Management of pig slurry of nitrogen fertilization of corn

摘要

A five-year lysimeter experiment was carried on a one meter deep loamy soil, pH 6,1, to test the effect of pig slurry management on crop production and water quality. The optimum nitrogen fertilizer rate (X_(min)) was calculated annually using the balance sheet method; X_(min) varied from 60 to 124 kg N ha~(-1). Pig slurry was annually applied i) in late spring, at three rates,: X_(slu), X_(slu + 75), X_(slu + 150) kg N ha~(-1), and ii) in mid autumn (S_(DCD)), at the rate of 3 1 m~(-2) (corresponding to 180-200 kg N ha~(-1)), mixed with a denitrification inhibitor (DCD, 25 l ha~(-1)). The slurry was manually incorporated, immediately after spreading. This five-year experiment suggests that: i) the optimum nitrogen fertilizer rate calculated according to the balance sheet method seems to strike an acceptable balance between high crop production and low level of water pollution, ii) this level of fertilization can be achieved with repeated and exclusive fertilization with pig slurry, iii) the two methods of slurry management (late spring or mid autumn, with DCD) gave similar results.