追施生物炭对稻麦轮作中麦季氨挥发和氮肥利用率的影响

【目的】利用田间定位试验，对比研究生物炭施入土壤经过三年老化及追施新生物炭对稻麦轮作体系中麦季土壤氨 (NH₃) 挥发、氮肥利用率和产量的影响。【方法】试验共设6个处理，其中对照处理2个为N0B0 (不施氮肥+不施生物炭)、N1B0 (单施N 250 kg/hm2)；2012年施用生物炭处理2个为N1B1 (N 250 kg/hm2 + 生物炭20 t/hm2)、N1B2 (N 250 kg/hm2 + 生物炭40 t/hm2)；2015年追施生物炭处理2个为N1B1 + B (N1B1 + 生物炭10 t/hm2)、N1B2 + B1 (N1B2 + 生物炭20 t/hm2)。【结果】与N1B0处理相比，N1B1和N1B1 + B处理NH₃挥发累积量分别减少36.6%、6.4%，氮肥利用率提高30.1%和14.1%，小麦产量增加55.6%和26.9%；而N1B2、N1B2 + B1处理NH₃挥发累积量分别增加20.3%、40.5%，氮肥利用率提高35.9%和14.3%，小麦产量增加72.5%和18.9%。与老化生物炭处理相比，追施生物炭处理显著增加了小麦季氨挥发累积量，并显著降低了小麦氮肥利用率和产量。【结论】农田中施用生物炭可明显增加小麦季产量和氮肥利用率。老化生物炭低施用量 (20 t/hm2) 处理能显著减少NH₃挥发损失，并且更有效的提高小麦氮肥利用率和产量。

Effects of biochar reapplication on ammonia volatilization and nitrogen use efficiency during wheat season in a rice-wheat annual rotation system

Objectives]A field experiment was conducted to investigate the effect of aged and fresh biochar amendment on ammonia volatilization, nitrogen use efficiencies and wheat yield during wheat season in a rice-wheat rotation system.Methods]Six treatments were carried out in this experiment, including two control treatments N0B0 (no nitrogen + no biochar), N1B0 (N 250 kg/hm2 nitrogen); two aged biochar amendment treatments N1B1 (N 250 kg/hm2 nitrogen + 20 t/hm2 biochar), N1B2 (N 250 kg /hm2 nitrogen + 40 t/hm2 biochar);two aged with fresh biochar amendment treatments N1B1 + B (N1B1 add 10 t/hm2 biochar), N1B2 + B1 (N1B2 add 20 t/hm2 biochar).Results]Results showed that the N1B1 and N1B1 + B treatments significantly decreased the cumulative NH3 volatilization by 36.6% and 6.4%, increased the nitrogen use efficiency by 30.1%and 14.1% and increased the wheat yield by 55.6%, 26.9% compare with N1B0. In contrast, compared with N1B0 treatment, N1B2,N1B2 + B1 treatments significantly increased the cumulative NH3 volatilization by 20.3% and 40.5%, the nitrogen use efficiency increase by 35.9% and 14.3% and the wheat yield significantly increased by 72.5%, 18.9%, respectively. Moreover, compared with the aged biochar amendment, biochar topdressing significantly increased the NH3 volatilization, and decreased the nitrogen use efficiency and wheat yield.Conclusions]Biochar amendment could significantly increase the nitrogen use efficiency and wheat yield during wheat season in paddy field. Aged biochar at the rate of 20 t/hm2 can decrease the ammonia volatilization loss while increase the nitrogen use efficiency and wheat yield.