Agroforestry as an alternative for the land application of poultry litter

Abstract

Agroforestry, particularly silvipasture systems that combine grass and trees, has been proposed an alternative for the common practice of poultry litter application to pastures. Poultry litter was applied at three rates (0, 11.2 and 33.6 Mg ha -1 ) to three managed vegetation systems (Festuca arundinacea Schreb. pasture, Pinus taeda L. plantation and a silvipasture system combining the two species). Following poultry litter application, short-term fate of N and P was monitored and three-year pine growth response was measured. Results indicate somewhat improved N and P nutrition and positive growth response of both pine and grass to litter application. Ammonia volatilization was the greatest pathway of N loss and loss through denitrification was minimal. Estimated loss of NH3-N during a 96-hour period following June litter application ranged from 0.2 to 15.3 kg ha -1 . Average soil solution NO3-N concentrations at 1-m depth exceeded 16 mg L -1 on one occasion in the pine plantation during the spring following application. Average concentrations did not exceed 2.21 mg L -1 in either the silvipasture or pasture. These results indicate that silvipastures can offer an alternative for poultry litter utilization while retaining many aesthetic and financial benefits associated with trees.