaps that the particular soil retained the added soluble phosphorus with such strength that this ex- traction was not effective in indicating its true avail- ability. This was especially true on soil 4, 11, 14, 15, 17, 18 and 20. Inasmuch as it seemed that the true avail- ability of the added phosphorus was not indicated in these ‘particular soils it was decided that perhaps an increase in either the ratio of extracting solution to soil or in the 3 time of shaking might improve the results of such chemical extractions. Thus the whole series of samples was subjected' to two additional extractions in which Spurway's active ex- tracting solution was used. Generally speaking, increasing either of these two previous mentioned factors resulted in an increased amount of phosphorus being removed from the soil except in certain instances where one or‘both of the. revised techniques failed to result in any improvement. The increased ratio of extractant to soil was no more effective at the two lower levels of added phosphorus on the Brookston -45.. silt loam from Kent county (soil 4) than was the original extraction. The same relationship existed also for the Oonover soil from Macomb county (soil 14). However, after as much as 80 ppm of soluble phosphorus had been added, each of these soils did release more phosphorus when sub- Jected to the action of a greater volume of solution. The increased shaking time was even less effective than was the increased amount of extracting solution. For example, in the case of the Isabella sandy loam.soil (soil 12) the increased time resulted in a decided drop in the amount of phosphorus removed from the soil at all levels of added phosphorus except where as much as 160 ppm had been made. The decrease in amount extracted was even greater in the Oshtemo sand (soil 18) and the muck (soil 20). In various other instances it was apparent that at the lower levels of added phosphorus even less distinction was able to be detected between the increments than had been apparent previously with Spurway's original technique. There was some tendency such as on soils 1, 3, 4, 6, 11, 14, 18 and 20 for this procedure to reflect no more and in some cases even less available phosphorus in a given soil after the addition of 20 ppm soluble phosphorus than had been the case in the original sample. In general the use of the weak acid extraction as out- lined in either of the three above techniques produced a sufficiently colored extract so that the intensity of the -45.. blue was sufficient to be easily detected with the colori— meter, even at the lower levels of availability. Even the extracts from the soils containing the greatest amounts of soluble phosphorus contained so little phosphorus that it was seldom necessary to dilute the extract to obtain an in- tensity within the range of the Evelyn photoelectric colori- meter. The use of Spurway's reserve extracting solution al- ways resulted in a reflection of the various additions of soluble phosphorus and thus did not result in such excep- tions as described for the active extraction, especially when the extraction time was one hour. This method did result in great variability depending upon the soil. According to this method the original samples, before the addition of soluble phosphorus, had a range from a low of only 6 ppm of available phosphorus to as much as 99 ppm available phosphorus. This method was by far the more variable with respect to differences be- tween individual soils. Furthermore, there are seemingly undesirable discrepancies in such techniques where only a strong acid extractant is used in the case of such soils as 4 and 11 where the amount of available phosphorus in- dicated is less after the addition of 160 ppm of soluble phosphorus than for a large number of the other soils even without the addition of soluble phosphorus. This method may also be criticized due to the inconvenience in measuring -47.. the amount of phosphorus in the extract. In the case of soils containing very large amounts it was frequently nec- essary to dilute several times and thus a considerable expenditure of time was made merely in a trial and error method of color develOpment in the unknown.samples. Due to the great variability in the amounts of phosphorus re- moved from untreated soils, no fixed dilution schedule could be adapted to provide for even the majority of samples. The use of those techniques suggested by Bray (5) pro- vided additional information relative to the apparent soluH bility of phosphorus in these soils. Bray (5) has recom- mended the use of a 1:10 ratio of soil to extracting solup tion in the neasurement of total available phosphorus or adsorbed phosphorus when ordinary field samples are being examined for fertilizer recommendations whereas the ratio of 1:50 has been recommended for research purposes. The various samples of soil in this study were all initially subjected to an extraction ratio of 1:10. Upon the completion of the measurement of the so-Oalled total available phosphorus it was at once apparent that this method had a distinct tendency to remove more phosphorus from the soil than did the use of the strong acid as em- ployed by Spurway in the reserve extraction previously dis- cussed. Only three exceptions to this were noted. In the case of three of the untreated Brookston soils (soils 2, 7 -48— and 8) this technique did not remove as much as Spurway's extraction. However, in all other cases, including these three soils in those instances where soluble phosphorus had been added, this method did result in greater values. This method did behave different than the previously described reserve extraction of Spurway in the sense that there was much less variability between soils. For example, the lowest value on an untreated sample using this tech- nique was 19 ppm, and then.for only one soil, as compared to a low value of 6 ppm for each of three soils using the reserve method. Excluding the Oshtemo sand, no value for any untreated soil exceeded 88 ppm whereas with the Spurway .reserve extraction the corresponding value on this same untreated soil (soil 8) was 99 ppm of available phosphorus. Inasmuch as the same acid, H01, is the acid involved in each of these extractions, it must be concluded that the presence of the fluoride ion has played a very significant role in causing the release of phosphorus from the soil to the extracting solution. In this way the exceedingly low values Obtained where only the hydrochloric acid alone is used tend to be eliminated. The reason for the three soils (soils 2, 7 and 8) having greater values with the reserve extraction than with the method of Bray for measuring the total available phosphorus undoubtedly lies in the greater normality of the acid in the former extracting solution. This method of Bray was apparently quite capable of -ug- reflecting the presence of added soluble phosphorus in every case on every soil. This method also provided only one instance (soil 4) in which the measured available phos- phorus after the addition of 160 ppm of soluble phosphorus was less than for the untreated samples of soils 2 and 8. The use of Bray's extracting solution for the measure- ment of total available phosphorus also provided one other important advantage over Spurway's reserve extraction. As noted above, the range of measured values with Bray's tech- nique was from 19 to 88 ppm on the untreated soils as com- ‘pared to a range of 6 to 99 ppm on the untreated soils when using Spurway's procedure for removing the reserve phos- phorus. This reduced range coupled with the fact that the Bray procedure utilizes a 10:1 extraction ratio as compared to 4:1 for Spurway's method meant not only a reduced range to contend with in working with the unknown samples but al- most the complete elimination of the necessity for diluting unknown samples, particularly on untreated soils, so that a great saving of time was rendered. neasurement of the adsorbed form of available phos- phorus provided additional information about the tenacity with which added soluble phosphorus is retained by a given soil. For example, in the case of soils 4, 9, ll, 12 and 19 in particular, the amount of available phosphorus removed 'by either of Spurway's procedures was comparatively low and thus it might be suspected that in comparison to other soils -50. which gave higher values where the same procedures were used these values are actually too low to reflect the true avail- ability of phosphorus in these soils. No doubt the true availability of phosphorus in these soils was less than that of other soils receiving the same treatment but it is ex- tremely doubtful if such wide variations could exist. It was noted previously that the addition of fluoride tended to eliminate these extreme variations between soils. The use of Bray's extracting solution for the removal of adsorbed phosphorus alone suggested that on several of these soils this form of phosphorus must be included in evaluating the available phosphorus in a given soil. Particularly with soils 4 and 11, both of which came from Kent county and to a lesser extent with such soils as the Miami loam (soil 9) and the Isabella sandy loam (soil 12) the content of avail- able phosphorus was quite low when measured only by removing the strictly acid soluble fraction as is done in Spurwayls method. The use of fluoride, even where it is in combine ation with such a dilute acid as 0.025N HCl as is used in- Bray's adsorbed acid extracting solution effected the re- lease of considerable additional nonpacid soluble phosphorus. This conclusion must be made when it is apparent by examinp aticnlof the value for Bray's adsorbed phosphorus that on certain of these soils virtually as much phosphorus is re— moved by the fluoride in 0.025N H01 as in 0.1N H01. There- fore, indirectly it is demonstrated that one of the major -51- reasons why Bray's total available phosphorus extraction technique eliminates the exceptionally low values observed with Spurway's methods is due to the action of the fluoride. Although only indirect evidence is available, it must be assumed that particularly in the case of the Isabella soils, the Miami soils and also the Brookston soil from Kent county as well as the Emmet soil that the quantity of ad- sorbed phosphorus is of no small importance particularly when considered as a prcportion of the total available phos- phorus present in such soils. Additionally, the soils were subjected to extractions with the same solutions of Bray at the 1:50 ratio of soil to extracting solution. Bray(5) has suggested that this type of extraction is more desirable from the research standpoint and particularly in those instances where an attempt is being made to correlate such values with plant growth response. Furthermore, this same author has suggested that such extractions should more nearly remove all of the adsorbed phosphorus from a given soil whereas a 1:10 ratio removes only approximately one-half the entire adsorbed portion. Therefore, if a correlation between the adsorbed form and plant response does exist, it is more desirable to know the entire amount than only a fraction of it. In the case of the soils considered in this investigation the inp creased ratio always resulted in higher values for both the adsorbed forms and the total available phosphorus. However, the prcportion removed by one ratio as compared to the other -52. was by no means constant for the entire group of soils. For example, in the case of such samples as soils 1, 11, l#, 18, and 19, increasing the ratio of extractant to soil did not increase the value for adsorbed phosphorus nearly so much as it did in the case of soils 8 and 16, in parti- cular, where the quantity removed as a result of a greater extracting ratio was nearly doubled in the latter. There- fore, inasmuch as no constant relation seemed to exist, even more importance might be placed upon using a relati- vely wide ratio of extracting solution to soil, particularly for research purposes where precise values representing a given fraction of phosphorus in the soil are of utmost‘ significance. The use of a wider ratio of extractant to soil also had the tendency to give even greater significance to the role of adsorption of phosphorus and removal by fluoride of phosphorus in chemical studies of this element in the soil. By comparing the last two columns of Table 5, it is apparent that in the cases of soils 4, 7, ll, 12, 16 and to a lesser extent with certain others that the equivalent of virtually all of the total available phosphorus can be extracted as adsorbed phosphorus if a ratio of 1:50 is employed. Thus additional clarification as to the exact status of the forms of phosphorus existing in the soil was provided. If only the values obtained as a result of a 1:10 extraction ratio had been considered, there prObably -53- would have been a tendency to have overlooked the true role of adsorption of the phosphorus for at least several of the above specified examples. In general, the chemical studies of available phosphorus in the soil shed considerable light upon the phosphorus fer- tility of the various soils concerned. Seemingly the employment of the fluoride ion in extracting the adsorbed portion of phosphorus cannot be overlooked and therefore any attempt to evaluate the true status of phosphorus avail- ability by means of either strong acid or weak acid ex- tractants is not entirely acceptable on at least some of the soils included in this study. -54.. Plant Growth Response The Influence of Added.Phosphorus on the Number of Wheat Heads Produced Data relative to the mean number of wheat heads pro- duced per individual treatment on each of the soils are presented in Table 6. There were obvious visual differ- ences in the size of the plants according to both soil series and phosphorus treatment. Therefore, it was be- lieved that a count of the number of wheat heads produced by each treatment might aid in explaining the plant re- sponse to phosphorus. . In.general, there was some tendency for the addition of phosphorus to increase the number of wheat heads pro- duced. This fact was usually most apparent for the first addition of phosphorus. On certain soils such as 2, 9, 12, 18 and 20 there was no apparent stimulation in the number of wheat heads produced as a result of the first addition of 0a(HgP04)2'H20. In the case of the Brookston silt loam from Hacamb county (soil 2) this tendency was probably due to the fact that this soil in the untreated state was capable of producing a large number of wheat heads due to a high state of native fertility. The other of the above soils had a much more pronoun- ced tendency to produce a smaller number of wheat heads, especially in the case of soils 12 and 18. These two soils -55- i in particular seemed to be especially low in fertility and upon the basis of plant growth characteristics, including size of heads formed, were amont'the most responsive to added phosphorus, especially at the higher levels. The data in Table 6 suggest that the various soil series had a definite tendency to vary probably even more than the levels of phosphorus within a given soil series. For exam— ple, the 01yde clay loam (soil 1?) averaged more than double the number of wheat heads for each level of added phosphorus than did such soils as the two Isabella specimens (soils 11 and 12) and the Oshtemo series (soil 18). Similarly the two Brookston soils from Macomb county (soils 1 and 2) and the Kent silt loam (soil 16) were especially capable of produc- ing large numbers of wheat heads, regardless of the added level of phosphorus. The Clyde and Kent soils were obtained from a wood lot and grassed area respectively and probably were of especially high fertility and therefore capable of producing a large amount of wheat heads. Likewise, the two Brookston soils were apparently in a high state of fertility as a result of soil management practices. Soil 1 was ob- tained from an area used for truck farming and Soil 2 was ob. tained from a grain stubble field which displayed an excellent growth of clover which suggested a relatively high level of _ fertility. Additionally, these two soils were in a well aggregated state as indicated by the apparent stability of the aggregates in the greenhouse cultures after several months of surface watering. -56- mopmoaaamn N no use: a ma m.HH an m ma m.aa m.ma om omH m.mH m.oa mm m.mm m. is NH m.HH m.mH om as m.m on m.mm ma m.oa m. as 0: ma m mm m. m ma oH .HH m. ma om ma 0H mm m.mm m. H oH m.m m. ma 0 .00 amo .00 .oo copes .so nopqaso.so peace: .00 neon nopeaao saasnsmH .00 neon saoomaa and seem daemon” sec." .33 seed 50H 83 apnea sec.“ 53H macs Mos: oscpsmo sumac pHHm anew noboaoo mHHonmmH mHHonmmH «sea: amend 83 $3 :3 G: R: 3: :5 _ 8: 8% ma ma m.aH ma ma m.¢m m.m~ m.m~ oma ma ms ma m. ma NH m.am mm :m, cm mH as as m. ma :H m.ma m.mm m. om o: 9 ma ma as 9 ma m.HH m.aH m.Hm am cm 9 ma HH on 9 m.oa m.ma m.am om o .oo .oo .oo .00 cu scandao soacdao aoapmno acapmuo .oo paou smsuwmm .oo nsooma.oo naoom: and smoa ssoa ssoa smoa seen smoH smoa wade ssoa vafim.msuon “sad: scpmxoonm.q00muoonm.sepmxoonm sepmxoonm scamxooam sepmxooam.sopmuconm locum E E E E E E .E E as. .msnosamond sound no camped maoansp one on msacnocom madam muofinmb on» new assesses» nod poonposa meson uses: no amass: games may .m cages -57- The Influence of Added Phosphorus on Yield of Plant Material Yield of Wheat Straw Data are presented in Table 7 relative to the mean weight of wheat straw produced by each treatment for the various soils studied in this investigation.. The weights, in.general, showed a tendency to increase as the level of added phosphorus was increased, especially as the initial lower amounts of phosphorus were added. The first incre- ment of phosphorus, 20 parts per million, produced an in- crease in all except two instances. One of these was on one of the apparently most fertile toils included in the study, the Kent silt loam (soil l6) and the Oshtemo loamy sand (soil 18) which, upon the basis of the appearance of plants and weight of material harvested, must be regarded as the least fertile of the soils in the study. 00mparatively speaking, the seemingly most infertile soils, upon the basis of chemically extractable phosphorus in the untreated samples, for instance the Isabella series (soils 11 and 12) and the Oshtemo sand (soil 18) gave the greatest percentage increase in weight of straw for the addition of phosphorus especially at the upper levels. This same general relationship also held for the Brookston soil from Kent county (soil 4) which behaved more like the .mopmoHHaeH N no use: a .-58- m.aH w.» m.mm H.mm a.oH o. H m.mH e.mH omH ”NH ans m.am m.mm m.mH m.NH H.HH m.aH om .MH m.m m.w~ a.m~ o.mH H.~H m.~ «.mH o: s.mH .m m. m H.H~ m.mH m.0H m.m m. H om a H a m o.m~ :.sm m.mH m.m m.m o.MH o .oo me. limo Ilsa Ilmuv» wHawH noses coanHo paces: .oo pace soquHo sHHonsmH .00 page aHoomsa and idea asdoH sdoH amHo smoH smoH smoH modem sdoH seed masons Hoes osopnmo osaHo HHHm «sou ncpoeoo «HHonsaH sHHonsmH HssH: uuosm Howl HmHV HNHV HoHv AMHV ANHV HHHV AoHv sousH nHwH ~.mH m.~m n.mH m.aH o.mm H.~m ~.mm omH o.mH era 0.0m «.3 .MH fimH 98 am om a.mH .om H.om m.mH m.sH n.mH o.~H .Hm o: m. H .sH m.oH s.sH «.HH :. H .mH n.mm om m sH m.:H m.» o.HH o.m assH .wH ~.mH o .oo .sml. .00 .au .oo .oul anw cpsHHo sousHHo poHpssc poHpmso .00 neon weaHmmm paces: paced: and sea smoa 50H 83H sac.” sec." 50H 33 50H :3 masons «Edd: dovaOOHm dovmxoonm flomeOOHm novaOOH floamMOOHm covaOOHm flopmMOOHm Imoam Amy Had «my «my Hey «my “my AHV sauna .msnosamona pound no maopoa msoHnmb on» op msHosooom mHHom mnoHHd> one son escapees» sea cessposa scape sees: me madam sH dommosdxo upanct cases one .N oHnma ~59- Isabella soil from the same county than like the majority of other Brookston soils included in this study. One other soil which gave a very marked increase in growth of straw according to the addition of phosphorus, especially at the upper levels, was the Brookston soil from Gratiot county (soil 7) which otherwise was similar to soil 6 except that it was taken from an uncultivated fence row. Apparently factors of fertility other than those associated with chemical availability of phosphorus enabled the unculti- vated soil to respond much more favorably to a given addi- tion of phosphorus. The variability of plant growth as reflected by the weight of straw between the individual soil series was even more marked than that within a given soil. This behavior was quite similar to that noted for the number of wheat heads produced. In a general sort of way those soils which apparently were of a high state of native phosphorus fertility as in- dicated by the chemical studies on the soil had a tendency to produce only slight response for a given addition of phosphorus. -60- Yield of Wheat Heads Table 8 presents data relative to the influence of the various additions of 0a(HgP04)2'Hgo upon the yield of wheat heads for the various soils. In general, the increased growth of the wheat plants was reflected more in the weight of the wheat heads than in the wheat straw. All of the soils were characterized by an increase in the weight of ‘wheat heads produced for the first increment of added phos- phorus. The increase in the yield of wheat heads was particup larly marked over the entire range of phosphorus additions on such soils as the Brookston loam from Kent county (soil 4), the two Isabella soils (soils ll and 12) and in the case of the Oshtemo sand (soil 18). The response, though rela— tively somewhat less, was also quite marked upon both the Brookston soils from Gratiot county (soils 5 and 69. It was also noted that, in general, even on the soils which have previously been pointed out as being of comparb atively high phosphorus fertility there was more response in the yield of wheat heads than there was in the straw. Such was the case with the two Brookston soils from Macomb county (soils 1 and 2) and to a lesser extent with the Kent silt loam (soil l6) and the 01yde clay loam (soil 1?). The only soil which perhaps showed no really pronounced tendency for an increased production of grain for the higher levels. of available phosphorus was the muck soil (soil 20). The -51- .movmodfinou N «a dds: s A Hm.HH .a a.H~ .oH om.nH om.sH so.» mm.HH omH m9oH ”w; .8 MN? RmH 9.3 mag. 093 on E. a as as as we we as a mm.m mmH ““113 :93 mm aw; HmuH. 3.» o noose oopoHHo bacon: .8 How oopoHHo oHHooooH .oo soon 3898 son est 38H 83 .38 53 33 IS 388 53 33 canon nos: 33an 0930 33 soon .3630 sHHoocmH mHHonmmH Heed. .823 83 $3 2.: 35 Rd 3: HHHV 83 88 . H 8.3 223 mde 3.: o .9 H9 H H.MH 8H 1%.? an .NH SSH «53 R .3 meH 8 .NH lHHo .nH ow mm.nH H.MH m:.oH mm.» mo.m mm.HH mH.mH Hn.oH o: 8.? o.nH 3.3 new.» 3.» 8.: N93 RdH om m90H m9m mod n .m H9n 5;. 9m m9m o .8230 e328 2380 3386 .8 Hoe .833 .6 £83: .8 2.82. and ssoH sued ssoH sued soon ssoH ssoH pHHm seoH pHHm.msson «and. mongoose cosmxooum sopmxoonm sopmuoosm sopmxoonm sopmuoosm sopmuocsm .623 E E Ga 5 :a E E 3 Bus .maosauona coups no macho." 25.2.: on» on 933006 933 unease on» new assesses» and 3260.3 modem pens: no mean 5 someones £332. .503 2a. .m 0.3.69 -62- same results were apparent in the straw production so that it may be assumed that under the conditions of this experi- memt phosphorus was not an important limiting factor in the growth of wheat plants on this particular soil. Once again the very marked fluctuation between soils was quite apparent. The very highly fertile uncultivated soils such as the Kent silt loam and Clyde clay loam pro— duced the greatest yields and the soils characterized by Observed stable structure such as the two Brookston soils from Macomb county gave very good yields also. All of the Brookston soils were capable of producing relatively good yields provided the level of available phosphorus was sufficient. Only the Isabella loam from Kent county (soil 11) and the Oshtemo sand (soil l8) appeared to be rather inferior in productivity even after very large additions of readily available phosphorus. Total Yield of Wheat Plant Material The data presented in Table 9 give the mean weights for each treatment for the entire wheat plants. It happened that the particular sample of Henry Spring wheat was badly infested with.smut. Probably the weight of heads was influenced somewhat more in certain treatments than in others by the presence of this disease. Also there was same tendency for a lack of uniformity in maturity. There- fore, the combined weight of straw and grain probably more . mopmoHHnos N no see: c Ho.mm ma.mH Mm.om sm.ms mm.mm ms.mm mw.om mm.om omH H.mm mm.mH m.as mo.ms a .wm no.0m mm.mH om.sm om mm.Hm a . m .m: mm.H: w .wm ms.Hm mm.:H sm.om o: m.om mm.m : .oe mm.oa mH.mm os.om, mm.HH mm.mm cm at o . 3.: 3.3 was as 8.: 3.3. o .ou mam» Alida! wloqxl “may .oo came sepsHHo paces: .00 snow sochHo mHHonmmH .00 neon mHoomza and some hang 83H .33 :33 33H 3 house amoH 83H macs Hos: oaopaoo ooaHo pHHu poem soooooo oHHooooH oHHooooH HaoHa noonm domv «wHV HNHV HoHv amHv HNHV HHHV HoHv coco mm.Hm om.mm mm.Hm ~.~m Hm.mm mo.mm mm.m Hm.mm omH «mumm :~.mm mm.am m.om so. u mm.Hm mm. m Hm.am ow mm.om mm.mm mm.mm Ht.nm om. m oH.mm mm. m 0 .HM o: m.m~ m.~m m.~m nH.mm Hm.mH H .mm mm.mn mm.mm cm 0 mm wH.sm mm.mH an.aH m:.HH m .mm mm.wm om.mm o . .ou .mm& .00 .ou‘ .ou .om .omHH soaqza sonsHHo poHpmsc pOHpmse .00 snow ImmHmmm bacon: paced: and 83H smoa Essa ado.” 30H :33 50a “3.8 H83” :3 macs “swag nonmxooum nonmxoonm scamxoonm sepmxoon sepmxoon cosmaoosm sopmxoonm Imonm «my Hav Hey Amy Hay Ana m_ Amv HHV sous . .mnnosamona poops no 3:3 333» on» on 93.300.» 933 263.3 one son escapees» .Hoa sensuous magma «cos: we madam sH summons: 9330.. Have» oases one .m 0.33. ~64- nearly reflect the true productive capacity of the various soils. In a general manner, the total weight of plants, like the previously discussed factors, showed that certain soils were more responsive to added phosphorus than others and emphasized the fact that certain apparently highly fertile soils are much more productive than such soils as the Isabella soils and Oshtemo sand. The data relative to yield of total plant material will be considered in detail in subsequent discussion in an at- tempt to correlate plant growth response to chemically measured available phosphorus. Therefore, detailed dis- cussion is not presented at this point. Photographs are presented in Plates 1 to 7, inclusive, of the wheat plants as of May 16, 1949. In general the {photographs tend to illustrate the rather marked response to the various additions of phosphorus on such soils as the Isabella loam from Kent county (soil 11) and on the Oshtemo loamy sand from.clinton county (soil 18). The intermediate response noted on certain of the soils is characterized in Plates 1, 2 and 4. Such soils as the Kent silt loam from Kent county (soil l6) and the 01yde clay loam from Macomb county showed very little response to added phosphorus as of May 16. M x ‘ " 2L\ ’ A‘ Mi“ W’s/"9,! 44:? t ., W .4 ‘ vv',’/(A\ w}: Ax: - .V‘ ‘ ‘ A) a 2.«.'r A-» x»-.i“'”5"T‘E-5=.-zf :w ' > 0‘ .- 1 ~A I. ' ‘4‘ ’ " k - A Plate 1. Brookston silt loam from Macomb county (soil 1) showing effect of added phosphorus on growth of wheat May 16 1949. Phosphorus additions in are: 1 = O, I 20, 3 = 40, 4 = 80, and 5 a 168? “‘A , - l 1.1“ g'cit‘.‘ :'.‘ J'- ., .1 p ‘ n \. _ _, '5'" ' '”‘" ‘ w—n—he r' -‘5‘ws—---“W“’”j Plate 2. Miami loam from Clinton county (soil 9) showing effect of added phosphorus on growth of wheat, May 16, 1949. Phosggcrus additions in ppm are: 1-o, 2:20, 3: ,4=sc, 5:160. .4 Plate 3. Isabella loam from Kent county (soil 11) showing effect of added phosphorus on growth of wheat May 16, 1949. Phosfigorus additions in ppm are: 1:0,2-2o,3- upso,and5-1oo. Conover loam from Clinton county (soil 13) showing effect of added phosphorus on growth of wheat May 16, 1949. Phosfigorus additions in ppm are: 1 = O, 2 = 20, 3 = , 4 = 80 and 5 = 160. Plate 4. Plate 5. ant silt loam from Kent county (soil 16) showing effect of added phosphorus on growth of wheat May 16, 1949. Phosfigorus additions in pgm are: 1 a o, 2 = 20, 3 = _, 4 = so, and 5 = 1 o. plate 6. 01yde clay loam from Iacomb county (soil 17) show- ing effect of added phosphorus on growth of wheat Kay 16, 1949. Phosfigorus additions in are: 1 = o, 2 = 20, 3 = , 4 = so and 5 = 1 o. -68- 'A Plate 7. Oshtemo loamy sand from Clinton county (soil 18) showing effect of added phosphorus on growth of wheat May 16, 1949. Phosghorus additions in ppm are:1=0, 2-20, 3: o, 4=8om5=160. -59- lgmato Yields The data reported in Table 10 provide additional in- formation relative to the phosphorus fertility relation— ships of certain of the soils mentioned previously in con- nection with the wheat studies. Also included in this table of data are four additional soils, Brookston from Tuscola county (soil 8), Conover clay loam from Macomb county (soil l4), Napanee loam from Macomb county (soil l5) and Emmet sandy loam (soil 19). A photographic record of tomato plant response for this particular crap is presented in Plates 8 to 17, inclusive, for each of the soils and certain additional comparisons between soils of the same series and different series are presented in Plates 18 to 22, inclup sive.‘ It was obvious early in the growth of the tomato plants that most of these soils were very much in need of added phosphorus for the successful growth of tomatoes. In the case of the Brookston loam from Kent county (soil 4) both Isabella soils (soils 11 and 12) and the Oshtemo sand (soil 18) the growth on the untreated cultures was hardly dis- tinguishable after the first week and in some instances the plants were dead at the time of harvest. Each of these soils was previously determined to be quite phosphorus de— ficient as indicated by the growth of wheat plants and by at least one or more of the chemical methods used for measuring phosphorus availability. -70- mm.s Hm.H mw.w mm.~ m~.m own ms.s mo.m om.m am.s so.m omH :Hgm ms.H Hm.a mm.s mm.m on we. mo.H mm.m Hm.m o.m o: mN e ”N c mw e ow 0 OH 0 o .du .ou:. .oo assmHeoH .oo coasHHo .oo bacon: bacon: sHHoommH sad smoH human uses hsmOH smoH smOH hmao smoa spasm masons nos-Rm ose ammo commas-a .Hoeosoo one new H ImoHE AmH- HmH- AmHv AaH- AmH- cocoa mo.m mo.m mm.m om.o He.: own sm.m 0:.m mo.~ H:.: m:.: omH mm.H mo. Mm.m oo.: me.m om om. sm.m o.m ms.a no. 0: mo. Ho.m am. 0:. mo. 0 .00 snow .00 mHoomsa .oo poHpsnu .oo aoHpeHc .00 neon sad soc." soc-H :83 58a so." masons mHHenmmH sopmuoonm covmaoonm sepmxoosm sopmuoonm Imosm -HH- -m- -t- -m- -s- sous. .erHoa-um one pound mo mHepoH maoHHsp on» o» wsHpsoooc mHHom msoHss> on» son escapees» sea escapees accesses «o madam sH consensus panoe use sees can .OH eHnsa -71- rookston loam from Kent county (soil 4) s 0 ng effect of added phosphorus on growth of tomatoes May 16, 1949. Phosphorus additions in ppm are: 1 = o, 2 = no, 3 = so, 4 = 160 and 5 = 320. 7...- Plate 8. A Plate 9. Brookston loam from Gratiot county (soil 5) showing effect of added phosphorus on growth of tomatoes May 16 1949. Phosphorus addition in ppm are 1 = o, é = 40, 3 = so, 4 a 160 and 5 . 320. Plate 10. Brookston loam from Gratiot county (soil showing effect of added phosphorus on growth of tomatoes May 16, 194 . Phosphorus additions in ppm are: l = 5 = 320. o, 2: o, 3=80,4=160and Plate 11. Brookston loam from Tuscola county (soil 8) showing effect of added-phosphorus on growth of tomatoes May 16, 19426 Phosphorus additions in ppm are: l = O, 2 a , 3 - 80, 4 - 160 and 5 = 320. -75- Plate 12. Isabella loam from Kent county (soil 11) showing effect of added phosphorus on growth of tomatoes May 16, 194 . Phosphorus additions in ppm are: 1 = O, 2 = O, 3 = 80, 4 a 160 and 5 a 320. Plate 13. Isabella sandy loam from Isabella county (3011 12) showing effect of added phosphorus on growth of tomatoes May 16, 194 . Phosphorus additions in ppm are: 1 = O, 2 = , 3 = 80, 4 - 160 and 5 . 320. -74- Plate 14. Conover clay loam from Macomb county (soil 14) showing effect of added phosphorus on growth of tomatoes May 16, 194 . Phosphorus additions in ppm are: 1 = O, 2 8 , 3 I 80, 4 - 160 and 5 - 320. Plate 15. Napanee loam from lacomb county (soil 15) showing effect of added phosphorus on growth of tomatoes May 16, 194 . Phosphorus additions in ppm are: 1 = O, 2 = , 3 = 80, 4 = 160 and 5 = 320. -75- Plate 16. Oshtemo loamy sand from Clinton county (soil 18) showing effect of added phosphorus on growth of tomatoes lay 16, 194 . -Phosphorus additions in ppm are: l = O, 2 a , 3 = 80, 4 = 160 and 5: Plate 17. Emmet sandy loam from Leelanau county (soil 19) showing effect of added phosphorus on growth of tomatoes May 16, 19426 Phosphorus additions in = 0, 2 = 9 3 = ppm are: 1 so, 4 = 160 and 5 - 320. Plate 18. -75- comparison between Brookston loam from a cul- tivated field in Gratiot county (bottom) and a corresponding soil sample collected from an adjoining fence row (top). Numbers correspond to phgsphorus treatments as mentioned in Plates 9 an 10. Plate 19. A comparison between Brookston loam from Tuscola county Stop) and Brookston loam from Kent county (bottom . Numbers correspond to phosphorus treat- ments as mentioned in Plates 8 and 11. Plate 20. -77- A comparison between Isabella sandy loam rom Isabella count (top) and Isabella loam from Kent county (bottom). Numbers correspond to phosphorus treatments as mentioned in Plates 12 and 13. Plate 21. The comparative response of tomatoes on various soils to added phosphorus (bottom row received no phosphorus top row 320 ppm). Soils are as follows: 1 = Brookston loam from Tuscola county (soil 8), 2 = Oonover clay loam from Macomb county (soil l4), 3 a Brookston loam from Kent county (soil 4), 4 8 Napanee loam from Macomb county (soil l5) and 5 = Brookston loam from Gratiot county (soil 6). Plate 22. The comparative response of tomatoes on various soils to added phosphorus (bottom row received no phosphorus, tap row 320 ppm). Soils are as follows: 1 = Brookston loam from Gratiot county (soil 5) 2 = Oshtemo loamy sand from Clinton county (3011 18), 3 = Isabella loam from Kent county (soil 11) 4 = Isabella sandy loam from Isabella county (soil 12) and 5 = Emmet sandy loam from Laelanau county (soil 19). 79- Even on the rather fertile heavy Brookston soils and such others as the Conover and Napanee, the growth on the untreated cultures was not great. However, these plants were apparently normal in appearance except due to the small stunted growth as a result of a lack of sufficient avail- able phosphorus in the soil. In most instances the greatest response to added phos— phorus occurred with the first increment or the addition of #0 ppm of soluble phosphorus in the form of Oa(HgPOu)2-Hgo. The only instances of appreciable response beyond this level were in the case of the Brookston soil from Kent county (soil u), the Oshtemo sand (soil 18), both Isabella soils (soils 11 and 12) and to a minor extent with the Emmet sandy loam (soil 19). All of these soils except the Emmet had performed similarly in the production of wheat. With the more fertile soils and even with the Brooke ston soil from Kent county, there apparently was no appre- ciable benefit after the addition of 160 ppm of phosphorus. In most of these cases the benefit was actually negligible after the addition of 80 ppm of phosphorus. With the tomatoes, as with the wheat plants, great differences were noted among the soils. These differences were not as great between the soils as within a given soil especially after the first addition of phosphorus. The heavy Brookston soils and such related heavy soils as the Napanee and Conover soils were definitely superior to the -80— lighter Iowa, and sands such as the Isabella soils, Osh- temo sand and Emmet sandy loam. However, with the excep— tion of Oshtemo sand, satisfactory growth was possible on these provided an adequate supply of phosphorus was furnished the soil. 1 al of a t ate 1 f ho horu The Phosphorus Content and Total Phosphorus Removed by Wheat Plants from the Various Soils The data presented in Table 11 show several interesting and significant facts. The percentage phosphorus content of the straw had a tendency to show a decline or no great in- crease in amount for most of the soils after the addition of the first increment of added phosphorus. There is a definite drOp in percentage composition of phosphorus on such 30118 a. the Brookston silt loam from Kacomb county (soil 2), the Brookston loam from Kent county (soil 4), the Brookston loam from Clinton county (soil 7), the Miami loam from C1inton county (soil 9), the Isabella sandy 16am from Isabella county (soil 12), the Conover loam from Clinton county (soil 1}), the Kent silt loam (soil 16), the Clyde clay loam (soil 17), the Oshtemo sand (soil l9) and the muck (soil 20). -31- Reference to Table 8 shows that for each of these soils there occurred a marked stimulation in the weight of wheat heads produced on each of these soils and no doubt this pronounced stimulation in amount of wheat head form- ation accounted for the lowering of the phosphorus percent- age in the straw. In the case of the Oshtemo sand another very marked depression occured in this percentage where the rate of phosphorus application was 80 ppm . This again coincides with a tremendous increase in the weight of wheat heads formed for this particular soil. Therefore, at least at the levels of phosphorus addition of 80 ppm or less, the actual percentage composition of the straw apparently de- pended more upon the stimulation of wheat level production than upon any other single factor. It cannot, however, be concluded that this stimulation of wheat head formation is related to the number of wheat heads formed. Reference to the data presented in Table 6 will reveal that, especially on the Oshtemo sand, there was no appreciable stimulation in number of heads. The same general condition holds for other of the above specified soils. Therefore, stimulation in the size of head and extent of grain deve10pment was undoubt- edly of greater importance than actual numbers of heads formed. For the majority of the soils a very marked stimulation in percentage composition of phosphorus in the wheat straw occurred, especially where 160 ppm of phosphorus had been ~82- noadoHHaon m we see: c mmH. mHH. «NH. mmH. mm. mum. n . omH. omH mmHu Hso. moH. emH. HH. H. MmH. mmH. om om. mmH. emH. mmo. H. u H. ~H. MH. 0: H. mmo. omo. awe. HH. omH. mmH. NH. cu m H emH. omH. sac. MMH. HmH. muH. smH. o la .a a an 4&1 J37 woven songs paced: .00 neon dosage ozone: .oo anew 0.333. and neon mecca Boo." hose seoH sec.” 3 hence eeoa see." anyone Mona 083an 0930 33 neon nobocoo eHHoneeH usage: «an; Image Roma AmHv «NHV neHv AMH. ANHV AHHV AoHv cocoa «mm. cam. «Hm. mum. mnH. eon. mm. aim. ooH moH. wsH. mmH. NNH. mnH. omH. mH. amH. ow Foo. maH. mmH. «NH. aHH. omH. mmH. mom. 0: ooH. mwo. emo. msH. :HH. maH. mHH. maH. om mHH. mac. use. ooH. «NH. wsH. muH. emH. o laud! 4&4, id? an!) |nadlllllqddl 43:1 c358 3958 903.30 903.30 .00 neon ednwam paces: paced: and 36H 83 28H 83 36H 33 33 fit 53 3% 3.3% «an; nopmxoosm sopmxoosm copoxoonm c3333 coauxoosm copmuoonm nopmxoonm nmonm AS 2; Ga 3V 2: RV A3 «Ha cocoa .maondmonn page no macho." adorns» ca 33300... 333 33.3» 23 non escapees» .Hod 3260.3 scape neon: no A .3308? no «snow 3 33393 agonnuona owaneoonon once: .3 033. -33.. added. This did not hold for the Brookston loam from Kent county (soil 4) and the Muck (soil 20) but in the case of the other soils the increase was very large. There was some variation in percentage composition from one soil to another but this was much less'than the other plant factors previously discussed. The percentage phosphorus values for the wheat heads showed considerably less variation than did the correspond- ing data for the wheat straw. In the case of many of the values reported in Table 12, there was apparently little or no influence of added phosphorus upon the actual composition of the heads produced. There were certain rather marked exceptions to this general statement. In the case of both of the Brookston loams from Gratiot county (soils 5 and 6) there was a pro~ nounced tendency for an increased percentage of phosphorus to result with the increasing levels of added phosphorus to the soil. The same situation held for the two Isabella soils (soils 11 and 12) and for the Kent silt loam soil from Kent county (3011 16). An interesting occurrence took place in the case of the Oshtemo sand. The addition of 20 ppm of phosphorus to the soil resulted in a very low content of this element in the heads. This seemingly can.be explained upon the basis of the fact that this addition of phosphorus to the soil nearly doubled the formation of wheat heads as evidenced in Table 8. -SH— Succeeding additions of phosphorus to this same soil re- sulted in an increase in the phosphorus content of the heads produced by this soil. The weight of phosphorus taken up in the straw in- dicated that for most of the soils there was a tendency for the plants to contain.more phosphorus in the straw in accordance with each increment of added phosphorus. This was very definitely true for the two upper levels of phos— phorus on all except the muck soil. There were certain exceptions to this tendency in the lower levels, however. Particularly for the first addition of 20 ppm in the case of such soils as the Brookston silt loam from Macomb county (soil 2), the Brookston loam from Clinton county (soil 7), the Miami loam from Clinton county (soil 9), the Conover loam from Clinton county (soil 1}), the Clyde clay loam from Macomb county (soil 1?), the Oshtemo sand (soil 18) and the Muck from Eaton county (soil 20), the straw actually contained less total phosphorus than the straw from the same soil where no phosphorus was added. All of these soils showed a marked increase in the weights of heads produced and it must, therefore, be assumed that this stimulation of head formation resulted in a heavy removal of phosphorus from the stems and leaves of the plant later in the growth period and thus the straw produced actually contained less total phosphorus than did that grown on untreated soil. On most of the other soils, however, there was a great increase in the total phosphorus ~85- mopeoHHdon N no see: c me. He. . as. as. me. me. me. oeH his mm. we we mic ON. mid. H.3e ow H+~e N 0 Re 0 Hn—ao N 0 mm. N:o 3 He. am. mm. mm. He. mm. . Ha. om we. mm. an. Hm. ma. mm. Hm. me. o .00 Add!» (tau 4mm, .da. .meUI scams coucHHo nsoon: .oo poem coucHHo daemoemH .00 neon eaoomaa and seem mason seOH amHo aeoa seoH oH apnea seoa seoa manage Moo: esopnmo oeaHo vaHm «new nobocoo eaaonemn canonmmm HseH: noonm Aomv Ava ANHV “mHv «mHV AmHv AHHV AoHv scene 9.. me. me. . m... . mm. 9.. 8H me. we. we. mu. we. mu. He. he” on me. em. 2. me. me. He. me. me. o: mic w e NM. Hm. is mm. ON. his ON Mic ”M. m o e Hie m o m e 0.: o 1a; an 1a) a 43F 1.3 Jedi opsHHo sepeHHc poHpeno poHpmnu .00 soon emanem nsooe: pecan: add 83 33 53 56H 93H 53 53H 33 53H 3% cache HemHa sopmxooum.s0pmxoonm copmuoonm sonmxoon sovmxoonm.sopmxoosm.s0pmuooum.mocha A3 C; 3v R; 3; «D 3.; 3v e83 .mononamonn amped no maoboa mncHne> on msHenoood mHHom maoanm> on» non pqospeoup sod muoceond meson neon: no a HepnosoHo no menu» nH commonawo monogamonn ommpnoouod ease: .ma canoe ~36- content of the straw at this soil phosphorus level. The major portion of the phosphorus contained in the plant was in the head portion as evidenced by comparing the data in Table 14 with that of Table 13 in all the soils ex- cept the Brookston silt loam from Macomb county (soil 1). Even in this case at all levels except the highest, 160 ppm, there was a slightly greater amount in the grain than in the straw. ‘ The tendency for the straw of the wheat plants to con- tain less phosphorus after the addition of 20 ppm of phos- phorus on certain soils did not persist in the case of the heads of the plants. In all cases the heads at this level contained more total phosphorus than did those grown on un- treated soil. This clearly emphasizes the importance of phosphorus in the role of the head formation. Generally speaking, the succeeding increments of added phosphorus resulted in a greater total accumulation of phos— phorus in the heads although this tendency was by no means absolute nor always particularly pronounced. Therefore, it appeared that after a certain amount of phosphorus entered into the formation of heads, this portion of the plant did not take up excessively great additional amounts. There was again great variation between the individual soils. This variation followed the same general trend as was usually noted for other characteristics of the wheat plants previously discussed. -87- messages“ N no coo: e nuwm ~.oH «.me H.5m ~.ma m.Hn m.~H ~.wm omH m.m~ m.m m.m~ m.~ o.mH m.mH ~.NH m. m cm m.m~ o.~ o.mn m.om m.oH m.~H a. m.m~ on m. m m.H w.em m.mH .NH m.mH ~.m o.mH om m em m.e m.mm H.nm .mH m.~ o.n a.mH o I'll-0dr. JO .3 (dd-Ill. Ida}. .qlq woven nochHo page: .00 neon c353 .339»: do poem magma. an acne mecca swoa .38 50H 50a 3” hence ado." 33H 3523 mos: esopnmo 0930 3.3 poem sopocoo eHHonemH dHHonemH Has; $23 Acme AmHV AeHv .eHv AMHV AmHV AHHV AoHv eoeee m.mn m.~ m.~m ~.mn m.mm m. m.m m.mm omH wHwH Hem 06m ohm and m.” o.mm Tm... om an an 2a n. M... n. saw a e e e N 0N." 00 N ONN e m.~H ~.eH m.~ o.HH m.oH m.m~ m.mm m.m o runmwl 44am 14mm- .cu .QNnIIIeIIJdu , .cuil coeeHHo couano poHaeee heavens .oo poem teenage paces: paces: sea awed Econ aeoa 50H 30H ado." ado.” 9.3m Seed 9.3m 350:9 «an; sepmxoonm qcpmxoonm scamuoonm c3333 soamxoonm copmxoosm cepmuoonm locum “av Asa «my “mv «av Amy Amv AHV fleece .osnondmond coupe no maeboa 352.: o». wsHuncoom mHHom magma» on» new escapees» nod tense neon: ho. a: scams mamuwaaga a." command: maondmond no page: once: .MH 0.3.3. -39- The total weight of phosphorus taken.up by the plants, as presented in Table 15, more nearly reflects the actual uptake of phosphorus from each of the soils at the various levels than did either of the previous sets of data consi- dered individually. The various soils, except for the Muck, each had a tendency to release phosphorus in accordance with the level of added phosphorus. The Much soil used in this experiment seemingly did not behave at all like the other soils, all of which are of mineral nature. The only other notable ex- ception where the first increment of added phosphorus did not result in at least as much or more of this element in the plants was in the case of the Oshtemo sand. With this soil there was actually less total phosphorus in the plant material after the addition of 20 ppm of phosphorus than at any other level on any soil. This probably can be explained upon the basis of poor growth for the two replicates of this particular culture. Although ten plants were allowed to remain in each jar, only eight heads of wheat were pro- duced on one jar. Therefore, it may have been the result of nothing more than abnormally poor plant growth that re- sulted in this particular exception. Only one other indi- vidual jar in the whole series produced so poorly in the entire series of jars and that was on an untreated jar of the Brookston loam from Kent county. -90. A consideration of the individual soils with regard to the total phosphorus released to plants indicates as great a variation as was true for the other factors previously considered. The Oshtemo sand, on the basis of these data, was the poorest soil for releasing phosphorus to plants. No doubt part of this is due to the tenacity with which the added phosphorus is held by the soil. This would be in accordance with the availability figures presented in Table 5 for this soil upon the basis of extraction with Spurway's active~ extracting solution. However, with the strong acid extraction of either Spurway or Bray this apparent unavail- ability was not in evidence. Therefore, the inability of this soil to release a large amount of phosphorus seemingly .cannot entirely be attributed to a low phosphorus avail- ability. The possibility of a lack of minor nutrient ele- ments as a limiting growth factor cannot be entirely over- looked as this material was essentially pure sand. The possibility of unfavorable physical condition must also be considered as this material is entirely without compound soil structure and no doubt the possibility of poor aera- tion and other limiting physical factors does exist. The remaining soils, with the exception of the Oshtemo sand and Muck as mentioned above behaved more or less in a regular fashion. There were soils such as the two Isabella soils (soils ll and 12), the two Brookston loams (soils 6 -91- momeHHdmn N no com: o m.ma a.mm .meH m.~HH .mOH o.mm m.mm m.mw omH NHNN m.am m.m0H o.woa . m.m~ m.mw :.om «.05 cm . m w.HH m.mm o.mm m.mm ~.mm H.mm m.am 0: H.em s.m .am m.om e.me m.ee o.am e.mm on a so H.m s.am e.ms m.mm H.mm e.s m.Hm o .00 .00 .00) #00 Q “CU dogma noncHHo Decomfi .00 snow dochHo mHHmnmmH .00 «com maoomna and some hemoa smoa amHo smoa smoa smoa apnea smoa smoa echoed Mona osopnmo opaao pHHm poem Hobocoo mHHmnmmH HamnmmH HsmHs Imonm Aomv HmHV Hva HmHa AMHV ANHV AHHV AoHa scene sumo m.m0H o.m0H m.~m o.- «.mHH m.emH m.m0H omH m.mw . m m.- m.e~ m.wm m.m0H e.om m.HOH ow n.3s e.em m.mm ~.em m.a m.m~ H.mm ~.wm 0: New 9% 9mm mém To: ax: mos was on m we m.ma H.om m.om o.mm o.em H.mm .ON 0 1400 .oo .oo .om« .ou, .oo .oo - coacHHo copsHHo poHpme poHpmsu .oo pdoM emcmem bacon: bacon: and smoa amoa smoa emoa emoa amoa emoa pHHm amoa pHHm anyone HemHa copmxoonm cosmxoonm nonmmoonm nonmuoonm nopmxoos sopmxoonm scamuoonm Imonm is E as E E E m— E 3 we. .msnondmond popes no mHo>oH mSOHHmp o» mannoocm mHHom mdoHnmb on» you pcmapmonp Hod madman poms: oHHpco on» cH pochpcoo msmeHHHHs cH mommmndxo manonnmond no pnwaoz ammo: .ma magma -92... and 7) and the Brookston loam from Kent county (soil n) which, expecially in the case of the untreated cultures, were able to release only comparatively small amounts of phosphorus. However, where soluble phosphorus was added, these soils were able to release a considerable amount at the upper levels and for the most part plant growth was at least moderately satisfactory. Therefore, the low supply- ing powers is at least in.part due to an initial very low supplying power for these soils. The Phosphorus Content and Total Phosphorus Removed by Tomato Plants From the Various Soils Data relative to the percentage phosphorus composition and total phosphorus contained in the tomato plants are pre- sented in Table 16. The tomato plants reflected much greater Variation in'both these values than did the wheat plants previously discussed. It was previously noted that in the case of the yield of tomato plants the increase was actually rather small after the addition of 80 ppm of phosphorus to the soil. This same statement cannot be made for either the percent- age phosphorus contained in the plant or the total accumup lation of phosphorus by a plant. Each addition of phosphorus resulted in an increased percentage of this element in the plant with the exception -93- .mopeoHHdos N no see: c mH.wm mm. mm.m owm. om.~a cam. oo.Ha cam. mm.wm on». own mH.om we. mm.HH 0mm. o~.mm men. on.mm mum. om.~m cam. omH 3.3 S. Hag. one. 3.3 mHm. 8.3 min. 93: men. on oeHoH mum. mm.m 0mm. 0H.HH oaH. .OH omH. mm.oH con. o: mm moH. m . OHN. om.H ooH. m.H m H. ;mH. oMH. o u mum. _ a. HmwmmmmmmmmmmH:HaaqnlIlswwuulnnmaaan:lumwlll:Haaqnuanudw . cope Jigllmulmmmmmxlljmulmwfimaqfl Ea saoa deem , aeoa seed unnond bosom possm aseOH osovnmo smOH condemn hmHo nobosoc buses eHHonmmH amend a: $5 a: :3 as 884 sm.mm o . om.mm com. mm. a. om. m m . mn.m~ mom. can mm.0H oH . mm.Hm can. om.mu mum. mm.mm mm. an.aH cos. owH an we was a. an m... an. a. was. a o O 0 ON OH“. NO NO 0 O . no. omH. mo.m omH. ee.H moH. ms.H meH. mHH. msH. e tnuamawnnuumwnulummgnnufiulmwusluummawn.uwwunudmmmmmmmmmmmmmnlllamaqniumw .8 seen 33% .o 332 iodzerqoui! oasmmo amoH mHHonmmH seOH copmxoonm smoa copmxoonm seoH soumuoonm seoH coomuooum Imonm :3 :3 HE E 2; e82 .monondmond coped no mao>oa mnoHHmb on mchnoooe mHHom mooHse> on» non escapees» nod moopesOP an nanosecond no canvas Hence sees and soHpHmodsoo mmmpcoonon lane: .3 oHoee .91;. of two instances. In the case of the Isabella loam from Kent county (soil 11) the first increment of added phos- phorus yielded plants with no higher percentage of phos- phorus than those from the untreated soil. However, the plants on the untreated soil made almost no growth whereas those at the level of 40 ppm of added phosphorus made a significant growth. The other exception was the instance of a slight decrease in percentage composition of phos— phorus at this same level in the case of the Napanee loam (8011 15). Here again a very marked increase in growth accompanied this addition so that the total recovery of added phosphorus was much greater than on the untreated soil. The percentage composition of the tomato plants for phosphorus was over 0.70% in several instances and as high as 0.82% in one instance at the upper level of added phos- phorus (320 ppm). This was probably much higher than was needed for maximum growth up to the stage of maturity to which these plants had progressed. It is somewhat diffi— cult to predict from the data exactly where the minimum perb centage composition for maximum growth did occur in tomatoes under these conditions. That is due to the fact that there was such a large increase in actual percentage composition for each added level and also because it is difficult to estimate the exact point where increased growth no longer -95.. resulted. However, in a general way it seems as though a percentage composition of approximately 0.40 - 0.45%pphos- phorus in the tomato plant was approximately enough to in- sure maximum growth up to the time of harvest. However, it should not be interpreted that such a level would be sufficient to insure maximum growth to a more advanced state of maturity. Assuming a hypothetical desired percentage composi- tion in the range of 0.40 - 0.45% for tomatoes, then it is possible to compare the relative phosphorus supplying powers of the soil. Such soils as the Brookston loam from Kent county (soil 4), the Conover clay loam from Macomb county (soil 14), the Napanee loam from Macomb county (soil ll) needed a considerably greater quantity of added phosphorus to attain this desired effect. Similar Obser- vations have previously been noted for this particular Brookston soil and the Isabella soil in the case of both the chemically measured phosphorus and the wheat yield re- eults. However, it cannot be concluded that either the Napa— nee or the Conover soil mentioned above were of inferior capability insofar as phosphorus supplying power is con- cerned. If the total milligrams of phosphorus contained in the plant are considered, it is seen that either of these soils compare favorably in this regard with either of the Brookston silt loams from Gratiot county (soils 5 and 6) -95. and actually exceed the other Brookston soils included in this investigation. Further consideration of the total recovery of phos— phorus in the upper portions of the tomato plants suggested that again both the Brookston loam and the Isabella loam from Kent county as well as the Oshtemo sand must be ranked inferior to the other soils included in this study. However, at least some attention to factors other than phosphorus fertility, which may have entered into the picture, must be given the Oshtemo sand. The plants actually attained the previously mentioned desired level of 0.45% phosphorus with the addition of only 80 ppm of phosphorus to this soil yet plant growth increase was negligible beyond this point des— pite the fact that a higher percentage of-phosphorus was con- tained. The possibility of minor element deficiency in this soil material or the presence of an undesirable physical con- dition has previously been mentioned and seemingly is once again indicated in the case of the tomato plant growth and phosphorus relationships. The Yield of a Second CrOp of Tomatoes on the Same Soils Previously Utilized for Tomato Production Tomatoes were grown as a second crop on the same soils discussed in connection with Table 10. The mean weights of the plants produced as a result of this crOpping are pre- sented in Table 17. -97— The plants did not attain as much size during the course of this second growth as did the initial crop. No doubt this was due to a more or less general depletion of soil nutrients, including the available phosphorus. In the case of the first crcp it has already been noticed that there was a tendency for the tomatoes to attain maximum size at the addition of 80 to 160 ppm of phosphorus. However, such was not the case with the second crop. It can probably be concluded that four of the soils produced a maximum growth for this second crcp at the 160 ppm level of added phosphorus. These soils are the two Brookston.loams from Gratiot county (soils 5 and 6), the Brookston loam from Tuscola county (soil 8), and the Conover clay loam from Macomb county (soil 14). These soils are apparently the most productive ones included in this study since the great- est yield of tomatoes resulted for this crop at a lower level of added phosphorus than it did on the other soils. The Napanee loam from Macomb county presented an inter- esting situation. This soil produced the largest yield of tomatoes at all levels of added phosphorus for the first crcp and yielded especially well at the two highest levels. However, with regard to the second crop it was definitely inferior to several of the other soils. Apparently, this soil was able to make accessible to plant utilization at the time of the first crcp a large percentage of its more avail- able portion of phosphorus and thus the second crcp of -93- .mopmoanon N no see: c Hum m.H m.H Tm Tm 0mm m.H m” -.H m. m. omH n.H m o.m :.m w.H on m. :. m.~ H. o.H ol- n m. a. m. -. o .oo smcmHooq .oo soasHHo .oo peace: .00 pecans .oo eHHonmmH sag soon needs some aseoa seoH seen ano soon apnea anyone possa osopnmo oocsanz noposoo eaHonmmH neonm Am: 3: . $3 :3 $3 toe-o4 eHH TN pm as me an m. o. -. m.m mm 8H . 9m 9m wH mH om n. m. m.-- mH m. o..- m o.H m. m. m. o .00 when .00 encomnn .oo panacea .oo panache .00 neon sag . amoH 98H 83H :33” ado-H mono-3 mHHonmmH nonmxoonm conmxoosm cepmxoonm nopmxoonm nmonm -HH- -e- -e- -m--; -e- e.ee. .msnondmond coped no mambon unease» on» on wsnpnooom canon unensmb mnp non pcoapmonp non none vacuum on» no moopmsop non measm_sn pommonaxo pawns: and onto: .NH canes -99.. tomatoes was inadequately furnished with this element. The total uptake of phosphorus by the first crcp was relatively large but not any more so than on the two Brookston loams from Gratiot county. Therefore, it appeared as though the Napanee was initially comparable to the Brookston soils in- sofar as supplying phosphorus, but at the time of the second crcp some factor of fertility was lacking and thus the soil became definitely inferior to the Brookston soils mentioned above. The inferior qualities of such soils as the Isabella loam from Kent county (soil 11) and the Oshtemo sand (soil 18) were again apparent in the growth of this second crcp of tomatoes. The Brookston loam soil from Kent county (soil 4) though behaving much like the Isabella soil from the same county in previously discussed characteristics was definitely superior to the latter in this trial. A photographic record is presented in Plates 2} to 32, inclusive of this second crop of tomatoes. The numbers of each jar in these photographes correspond to that of the original treatment as explained previously. A comparison of all soils is provided in Plate 33. -100— Plate 23. The second crop of tomatoes on Brookston loam from Kent county (soil ). IE1 Plate 24. The second crcp of tomatoes on Brookston loam from Gratiot county (soil 5). ~101- gaff W - gill-Hg. Plate 25. The second crcp of tomatoes on Brookston loam from Gratict county (soil ). Plate 26. The second crop of tomatoes on Brookston loam from Tuscola county (soil 8). -102— m 'l"- __ , _ , “ I. A Plate 27. The second crop of tomatoes on Isabella loam from Kent county (soil ll). 4| Plate 28. The second crop of tomatoes on Isabella sandy loam from Isabella county (soil 12). -1o3- Plate 29. The second crcp of tomatoes on Conover clay loam from Macomb county (soil l4). ‘J-i \\::§:; alljii‘ r‘ i " .‘v ,es r“ _“ § 1. I 2 3 4 5 LEE—Hg, Plate 30. The second crop of tomatoes on Napanee loam from Macomb county (soil l5). -104- Plate 31. The second crop of tomatoes on Oshtemo loamy sand from Clinton county (Soil 18). Plate 32. The second crop of tomatoes on Emmet sandy loam from Leelanau county (soil 19). Plate 33. -105_ A comparison between tomatoes receiving the init- ial maximum amount of added phosphorus (320 ppm) for the various soils as follows: Top row: l.- Brookston loam from Tuscola county, (soil 8). 2.- Conover clay loam from Macomb county (3°111u;. 3.- Brookston lfim from Kent county so 4.- Napanee loam from Macomb county (soil 15). 5.- Brookston loam from Gratiot county (soil ). Bottom row: 1.- Brookstonllgam from Gratiot county :01 . 2.- Isabella loam from Kent County (soil ll). 3.- Oshtemo loamy sand from Clinton county (soil 18). 4.- Isabella sandy loam from Isabella county (soil 12). 5.- Emmet sandy loam from Leelanau county (9011 19). -106- The Yield of Tomatoes Following the Production of Wheat Data are presented in Table 18 to indicate the dry weights of tomato plants produced following the growth of wheat. Due to considerable variability in the weights of plants as affected by treatment , it is doubtful whether or not these values indicate very much about the phosphorus fertility of a given soil. There is some indication on such soils as l, 2, 3, 5, 6, 9, 10, 11, 13, 16 and 17 that the yields tend to increase with each increment of added phosphorus and in this respect the behavior is perhaps similar to that previously noted. However, with certain of the other soils, especially the Oshtemo sand (soil 18) there is little evidence that the dry weight indicates any response to phosphorus. The growth was very poor in the various cultures of this soil suggesting once again the possibility of growth factors other than phosphorus fertility entering into the limitation of growth. Probably the most significant fact indicated by the production of this crcp was that of the considerable varia- tion in the soils. As indicated above, the Oshtemo sand produced the poorest yield and also the Isabella loam from Kent county (soil 11) was a very poor growth medium. The Brookston loam from Kent county (soil 4) was comparatively inferior at the lower levels of phosphorus additbm.but at -107- the upper levels this soil compared favorably with the other Brookston soils. Therefore, this soil behaved more favor- ably than did the Isabella 1oam from the same county. An interesting comparison is afforded in the case of the two Brookston loam soils from Gratiot county. These soils are identical except for the fact that soil 6 was taken from an uncultivated fence row whereas soil 5 was db- tained from a cultivated field. It was especially apparent in the case of this second crcp of tomatoes fallowing the wheat that the former was a much more favorable growth medium. The Miami soils (soils 9 and 10), the Isabella sandy loam from Isabella county (soil 12) and the Conover loam from Clinton county (soil 1}) all were satisfactory growth media at one or more of the various levels of added phos- phorus. However, it was interesting to note that the Kent silt loam (soil 16) and especially the Clyde clay loam (soil 1?) were somewhat superior to the majority of the soils. Both of these were collected from uncultivated areas. The luck soil gave some little indication of response to added phorphorus at the time of this second crcpping and this was the first indication of such response. Plates 34 to #9, inclusive, provide a photographic re- cord of the growth of tomato plants following wheat. The numbers for the various Jars in each of these pictures indi- cate the following amounts of added phosphorus for the -108- $3.339.» N no see: c a. m. .3 of a. mi m.~ 9m 03 mHN ha mm 06 TN o...“ 54 m.... on a .. w. a a x a a e e e o. e .30 o a n m. 3 T e; m; m. 9m 0 1.187} .4“ du la Jarl $3.3— eopeflo .8 peace: .8 econ e338 «Zone: .8 neon e332. sun so aseoa soon he? anon seen H .383 aeoa seen 3939 Men: 093an 3.30 page econ noponoo Sampson agenda «3.:— $23 “owe “may «use «may .msv «may «any loss eoee< 3. 5.... 9m ed Tm 9m m.m a. SH. a”: cum in em nun. m5 9m 9m on m.” m H 9m ad ad mi o.m «A 3 m md m. oA m.~ T: ad in cm 9m a; mm TH 04 mum Tm 04 o .ou Jdu wed maul Jamar BfiS songs possess panacea .8 Sou sandman .6 peace: .6 peace: sea 53 53 33 53 83 53 33 33 53 .33 33% .232. .3933on cepmxoonm coamxoonm coumuoonm copmuoonm cepmxoonm copmuoon nmonm AS CV 3V 3. 2; A3 A3 3V one“: .pceapcoup Hen unwaet use no madam ca commennxe .aeemt no 39395 on» 95.5.58" 0.33 comb 3269.5 madman cause» no was?» cede: .mH manna Plate 3 . Tomatoes after wheat on Brookston siltflloam from nacomb county (soil 1) Plate 35. Tomatoes after as}... aha}... 3111; loam from Macomb county (soil 2). "a . 7' _ Plate 36. Tomatoes after wheat on Brookston loam from Saginaw county (soil 3). J Plate 37. Tomatoes after wheat on Prookston loam from Kent county (soil 4). -111- Tomatoes after wheat on Brookston loam from Gratiot county (soil 5). Plate 3 . omatoes after wheat 65’sfooigian loam from Gratiot county (soil 6). -112- Plate # . Tomatoes after wheat on Brookston 1636 from Clinton county (soil 7). L A Plate 41. Tomatoes after wheat on Miami loam from Clinton county (soil 9). Jada-.0 J > Plate 42. Tomatoes after wheat on Miami loam from Tuscola county (soil 10). a A Plate #3. Tomatoes after wheat on Isabella loam from Kent county (soil 11). -114- Plate ##. Tomatoes after wheat on Isabella sandy loam from Isabella county (soil 12). Plate #5. Tomatoes after wheat on Conover loam from Clinton county (soil 13). Plate #6. Tamatoes after wheat on Kent silt loam from Kent county (soil 1 . Plate #7. Tomatoes after wheat on Clyde clay loam from Macomb county (soil 17). -116- 4| Plate #6. Tomatoesgaftergwheat on Oshtemo loamy sand from Clinton county (soil 16). Plate #9. Tomatoes after wheat on Muck from Eaton county (coil 20). -117- Plate 50. A comparison of tomatoes after wheat on Brookston loam from Gratiot county cultivated field (bottom row) with tomatoes on the same soil from an adjoining uncultivated fence row (top row). -118- initial crcp of wheat: l = 0 ppm, 2 = 20 ppm, 3 = #0 ppm, # = 80 ppm and 5 I 160 ppm. Plate 50 provides a compari- son'between the cultivated and uncultivated field soils obtained from Gratiot county. Relationship of Plant Growth Response to Available Phosphorus as Measured by Various Chemical Means. The ultimate practical value of any chemical method for assaying soil fertility depends upon the suitability of that method for predicting plant growth response from the addition of a given quantity of the nutrient under consider- ation. Therefore, it was decided to measure the accuracy of certain of the chemical methods already described in terms of predicting plant growth response. Six of the chemical methods were considered in this manner. The two modified methods of Spurway's active extraction were not in- cluded because of their unsatisfactory behavior and because such modifications have never been actually used in a practical system of measuring the availability of soil phosphorus. As pointed out by Bray (6) the German scientist Mit- scherlich has carefully investigated plant growth response and shown that “the yield increases in prcportion to the amount by which the current yield fails of the maximum yield, A”. Mathematically this may be expressed: -119- dy : (A-y)c (1) dx where y = yield, x = amount of nutrient added per amount of soil, A,= maximum yield, and c = prcportionality constant. This equation may be intergrated and a I'worlcing equation“ is provided as follows: Log (A - y) - Log A - c(x +‘b) (II) where A = maximum yield, y = yield obtained when x units of a nutrient are added to the soil, x - units of nutrient added per amount of soil, b = original nutrient content expressed in units of the added nutrient x, c = proportionality con, stant. Equation (II) was found by Bray (6) to be unsatisfac- tory'because of the inability to use the x value in his work because of insufficient data and, therefore he modified equation (II) as follows: Log (A - y) 3 Log A - °lbl (III) where 01 - the proportionality constant, bl = the amount of nutrient in the surface soil as measured by the soil test, A = yield when potash is not deficient, y a yield when no potash is added. The value of this modified equation lies in.the fact that it eliminates the value x, or fertilizer added, and can be applied directly to the experimental data- where values for the chemically measured available portion of a nutrient are available. Bray originally applied the -120— above concept to exchangeable potassium as related to plant growth response and subsequently to available phosphorus measurements as mentioned in the introduction of this paper. Therefore, it was decided to extend this concept to the phosphorus ayailability studies included in this investiga- tion. In order to calculate the 01 value, it is necessary to evaluate A, y and b1 in equation (III). Inasmuch as in the case of every soil there was one level of added phos- phorus which produced a maximum yield it was decided to re- gard this as the yield obtainable when phosphorus was not deficient. This involves the assumption that sufficient added phosphorus had been applied to assure such a condition. Inasmuch as the equivalent of 3600 pounds per acre of 0—20—0 had been applied at the upper level, it does not seem illogical to make such an assumption. Also there were three instances where the maximum yield of wheat was attained before this point of application and in the other instances the trend of yields strongly suggests that the approximate ultimate maximum for each particular soil had been attained. Thus the yield at such levels was given the 100% yield value or became A in equation (III). The value of y was in the case of each soil that value at each particular level of phosphorus availability below the maximum yield (100% yield) or the level of the A.valuc. Therefore, all of the soils actually included in this ~121- evaluation are represented with four y values except three which have only three y values due to the fact that the maximum.yield was attained with the level of 80 ppm of added phosphorus. The percentage yield values are pre- sented in Table 19. The b1 values are the actual values for available phosphorus content as measured by the various methods pre- viously mentioned. The values used are those obtained in the laboratory experiments as outlined under “Methods of Procedure". By the use of equation (III) the °l values (prcportionp ality constant values) were then calculated for each of the respective cultures where the yield was less than 100%. The above calculations were made only for the wheat cultures and upon all soils except the Oshtemo sand and the Muck. The Oshtemo material is not a true soil in the usual sense and the muck material was not regarded as such and since little or no tendency to respond to added phosphorus was displayed by it these materials were omitted from mathe— matical consideration. The yield of total wheat plant was used rather than either the straw or the head portion alone because it was believed that under the conditions of this greenhouse ex- periment the entire plant was a better criterion of growth. response than either portion alone. The formation of heads -122- was interfered with to a certain extent by the presence of smut and the maturity was somewhat irregular. Therefore, this portion was not used alone. Graphical presentation is made of the plot of percent- age yield versus actual content of chemically available phosphorus, as measured by each of the six mentioned methods, in Figures 21 to 26 inclusive. Also plotted in each case are the available phosphorus values for each soil corres- ponding to 100%ryield. However, these b1 values at 100% did not enter into the solving of the equation for the plot of the curve indicated. The 01 value was calculated for each yield (y) of less than 100% and these are presented in detail in Table 20. The mean of these was obtained and from this mean the curve for each plot was obtained. Examination of each of the graphs suggests a more or less general correlation between available phosphorus con- tent and percentage yield as indicated by the scatter of points in connection with the plot of the curve. This corre- lation does not appear to be outstanding in the case of either Figure 21 or 22 in which the two methods of Spurway were utilized. Considerable improvement is noted for the graphs in both Figures 23 and 2# where the field methods for extracting total available phosphorus and adsorbed phosphorus, respectively, at a ratio of 1 part of soil to 10 parts of solution were employed. Figure 25 in which a graph is made -123- 0.00..“ 0.00” 0.00H 0.00..” o.oo.n 0.00..” I of” 0.:m m.mm «.mm m.am m.mm H.om o.oon om m. w m.wm m.mm .mp m.a~ m.mm .am on m” m H.~m 0.3m ~.H~ m.mm e.nm .em cm 3 3.3 Was :dn .3 {3 mi. 0 .ou 4mm wmu .uqulll. .a u paces: .oo anon nopeaao eaaonuau .oo «sou shoousa eoaeaao and seoH heao seoa sued ea hence seoa aeoa seed unseen sumac page anon nopocoo eHHonmmH enaonmun dead: «sea: amonm «any «may «may «mav «adv «cal «my “tuna I 0.00..“ odoa o.oo.n 0.004. 0.00..” I 00H o.ooH :.~m o.mm e.mm a.mm o.ew o.ooH ow e.Hm o.mm m.om m.Hm m.ma m.mw m.mw o: o.o~ m.~m m.mw H.oo :.mo o.m~ w.~m om o.oo ~.m: m. o H.mm m.mm o.mo o.m~ o .Illdmuui InwWI, .meqn almafll c358 “.0330 63.95 .00 neon wecHMmm .8 paces: .8 bacon: and scoa ssoa seoa sdoH coma seoa pane seoa page unnomd cepmxoonm copmuooum copuxoon copmmoonm_copmuooum cepmxooum_copmuoonm :momm at 3v .3 2; RV «my .3 eoeea .usnondmoca coupe mo cached unease» . pm maaom mdounmb on» so.“ madman «some dope» no 33.» owmpcoonom .9” 0.3m.“ -l2#- mSo . 38 . ans . mes . tho . 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I-I - -1 -14.-.) 1.- 41 11 4" now -128- B e o o o. e «o o o o e e lOOH issue 10 pretf easzuoozed .pmonw no onnm one mnaondmozd eHanHmae Hence decrees demcomveHem .mm ossth oHpen mcHaomnuxe oHAH memo: coHHHHs nod ovumd :H menonduoma oHnuHHsbe Hence oemlbw.ml-.-ibo_m . omHfi; .o.wH.i--. ...-.oi..~H- --..----o.m.H. .-----..oo.H _ om --; om. on om o dl J a 5 ex means 30 ptetfi oasiuecrcd -129- . ... om 00H omH OHH .amenw no “Hana Hmuoa use ocuondmona penmomom somepon demsoHumHom. .dm onana capes wcHaomsvxo OHHH mcams couaama and owned dennondmond oonnomo< Lo: 00H om pm -130- a 4 cc. 0w . oa a ‘11 s cm -omw. o .oH -om -om o: -om -om -om -om -om -Ooa '4eoqa JO ptetf afieaueoroa cam 4| -131- oHsma mchoempxo emuH memos modHHHs nod waned cH assondmomd eHanHepm Hopes 0mm 4 .pmoms Ho uHon use msaomdmona oHnsHHmbm Hope» snowmen dHnmdoHamHmm. com 0. end 0mm Dfid OWH owa om 0.. .mm enemas om 0 dl) O 000 mm H O NKOm-‘t icon: 30 p191! oBsiueored 000 ‘0 O O\ OOH o: -132. CNN .umoze mo omen» Homo» one monogamomd commemom cmoeaop demcoHpeHom oHpmu mcmpommpxe omuH mcHo: coHHHHs mod magma :H monogamoma commemo4 a com ooH ooH oeH omH ooH om oo o: «1 d d d! «l d H . a one... o 00 e e \O .mm enemas om o . ;.H d . -am 3 ( O a m o a 47m «.7 \ a \ a, x w. .om m” 100 m. m. -05 O B a... Low mom JooH -133... of the relationship between total available phosphorus ex- tracted at a ratio of 1:50 and plant growth response indi- cates a relatively wide scatter of points and, therefore, a somewhat inferior correlation. Apparently the best corre— lation is found in Figure 26 where the scatter of points is not large and where a large number of the points fall on or very near the calculated curve. A better conception of the reliability of any given chemical method of measuring phosphorus availability is furnished by the statistical analyses provided in Table 21. The c1 value of equation (III) relates the chemically meaH sured available phosphorus value to the plant response by means of the equation. The more nearly this value remains constant over a large group of soils for a given method the more reliable this method may be considered in actual capa— bility to predict yield response. Therefore it was decided to measure the variability of the sample for each system utilized in the mathematical evaluation. The standard de- viation, coefficient of variability and standard error of estimate were calculated for each series of c1 values. Also included in Table 21 is the mean cl value for each method of extraction. This value corresponds to the one used in calculating the curve presented for each of the graphs. -13#— Statistical analysis of c1 values for the various Table 21. chemical methods of measuring phosphorus avail- ability. Chemical Method of Measuring Available Phosphoru Statistic (1) (2) (5) (6) (7) (3) Spur- Spur- Bray's Bray's Bray's Bray's way's way's Total Adsorbed Total Adsorbed Active Reserve Avail- (1:10) Avail- (1:50) able able (1:10) (1350) Y .1311 .0211: .0129 .028# .0102 .0169 4‘ .0685 .0133 .0050 .011# .00#2 .0050 V, 67.50 62.2# 38.53 #0.1# #0.7# 29.60 ‘x(actual .01227 1300185 1.00069 3.00158 $.00058<=.00069 a (“M 9.15 “5.65 35.35 t 5.56 z 5.68 “1.11 The actual values for the standard deviation (0') do not permit a comparison of variability of the 01 values. However, the use of the coefficient of variation (V) which expresses the standard deviation as a per cent of the mean (5?) does provide a means whereby the various systems can be compared. Upon the basis of such a comparison it is seen that the variation in the c1 values is considerably greater for the two Spurway systems than for any of the other methods. Detailed examination of the individual c1 values indi- cates that the Spurway active extraction failed, especially on the Isabella loam from Kent county and to a certain extent on such soils as the Clyde clay loam from Macomb county and -135- the Kent silt loam from Kent county. The Spurway reserve extraction varied the most from the mean on such soils as the two Brookston silt loams from Macomb county, the Brookston loam from Saginaw county and the Brookston 10am from Kent county. However, the variability was also rather general throughout all of the Series of Samples. The variation from the mean was greatest in the case of Bray's total availably phosphorus extraction (1:10) on such soils as the two Brookston silt loams from Macomb county and the Brookston loam from Saginaw county. The use of Bray's adsorbed phosphorus extracting solution apparently did not vary so greatly for any individual soil as some of the other techniques, except possibly for the Clyde clay loam. In the case of the 1:50 extraction ratios, the measure- ment of total available phosphorus did not produce any spectacular changes from the use of the same solution at a ratio of only 1:10. However, with the use of the adsorbed extracting solution at a 1:50 ratio a considerable improve- ment in results was obtained and as a consequence the best single method for chemically measuring available phosphorus under the conditions of this investigation resulted. There was still some variation among the 01 values as compared to the mean value, but as evidenced by the coefficient of vari- ation (\l) and standard error of estimate ( a; 01)) this method was a notable improvement over the other Bray -l36- techniques and especially an improvement over the methods of Spurway. In explaining the advantages of any one system of measuring available phosphorus over another certain funda- mental concepts must be considered. Seemingly the role of adsorption of phosphorus is extremely important in phos- phorus fertility relationships of the Michigan soils in. cluded in this study and therefore any chemical method of measuring phosphorus availability should include this con- sideration. In the case of the Isabella soil from Kent county, Spurway's active extraction failed especially to correlate with plant growth response due largely to the fact that very little phosphorus was soluble in this extracting sclup tion even after the addition of as much as 160 ppm of com- paratively soluble phosphorus. Similarly even with Spur- way's reserve extraction the available phosphorus value was low. An explanation of this apparently lies in the fact that the adsorbed phosphorus content is comparatively high and plays a major role in the portion of this element reddily available to plants. The measurement of the total available phosphorus or the adsorbed phosphorus by Bray's methods in this soil gave values which were somewhat low for the untreated soil but the values were very good for soils to which soluble phosphorus had been added. There- fore, the significance of the adsorbed portion of the -137- phosphorus seemingly must be considered in attempting to correlate crop response to the chemically measured portion of available phosphorus. Already it has been pointed out that a ratio of 1:50 was desirable in extracting the adsorbed form of phosphorus purely because such an extraction was capable of more nearly giving a true measure of this portion of the element. Further evidence to support this contention was provided in the studies of the correlation between plant growth and chemically measured available phosphorus. No doubt one of the main reasons why the adsorbed phosphorus extracted at a 1:50 ratio correlated better with growth response was the fact that a more accurate measurement of this portion of phosphorus was provided. Indirectly this improvement would, therefore, seem also to add support to the significance of the adsorbed portion of phosphorus as a factor in plant growth. The standard error of estimate of the mean of the 01 values for the extraction of adsorbed phosphorus at a 1:50 ratigri #.11%. jBray (6) reported a standard error of esti- mate in connection with his work on the relationship of ex- changeable potassium to crcp response of‘t 5.0%. Therefore, upon the basis of a well established method for potassium measurement and its use in a practical way, it would seem as though, under the conditions of this investigation, a method of eQual reliability has been provided for the -133- measurement of available phosphorus in the soil. Certain other investigations in regard to the measure- ment of chemically available phosphorus and correlation of the same to crap response have been attempted in Michigan but seemingly with less success than resulted in the case of this present study. Most notable among these has been the study of Bowers (2). This investigator found no better correlation between “total adsorbed phosphorus" and the re- sponse of alfalfa to added phosphorus than between “acid soluble phosphorus" and alfalfa response. However, the chemical methods used to separate the above two fractions are not similar to those utilized in this study which are the recommended methods of Bray (5). Therefore, it may be assumed that at least a part of the discrepancy noted in these two investigations of Michigan soils may be due to a basic difference in analytic techniques employed. No attempt was made to correlate actual tomato plant growth response with chemically measured available phos- phorus. The plants were harvested in a very immature state and no doubt for this reason failed to show the great Graduations in yield that the wheat plants did. The greatest actual response in the case of the first crop of tomatoes usually occurred with the addition of the first increment of added phosphorus and here the increase was so very great that few percentage yield points occurred be- tween low values of only a few percent and the point where -139— approximately 80 per cent yield had been attained. In the case of the second crOp of tomatoes, the variation in replicates of the same culture was so great that it did not appear logical to use these data in any correlation studies. -140. SUMhAR! ANu CONCLUSIONS A study was made in which both the chemical avail- ability of phosphorus and availability of this element as measured by plant growth response were investigated. Addi- tionally the first crcp of tomatoes and the wheat plants were analyzed for phosphorus content in an effort to ex- plain certain fundamental facts relative to phosphorus availability. Eight chemical methods of extracting the available phosphorus in twenty Michigan soils or soil materials were attempted. These soils had received added increments of Oa(HgPOh)2-H20 up to the equivalent of 3600 pounds per acre of superphosphate (0-20—0). The different extracting procedures gave widely varying results. In general the amount of chemically measured avail- able phosphorus as extracted by Spurway's active extracting solution was Quite low in comparison to that extracted by solutions containing hydrochloric acid. In the case of certain soils, the method was not particularly effective in indicating a higher level of available phosphorus even though very large amounts of Ca(HaPOu)2-H20 had been added. Increasing the shaking time employed in extraction was essentially of no benefit on many of these soils and like- wise an increase in ratio of extracting solution to the amount of soil was not always beneficial. -l‘+l- Spurway's reserve extracting solution was more effect- ive in indicating the increased availability of added phos- phorus in each of the soils than was the active extraction solution. The results obtained by this method, however, did fluctuate considerably more from one soil to another. Consequently there seems to be some question as to its re- liability. Additionally the method as used according to the accepted procedure proved very inconvenient to use due to the frequently very large amounts of phosphorus contained in the extracts and the resulting difficulty in reading the intensity of color. The use of any of the methods of Bray provided a con- siderably clearer picture of phosphorus availability in the soil because of the inclusion of at least a portion of ad- sorbed or replaceable phosphorus in the extract which tends to be overlooked in an extraction involving only an acid solution. It became apparent that an extraction of the ad- sorbed phosphorus at a ratio of 1 part of soil to 50 parts as solution was especially desirable since a more complete removal of the adsorbed phosphorus was brought about. Addi- tionally these methods are more easily adOpted to colore- metric measurement of the phosphorus due to a lesser con- centration of the element in the extract and also a reduc- tion in the variability of the extract in its content of the element. -142- Various plant characteristics such as number of wheat heads produced, the amount of plant material produced in both the straw and head portions of the wheat plant and the phosphorus content of the plant material were investi— gated. Bimilar studies were made on tomato plants of a first crcp on certain of these soil. In general the addition of phosphorus had a tendency to increase the number of heads formed although this was by no means a reliable method of measuring the phosphorus stimulating effects. The yield of plant material in the case of wheat generally indicated an increase as a result of each addi- tion of phosphorus. The greatest response in plant growth resulted on those soils which were noted to be especially low in chemically available phosphorus. The total yield of wheat plants apparently was a better measure of response to added phosphorus than either the head or straw portion alone and this was used in detail in an attempt to corre- late growth response to chemically measured phosphorus. Tomato yield data indicated a very great response to the addition of phosphorus, especially to the addition of only #0 ppm of this element, for all of the soils included in the study. Additional evidence as to the lack of native phosphorus fertility was provided on such soils as those obtained from Kent county, Michigan and pronounced indications of the lack of growth producing capabilities -143- of the Oshtemo sand were provided. In general the chemical analyses of plant material provided information much like that obtained from plant growth response. The actual phosphorus percentage of the straw portion of the wheat plants did not always reflect the addition of phosphorus to a soil and occasionally the total amount contained in the straw likewise did not indi- cate the true picture. However, this apparent discrepancy was accounted for by increased stimulation of head produc- tion. The variation of phosphorus content in the head por- tion of the plant was not great from one soil to another or within a given soil series depending upon the level of added phosphorus. However, the variation in percentage content of the straw was great depending upon either of the above factors. The phosphorus content of tomato plants was consider- ably more variable than that of the wheat plants depending upon the level of added phosphorus. An indication was made that approximately a percentage composition of 0.40 - 0.45 was sufficient to provide maximum or near maximum growth to the point at which these plants were harvested. The yield data for a second crcp of tomatoes following the initial crOp or likewise a crcp of tomatoes following wheat did not provide as much information as either of the initial crops. However, there was some indication of a general depletion of fertility by the first crop of tomatoes 4141+— and in the case of the wheat soils additional information was provided as to the suitability of the various soils for plant growth media. An attempt was made to correlate growth response with chemically measured available phosphorus. The principles of Mitscherlish as modified by Bray were employed. A general applicability of such principles was indicated by graphic interpretation. The two methods of Spurway were apparently of about the same suitability and as such were distinctly poorer than any of the methods advocated by Bray and his associates. The use of either the customary method of Bray for mea_ suring total available phosphorus or adsorbed phosphorus at an extraction ratio of 1:10 gave comparable results. In- creasing the extraction ratio to 1:50 did not improve the method for measuring total available phosphorus as evidenced by correlation with plant yield response. However, the in- creasing of the ratio to 1:50 for the adsorbed phosphorus extraction did result in a notable improvement and also re- sulted in the best single method employed under the condi- tions of this experiment. Certain apparent discrepancies in this investigation in comparison to that of a similar investigation on Michigan soils were recognized. However, a study of the analytical method employed in the two studies indicates that the studies are not entirely comparable and therefore the results cannot necess- arily be considered in disagreement. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) -145. LITERATURE CITED 1946 Photometer method for Ill. Agr. Arnold, C.Y. and Kurtz, T. determining available phosphorus in soils. Exp. Sta. Agron. Dept. Pamphlet AG 1306. Bowers, A. H. 1947 The relation between forms of soil phosphorus and response of alfalfa and small grain to added phosphate. M.S. Thesis, Michigan State College. Bray, R. H. and Dickman, S. R, 1941 Adsorbed phosphates in soils and their relation to crcp responses. Soil Sci. Soc. of Amer. Proc. 6: 312-320. 1942 Tenative fluoride Bray, R. H. and Dickman, S. R. Ill. Agr. extraction methods for soil phosphorus. Exp. Sta. Agron. Dept. Pamphlet AG 1006. Bray, R. H. 1942 Rapid tests for measuring and dif- ferentiating between the adsorbed and acid-soluble forms of phosphate in soils. Ill. Agr. Exp. Sta. Agron. Dept. Pamphlet AG 1028. Bray, R. H. 1944 Soil—plant relations : I. The quan- titative relation of exchangeable potassium to crcp yields and to crop response to potash additions. Soil Sci. 58: 305-324. 1945 Photometer method for determining Bray, R. H. _Ill. Agr. Exp. Sta. available potassium in soils. Agron. Dept. Pamphlet AG 1275. Bray, R. H. and Kurtz, L. T. 1945 Determination of total, organic, and available forms of phosphate in soils. Soil Sci. 59: 39—45. Bray, R. H. 1946 Soil-plant relations : II. Balanced fertilizer use through soil tests for potassium and phosphorus. Soil Sci. 60: 463-473. Bray, R. H. 1949 Correlation of soil tests with crap response to added fertilizers and with fertilizer requirement. Diagnostic Techniques for Soils and Crops. Published by The American Potash Institute. 1941 Replacement of Soil Dickman, S. R. and Bray, R. H. adsorbed phosphate from kaolinite by fluoride. Sci. 52: 263—273. (12) (13) (14) (15) (16) (17) (18) -l46— Lawton, K., Robertson, L. 8., Cook, R. L., and Rood, P. J. 1947 A study of the correlation between rapid soil tests and response of legume bay to phosphorus and potassium fertilization on some Michigan soils. Soil Sci. Soc. of Amer. Proc. 12: 353-358- Peech, M. and English, L. 1944 Rapid microchemical soil tests. Soil Sci. 57: 167-195. Spurway, C. H. 1944 Soil testing. Mich. Agr. Exp. Sta. Tech. Bul. 132 (3rd rev.). Ulrich, A. 1945 Critical phosphorus and potassium leiels in ladino clover. Soil Sci. Soc. of Amer. Proc. 10: 150-161. Ulrich, A. 1949 Plant analysis - methods and inter- pretation of results. Diagnostic Techniques for soils and crcpq.flublished by American Potash Institute. Veatch, J. 0. 1933 Agricultural land classification and land types of Michigan. Mich. Agr. Exp. Sta. Spec. Bul. 231. Watson, A. J. 1949 The effect of varied levels of nitrogen, phosphorus, potassium and boron in soil on the yield and chemical composition of greenp house tomatoes. Ph.D. Thesis, Michigan State College.