Anaerobic Incubation without Shaking over a Prolonged Period as a Method to Determine Mineralizable Nitrogen in Rice Soils

摘要

Fertilization rates of nitrogen (N) in rice crop are based on crop needs and the capacity of the soil to supply N, which is determined by several methods. This study evaluated a method of anaerobic incubation without shaking for extended periods of time. Three rice soils of the Inceptisol, Alfisol, and Vertisol orders were fertilized with N rates of 0, 80, and 160kgha(-1) and incubated for 0, 7, 14, 21, and 28 d at 20 and 40 degrees C. The methodology also used short-term anaerobic incubation and constant shaking for 7d at 40 degrees C. Field experiments were conducted with rice in the same soils with equal N rates, and extracted plant N was compared with mineralized N. Results indicated that the methodology without shaking is comparable to the constant shaking procedure for short-term incubations. However, incubations without shaking for longer periods of time had the greatest relation to crop extracted N.