Short-term nitrogen dynamics in soil amended with poultry litter containing woodchip bedding

Abstract

Concurrent N mineralization and immobilization in soils receiving poultry litter containing woodchip bedding may reduce synchrony between the short-term N supply and crop N demand. Therefore, we used soil chemical tests, ion exchange membranes, and wheat N uptake to assess N dynamics in a poultrylitter- amended soil. Air-dried soil was thoroughly mixed with five poultry litter rates (50, 100, 150, 200, or 250 mg total N kg-1) and preincubated for 7 d in a controlled environment chamber. After preincubating, soil was placed in 10-cm-diameter pots and planted with spring wheat (Triticum aestivum ‘Wilkin’), or left unplanted and monitored with anion and cation exchange membranes for 45 d. Soil nitrate (NO3-N) concentration increased with poultry litter application rate at the end of the preincubation period, but subsequent wheat N uptake did not, suggesting that little net N mineralization occurred during the 45 d of wheat growth. The membrane data indicated a shift from net N immobilization during the early part of the wheat growth period to net mineralization during the latter portion of the wheat growth period. We conclude that alternating N mineralization and immobilization in soils receiving poultry litter containing woodchip bedding limited the short-term N supply to wheat.