The research objectives were the production of compost for transplant root media and managing fertility and disease in vegetable cropping systems. The priorities were on using local organic materials to capture carbon and nutrients, proliferation of beneficial microorganisms and reducing the need for off farm inputs, particularly in an organic certification system. Composts were made and the soluble and total nutrients, electrical conductivity, pH, percent organic matter, the final C:N ratio and bulk density are reported and correlated to the growth of transplants in greenhouse bioassays. In the first experiments (Chapter I), small-scale (1yd3) thermophilic compost piles were constructed with variations in feedstocks to produce ten treatments focused primarily on starting carbon to nitrogen ratios, and the feedstock contributions observed in the physiochemical characteristics of the finished composts. Fall-collected leaves and on-farm fresh cut grass (1:1 v:v) as a base recipe and variations thereof by adjusting volume ratios of those feedstocks, or adding (1:1:1) dairy/horse manure, coffee grounds, shredded office paper, softwood shavings, or sphagnum peat, wrapping the base mix in plastic, and a standard mixture developed and used in previous research. Three species of plants: cucumber (Cucumis sativus), kale (Brassica oleracea), and tomato (Solanum lycopersicum) were grown and evaluated for dry and wet weights, plant heights, root ratings and number of leaves. Growth response in compost substrates were not consistent between species. Composts containing peat as an ingredient had lower pH and generally resulted in better growth of transplants while growth was minimal in wood shavings compost. Cucumber transplants were grown in the composts after storage for 2, 3 or 4 years which identified differences in growth as the compost characteristics had changed over time. A second group of experiments (Chapter II) had the same base feedstocks with the addition of biochar (BC) and anaerobic digester effluent (ADE), on their own and combined. For cucumbers grown in these compost mixes, addition of biochar improved all metrics of transplant growth; in contrast, addition of ADE reduced several metrics of transplant health including shoot dry weight and root ratings. Most of the compost media produced acceptable transplants of varying quality without additional fertility added over the 3 to 5-week greenhouse production period. A laboratory vermicomposting bioassay (Chapter III) was designed to evaluate the effects of pineapple, melon, onion, carrot, spent coffee grounds (SCG) and a mixture of all five kitchen preparation residues from campus food service as vermicomposting feedstocks. Data were collected for the impact on worms, finished compost chemical characteristics and biota by community level physiological profiling using Biolog EcoPlates. SCG as a feedstock had elevated total N but nearly undetectable soluble NO3-N, and greater microbial community functional diversity. Compost teas from three composts (dairy-manure based and leaf/grass/coffee based thermophilic composts, and food waste based vermicompost) were assessed for impacts on tomato leaf mold (Fulvia fulva) and winter squash powdery mildew (Podosphaera xanthii) management in a farm setting (Chapter 4). Aerated compost teas (CT) were produced for weekly foliar application on two tomato (Solanum lycopersicum) varieties and three winter squash varieties (Cucurbita moschata, C. pepo, and C. maxima) (five separate experiments). While there was some efficacy for management of disease in some of these plant/pathogen systems, this varied by species/variety; and as disease pressure increased over the season CT efficacy ceased. Use of a spreader-sticker appeared to increase disease management in some trials.
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