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This is to certify that the
thesis entitled

EFFECT OF THE TIMING OF NITROGEN APPLICATION ON SOIL
NITROGEN AND NITROGEN USE EFFICIENCY OF VITIS
LABRUSCA IN A SHORTSEASON REGION

presented by
Randall J. Vos

has been accepted towards fulfillment
of the requirements for the

MS. degree in Horticulture

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EFFECT OF THE TIMING OF NITROGEN APPLICATION ON SOIL
NITROGEN AND NITROGEN USE EFFICIENCY OF VITIS LABRUSCA IN A
SHORT-SEASON REGION
By

Randall J. Vos

A THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
Department of Horticulture

2003

ABSTRACT
EFFECT OF THE TIMING OF NITROGEN APPLICATION ON SOIL
NITROGEN AND NITROGEN USE EFFICIENCY OF VITIS LABRUSCA IN A
SHORT-SEASON REGION
By

Randall J. Vos

Nitrogen (N) is applied to vineyards from prior to budbreak to post-harvest,
depending on the region. The goals of this work were to determine the how the time of N
application affects soil N levels and fertilizer N recovery by Vitis Iabrusca L. grapevines
in Michigan, a short-season region. Labeled ammonium nitrate (15 NH4‘5N 03) was
applied to the soil beneath the vines at a rate of 68 kg N/Ha at different times between
budbreak and six weeks after bloom. Soil was sampled after the fertilizer applications to
follow the inorganic N dynamics. The vines and soil were excavated at the end of the
growing season to quantify fertilizer N recovery. By the end of the season, grapevines
contained less than 20% of the N applied. Vines fertilized at budbreak generally
contained less fertilizer N and allocated a greater fraction of the fertilizer N to the fruit
and leaves. Vines fertilized later in the season allocated more of the absorbed fertilizer N
and total N from all sources, to the roots. At the end of the season, more fertilizer N
remained in the soil from the later applications. High levels of inorganic N were
maintained the longest in the soil, following the N applications at bloom. Based on these
findings, applications of N to vineyards in short-season regions are recommended to be
between bloom and six weeks after bloom, due to a higher recovery of fertilizer N in the

vines and more fertilizer N remaining in the soil than the budbreak applications.

DEDICATION

I would like to thank my friends and family back home and elsewhere for their
continued sustenance during my time at MSU. I would like to specifically thank the
people at MSU whom have made my time here more than just getting a degree, especially
my officemate Marlene Ayala. I would also like to thank the community that I grew to
be a part of, people who still practice true hospitality: Mauricio Canoles, Marcus Duck, b

Janelle Glady, Eric Hanson, Karen Maguylo, Adriana Nikoloudi, Ron Perry, Dario

 

Steffanelli, Costanza Zavalloni, Roberto Zoppolo, etc. .

“No good tree bears bad fruit, nor does a bad tree bear good fruit. Each tree is
recognized by its own fruit. People do not pick figs from thorn bushes, or grapes from
briars. The good man brings good things out of the good stored up in his heart, and the
evil man brings evil things out of the evil in his heart. For out of the overflow of his

heart his mouth speaks” Luke 6:43 -45 (N IV)

iii

ACKNOWLEDGEMENTS

I would like to acknowledge and extend thanks to Tom Zabadal for serving as my
major professor and for expanding my knowledge of viticulture.

Eric Hanson has served as my co-advisor and I wish to thank him for assistance
on many occasions while at MSU and for my many visits both personal and research
related. L

I would to also acknowledge David Rothstein, whom served on my committee

and provided insight into this research project.

 

Many others have done a lot of work during this project. The staff at the
Southwest Michigan Research and Extension Center, especially Brian Hauch and Dave
Francis, were a great help in this project and made my summers at SWMREC more

enjoyable.

iv

 

PREFACE

This thesis was written in the format for the American Journal ofEnology and

Viticulture. The Review of Literature is not intended for publication.

 

TABLE OF CONTENTS

LIST OF TABLES .............................................................................. vii
LIST OF FIGURES ............................................................................ viii
REVIEW OF LITERATURE ............................................................... 1
Introduction ........................................................................ 1

Global Environmental Impact From Nitrogen Fertilization ................ 2
Contamination of Water .................................................. 2

Atmospheric Pollution ..................................................... 3

Soil and Nitrogen Dynamics ...................................................... 3

Nitrogen in Vineyards ........................................................... 4
Contamination of Water by Viticultural Nitrogen Fertilizatic ....... 4

Mineralization of Organic forms of Nitrogen in Vineyards. ......... 4

Fate of Fertilizer Nitrogen in Vineyards ............................... 4

Grapevine Root Growth .......................................................... 5

Nitrogen Fertilization Practices in Vineyards ............................. 6

Efl'ects of Nitrogen Fertilization on Plant Physiology ........................ 7

Cold Hardiness ............................................................ 7

Fruit Quality ............................................................... 7

Nitrogen Dynamics in the Grapevine ........................................... 8

Nitrogen Uptake and Accumulation by Grapevines ........................ 10

Fertilizer Nitrogen Use Efficiency in Grapevines ............................ 12
Summary .......................................................................... 14
Literature Cited ................................................................. 16

EFFECT OF THE TIMING OF NITROGEN APPLICATION ON SOIL
NITROGEN AND NITROGEN USE EFFICIENCY OF VITIS LABRUSCA

IN A SHORT-SEASON REGION ...................................................... 20
Introduction ....................................................................... 20
Materiab and Methods ......................................................... 23
Results ............................................................................. 29
Discussion ........................................................................... 45
Conclusions ....................................................................... 53
Literature Cited ..................................................................... 55

APPENDICES .......................................................................... 57

vi

LIST OF TABLES

Table 1: Effect of time of nitrogen (N) application on dry matter,
fertilizer N, and total N in the fi'uit of individual 'Niagara' vines
fi'om Study 1 in 2001 . ............................................................ 33

Table 2: Effect of time of nitrogen (N) application (67.6 kg N/Ha) on
on the amount of fertilizer N remaining in the soil in Oct, for
Study 1 'Niagara' 2001 ............................................................ 34

Table 3: Effect of time of nitrogen (N) application on dry matter,
fertilizer N, and total N in the hit of individual 'Concord' vines
fi'om Study 2 in 2002. ............................................................ 35

Table 4: Effect of time of nitrogen (N) application (68.1 kg N/Ha) on

on the amount of fertilizer N remaining in the soil in Oct, for
Study 2 'Concord' 2002 ............................................................ 36

vii

LIST OF FIGURES

Figure 1: Effect of time of N application to ‘Niagara’ vines in 2001,
Study 1, on (A) fertilizer N absorbed by the vines, (B) total N
in the vines, and (C) dry matter of vines at the end of the season.
Lower case letters represent differences (LSD P=0.05) in the
same vine organs. Budbreak= 30 April; Bloom= 8 June;
3WPB= 30 June; 6WPB= 18 July. ...................................... 37

Figure 2: Effect of time of N application on the partitioning of fertilizer N
in ‘Niagara’ grapevines at the end of the season in 2001, Study 1.
Letters represent separation of treatment means of the same vine
organs (LSD P=0.05). Budbreak= 30 April; Bloom= 8 June;
3WPB= 30 June; 6WPB= 18 July. ............................................. 38

Figure 3: A comparison of soil temperatures at depths of (A) 5, (B) 15,
and (C) 45 cm at ~1430 hr under existing sod groundcover
(control) or 5 mil plastic installed on 06 May. Data points
represent the mean of 2 observations. .......................................... 39

Figure 4: Effect of time of N application to ‘Concord’ vines in 2002,
Study 2, on (A) fertilizer N absorbed by the vines, (B) total N
in the vines, and (C) dry matter of vines at the end of the season.
Upper case letters and lower case letters represent differences
(LSD P=0.05) in the whole vine and vine organs, respectively.
Budbreak= 14 May; Bloom= 19 June; 6WPB= 29 July. .................... 40

Figure 5: Effect of time of N application on the partitioning of fertilizer N
in ‘Concord’ grapevines at the end of the season in 2002, Study 2.
Letters represent separation of treatment means of the same vine
organs (LSD P=0.05). Budbreak= 14 May; Bloom= 19 June;
6WPB= 29 July. ........................................................ 41

viii

Figure 6:

Figure 7:

Figure 8:

Schematic of a portion of the vineyard plot, showing a treated vine

and adjacent vines in the ‘Concord’ 2002, Study 2. Shading

represents the treated and excavated vineyard floor and vine.

Values represent the percent of nitrogen in the leaves that is from

labeled fertilizer. Values of the vines adjacent to the treated vine

represent the means of three vines and standard errors. The

treated vine values represent the mean and standard error of all

the treated vines. ............................................................ 42

Inorganic N (NH4 and N03) and nitrate N at 1, 15, 29, and 43

days following each fertilizer application in the soil profile at

(A) 0-15.3 cm (B) 15.3-30.5 cm (C) 30.5-40.8 cm (D) 40.8-

61.0 cm in vineyard soil of ‘Concord’ in 2002, Study 2. Bars

represent standard error and * denotes the time of fertilizer

application at Budbreak= 14 May; Bloom= 19 June; 6WPB=

29 July, respectively. .............................................................. 43

Accumulated rainfall and irrigation for each fertilizer treatment on

the soil sampling dates following each fertilizer application in 2002

during Study 2 at the Southwest Michigan Research and Extension

Center, Benton Harbor, MI. Budbreak= 14 May;

Bloom= 19 June; 6WPB=29 July. ................................................... 44

ix

REVIEW OF LITERATURE

INTRODUCTION

Nitrogen (N) is an essential nutrient for plant growth and is the most frequently
applied nutrient to vineyards. Nitrogen is a component of amino acids, chlorophyll, and
lecithins in plants. The N requirement for grapevines is generally lower than that for
other crops (Christensen et a1. 1978). Nitrogen fertilization can increase vineyard yields
(Ahmedullah and Roberts 1991; Bell and Robson 1999; Kliewer et a1. 1991; Partridge
and Veatch 1931) and compensates for N removed from the vineyard through crop
harvest (Williams 1987).

Nitrogen from fertilizer is either taken up by the plants, incorporated into soil
organic matter, or is lost fi'om agricultural systems via leaching, erosion, volatilization,
and denitrification. Application rates of N in fruit production are usually much higher
than the total amount removed by the crop. Nitrogen use efficiency (NUE) is a term used
to quantify fertilizer N uptake by plants. NUE is the amount of fertilizer N taken up by
the plant, divided by the total amount of N that was applied (Weinbaum et a1. 1992).

Studies using fertilizers enriched with 15N as a tracer have shown that agricultural
crops absorb only a portion of applied N. The stable isotope of N, 15N, has eight neutrons
compared to the more commonly found 14N which has seven neutrons. Natural
abundance levels of stable N isotopes are 0.37% 15N and 99.63% of 1"’N. The different
quantities of each N isotope can be measured by mass spectrometry (Dawson and Brooks
2001). Studies in vineyards indicate that vines recover from 7 (non-irrigated vineyards)

to 42% (irrigated vineyards) of the N fertilizer during the season in which it was applied,

depending on the time of application, irrigation method, and climate (Hanson and Howell
1995; Williams 1991). Other woody fruit crops, such as blueberries and citrus, recovered
35 to 61% of applied N (Dasberg 1987; Retamales et al. 1989). More efficient recovery
of N fertilizer has been reported for annual crops (corn and barley) with up to 43 to 85%
NUE (Mahli et al. 1995; Reddy and Reddy 1993; Tran and Giroux 1998).

These studies indicate that grapevines exhibit a lower NUE than other crops.
Therefore, there is a need to determine the most efficient time of N applications to
vineyards to increase the NUE of grapevines for economic as well as environmental
reasons.

MAL ENVIRONMENTAL IMPACT FROM NITROGEN FERTILIZATION

The use of industrially fixed N is increasing in agriculture. In 2001, agriculture
worldwide used 83 million tons of N produced by industrial fixation via the Haber-Bosch
process. Sixty-one million tons of industrially fixed N were used in agriculture in 1961
(J enkinson 2001). Anthropocentric activities such as N fertilization in agriculture, have
created a situation where N can be viewed as either a nutrient or a pollutant, depending
on its location and form.

Contamination of Water:

Nitrogen is commonly lost from soil via the leaching of nitrate (N03); ultimately
N03 can end up in both ground- and surface water. Excess N03 in drinking water, which
commonly originates from groundwater, can cause adverse health complications in
humans such as methemoglobinemia. Nitrogen in combination with high levels of

phosphorus can also cause eutrophication of surface water (N ewbould 1989).

Atmospheric Pollution:

Nitrogen accumulates in the atmosphere in four major forms: N0, N02, N20, and
NH3. Contributions of N20 and NH3 to the atmosphere can be traced to agriculture.
Agricultural soils contribute 10 million tons of NH3 gas per year and release 2.1 million
tons of N20 into the atmosphere each year, which is a third of the total N20 released due
to human activity. Whereas greenhouse gases such as NH3 are only in the atmosphere for
a matter of hours or days, the half-life of N20 can be as long as 130 years. Therefore, the
persistence of N20 in the atmosphere is cause for concern because of its lasting impact on
the atmosphere (J enkinson 2001).

SOIL AN D NITROGEN DYNAMICS

Most of the N in soil is in organic forms. The availability of N independent of
fertilization (native N) is closely related to the amount of organic matter in the soil.
Mineralization is the process of the conversion of organic N into inorganic forms. The
inorganic forms of N, ammonium (NI-I4) and nitrate (N03), are available for uptake by
plants and N03 is very mobile in the soil. Nitrogen in soil organic matter is mineralized
at a rate of 1.5 to 3.5% per year (Brady and Weil 1996).

Nitrification is the conversion of NH4 to N03 via microbial oxidation.
Ammonium-based N fertilizers must be converted to N03 for uptake by most plants;
therefore, nitrification is often an important aspect of plant NUE. The rate of nitrification
in temperate soils is maximal at 25 to 35°C, and is nearly negligible below 10°C (Brady

and Weil 1996; Prasad and Power 1997).

NITROGEN IN VINEYARDS
Contamination of Water by Viticultural Nitrogen Fertilization:

German vineyards have been cited as a contributor of N03 to groundwater
(Schaller 1991). Groundwater N03 concentrations from Viticultural areas in Germany
were 8 to 30 times higher than those from forested areas. In addition, surface water
flowing out of the vineyards had 50-75% higher nitrate concentrations than water
upstream of the vineyards (Schaller 1991).

Mineralization of Organic forms of Nitrogen in Vineyards:

Fertilizer N applied to vineyards was most effective at increasing productivity of
the vines in shallow soils with low organic matter (Partridge and Veatch 1931). Partridge
and Veatch (1931) concluded that the amount of soil organic matter had a major impact
on vine vigor and productivity. Mineralization rates for native N in vineyards can range
from 2.9 to 3.1% (Schaller 1991).

Estimates in German vineyards (Schaller 1991) report that mineralization of
native N in tilled (non-vegetative row middles) vineyards can supply the total N needs of
a grapevine throughout the growing season. In vineyards with a vineyard floor of grass
vegetation, a shortage of native N for the grapevines is most likely to occur shortly after
budbreak due to the additional N demand by the grass vegetation (Schaller 1991 ).

Fate of Fertilizer Nitrogen in Vineyards:

Hajrasuliha et al. (1998) followed the fate of 15 N enriched ammonium
((NH4)2S04) and nitrate (KN 03) fertilizers applied to 3-year-old, trickle-irrigated
‘Thompson Seedless’ (Vitis vinifera) grapevines. Vines were fertilized with 50 kg N/Ha

in late April, and destructively harvested at fruit harvest in late September. At vine

harvest, N03 treated vines contained 22% of the fertilizer N; 13% was soil organic N; and
66% remained as soil inorganic N. The NH; applications resulted in similar recoveries of
the fertilizer N in the vines (24%), while 19% was bound as soil organic N, and 48%
remained as soil inorganic N. The majority of the fertilizer N that was incorporated into
organic forms of soil N was in the top 60 cm of the soil. The NH; and N03 fertilizers had
leached to a depth of 150 cm or more than 240 cm, respectively. It is presumed that
much of the inorganic N in the N03 form would likely leach below the rooting zone
during the subsequent winter and spring.
GRAPEVINE ROOT GROWTH

Grapevine roots are an important tissue in the uptake, storage, and translocation of
N within the vine (Bates et al. 2002; Conradie 1980). The bulk of nutrient and water
uptake by vines occurs at the tips of actively growing feeder roots, called the absorption
zone. The absorption zone does not have the corky outer layer, which is present on older
roots (Winkler et a1. 1974). The most dynamic root turnover during the season occurs in
fine roots (feeder roots) (Bates et al. 2002). The feeder root system may go through
multiple cycles of growth, senescence, and re-growth during a growing season (Winkler
et al. 1974). Conradie (1980) observed that active N accumulation after fruit harvest
coincides with increased root growth in South Africa. Therefore these studies suggest
that N uptake by grapevines may coincide with periods of active root growth.

The number of actively growing root tips fluctuates throughout the growing
season. Van Zyl (1988) showed that the most active period of root tip proliferation in
mature V. vinifera ‘Columbard’ on the 99R rootstock in South Afiica, occurred during

bloom, for a month following fruit harvest, and to a lesser extent during veraison. At

these times, vines had 2 to 15 times more actively growing root tips than during the rest
of the season.

Seasonal changes in root growth and N content also occurred in 3-year-old
‘Concord’ vines in a short-season region in New York (Bates et al. 2002). Dry matter
accumulation for fine roots (<2 mm) was the most dynamic. Peak periods of fine root
growth occurred from late spring dormancy to budbreak, 32 days post-bloom to veraison,
and fiom fruit harvest to leaf fall. Fine root dry matter increased 5 fold from April (bud
swell) to the beginning of November (dormancy).

NITROGEN FERTILIZATION PRACTICES IN VINEYARDS

Fertilization with N is recommended in vineyards to stimulate increased
production. Recommendations for fertilizing mature vineyards in Michigan are 57 kg
N/Ha, between budbreak and bloom (Hanson 1996). Fertilization recommendations for
mature vineyards in New York and Pennsylvania also suggest N applications between
budbreak and bloom (Bates 2001). Recommendations from other short-season regions
are N applications 30 days before the commencement of vine growth in the spring
(Cahoon et al. 1991; Funt et al. 1997). Winkler et al. (1974) recommends that fertilizer N
be in the rooting zone when vine growth begins in the spring. The University of
California Cooperative Extension, Tulare County recommends N fertilization to
vineyards at a rate of 28 to 57 kg N/Ha applied between after budbreak to hit set, or
after fruit harvest (Peacock et al. 1996).

Fertilization practices are adjusted by observing vine growth. Excessive N
fertilization can cause negative impacts (such as shading) on the vine due to excessive

growth (Hanson 1996; Peacock et al. 1996; Smart 1991).

EFFECTS OF NITROGEN FERTILIZATION ON PLANT PHYSIOLOGY
Cold Hardiness:

There is evidence that low N levels enhance the cold hardiness of plants. Rapidly
growing shoots of conifers were more susceptible to cold temperature injury than shoots
that were growing Slowly (Alden and Herman 1971). Late season N applications may
induce plant growth late in the season and impede natural cold acclimation and shoot
matrnity. Fall applications of N to apple orchards can decrease cold hardiness (Pellett
and Carter 1981). High levels of soil fertility have been correlated with an increase in
frost injury to some grapevines (Alden and Herman 1971).

However, Wample et al. (1991) reviewed the literature on the interactions of N
and cold hardiness in grapevines, and concluded that N nutrition has only a small impact
on cold hardiness, and that factors such as rootstocks, sun exposure, cropload, and
climate affect cold hardiness more directly than N management. Wample (1993)
reported that N fertilization from the beginning of the growing season until fruit harvest
will have little affect on reducing the cold hardiness of ‘Riesling’ grapevines.

Fruit Quality:

There is a general belief that N fertilization of grapevines reduces some of the
quality aspects of fruit (sugar, anthocyanins, fruit color, etc.), but the experiments that
have been performed to investigate this relationship often have variable results (Smart
1991).

The timing of N applications to grapevines can have variable effects on fi'uit
quality. Christensen et al. (1994) investigated the responses of grapevines to N applied at

different times in the growing season. Treatments consisted of no N, or N applied to

vines either at budbreak, fruit set, veraison, or post-harvest. Four V. vinifera cultivars
were studied (‘Barbara’, ‘Chenin blanc’, ‘French Colombard’, and ‘Grenache’). Nitrogen
applied to vines at veraison had small negative impacts on the fruit quality of ‘Chenin
blanc’ and ‘Grenache’. The negative effects on the fruit included a slightly reduced
yield, higher incidence of fruit rot, lower titratable acidity, and higher pH. The authors
concluded that fertilizing with N at times other than veraison would slightly increase fruit
quality in N sensitive cultivars.

Dukes et al. (1991) concluded that fruit quality, as measured by titratable acidity,
pH, and soluble solids concentration, of V. vinifera ‘Sauvignon blanc’ was not affected
by the time of urea application. However fruit from vines fertilized between fruit set and
fruit harvest had significantly higher total N concentration (TNC) in both the free-run and
cold-settled juice than those fertilized at budbreak or post harvest. A decrease in
fermentation time to dryness was correlated with an increase in TNC of the cold-settled
juice. The authors concluded that higher TNC, which can be affected by the timing of N
application, reduced fermentation time and improved wine quality. Goldspink and
Gordon (1991) obtained comparable results by increasing TNC with N applications
between fruit set to veraison.

NITROGEN DYNAMICS IN THE GRAPVINE

There is evidence that grth of the vine early in the growing season is
substantially dependent on N reserves in the vine (Conradie 1980; Conradie 1986;
Lohnertz 1991; Werrnelinger 1991; Williams 1991). Mobilization of N from perennial
(woody) tissues of the vine prior to bloom is independent of N levels in soil (Lohnertz

1991; Werrnelinger 1991). Later in the growing season the main source of N for growth

is from soil N, but N reserves from woody tissue (roots and trunk) can be mobilized when
soil N levels are insufficient (Wermelinger 1991; Williams 1991).

Woody tissues act as a buffer in the N dynamics within the grapevine. Lohnertz
(1991) described the change of N content within the woody parts of 25 year-old V.
vim'fera ‘Riesling’. Between leaf unfolding and veraison, N in the woody tissues was
released at rates of approximately 20-150 g N/Ha/day. From veraison until fruit harvest,
woody tissue accumulated N at rates of 30-200 g N/I-Ia/day. It could not be determined
what portion of this increase of N in the woody tissues was due to mobilization from the
leaves or to additional uptake of N fi'om the soil.

Bates et al. (2002) excavated 3 year-old ‘Concord’ vines in New York on eight
dates from dormancy in the spring to leaf fall. When the vines were dormant in the
spring, the roots contained 75% of the total N in the vines. From budbreak to 2 weeks
prior to bloom, N accumulated in thin and fine roots. From bloom to the end of rapid
shoot growth, there was a net loss of N from the entire root system and large
accumulation of N in the shoots and fruit. Substantial accumulation of N in the root
tissue occurred after fruit harvest.

Studies with potted vines in South Africa have shown that 20-30% of N needed
for the growth of annual tissues from budbreak to the end of bloom comes from
mobilized N from perennial vine structures (Conradie 1980; 1986). Similar results were
observed in field studies in Germany and California, where 20 to 40% of N used for
growth from budbreak to bloom, was mobilized from perennial structures (Lohnertz

1991; Schaller 1989 cited in Werrnelinger 1991; Williams 1991).

Conradie (1991) observed that potted vines began active root uptake of nutrients
began when soil temperatures reached 10°C, and concluded that if there was a delay in
the soil temperature reaching 10°C early in the season, more N reserves than normal
would be mobilized from the perennial structures of the vine to accommodate early
season growth.

NITROGEN UPTAKE AND ACCUMULATION BY GRAPEVINES

Grapevines take up soil N predominantly in the nitrate form (Roubelakis-
Angelakis and Kliewer. 1992; Winkler et al. 1974). The determination of the stages of
vine development in which N is most rapidly accumulated in the vine will help to identify
optimum times for N fertilization.

Hanson and Howell (1995) destructively harvested mature V. labrusca ‘Concord’
vines in Michigan to quantify the N accumulation throughout the growing season. The
vines were fertilized at budbreak with 90 kg N/Ha and harvested at 2- to 4-week
intervals. The pattern of N accumulation paralleled the pattern of dry-matter
accumulation. The rate of N accumulation was highest during the period from 2 weeks
after budbreak to fruit harvest, except for a brief decline during veraison.

A similar study in Germany (Lohnertz 1991), with 25-year-old V. vinifera
‘Riesling’ vines, showed comparable results. The time of most rapid N uptake started 2
weeks prior to bloom and lasted until the pea-size-berry stage (4 weeks prior to veraison).
During this period, N absorption rates for the vines ranged from approximately 600 to
1700 g N/ha/day. Absorption rates were 50 g N/Ha/day from budbreak to 2 weeks prior
to bloom, and 200 g N/Ha/day from the pea-size-berry stage to veraison. During the first

2 weeks after veraison, N was absorbed at a rate of approximately 800 g N/Ha/day.

10

Lohnertz concluded that fruit quality can be influenced by N uptake during veraison due
to the large uptake of N at that time, and that vines continued to absorb N until vegetative
growth stopped.

Potted vines of ‘Chenin blanc’ V. vinifera absorbed N most rapidly from bloom
until veraison (Conradie 1980). Later studies by Conradie (1986; 1991) indicated that
rapid N uptake occurred after bloom through fruit harvest. A Hoagland solution
containing l5N labeled KN 03 was applied to the vines at different phenological stages
and was leached out of the pots at the end of those stages. The rate of absorption by
individual vines was 210 mg N/vine/week, from budbreak until the end of rapid shoot
growth. The most rapid uptake occurred at rates of 450 and 366 mg N/vine/week, from
the end of rapid shoot growth to veraison and from veraison to fruit harvest, respectively.
Vines absorbed 138 mg N/vine/week after fruit harvest (Conradie 1986).

Williams (1991) excavated whole 5 year-old, unfertilized, V. vimfera ‘Thompson
Seedless’ vines over a 2-year period. Whole vines were sampled beginning at 3 months
before budbreak until fi'uit harvest. The N accumulation pattern varied each year. In the
first year, high N accumulation rates (approximately 480 g N/Ha/day) occurred for 130
days following budbreak. The accumulation rate was constant during this period except
for a low uptake during bloom. In the first year there was no accumulation of N from
130 days after budbreak until fi'uit harvest. In the second season the accumulation rate
was very consistent (approximately 430 g N/Ha/day) for the entire 180 days between
budbreak and fruit harvest. The authors did not speculate on reasons for the differences

between the years, but they may reflect yearly weather variations.

11

Some general patterns of N accumulation emerge from these studies. Nitrogen
accumulation parallels dry matter accumulation in grapevines (Conradie 1980; Hanson
and Howell 1995; Werrnelinger 1991). During active shoot and fruit growth, grapevines
require more N (Peacock 1982). The period of greatest N uptake throughout the various
Viticultural regions generally occurs from bloom to veraison.

FERTILILZER NITROGEN USE EFFICIENCY IN GRAPEVINES

Several factors influence the Optimum time of N application to maximize N
uptake in grapevines. Equally important factors are the rate of N uptake, duration of the
uptake, and climatic conditions such as precipitation and temperature, also affect N
fertilizer uptake.

Conradie (1986) reported that the stage from the end of rapid shoot grth to
veraison accounted for 19% of the total N taken up by the vines during the growing
season. Nitrogen absorbed during the post-harvest phenological stage accounted for 27%
of the total N accumulated in the vines. In other studies the post-harvest period of N
absorption accounted for as much as 34% of the total N accumulated during the growing
season (Conradie 1980; 1991). Therefore, Conradie (1980; 1986; 1991) suggests that
post-harvest applications of N would be used efficiently by grapevines in South Africa.
Conradie (1986) concluded that the uptake of N during post-harvest is dependent upon
the presence of a functional leaf canopy. Therefore, the longer the canopy is retained the
more N can be absorbed after fruit harvest.

In California, N fertilizers applied later in the season were absorbed by vines
more efficiently, than those applied in the spring. Peacock et a1. (1989), applied

( ‘5 NH4)2S04 at a rate of 112 kg N/Ha to mature, firrrow irrigated ‘Thompson Seedless’

12

vines. The applications were made in two vineyards, at three different times: early March
(Budbreak), early July, and late September (post-harvest). The most efficient time of
application in the one vineyard was September, while the most efficient time at the
second site was July. The authors attributed the difference between the two vineyards to
a low soil pH at the second site, which would delay nitrification, making the September
application less available for uptake prior to leaf senescence. The authors suggest that
post-harvest applications be made at least 3 to 4 weeks prior to leaf fall, and that N03
fertilizers should be used because they can be taken up directly by the vines. March
applications of N fertilizers were prone to leaching and denitrification at both sites.
Conradie (1980) also attributed a lower NUE in spring applications in South Afiica to
leaching. The Peacock et al. (1989) study provides only a recovery of fertilizer N for a
sampling of the vegetative tissues and not the entire vine.

Williams (1991) found that with drip-irrigated 6 year-old ‘Thompson Seedless’
vines in California, a single fertilizer application resulted in higher NUE than small,
repeated applications. Vines that had previously never been fertilized were fertilized
with 15N labeled potassium nitrate. One application of 25 g N/vine when berries were 8
mm (mid-May) resulted in 42% accumulation of applied N in the vine. Ten applications
of 2.76 g N/vine, beginning at around budbreak and continuing at 2-week intervals,
resulted in 34% recovery.

Most of the N Viticultural studies discussed have been associated with long-
season Viticultural regions. In Michigan, a short-season Viticultural region, Hanson and
Howell (1995) applied double 15N labeled NH4N03 (50 kg N/Ha) to mature vines of the

French-American hybrid ‘Seyval blanc’. Vines were either treated with fertilizer during

13

budbreak or bloom, and were destructively harvested when the leaves began to senesce.
Vines fertilized at budbreak absorbed 7.1% of the applied N, while those fertilized at
bloom absorbed 10.6% of the N. There was no statistical difference between the amount
of fertilizer N in the vines from the two application times and the application times in this
study were only 45 days apart. A wider range of application times of N in a short-season
climate has not been investigated.

Substantial N accumulation in the vine after fruit harvest is only a significant
factor in long-season regions. For example, in South Afiica there can be a 3-month post-
harvest period of active canopy before leaf senescence begins (Conradie 1980; 1991). In
short season regions, leaf senescence frequently occurs soon after harvest, therefore post—
harvest applications of N may not be as effective because a functioning leaf canopy is
absent (Bates et a1. 2002; Hanson and Howell 1995; Lohnertz 1991). Effectiveness of
post-harvest applications of N in long-season areas may also be reduced with late
ripening varieties (Conradie 1991).

SUMMARY

Efficient N fertilization of vineyards involves identifying the stage of vine growth
when N uptake is most rapid, quantifying the duration of the uptake, investigating soil-
fertilizer interactions, and correlating climatic conditions such as precipitation and
temperature with N uptake. Evidence from long-season regions supports the value and
efficiency of grapevine utilization of post harvest applications of N. This is likely not
feasible in short-season areas, where leaves senesce during or shortly after fruit harvest.

Information on NUE and the timing of N fertilization in Short-season regions is limited.

14

Research using 15 N labeled fertilizers has been done primarily on V. vinifera and to a
lesser extent on F rench-American hybrids.

No field studies have been conducted to compare the NUE of different times of N
application in the short-season Viticultural regions such as Michigan and New York for V.
labrusca, the predominant grape species grown there. A wide range of times of N
application for grapes has not been thoroughly investigated for any species of grapes in
short-season regions. Furthermore, although the efficiency of the uptake of N fertilizers
by grapevines has been documented in several situations (Conradie 1980; 1986; 1991;
Hanson and Howell 1995; Williams 1991), the fate of the N fertilizer that was not
absorbed by grapevines has not been well documented, especially in short-season
regions. This is an important issue because the majority of applied N is not taken up by
vines. The fertilizer N not used by the grapevines will either be incorporated in soil
organic matter, remain in inorganic forms, or be volatilized. This portion of the fertilizer
N may eventually become spatially inaccessible to the grapevines and therefore have the

potential to become an environmental contaminant.

15

LITERATURE CITED

Alden, J and R.K. Hermann. 1971. Aspects of the cold hardiness mechanisms in plants.
Bot. Rev. 37:37-142.

Ahmedullah, M. and S. Roberts. 1991. Effect of soil—applied nitrogen on the yield and
quality of Concord grapevines. . In International Symposium on Nitrogen in
Grapes and Wine. J.M. Rantz (Ed.), pp. 200—201. Seattle, WA.

Bates, TR. 2001. Vineyard nutrient management.
http://lenewanetsvnc.net/public/Bates/NutrientRec.htm#Chart.

Bates, T.R., R.M. Dunst, and P. Joy. 2002. Seasonal dry matter, starch, and nutrient
distribution in ‘Concord’ grapevine roots. HortScience 37(2):313-316.

Bell, SJ. 1991. The effect of nitrogen fertilization on growth, yield, and juice
composition of Vitis vinifera cv. Cabernet Sauvignon grapevines. In
International Symposium on Nitrogen in Grapes and Wine. J .M. Rantz (Ed.),
pp. 206-210. Seattle, WA.

Bell, SJ and A. Robson. 1999. Effect of nitrogen fertilization on growth, canopy
density, and yield of Vitis vinifera L. cv. Cabernet Sauvignon. Amer. J. Enol.
Vitic. 50:351-358.

Brady, NC. and RR. Weil. 1996. The nature and properties of soils. Prentice Hall, New
Jersey.

Cahoon, G., M. Ellis, R. Williams, and L. Lockshin. 1991. Grapes: production,
management, and marketing. The Ohio State University Ext. Bulletin 815.

Christensen, L.P., A.N. Kasimatis, and FL. Jensen. 1978. Grapevine nutrition and
fertilization in the San Joaquin Valley. Calif. Div. Sci. Publ. 4087.

Christensen, L.P., M.L. Bianchi, W.L. Peacock, and DJ. Hirschfelt. 1994. Effect of
nitrogen fertilizer timing and rate on inorganic nitrogen status, fruit
composition, and yield of grapevines. Amer. J. Enol. Vitic. 45:377-387.

Conradie, W.J. 1980. Seasonal uptake of nutrients by ‘Chem'n blanc’ in sand culture: I.
nitrogen. S. Afr. J. Enol. Vitic. 1:59-65.

Conradie, W.J. 1981. Nutrient consumption by ‘Chenin blanc’ grown in sand culture
and seasonal changes in the chemical composition of leaf blades and petioles. S.

Afr. J. Enol. Vitic. 2:15-18.

Conradie, W.J. 1986. Utilization of nitrogen by the grape-vine as affected by time of
application and soil type. S. Afr. J. Enol. Vitic. 7:76-83.

16

Conradie, W.J. 1991. Translocation and storage of nitrogen by grapevines as affected by
time of application. In International Symposium on Nitrogen in Grapes and
Wine. J .M. Rantz (Ed.), pp. 32-42. Seattle, WA.

Dasberg, S. 1987. Nitrogen fertilization in citrus orchards. Plant Soil. 100:1-9.

Dukes, B., B. Goldspink, J. Elloitt, and R. Frayne. 1991. Time of nitrogenous
fertilization can reduce fermentation time and improve wine quality. In
International Symposium on Nitrogen in Grapes and Wine. J .M. Rantz (Ed.),
pp. 249-254. Seattle, WA.

F unt R.C., M.A. Ellis, and C. Welty (Ed.). 1997. Midwest Small Fruit Pest Management
Handbook. The Ohio State University Ext. Bulletin 861.

Goldspink, B. and C Gordon. 1991. Response of Vitis vinifera cv. Sauvignon blanc
grapevines to timed applications of nitrogen fertilizers. In International
Symposium on Nitrogen in Grapes and Wine. J.M. Rantz (Ed.), pp. 255-258.
Seattle, WA.

Hajrasuliha, S., D.E. Rolston, and D.T. Louie. 1998. Fate of 15N fertilizer applied to
trickle-irrigated grapevines. Amer. J. Enol. Vitic. 49: 191 -1 98.

Hanson, E.J. and GS. Howell. 1995. Nitrogen accumulation and fertilizer use efficiency
by grapevines in short-season growing areas. HortScience. 30:504-507.

Hanson, E.J. 1996. Fertilizing fruit crops. Michigan State University Extension.
Bulletin E-852.

Kliewer, W.M., C. Bogdanoff, and M. Benz. 1991. Responses of Thompson Seedless
grapevines trained to single and divided canopy trellis systems to nitrogen
fertilization. In International Symposium on Nitrogen in Grapes and Wine. J.M.
Rantz (Ed.), pp. 282-289. Seattle, WA.

Jenkinson, D.S. 2001. The impact Of humans on the nitrogen cycle, with focus on
temperate arable agriculture. Plant Soil 228:3-15.

Lohnnertz, 0. 1991. Soil nitrogen and the uptake of nitrogen in grapevines. In
International Symposium on Nitrogen in Grapes and Wine. J .M. Rantz (Ed.),
pp. 1-11. Seattle, WA.

Mahli, S.S., M. Nyborg, and ED. Solberg. 1996. Influence of source, method of

placement and simulated rainfall on the recovery of 15N-labelled fertilizers
under zero tillage. Can. J. Soil Sci. 76:93-100.

l7

Newbould, P. 1989. The use of fertiliser in agriculture. Where do we go practically and
ecologically?. Plant Soil 115:297-311.

Partridge, N.L. and J .0. Veatch. 1931. Fertilizers and soils in relation to Concord grapes
in southwest Michigan. Michigan State University Ag. Exp. Station Technical
Bulletin No. 114.

Peacock, B., P. Christensen, and D. Hirschfelt. 1996. Best Management Practices for
Nitrogen Fertilization of Grapevines. Univ. of Calif. Coop. Ext.. Publication #
NG4-96.

Peacock, W.L., F .E. Broadbent, and LP. Christensen. 1982. Late-fall nitrogen
application in vineyards is inefficient. Calif. Agric. 36:22-23.

Peacock, W.L., L.P. Christensen, and F .E. Broadbent. 1989. Uptake, storage, and
utilization of soil—applied nitrogen by ‘Thompson Seedless’ as affected by time
of application. Amer. J. Enol. Vitic. 40:16-20.

Pellett, HM. and J.V. Carter. 1981. Effect of nutritional factors on cold hardiness of
plants. Hort. Rev. 3:144-171.

Prasad, R. and IF. Power. 1997. Soil fertililty management for sustainable agriculture.
Lewis Publishers, New York.

Reddy, GB. and KR. Reddy. 1993. Fate of nitrogen-15 enriched ammonium nitrate
applied to corn. Soil. Sci. Soc. Amer. J. 57:111-115.

Retamales, J .B. and E.J. Hanson. 1989. Fate of 15N-labeled urea applied to mature
highbush blueberries. J. Amer. Soc. Hort. Sci. 114(6):920-923.

Roubelakis-Angelakis, K.A. & W.M. Kliewer. 1992. Nitrogen metabolism in grapevines.
Hortic. Rev. 14:407-452.

Schaller, K. 1991. Ground water pollution by nitrate in Viticultural areas. In
International Symposium on Nitrogen in Grapes and Wine. J.M. Rantz (Ed.),
pp. 12-22. Seattle, WA.

Smart, RE. 1991. Canopy microclimate implications for nitrogen effects on yield and
quality. In International Symposium on Nitrogen in Grapes and Wine. J.M.
Rantz (Ed.), pp. 90-101. Seattle, WA.

Tran, ST. and M. Giroux. 1998. Fate of 15N-labelled fertilizer applied to corn grown on
different soil types. Can. J. Soil Sci. 78:597-605.

18

van Zyl, J .L. 1988. Response of grapevine roots to water regimes and irrigation systems.
In The grapevine root and its environment. J .L. van Zyl (Ed.) pp. 30-43.
Republic of So. Afiica Dept. Agr. and Water Supply, Stellenbosch, So. Africa.

Wample R.L., S.E. Spayd, R.G. Evans, and R.G. Stevens. 1991. Nitrogen fertilization
and factors influencing grapevine cold hardiness. In International Symposium
on Nitrogen in Grapes and Wine. J.M. Rantz (Ed.), pp. 120-125. Seattle, WA.

Wample R.L., S.E. Spayd, R.G. Evans, and R.G. Stevens. 1993. Nitrogen fertilization
of ‘White Riesling’ grapes in Washington: nitrogen seasonal effects on bud cold
hardiness and carbohydrate reserves. Amer. J. Enol. Vitic. 44(2): 159-167.

Weinbaum, S.A., R.S. Johnson, and TM. DeJong. 1992. Causes and consequences of
over fertilization in orchards. HortTechnology. 2:112-121.

Werrnelinger, B. 1991. Nitrogen dynamics in grapevine: physiology and modeling. In
International Symposium on Nitrogen in Grapes and Wine. J .M. Rantz (Ed.),
pp. 23-31. Seattle, WA.

Williams, LE. 1987. Growth of ‘Thompson Seedless’ grapevines: H. nitrogen
distribution. J. Amer. Soc. Hort. Sci. 112(2):330-333.

Williams, LE. 1991. Vine nitrogen requirements-utilization of N sources from soils,
fertilizers, and reserves. In International Symposium on Nitrogen in Grapes and
Wine. J.M. Rantz (Ed.), pp. 62-66. Seattle, WA.

Winkler, A.J., J .A. Cook, W.M. Kliewer, and LA. Lider. 1974. General viticulture.
University of California Press, Berkley.

19

EFFECT OF THE TIMING OF NITROGEN APPLICATION ON SOIL
NITROGEN AND NITROGEN USE EFFICIENCY OF VITIS LABRUSCA IN A
SHORT-SEASON REGION

INTRODUCTION

Nitrogen (N) accumulation and movement in woody plants is a dynamic process
that is difficult to quantify because N accumulates and is retained in the tissues of
perennial plants over multiple seasons. The pattern of N accumulation in grapevines
during the growing season has been studied in many Viticultural regions (Conradie 1980;
Hanson and Howell 1995 ; Lohnertz 1991; Williams 1991). Nitrogen is the most
commonly applied fertilizer amendment to vineyards (Christensen et a1. 1978), yet little
is known about the optimal timing of field applications, especially in short-season areas.
Fertilization recommendations for vineyards range from pre-budbreak applications
(Cahoon et al. 1991; Funt et al. 1997; Winkler et a1. 1974); applications from budbreak to
bloom (Bates 2001; Hanson 1996; Wolf and Poling 1995); or any time after budbreak
until fi'uit set, or a post-harvest application in Sept (Peacock et al. 1996). Regardless of
the region, the most commonly recommended time for N application to vineyards is at
budbreak.

The patterns of N accumulation by Vitis labrusca L. ‘Concord’ have been
described in the short-season regions of Michigan (Hanson and Howell 1995) and New
York (Bates et al. 2002). The most rapid accumulation of N by the grapevines in the
study by Hanson and Howell (1995) was from 2 weeks prior to bloom until fruit harvest.
Sequential destructive vine harvests by Bates et a1. (2002) showed that 85 % of the total N

accumulated by the 3 year-old ‘Concord’ vines in the growing season occurred from

20

bloom to veraison. A similar pattern of N accumulation was observed in mature V.
vinifera ‘Riesling’ in Germany (Lohnertz 1991). Conradie (1986) found that the most
rapid absorption of N by potted vines of ‘Chenin blanc’ occurred from the end of rapid
shoot grth until fruit harvest.

Labeled 15N fertilizers are usefirl to investigate N use efficiency (NUE), which is
the percentage of applied fertilizer N absorbed by grapevines. NUE of grapevines has
varied considerably among lsN field studies. Hanson and Howell (1995) found that
‘Seyval blanc’ vines absorbed 7% of N applied at budbreak and 11% of N applied at
bloom. Williams (1991) reported a higher NUE for N applied to irrigated ‘Thompson
Seedless’ vines in California. May applications of N to vines that were furrow or drip
irrigated resulted in a NUE of 14% and 42%, respectively.

The optimum time for N application may vary with region. South African studies
(Conradie 1980; 1991) indicate that post-harvest applications of N are efficient, because
up to 34% of the total N absorbed by ‘Chenin blanc’ occurred after fruit harvest. A study
in California (Peacock et al. 1989) reported that vines utilized July and September (post-
harvest) applications of N more efficiently than March (budbreak) applications. Late
season or post-harvest applications of N are assumed to be less effective in short-season
regions, where there is often a short period of active canopy following fruit harvest
(Bates et al. 2002, Hanson and Howell 1995; Lohnertz 1991).

Vineyard fertilization practices have been linked to increased levels of nitrate in
surface and groundwater in Germany (Schaller 1991). This is presumably due to the low
NUE of grapevines, which results in a large portion of the fertilizer N being left in the

soil. The mobility of fertilizer N in vineyards has been investigated by tracing the fate of

21

N fertilizers applied in the spring to drip irrigated ‘Thompson Seedless’ vines in
California (Hajrasuliha et al. 1998). By late September 57% of the applied N was still in
inorganic forms of N in the soil and 16% was organic N. Throughout the course of the
growing season, there was considerable movement of fertilizer N through the soil profile
and fertilizer N was found at the deepest sampling depth (2.4 m) when the vines were
excavated.

The majority of the N research with grapevines has been done in long-season
regions with V. vinifera varieties. The application of this information to short-season
Viticultural regions may be limited because of the critical difference in the duration of
active vine canopy after fruit harvest. Few studies have addressed these issues in short-
season regions or have looked into the N dynamics of V. labrusca, which is the
predominantly grown species in these areas. There has also been little investigation on
the fate of the substantial portion of fertilizer N that is not used by grapevines or how the
time of N application impacts the persistence of the fertilizer N in the soil. The following
studies were performed with V. labrusca to investigate how the time of N application in a
short-season region, Michigan, affects NUE of the grapevines and the fate of fertilizer N

that is not used by the vines.

22

MATERIALS AND METHODS

These studies were conducted in 1990 plantings of Vitis Iabrusca L. ‘Concord’
and ‘Niagara’ located at the Southwest Michigan Research and Extension Center, Benton
Harbor, Michigan. Vines were Spaced at 3.0 In between rows and 2.1 m between vines
(1555 vines/Ha) in a Spinks loamy fine sand. The grapevines were trained to the Hudson
River umbrella system, and were annually balance pruned to retain 44 nodes/kg of cane
prunings, up to a maximtun of 65 nodes per vine.

Study 1: ‘Niagara’. In 2001, 24 V. labrusca ‘Niagara’ vines were selected and
arranged in a randomized complete block design, and were blocked with 6 replications
according to vine pruning weights. The treatments consisted of applications of 124.4 g of
double-labeled 15NH415N03 (43.5 g N/vine or 67.6 kg N/Ha) at 15 atom percent 15N.
Single vines were treated at one of four times: budbreak (30 April); bloom (8 June); 3
weeks post-bloom (3WPB) (30 June); and six weeks post-bloom (6WPB) (18 July). The
fertilizer was dissolved in 10 L water and applied evenly with a backpack sprayer to a 3.0
by 2.1 m area surrounding the vine. The vineyard was irrigated with 2.5 cm of water
following each fertilizer application and at 2-week intervals there after. Between
fertilizer and irrigation applications, the vineyard floor was covered with clear plastic to
exclude rainfall. A one-vine minimum buffer was maintained between all treated vines.
Vines buffering the treated vine were not fertilized during 2001.

Fruit was harvested and weighed on 11 Sept. Above ground vine tissues were
removed prior to leaf senescence on 27 Sept. Roots were removed with a backhoe on 1
and 3 Oct by excavating the 3.0 by 2.1 m area of the vine space to a depth of 45 cm. The

soil was sifted through a 1 by 1 cm wire screen to remove the roots. Roots were rinsed

23

with water to remove attached soil. Vine tissues were separated into five categories:
fruit; leaves; shoots; trunk (non-root woody tissue from above and below ground); and
roots.

The vegetative tissues were shredded in a brush chipper, immediately weighed,
and the chipper was cleaned between samples. A representative sample of ~10% of the
total fresh weight was dried at 37°C in a forced air oven until there was no change in
mass. Dry root, shoot, and trunk samples were ground separately in a Wiley Mill to pass
through a 2 mm screen. Leaf samples and the previously ground root, shoot, and trunk
samples were then ground separately in a Wiley Mill to pass through a 0.3 mm screen.
Berry samples were taken randomly from the harvested clusters, weighed, freeze dried,
and re-weighed to determine dry matter, and then ground in a small coffee grinder.

Soil samples were taken from each of the treated vine spaces during the root
excavations at depths of 0 to 45 cm and 45 to 90 cm. Each sample was ground with a
mortar and pestle and a Kjeldahl digestion was performed on each sample to determine
soil N content.

Total N and 15N content in the tissues and soils were determined with a Europa
Scientific Tracer Mass (Crewe, England) mass spectrometer. Natural abundance of 15N
for vine tissues and soil was determined via mass spectrometry on leaf and soil samples
from untreated areas of the vineyard (0.368 and 0.386, respectively). The amount of
tissue and soil N that was derived from the fertilizer was calculated using the mass
spectrometry values and natural abundance of ‘5 N, according to Cabrera and Kessel

(1989). The partitioning of fertilizer N within the grapevines was calculated by dividing

24

the fertilizer N in the various vine tissues by the total amount of the fertilizer N absorbed
by the vines.

Bulk density measurements were obtained by weighing dried soil cores taken to a
depth of 90 cm at 6 sites within the vineyard. Soil volume of the vine space at a given
depth was calculated by multiplying the vine space area (2.1 by 3.0 m) by the sampling
depth. Soil mass of the vine space for a given sample depth was calculated by
multiplying the soil volume by the soil bulk density (1.5 g dry soil/cm3). Soil N levels
within the vine space were calculated by dividing the soil mass of the vine space by the
sample weight, and then multiplying by the total N and fertilizer N levels from the soil
samples. Grapevine dry matter was calculated by multiplying the percent dry matter of
the samples, by the total fresh weight of the vine tissue. Nitrogen levels in the vine
tissues were calculated by multiplying the percent N of the mass spectrometry samples,
by the dry weight of the vine tissues. Conversions of the soil and vine N levels to a Ha
basis were made by multiplying the single vine data by the planting density of 1555
vines/Ha.

Due to questions raised about the effect of plastic mulch on soil temperatures and
vine nutrient uptake in Study 1, thermocouples were buried in 2002 at depths of 5, 15,
and 45 cm at four sites in the ‘Niagara’ vineyard. Two Sites were covered with a 3 by 3
m section of 5 mil clear plastic mulch. The other two sites were left uncovered.
Temperature measurements were recorded at ~143O hr throughout the 2002 growing
season.

Study 2: ‘Concord’. This study was conducted in 2002 in a block of frost

irrigated V. labrusca ‘Concord’, because the ‘Niagara’ vineyard sustained fi'ost damage.

25

Vines of equal vigor and bud survival were selected and arranged in a completely
randomized design. Treatments consisted of a N application at either budbreak (14 May),
bloom (19 June), or 6WPB (29 July). Each treatment was replicated on 7 vines in a
completely randomized design. Groundcover in and directly around the treated vine
space was killed prior to budbreak with glyphosate herbicide, and sprayed periodically
during the season to maintain a vegetation-free vine space. Fertilizer application
materials, rates, and methods were the same as in Study 1, except that the fertilizer was
enriched to 9% atom 15N and 43.8 g of actual N was applied per vine (68.1 kg N/Ha).
Vines bordering the treated vines were not fertilized during the 2002. Plastic was not
placed over the soil. Immediately following each fertilizer application, 2.5 cm of
irrigation was applied with solid-set sprinklers. Additional irrigation was applied in the
season during a drought period on 22 July, and on 19 and 21 May to protect developing
buds during freezing temperatures.

Fruit and above ground vine tissues were harvested on 24 Sept and 1 Oct,
respectively. Vine tissues were harvested, segregated, and sub-sarnpled as in Study 1.
Roots were excavated on 8 and 10 October. Half of the vine spaces of three vines were
excavated to a depth of 90 cm in order to compare the root recovery in the top 0.45 m of
soil to that of 45 to 90 cm. Vine tissues in Study 2 were first weighed, shredded, and then
sampled and processed as in Study 1.

Leaves were harvested from three shoots per vine from three of the grapevines
adjacent to three of the treated vines (one fiom each treatment) to quantify the amount of
fertilizer N that was taken up by the bordering vines. The bordering vines that were

sampled were not adjacent to any other treated vines in the plot. The amount of leaf N

26

derived from the fertilizer for the buffering vines was calculated the same as the treated
vines.

Soil samples were taken at depths of O to 60 cm and 6 to 90 cm when the roots
were excavated. These samples were processed and analyzed as in Study 1 except the
mass spectrometry was done at the UC Davis Stable Isotopes Facility. Only three
replications of the 60 to 90 cm soil samples were analyzed for 15N content.

Soil was collected at 1, 15, 29, and 43 days after each fertilizer treatment by
removing four 1.8 cm diameter cores per plot, representing four depths: 0 to 15.3 cm;
15.3 to 30.5 cm; 30.5 to 45.8 cm; and 45.8 to 61.0 cm. Sampling of the soil profile was
accomplished by pushing the soil probe to a depth of 61 cm and then dividing the soil
core into quarters. Soil was dried at 37°C and inorganic N in the soil samples was
quantified by extracting 15 g of soil with 75 ml of 1N KCL. The soil-KCL solution was
agitated at 180 revolutions/minute for 45 minutes. The soil solution was filtered with
Whatrnan #2 filter paper that had been previously soaked in de-ionized water and dried.
All soil extracts and Kj eldahl digestions were analyzed at the Soils Testing Laboratory of
Michigan State University.

Experimental Analysis. The experimental model in Study 1 was a randomized
complete block design with 6 replications. Both Study 1 and 2 were analyzed using SAS
statistical analysis software (Cary, North Carolina). A two-factor analysis of variance
was used to analyze Study 1 with time of N application being the treatment, and pruning
weights being the blocking factor. Study 2 was a completely randomized design with 7

replications, analyzed with a one factor analyses of variance, with the time of N

27

application being the treatment. When treatment effects were significant at P 0.05,

means were separated by a Fisher’s Least Significant Differences (LSD) test at P= 0.05.

28

RESULTS

Study 1: ‘Niagara’. Cool, cloudy weather during bloom in 2001 limited the fruit
set and yield from the ‘Niagara’ vines. Vine yields were extremely variable and averaged
1.6 t/Ha across all plots. Time of N application had no effect on the total dry matter of
the grapevines (P=0.30) (Figure 1). Root dry matter (P=0.0034) was higher in the 3WPB
and 6WPB treatments than in the earlier two treatments. Trunk dry matter (P=0.057) and
fruit dry matter (Table 1) were affected by the time of N application at only a 90%
confidence level.

The total N content of the grapevines was not affected by the time of N
application (P=0.46). Total N in the roots was higher in the 6WPB treated vines than the
Budbreak and Bloom treatments (P: 0.012). The total N in the fruit (P=0.060) was
affected by the treatments at only a 90% confidence level (Table l).

Vines recovered the equivalent of 10.6, 11.8, 12.1, and 12.6 kg/Ha of fertilizer N
when fertilized at budbreak, bloom, 3WPB, and 6WPB, respectively (Figure 1).
Although these data might suggest a trend of increasing NUE with the later application
time, the data were extremely variable and NUE was not Significantly affected by the
time of N application (P=0.58). Linear regression analysis using days after the Budbreak
treatment as the independent variable and total fertilizer N in the vines as the dependent
variable, was also not significant (P=0.15). The NUE for the study ranged fi'om 15.7%
(Budbreak) to 18.6% (6WPB). When looking at specific tissues within the vines, there
was a significantly higher amount of fertilizer N in the root tissue (P=0.0018) of the

6WPB treated vines than the other treatments. The fertilizer N content of the fi'uit

29

(P=0.015) was significantly higher in the vines of the Budbreak treatment than with the
later N applications.

The partitioning of fertilizer N into vine parts, expressed as a percentage of total
vine fertilizer N, was also affected by the time of application (Figure 2). A higher
proportion of fertilizer N was partitioned to the fi'uit of vines fertilized at budbreak
(P=0.016) than any other treatments. The partitioning of fertilizer N to the leaves was
higher in the Budbreak and Bloom treatments than 6WPB (P=0.0085). Roots from the
6WPB treated vines had a higher percentage of fertilizer N (P=0.0029) partitioned to
them than did the other treatments.

At the end of the season more fertilizer N remained in the top 45 cm soil from the
3WPB treatment than the Budbreak and Bloom treatments (Table 2). Timing of N
application did not affect fertilizer N levels in the 45 to 90 cm soil depth. The total
amount of fertilizer N remaining in the 0 to 90 cm soil profile in Oct was 29, 35, 44, and
39% of the amount applied at budbreak, bloom, 3WPB, and 6WPB, respectively.

Soil temperatures were consistently higher in the plots that were covered with
plastic. The mean soil temperatures for the plotted dates were 5.4, 2.6, and 1.7°C higher
under the plastic than the non-plastic covered soil, for the respective 5, 15, and 45 cm
depths (Figure 3).

Study 2: ‘Concord’. The ‘Concord’ vines in 2002 produced more typical yields
(overall mean 11.7 t/Ha). The dry matter content of the whole vines or individual vine
tissues were not significantly affected by the time of N application (Figure 4), except for

the root dry matter (P=0.074), which was only affected by the treatments to a 90%

30

confidence level. Excavation of roots to a depth of 90 cm showed that 94.7% i 2.5 of the
roots that were recovered were in the top 45 cm of soil.

The total N content of roots was higher in the vines treated at bloom than those
treated at budbreak (P=0.041). Total N of the fruit was affected by the time of N
fertilizer application at a 90% confidence level (Table 3).

Vines recovered more fertilizer N when applied at bloom (11.4 kg/Ha) and 6WPB
(10.1 kg/Ha), that when fertilized at budbreak (6.7 kg/Ha) (Figure 4). NUE was
significantly higher in the Bloom and 6WPB treatments (16.7 and 14.8%) than in the
Budbreak treatment (9.8%) (P 0.0001). Fruit contained more fertilizer N when the vines
were treated at budbreak and bloom as compared to the 6WPB treatment (P=0.023).
Budbreak applications resulted in significantly less fertilizer N in the roots than Bloom or
6WPB applications (P 0.0001). The amount of fertilizer N in the leaves was only
significantly affected by the treatments to a 90% confidence level (P=0.074). The N
treatments did not significantly affect juice soluble solids, pH, or titrable acid levels of
the fruit (overall means: 16.5 Brix, P=O.81; 3.5 pH, P=0.68; 0.35 TA, P=0.55).

The percentage of fertilizer N partitioned to the fi'uit of the vines was highest in
the Budbreak treatment and lowest in the 6WPB treatment (P 0.0001) (Figure 5).
Leaves from the vines treated at budbreak had a higher proportion of fertilizer N than
those fiom the other treatments (P=0.0037). Fertilizer N was partitioned more to roots in
the Bloom and 6WPB treatments than the Budbreak treatment (P=0.0009).

The vines adjacent to the treated vines absorbed fertilizer N. The N from
fertilizer in the leaves of the buffer vines was 8, 9, and 36% of the average 15N fertilizer

enrichment of the leaves fi'om all the treated vines, for the vines straight across the row,

31

diagonally across the row, and in the same row adjacent to the treated vines, respectively
(Figure 6).

Later N applications resulted in higher fertilizer N levels remaining in the soil in
Oct (Table 4). Fertilizer N levels in the 0 to 60 cm depth of soil were highest in the
6WPB treatment and lowest in the Budbreak treatment. Fertilizer N levels in the 60 to 90
cm depth of soil were low enough to possibly impair the ability of mass spectrometry to
precisely quantify N and 15N levels, although there still appears to be more fertilizer N in
the 6WPB treatment than the Budbreak treatment. In Oct, the sampled soil profile
contained 13, 35, and 61% of the fertilizer N applied at budbreak, bloom, and 6WPB,
respectively.

Inorganic levels of N were variable in the soil samples following the fertilizer
applications (Figure 7). The day after fertilization there was a high proportion of
ammonium N to nitrate N in the soil of all the treatments, as compared to the later
sampling dates. In the Budbreak and 6WPB treatments, inorganic levels of N rapidly
declined 2 weeks after the fertilizer application. High levels of inorganic N were
measured the longest in the vineyard soil of the vines that were fertilized at bloom.

Vines treated at budbreak received more precipitation during the 15 days after N
application (9.5 cm), than the Bloom (3.3 cm) and 6WPB (6.2 cm) treatments (Figure 8).
Forty-three days after each of the fertilizer applications the vines treated at budbreak,

bloom, and 6WPB had received 19.3, 14.0, and 18.0 cm of precipitation, respectively.

32

Table 1: Effect of time of nitrogen (N) application on
dry matter, fertilizer N, and total N in the hit of
individual 'Niagara' vines from Study 1 in 2001.

 

 

Time of N glvino

Application Dry Matter Firmizor N Total N
Budbreakz 440 0.45 ay 4.4
Bloom 130 0.16 b 1.7
3WPB 150 0.10 b 1.6
6WPB 100 0.07 b 1.3
P-value 0.057 0.016 0.060

 

zBudbreak= 30 April; Bloom= 8 June; 3WPB= 30 June;
6WPB= 18 July

’means within columns followed by a different letter are
signifcantly different by LSD (P=0.05).

33

Table 2: Effect of time of nitrogen (N)
application (67.6 kg N/Ha) on the amount
of fertilizer N remaining in the soil in Oct,
for Study 1 'Niagara' 2001

 

 

 

Time of N Fertilizer N (kg/Ha)
Application 045 cm 45-90 cm
Budbreakz 11.2 by 8.4
Bloom 11.5 b 12.1
3WPB 21.1 a 8.5
6WPB 15.0 ab 11.7
p-value 0.02 0.75

 

zBudbreak= 30 April; Bloom= 8 June;
3WPB= 30 June; 6WPB= 18 July
’means within columns followed by a different

letter are signifcantly different by LSD (P=0.05).

34

Table 3: Effect of time of nitrogen (N) application on
dry matter, fertilizer N, and total N in the Mt of
individual 'Concord' vines from Study 2 in 2002.

 

 

Time of N glvine

Application Dry Matter Fertilizer N Total N
Budbreakz 1730 0.69 a" 14.9
Bloom 1550 0.71 a 11.8
6WPB 1250 0.36 b 10.3
P-value 0.137 0.023 0.077

 

zBudbreak= 14 May; Bloom= 19 June; 3WPB= 29 July
' means within columns followed by a different letter are
signifcantly different by LSD (P=0.05).

35

Table 4: Effect of time of nitrogen (N)
application (68.1 kg N/Ha) on the amount
Of fertilizer N remaining in the soil in Oct,
for Study 2 'Concord' 2002

 

 

 

Time of N Fertilizer N (kg/Ha)
Application 0-60 cm 60-90 cm
Budbreakz 6.4 c” 2.4 by
Bloom 20.1 b 3.8 ab
6WPB 32.8 a 8.6 a
p-value 0.0007 0.046
zBudbreak= 14 May; Bloom= 19 June;

3WPB= 29 July

’means within columns followed by a different
letter are signifcantly different by LSD (P=0.05).

36

 

15

A. Fertilizer N

 

 

 

 

 

_l
0

knga (X1000)

U1

 

 

 

Budbreak Bloom 3WPB 6WPB
Time of Application

I Roots D Trunk I Shoots El Leaves I Fruit

Figure 1: Effect of time of N application to
‘Niagara’ vines in 2001, Study 1, on (A)
fertilizer N absorbed by the vines, (B) total N in
the vines, and (C) dry matter of vines at the end
of the season. Lower case letters represent
differences (LSD P=0.05) in the same vine
organs. Budbreak= 30 April; Bloom= 8 June;
3WPB= 30 June; 6WPB= 18 July.

37

Fertilizer N in \fines (%)

 

 

 

Budbreak Bloom 3WPB 6WPB

Tune of Application
I Roots Cl Trunk I Shoots El Leaves I Fruit

Figure 2: Effect of time of N application on the
partitioning of fertilizer N in ‘Niagara’
grapevines at the end of the season in 2001,
Study 1. Letters represent separation of
treatment means of the same vine organs (LSD
P=0.05). Budbreak= 30 April; Bloom= 8 June;
3WPB= 30 June; 6WPB= 18 July.

38

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O

 

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40 *
4" \ ,g
30 + lv—r’r ‘0’ .
20 ""
10
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Temperature (°C)
N w #-
o c:

9 5:
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‘T0
A
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'0
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l
l
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May June July
Date

- O - Control —0— Plastic
Figure 3: A comparison of soil temperatures at
depths of (A) 5, (B) 15, and (C) 45 cm at ~1430
hr under existing sod groundcover (control) or 5
mil plastic installed on 06 May. Data points
represent the mean of 2 observations

39

 

15

_ A. Fertilizer N

 

 

 

_ B. Total N

 

  

kgIHa (X1000)

 

 

Budbreak Bloom 6WPB
Tlme of Application

I Roots D Trunk I Shoots El Leaves I Fruit

Figure 4: Effect of time of N application to
‘Concord’ vines in 2002, Study 2, on (A)
fertilizer N absorbed by the vines, (B) total N in
the vines, and (C) dry matter of vines at the end
of the season. Upper case letters and lower case
letters represent differences (LSD P=0.05) in the
whole vine and vine organs, respectively.
Budbreak= 14 May; Bloom= 19 June; 6WPB=
29 July.

40

Fertilizer N in \fines (%)

 

 

 

Budbreak Bloom 6WPB
Time of Application

I Roots El Trunk I Shoots l:l Leaves I Fruit
Figure 5: Effect of time of N application on the
partitioning of fertilizer N in ‘Concord’
grapevines at the end of the season in 2002,
Study 2. Letters represent separation of
treatment means of the same vine organs (LSD
P=0.05). Budbreak= 14 May; Bloom= 19 June;
6WPB= 29 July.

41

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--~~-o Budbreak: Inorganic N --o-~ Budbreak: Nitrate N

——o— Bloom: Inorganic N + Bloom: Nitrate N
—-0-- 6WPB: Inorganic N —I - 6WPB: Nitrate N

Figure 7: Inorganic N (NH; and N03) and nitrate
N at 1, 15, 29, and 43 days following each
fertilizer application in the soil profile at (A) 0-
15.3 cm (B) 15.3-30.5 cm (C) 30.5-40.8 cm (D)
40.8-61.0 cm in vineyard soil of ‘Concord’ in
2002, Study 2. Bars represent standard error and
* denotes the time of fertilizer application at
Budbreak= 14 May; Bloom= 19 June; 6WPB=
29 July, respectively.

43

N
O

 

Precipitation (cm)
a 3.

01
l

 

 

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1 15 29 43
Days After Fertilization

I Budbreak 1:] Bloom B 6WPB
Figure 8: Accumulated rainfall and irrigation for
each fertilizer treatment on the soil sampling
dates following each fertilizer application in 2002
during Study 2 at the Southwest Michigan
Research and Extension Center, Benton Harbor,
MI. Budbreak= 14 May; Bloom= 19 June;
6WPB=29 July.

44

DISCUSSION

There was a trend for N applications later than budbreak to be taken up by the
vines more efficiently, this was most evident in Study 2 with ‘Concord’. This general
trend was also seen in Study 1 with ‘Niagara’ vines, but was not significant due to a large
variability of the vines. More efficient absorption of N applications later than budbreak
has been Shown in other studies. Hanson and Howell (1995) found that applications of N
at budbreak to ‘Seyval blanc’ had a 7% NUE while vines treated at bloom had a 11%
NUE, though the difference in NUE was not significant. Peacock et al. (1989) concluded
that in California vineyards, budbreak N applications were not absorbed by vines as
efficiently as July and Sept (post-harvest) applications.

There are several reasons why N applied at bloom and post-bloom may be taken
up by vines more effectively than N applied at budbreak. Budbreak applications of N in
some regions are more prone to leaching due to precipitation patterns (Conradie 1980;
Peacock et al. 1991). Twenty to 40% of N used for grapevine growth from budbreak to
bloom is mobilized from perennial vine structures (Conradie 1980; 1986; Lohnertz 1991;
Schaller 1989 cited in Werrnelinger 1991; Williams 1991). Mobilization of N from
perennial structures of the vine prior to bloom is independent of soil N levels (Lohnertz
1991; Werrnelinger 1991). Low soil temperatures early in the growing season can impair
the uptake of N by woody plants (Dong et al. 2001). Conradie (1991) reported that
grapevine root absorption of nutrients was initiated when soil temperatures reached 10°C.

The documented N accumulation pattern for ‘Concord’ in short-season
Viticultural regions (Bates et al. 2002; Hanson and Howell 1995) supports the findings

that applications of N from bloom to 6WPB will be used by the vines more efficiently

45

 

than budbreak applications. According to Bates et al. (2002), 85% of the N absorbed in
the season occurred from bloom to veraison. Hanson and Howell (1995) found over 80%
of N absorption occurred between bloom and fruit maturity.

Plastic mulch in the vineyard raised soil temperatures prematurely in the growing
season (Figure 3). At early stages of growth, apple trees at the same phenological stage
absorbed significantly more N when the rooting zone was at a higher temperature (Dong
et al. 2001). High soil temperatures under the plastic may have stimulated N uptake to
begin earlier in the season in Study 1 than normal, and may have increased uptake of
fertilizer applied at budbreak. This effect may have lessened the effect of the time of N
application on the NUE of the grapevines in Study 1. The impact of plastic mulch, in
addition to cultivar and weather differences, may have caused the lack of large
differences in NUE between the treatments in Study 1 as compared to the treatment
differences within Study 2.

Inorganic N levels drop off rapidly following N applications (Figure 7). The
inorganic N levels of the soil and precipitation accumulation (Figure 8) following the
fertilizer applications do not accurately explain the differences in vine and soil recovery
of fertilizer N. Lohnertz (1991) reported that vine N status can not be predicted by soil
inorganic N levels. High levels of inorganic N were recorded following the N application
at bloom, but fertilizer N recovery in the vines was not higher than the 6WPB
applications, where inorganic N levels dropped of rapidly after the fertilizer application
(Figure 7). Inorganic N levels drop off rapidly after fertilization at 6WPB and budbreak,
but when N applications were applied at 6WPB, fertilizer N was recovered by vines more

efficiently than at budbreak. Thus the low NUE of N applied at budbreak is most likely

46

due to limited ability of the vines to absorb N at budbreak and not solely because of low
inorganic N levels or by precipitation following the fertilizer application.

Fruit from the vines fertilized at budbreak contained more fertilizer N than the
6WPB treatments for both Study 1 and 2 (Figures 1 and 4). The percent of the fertilizer
N partitioned to the fruit also followed this pattern (Figures 2 and 5). The higher
allocation of fertilizer N to the fruit from the early N applications could be related to a
need for N in the growth of clusters early in the growing season. Conradie (1986)
reported that the major sink of N absorbed by the vines from the end of bloom until the
end of rapid shoot growth was the fruit clusters. Hanson and Howell (1995) reported no
difference between partitioning of fertilizer N to fruit from N applied at budbreak and
bloom.

The percent of absorbed fertilizer N partitioned to the leaves was lower with the
later application times in both Study 1 and 2 (Figures 2 and 5). A similar pattern was
reported by Conradie (1991) where at fruit harvest, a higher proportion of spring
absorbed N (30%) was partitioned to leaves than summer absorbed N (22%). Data from
Hanson and Howell (1995) do not correspond to this trend, where applications of N at
bloom resulted in more fertilizer N in the leaves than budbreak applications to ‘Seyval
blanc’.

When N was applied at budbreak there was less fertilizer N in the roots, than with
the 6WPB applications (Figures 1 and 4). The percent of fertilizer N absorbed, that was
partitioned to the roots was also lower for the N applied at budbreak than for N applied
6WPB (Figures 2 and 5). These trends did not occur in the study on ‘Seyval blanc’ by

Hanson and Howell (1995). Conradie (1986) concluded that late N applications (post-

47

harvest) in the long-season region of South Afiica resulted in preferential allocation of
the fertilizer N to perennial storage structures of the grapevines. Data fiom this study
suggest that the storage of N reserves begins earlier in the season in short-season regions.

Overall these data indicate that N applied early in the growing season in Michigan
to V. labrusca is allocated towards annual vine tissues (leaves and fruit), whereas the N
from the later applications is preferentially allocated to roots of the grapevines, which
may increase N reserves within the vine.

When N was applied later in the season, there was a higher amount of total N in
the roots, which is likely due to increased root grth from the vines that had N applied
to them later in the season (Figures 1 and 4). In Study 1, there were significantly higher
amounts of root dry matter in the 3WPB and 6WPB treatments than the earlier treatments
(Figure 1). There was a similar trend for lower root dry matter in the Budbreak treated
vines in Study 2, but it was only significant to a 90% confidence level (P=0.074).
Similarly, less root dry matter was previously reported (Hanson and Howell 1995) for
vines that received N at budbreak than those fertilized at bloom. According to Comedic
(1986), applications of N that lead to more N in the perennial structures of the vine are
more important that those that allocate N to the annual structures because of the large
impact these have on N reserves that influence the following season’s growth. It is
unknown what affects increased amounts of N and dry matter accumulation in the roots
of the vines in these studies will have on long term vine growth.

Later applications of N are likely to have more of the fertilizer N in the soil
because the fertilizer N had less time to leach from the sampled soil profile by the time

the vines were excavated in Oct (Tables 2 and 4). However there are other possible

48

 

explanations for the difference in retention of fertilizer N in the soil. Higher amounts of
fertilizer remaining at the end of the season from later applications could be attributed to
higher immobilization of fertilizer N. The low levels of soil inorganic N (Figure 7) six
weeks after the 6WPB fertilizer application (mid-Sept) suggests that the large amount of
fertilizer N remaining in the soil in the 6WPB treatment at vine excavation (early Oct)
would likely be in organic forms. Considerable amounts of N fertilizer applied to citrus
orchards can be quickly integrated with soil organic matter (Weinbaum 1992). It is
unknown if the amount of fertilizer N remaining in the soil in Oct can be correlated to
soil N levels in the subsequent growing season. The soil data from Study 2 are assumed
to be more representative of a normal growing season and terms of soil temperatures and
rainfall events, than with Study 1.

At the sampling times in Sept and Oct, the ‘Niagara’ vines and soil (to a 90 cm
depth) in Study 1 contained 44.7, 52.4, 61.9, and 58.2% (30.2, 35.4, 41.7, and 39.3 kg
N/Ha) of the applied fertilizer N for the Budbreak, Bloom, 3WPB, and 6WPB treatments,
respectively. ‘Concord’ vines and soil in Study 2 contained 22.8, 52.8, and 75.7% of the
applied fertilizer N (15.5, 35.3, 51.5 kg N/I-Ia) for the Budbreak, Bloom, and 6WPB
treatments, respectively.

Hajrasuliha et al. (1998) reported high recoveries (90 to 100%) of spring applied
15 N fertilizer in the above ground portions of the grapevines and soil in late Sept. This
higher recovery rate compared to that of Study 1 and 2 could be attributed to deeper soil
sampling (2.4 m deep) and the method used to apply N (fertigation). Fertilizer N applied
as nitrate had mostly leached to a depth between 1.2 and 1.5 m. Twelve to 19% of the

applied fertilizer N, was converted to organic N and the majority of it was located in the

49

 

top 60 cm of soil. The data from this experiment suggest that much of the N unaccounted
for in our studies may have been leached below the 90 cm sampling depth. The relative
proportion of organic to inorganic forms of fertilizer N at the vine harvest in our studies
is unknown. However, it would be reasonable to expect that a substantial portion of the
fertilizer N in the shallow section of soil in Oct was in organic forms of N.

Vines adjacent to the treated vines in Study 2 recovered considerable amounts of
the fertilizer N (Figure 6). The vines adjacent to the treated vines were not fertilized, and
because they had less available N in their vine space they may have absorbed more
fertilizer N from the 15 N treated vineyard floor. The high levels of fertilizer N adjacent to
the treated vines were comparable to the recovery of fertilizer N by adjacent vines in
Stroehlein et al. (1990). In previous viticulture 15N fertilization experiments investigating
NUE of entire field-grown vines (Hajrasuliha et al. 1998; Hanson and Howell 1995;
Williams 1991), there was no sampling of the vines adjacent to the treated vines.

If the values of the fertilizer recovery of all the adjacent vines were factored into
the total NUE of the fertilizer application (Figure 6), the NUE on a vineyard basis could
be double. This indicates that it is possible to determine relative differences of efficiency
between times of N application by only excavating the treated vines. However, such
estimates are insufficient to determine total NUE of field N applications by sampling
only the treated vines, due to the extensive, spreading grapevine root systems (Perry et
al.1990; Winkler et al. 1974). By sampling only the vines directly fertilized with labeled
fertilizer, there is a low estimation of total vineyard recovery of fertilizer N because

adjacent vine uptake of fertilizer N is not taken into consideration.

50

 

It appeared that more roots were located in the soil of the vegetation free strip
beneath the vines, than in the vegetative row middles. The majority of the roots in Study
2 were in the top 45 cm of soil, with only a small portion (5%) recovered fiom 45 to 90
cm depth of soil. Although vines were excavated only to 45 cm in Study 1, few roots
were observed penetrating below 45 cm. A high proportion of roots of ‘Concord’ vines,
was also found in the top 45 cm of soil by Perry et al. (1983). Approximately 75% of the
root dry matter, sampled to a 75 cm soil depth, was found in the in top 45 cm. Therefore,
fertilizer N that leached below 45 cm would not have been accessible to the roots of the
vines in our studies, since most of them were in the top 45 cm of soil.

Although NUE values for this study were low (9.8 to 18.6% of applied N), they
were higher than those in an earlier study in Michigan, in which ‘Seyval blanc’ vines
recovered 7.1 to 10.6% of applied N (Hanson and Howell 1995). Low values in the
previous study may have resulted from competition for N from the sod vineyard floor,
and the fact that the vines were smaller (6.4 kg dry matter/vine) than those in our studies
(10.4 kg). Williams (1991) reported a similar NUE of 14% for N applies in May to
furrow irrigated vineyards, but 42% recovery for drip irrigated vines. The higher NUE of
the drip-irrigated vines is likely attributed to fertilizing in a more targeted manner to the
root zone.

There was little to no fruit in Study 1 versus an average crop in Study 2, this may
have affected fertilizer N uptake. It is unknown whether the crop level of grapevines
affects N uptake, but our data suggest it is unlikely Since the mean NUE efficiency of
Study 1 (17.3%) was higher than that of Study 2 (13.9%). Another difference between

the studies was that more root dry matter was found in the ‘Concord’ vines in Study 2

51

than with the ‘Niagara’ vines in Study 1 (Figure 1 and 3). Reasons for this are unknown,
but cultivar and vineyard site could have affected the amount of root dry matter. Large
differences in the rooting patterns of different grape cultivars have been previously
reported (Perry et al. 1983).

Nitrogen application rates in mature commercial vineyards in Michigan range
from 0 to 227 kg N/Ha (Tom Zabadal, personal communication). NUE of N applications
is considered to be inversely related to the rate of N application (Weinbaum et al. 1992).
At higher rates of fertilization, more total fertilizer N could be absorbed by the vines, but
the NUE would likely decrease with increasing rates.

The majority of the N in the vines in both studies was not from fertilizer N
applied during the season in which they were excavated. Fertilizer N represented 6.4 to
7.2% of total vine N in the 2001 study with ‘Niagara’ vines, and only 3.6 to 5.4% for
‘Concord’ vines in 2002. Hanson and Howell (1995) report that vigorous, mature
‘Concord’ vines in Michigan absorbed 57 g N/vine (77 kg N/Ha) in a growing season.
This means that the majority of the N accumulated in the vine during a growing season is
not from fertilizer N applied in that season, because the grapevines in our studies only
recovered the equivalent of 6.7 to 12.6 kg N/Ha of the 68 kg N/Ha fertilizer application.
This indicates that native N provided the majority of N absorbed by the vines in our

studies.

52

CONCLUSIONS

These studies indicate that V. labrusca grapevines recover a relatively small
portion of applied fertilizer N (9.8 to 18.6%) under Michigan growing conditions.
Ammonium nitrate applications to ‘Concord’ vines at budbreak were not used as
efficiently by the vines as applications at bloom or six weeks after bloom, therefore
vineyard uptake of fertilizer N may be enhanced by applying N from bloom until six
weeks post-bloom instead of at budbreak. This trend also occurred in ‘Niagara’, but the
N uptake pattern and movement of fertilizer N through the soil may have been affected
by the use of plastic mulch

Both Study 1 and 2 resulted in very consistent patterns of fertilizer N partitioning
patterns within the vines, in spite of both cultivar and seasonal differences between the
two studies. V. labrusca vines fertilized at budbreak allocated significantly more of the
fertilizer N to the reproductive organs (fruit) and leaves, than later applications of N.
Later times of application resulted in more fertilizer N being allocated to the roots of
‘Concord’ and ‘Niagara’ grapevines. Whereas N applied to V. Iabrusca grapevines early
in the growing season is preferentially allocated to the growth of annual tissues (leaves
and fruit), fertilization later in the season (6WPB) resulted in more fertilizer N and more
total N from all sources being allocated to perennial vine structures (roots).

The majority of the fertilizer N (82-90%) that was applied to the vines at a rate of
68 kg N/Ha, was not used by the treated vines in that growing season. Root distribution
data indicate that much of the fertilizer N below the 45 cm depth would not be accessible
to the vines in this study. There were notable treatment differences in the amount of

fertilizer N that remained in the soil. Generally the later applications had more fertilizer

53

N remaining in the soil when the vines were excavated. It is unknown exactly how much
of the fertilizer N in the treated vine spaces was incorporated into soil organic matter and
could be potentially available to vines in subsequent growing seasons. Therefore an
advantage of the Bloom and 6WPB N applications might not only be a higher NUE than

the budbreak applications, but also a higher retention of fertilizer N in the soil.

54

 

LITERATURE CITED

Bates, TR. 2001. Vineyard nutrient management.
http://lenewa.netsync.net/public/Bates/NutrientRec.htm#Chart.

Bates, T.R., R.M. Dunst, and P. Joy. 2002. Seasonal dry matter, starch, and nutrient
distribution in ‘Concord’ grapevine roots. HortScience 37(2):313-316.

Cahoon, G., M. Ellis, R. Williams, L. Lockshin. 1991. Grapes: production,
management, and marketing. The Ohio State University Ext. Bulletin 815.

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56

APPENDICES

57

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Dune

 

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wagon 33.62.. 2:. manage Eggnog 2vo o: 3 Z8. Awe—@9639 5 ago 3523. BE No .75. ax €85 mane £033.

58

Fertilizer Derived N g/vine (% of total in vine)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Niagara 2001
Time of N
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 1.02 (2.3) 0.83 (1.9) 1.26 (2.9) 3.24 (7.4) 0.45 (1.0) 6.81 (15.5)
Bloom 0.99 (2.3) 1.04 (2.4) 1.58 (3.6) 3.84 (8.8) 0.16 (0.4) 7.60 (17.4)
3WPB 1.64 (3.7) 0.99 (2.3) 1.60 (3.6) 3.49 (8.0) 0.10 (0.2) 7.81 (17.8)
6WPB 2.47 (5.6) 0.97 (2.2) 1.45 (3.3) 3.17 (7.2) 0.07 (0.2) 8.13 (18.6)

applied 43.8 g N/vine
Total N g/vine (% of total N/vine)

Niagara 2001
Time of N
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 26.7 (25.3) 19.3 (18.3) 16.6 (16.7) 38.8 (36.7) 4.3 (4.0) 105.7 (100)
Bloom 23.2 (22.1) 20.1 (19.2) 18.6 (17.7) 41.5 (39.5) 1.7 (1 .6) 105.1 (100)
3WPB 36.6 (31.3) 22.4 (19.1) 18.7 (16.0) 37.6 (32.2) 1.6 (1 .3) 116.9 (100)
6WPB 40.0 (33.5) 25.4 (21.3) 16.8 (14.1) 35.8 (30.0) 1.3 (1 .1) 119.4 (100)

Dry Mass kg/vine (% of total dry matter/vine)

Niagara 2001
Time of N
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 1.74 (20.6) 2.51 (29.7)) 2.24 (26.5) 1.51 (17.9) 0.44 (5.2) 8.44 (100)
Bloom 1.65 (19.6) 2.58 (30.6) 2.44 (29.0) 1.60 (19.1) 0.13 (1.6) 8.40 (100)
3WPB 2.34 (25.7) 2.83 (30.9) 2.32 (25.4) 1.49 (16.4) 0.15 (1 .6) 9.13 (100)
6WPB 2.62 (27.8) 3.08 (32.6) 2.19 (23.2) 1.43 (15.2) 0.10 (1.1) 9.43 (100)

 

Appendix 2: Effect of time of N application to 'Niagara' vines in 2001, Study 1, on the
fertilizer N, total N, and dry matter within the vines at the end of the season.
Budbreak=30 April; Bloom= 8 June; 3WPB= 30 June; 6WPB= 18 July.

59

 

Fertilizer Derived N g/vine (% of applied)

 

 

 

 

Concord 2002
Time of N j I _
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 1.09 (2.5) 0.44 (1.0) 0.51 (1.2) 1.6 (3.7) 0.69 (1.6) 4.32 (9.9)
Bloom 3.04 (7.0) 0.56 (1.3) 0.76 (1.7) 2.23 (5.1) 0.71 (1.6) 7.30 (16.8)
6WPB 3.09 (7.1) 0.63 (1.4) 0.73 (1.7) 1.70 (3.9) 0.36 (0.8) 6.51 (15.0)

 

applied 43.5 g vaine

 

Total N g/vine (% of total vaine)

 

 

 

 

 

'Concord 2002
Time of N _ j
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 48.9 (40.2) 17.1 (14.1) 10.4 (8.6) 30.4 (25.0) 14.9 (12.2) 121.5 (100)
Bloom 62.5 (46.2) 15.4 (11.4) 12.2 (9.0) 33.3 (24.6) 11.8 (8.7) 135.3 (100)
6WPB 59.7 (45.8) 16.2 (12.4) 12.0 (9.2) 32.1 (24.6) 10.3 (7.9) 130.2 (100)

 

 

Wy Mass kg/vine (% of total dry matter/vine)

 

 

 

 

Concord 2002
Time ofN j k
Application Roots Trunk Shoots Leaves Fruit Total
Budbreak 3.82 (33.0) 3.16 (27.3) 1.41 (12.2) 1.46(12.6) 1.73 (14.9) 11.58(100)
Bloom 4.97(38.1) 3.17(24.3) 1.73(13.3) 1.61 (12.3) 1.55(11.8) 13.03(100)
6WPB 4.63(38.7) 2.81 (23.5) 1.68(14.0) 1.59(13.3) 1.25(10.5) 11.96(100)

 

Appendix 3: Effect of time of N appliwtion to 'Concord' vines in 2002, Study 2, on the
fertilizer N, total N, and dry matter within the vines at the end of the season.
Budbreak= 14 May; Bloom= 19 June; 6WPB= 29 July.

60

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