免耕条件下控释肥对麦季氧化亚氮排放的影响

Effects of controlled release fertilizer on nitrous oxide emission during winter wheat-growing season under no-tillage condition

为明确免耕条件下控释肥对麦季氧化亚氮减排的效果,本试验以长江下游典型稻麦轮作农田为对象,采用静态箱-气相色谱法研究了免耕条件下控释肥料（ Osomcote和Nutricote）和普通肥料（碳酸氢铵、尿素和复合肥）处理对麦季氧化亚氮排放和冬小麦（ Triticum aestivum L.）产量的影响。结果显示：不同肥料处理在施用基肥后均出现1个氧化亚氮排放高峰,小麦播种至越冬始期的氧化亚氮累积排放量占全生育期总排放量的50%～73%。不同处理麦季氧化亚氮总排放量和小麦产量均表现为尿素处理〉复合肥处理〉碳酸氢铵处理〉Osomcote控释肥处理〉Nutricote控释肥处理〉无氮对照,氧化亚氮总排放量依次是2.55 kg/hm^2、2.39 kg/hm^2、1.99 kg/hm^2、1.70 kg/hm^2、1.37 kg/hm^2和0.97 kg/hm^2,小麦产量分别为6.23 t/hm^2、6.13 t/hm^2、5.84 t/hm^2、5.02 t/hm^2、4.79 t/hm^2和3.21 t/hm^2。与普通肥料处理相比,控释肥处理氧化亚氮排放减少15%～46%,小麦减产14%～23%。表明,免耕条件下控释肥的施用在减排麦季氧化亚氮的同时显著降低了小麦产量。

No-tillage has been promoted as an effective agricultural practice for enhancing soil carbon sequestration. However, the impact of fertilizer application on nitrous oxide （N2O） emission under on-tillage conditions is currently not well documented. By using static chamber/gas chromatographic techniques, the effects of controlled release fertilizer and common fertilizer on N2 O emissions during winter wheat （ Triticum aestivum L. ） growing season under no-tillage conditions of a rice-wheat cropping system in the lower reaches of the Yangtze River were studied. Only one peak of N2 O flux was observed after basic fertilizer application. N2 O accumulative emissions from sowing to wintering accounted for 50%-73% of the total emis-sion during winter wheat-growing season. Total N2 O emissions and wheat yield under different treatments followed the same order：common urea〉common compound fertilizer〉common ammonium bicarbonate〉Osomcote controlled release fertilizer〉Nu-tricote controlled release fertilizer〉no nitrogen fertilizer. Total N2 O emissions were 2. 55 kg/hm2 , 2. 39 kg/hm2 , 1. 99 kg/hm2 , 1. 70 kg/hm2 , 1. 37 kg/hm2 and 0. 97 kg/hm2 , respectively, and wheat yield were 6. 23 kg/hm2 , 6. 13 kg/hm2 , 5. 84 kg/hm2 , 5. 02 kg/hm2 , 4. 79 kg/hm2 and 3. 21 kg/hm2 , respectively. Compared with common fertilizers, total N2 O emissions for controlled release fertil-izers were 15%-46% lower, and wheat yield were 14%-23% lower, respectively. The results indicated that controlled release fertilizer could decrease N2 O emissions and wheat yield during winter wheat-growing season.