Soil fertility and crop growth under poultry/crop integration

Innovative sources of soil fertility are of utmost importance to growers in light of rising fertilizer costs and environmental concerns. Integrating livestock and crop production is one channel by which agricultural practitioners can enhance soil fertility. For this research, soil fertility was analyzed in pastured poultry/crop agroecosystems to determine whether free-ranging birds and pasture could be used to replace or supplement non-manure-based fertilizers. Soils from adjacent cropped areas were compared to plots with a recent history of pastured poultry use on two farms, and crop plants were grown in each type of soil in a replicated greenhouse experiment. Spatial variation in soil fertility was also assessed relative to location of poultry coops. Pastured poultry plots had elevated soil total C, total N, NH4+-N, NO3--N, Olsen P, exchangeable K, organic matter, cation exchange capacity and electrical conductivity relative to the control of typically managed organic farm soils without pastured animal inputs. These soil fertility changes conferred greater biomass and height to sunflowers and beans grown in these soils relative to control soils for most treatments. Results suggest that pastured poultry can effectively fertilize soil for certain crops but that a need exists for more research into (1) phosphorus management and (2) ensuring a spatially uniform distribution of manure.