Submitted to: Compost Science and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2004
Publication Date: 6/1/2005
Citation: Means, N.E., Starbuck, C.J., Kremer, R.J., Jett, L.W. 2005. Effects of a food waste-based soil conditioner on soil properties and plant growth. Compost Science and Utilization. 13:116-121. Interpretive Summary: Food waste is comprised of uneaten portions of meals and trimmings from food preparation in kitchens, restaurants, and grocery stores. Food waste is a major component of generated municipal wastes, accounting for over 26 million tons in 2001. Disposal of food waste into landfills or by incineration is very costly; accumulation of food waste in landfills can lead to environmental pollution and to health hazards. An alternative to handling food waste as disposable material is to use it in developing value-added products. By using a composting process, food waste can be processed into a high quality soil amendment (soil conditioner) rich in nutrients that are recycled from the waste material and are available to growing plants. Composts also stimulate soil biological activity that helps release nutrients for plant use and improve soil structure, thereby reducing soil erosion. We evaluated whether soil biological activity and growth of melon plants could be enhanced by treating soil with composts generated from food waste. Food waste, collected from a university campus dining hall, was mixed with wheat bran, placed into 50-gallon containers, and allowed to decompose for up to 20 days to generate the compost. The compost was then tilled into field soil prior to planting melons. Soil biological activity, measured as enzyme activity, did not increase consistently after compost application, however, activity levels were similar to those in soils receiving chemical fertilizer. Melon production was also inconsistent in the compost-treated soils compared to soil but was never less than production on fertilized soil, suggesting that the compost was effective in providing adequate fertility for an optimum crop yield. Long-term studies are continuing in order to determine if soil microbial activity and plant growth can be enhanced exclusively by soil conditioners based on composted food waste. Our results have important implications for scientists, extension personnel, waste and recycling managers, and a diversity of growers from farmers to home gardeners. The use of food waste in producing composts for amending soils removes a major and problematic component from the waste generation cycle and provides a valuable, recycled product that can benefit soil fertility and crop productivity.
Technical Abstract: Composting food wastes can decrease disposal costs and provide soil conditioners that are useful for improving soil quality and crop plant growth. In-vessel fermentation of high moisture, high nitrogen food wastes circumvents odor and pest problems associated with aerobic composting processes. The objective of this study was to evaluate the effects of a soil conditioner prepared from food wastes on soil microbial activity, soil nutrient levels, and melon (Cucumis melo reticulata) growth and yield. Food waste, generated from a residence dining hall, was fermented with and without a microbial inoculant for 20 days. The resulting soil conditioners were incorporated into soil (Mexico silt loam) by tilling to a 15-cm depth using a roto-tiller. Melon seedlings were transplanted three weeks after soil amendment. Soil nutrient levels and microbial activity were monitored periodically during the growing season to detect effects of the soil conditioners on soils and plant growth. Fruit weight per plant was significantly (P'0.05) increased with the microbially-inoculated soil conditioner compared to the control in both years, but was not different from the non-inoculated soil conditioner in 2000 or the fertilizer treatment in 2001. Soil conditioners produced from food wastes inoculated with selected microorganisms were as effective as a fertilizer in promoting soil microbial activity and melon growth. Long-term studies (> 2 yr) are needed to verify that enhancement of microbial activity and plant growth are due exclusively to EM-based soil conditioners.