The simulating test of the environmental capacity of biogas fertilizer utilization on wheat and corn planting system

With the rapid development of biogas project that produce massive biogas fertilizer, it is necessary to determine the environmental capacity of biogas fertilizer utilization. In this study, the environmental capacity of biogas fertilizer application on wheat and corn planting system were investigated by soil column simulating experiments. The results showed that (1) the environmental capacity by biogas fertilizer application is higher than that by using the same amount chemical fertilizer; With the content of nitrate nitrogen <;20 mg L^-1 in the grade III of ground water criteria as assessment standard, biogas fertilizer application with 200 kg N hm^-2 during wheat growth period would not contaminate ground water while using the same amount chemical would contaminate the ground water; (2) In wheat and corn planting system, using 275 kg N hm^-2 biogas fertilizer would not contaminate ground water, however, when the biogas fertilizer application rate rise to 350 kg N hm^-2, it would be risk to the ground water. Under the circumstance in this experiment, the environmental capacity of biogas fertilizer utilization on farmland is more than that of Lausanne experiment station (175 kg N hm^-2) and Wang et al. (203 kg N hm^-2).