Session- Compost Utilization I
Using Compost and Cover Crops to Reduce Fertilizer Requirements in Sweet Corn Production
ABIGAIL A MAYNARD (1)
(1) Department of Soil and Water, Connecticut Agricultural Experiment Station, USA
Sweet corn requires high amounts of nitrogen which is usually supplied by inorganic fertilizer. As available nitrogen in compost is not abundant early in the growing season, using compost in combination with a winter cover crop could increase early nitrogen concentrations as the nitrogen in cover crops is easily mineralized. A leguminous cover crop planted in fall after harvest not only fixes nitrogen but also absorbs residual soil nitrogen from the previous crop and minimizes winter leaching of nitrogen to the ground water. For three consecutive years, two cultivars of sweet corn (Zea mays L.) were planted on a Merrimac sand loam (Entic Haplorthod). The six treatments included: hairy vetch (Vicia villosa Roth) plus compost plus 1456 kg/ha 10-10-10 (N-P(2)O(5)-K(2)O) fertilizer, vetch plus compost plus 728 kg/ha 10-10-10 fertilizer, compost plus 1456 kg/ha 10-10-10 fertilizer, compost plus 728 kg/ha 10-10-10 fertilizer, 1456 kg/ha 10-10-10 fertilizer with no vetch or compost (full control), and 728 kg/ha 10-10-10 fertilizer with no vetch or compost (half control) (1999 and 2000 only). Unscreened leaf compost was applied at a rate of 112 Mg/ha and rototilled into the soil to a depth of 15 cm. For both corn cultivars studied, the size of the ears (average weight, length, and number of rows) was significantly increased by compost additions in plots amended with compost for three years compared to unamended plots. The number of ears/plant was not significantly different. For one cultivar, the full rate of inorganic fertilizer did not produce optimum yields of sweet corn. It was shown that optimum yields could be attained by supplementing inorganic fertilizer with leaf compost. Annual compost amendments reduced by one-half the inorganic fertilizer requirement and increased the organic matter and the concentration of some nutrients in the soil justifying the time and labor in applying compost. Vetch had no effect on corn yield or ear characteristics because its biomass had not become well established between fall planting and spring plowing. Perhaps a two-year cover crop rotation with compost amendments would provide greater corn yields.
Growth, Yield, Its Components and Nutrient Status of Field Grown Tea (Camellia Sinensis L. (O.) Kuntze) in Compost Amended Soils
(1)A J MOHOTTI, (1)K M Mohotti, (1,2)M P T Premaratne1, and (2)U R Sangakkara
(1) Tea Research Institute, Talawakele, Sri Lanka, (2) Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka, Sri Lanka
Experiments were conducted at the Tea Research Institute of Sri Lanka in an ongoing organic tea field experiment, in order to ascertain the effects of different soil amendments on growth, yield, its components, soil and foliar nutrient status as compared with the recommended conventional inorganic fertilizer. The different materials were comprised of compost and two agro-industrial by products, viz. tea waste and neem oil cake. The tea yield and total bush dry weight were not significantly affected due to different composts compared to that of conventionally grown tea, in the first pruning cycle. Conventional treatment had high shoot dry weight, shoot extension rate and larger number of active shoots which resulted in higher yield. All the organic materials in used quantities supplied nutrients in adequate amounts for tea. Ample availability of micro-nutrients in compost and tea waste could have contributed to their greater yields. Data also suggested limited usage of neem oil cake in organic tea despite its pesticidal properties; N availability in neem oil cake was low, had lowest organic C and most other nutrients, which contributed to the lowest yield. The potentials of using tea waste and compost in organic tea cultivation to sustain greater yields are discussed.
Worm Castings: An Alternative to Sphagnum Peat Moss in Organic Tomato (Lycopersicon Esculentum Mill.) Transplant Production
Monica Ozores-Hampton and Charles S. Vavrina.
University of Florida, IFAS, Southwest Florida Research and Education, Immokalee, Florida., USA
Inorganic fertilizers are not allowed under organic production guidelines, therefore worm castings (WC) can be a potential alternative media in the production of tomato transplants. Worm castings can be applied at rates of up to 70% as an alternative to commercial peat moss media in organic tomato transplant production. The use of WC under non-organic transplant media during the summer and fall can be beneficial, since heavy irrigation due to temperatures can leach inorganic fertilizer from conventional mixtures of peat:vermiculite. During the summer and fall WC released adequate N for optimal transplant growth, especially at high rates (70%). Presently, organic transplant growers are not satisfied with home made peat/compost/poultry manure as a media, therefore WC can be a viable alternative as a N source.
The Long-Term Vegetable Production Experiment: Plant Growth and Soil Fertility Comparisons Between Fertilizer and Compost-Amended Soils
P.R. WARMAN
Canada
A comparative study from paired compost (only) and conventionally-fertilized vegetable plots has been conducted for 11 years in a sandy loam soil near Truro, N.S.; likely the longest study of its kind in Canada. The treatments have been applied annually to 6 rotation plots planted to different vegetable crops. Compost and fertilizer applications have been based on the results of soil sampling and soil test recommendations, assuming 50 or 100% availability of the total N in the composts and fertilizers. The composts have been made using animal manure, food waste, yard waste and straw or racetrack manure. Marketable yields have been taken annually and plant tissue samples have been analysed for macro- and micronutrients, while soils have been sampled for pH, organic C, CEC and Mehlich-3 extractable nutrients since 1994. This paper reports the results of the 1999 and 2000 cropping years. Crop yield response was inconsistent between the two amendments; yields of peppers, beans and broccoli varied from year to year. The fertilized plots, however, produced higher tomato yields, while the compost-amended plots produced higher carrot and onion yields in both years. There were few significant effects of treatments on plant tissue content; of the essential plant nutrients, only B was higher in the compost-amended plots in the two years. Of 19 soil parameters evaluated the C and the CEC content and the Mehlich-3 extractable Ca, Mn and B content of compost-amended soils were higher following the harvest in both study years, somewhat consistent with the previous 3 years. This study will end with the 2001 cropping year; in addition to the above parameters, emphasis will be placed on potential soil biochemical changes as a result of the amendments.