控释肥对土壤氮素反硝化损失和N_2O排放的影响

在实验室培养条件下,研究了3种控释肥对土壤氮素硝化反硝化损失和N2O排放的影响。结果表明,控释肥具有明显控制氮素释放的作用。在培养的前23d,控释肥处理的土壤NH4＋-N含量低于尿素处理,而后则高于尿素处理。各肥料处理土壤NO3--N含量均随培养时间逐渐增加,但不同肥料处理间差异不显著。28d培养期间,施入控释肥的土壤反硝化氮损失量为30.33～30.91mg N·kg-1土,比施加尿素处理土壤低13.83～14.41mgN·kg-1土,差异达到显著水平（P〈0.05）,控释肥降低氮肥的反硝化损失达3.45～3.60个百分点。控释肥处理土壤N2O累积释放量约为15.71～20.45mgN·kg-1土,比尿素处理高0.86～5.60mgN·kg-1土,但差异未达到显著水平。

Effects of Controlled Release Fertilizers on Nitrogen Loss by Denitrification and N_2O Emission

A 28-days incubation experiment was conducted to study the effects of three Controlled Release Fertilizers（CRFs）on the nitrogen loss by denitrification and N2O emission.The results showed the CRFs had significant delayed effect on the nitrogen release.Before day 23th of the incubation,the soil NH4＋-N contents in CRFs treatments were lower than that in urea treatment,and the fact was opposite after day 23th.The soil NO3--N contents in all fertilizer treatments increased with the time of incubation,but,there were no significant differences among treatments.After 28 days,the N loss amounts by denitrification were 30.33～30.91 mgN·kg-1 soil in CRFs treatments,which were 13.83～14.41 mgN·kg-1 soil lower than that of urea treatmen（tP0.05）.The CRFs decreased the rates of denitrification losses in nitrogen fertilizer by 3.45～3.60 percentage point.The N2O emission amounts were 15.71～20.45 mgN·kg-1 soil in CRFs treatments which were 13.83～ 14.41 mgN·kg-1 soil higher than in urea treatment,but,the differences did not reached significant levels.