Monday, November 13, 2006

Soil Properties and Crop Performance of Vegetable Soybeans Following Application of Poultry Litter.

Reina Blair, Mary Savin, and Pengyin Chen. University of Arkansas, 115 Plant Science Building, 115 Plant Science Building, Fayetteville, AR 72701, United States of America

Poultry litter incorporated into soil growing legumes may help improve soil and crop quality in specialty soybean production. Organic matter from poultry litter may increase soil microbial and enzymatic activities, driving nutrient cycling and availability. By providing large amounts of P and K,  poultry litter may improve plant nutrient uptake, seed quality and yield response in soybeans. A greenhouse and field study were conducted in the spring and summer, 2006, to investigate whether soil biology and available nutrients, and consequently crop yield and seed quality properties, were affected pre-emergence and at specific plant growth stages for a vegetable soybean experimental line. Pelletized poultry litter (greenhouse only), formulated poultry litter (field only), or commercial inorganic fertilizer (greenhouse and field) was incorporated at rates of 56, 112, or 168 kg P ha-1 into a high-P soil (124 kg P ha-1). Greenhouse study results suggested that pelletized litter at different rates had immediate effects on several soil properties, but no marked differences were observed in crop performance as measured by plant emergence and height. While there were few effects on P enzyme activities, microbial biomass C was significantly affected (p<0.05), but differences were not consistent throughout all sampling stages. Inorganic N was significantly higher (p<0.05) in fertilized pots as compared to the control, generally with concentrations increasing with application rates. Both fertilizer types resulted in a significant decrease in soil pH in the vegetative growth stages, but pH values in litter treatments recovered and were not different from control at the R1 stage (p<0.05). In the field study, poultry litter applied at all three rates inhibited plant emergence, but not plant height. Results from this project may be helpful in designing management strategies for use of poultry litter in soybean crops where there may be concerns of environmental and crop quality.