减氮配施有机肥对夏玉米——冬小麦土壤硝态氮及氮肥利用的影响

Effects of Nitrogen Reduction and Combined Application with Organic Fertilizer on Soil Nitrate Nitrogen and Nitrogen Fertilizer Utilization Efficiency in Summer Maize and Winter Wheat Systems

为实现华北平原夏玉米-冬小麦的高产及氮肥的高效利用,采用田间小区试验方法,研究了氮肥减量及其与有机肥配施对夏玉米-冬小麦轮作体系内土壤硝态氮分布及氮肥利用的影响。结果表明:与不施氮处理(CK)相比,施用氮肥增加了冬小麦和夏玉米的生物量和产量,而在农民习惯施氮基础上减量1/3不会显著影响到生物量和产量。其中减氮配施有机肥(ONM)处理的周年总产最高,相比习惯施氮(CN)和减氮处理(ON)分别提高了1.85%和3.78%。处理CN的0~180 cm土壤硝态氮累积量的周年变化均值达502.7 kg hm^-2,分别是处理CK、ONM、ON的2.95、2.17、1.56倍。与处理CN相比,处理ONM显著降低了剖面(0~180 cm)土壤中的硝态氮含量,其中在夏玉米季和冬小麦季的降低幅度分别为18.1%~66.7%和37.3%~87.2%。处理ON和ONM相比处理CN,植株周年总吸氮量无显著性差异,氮肥利用率却得到了显著提高。其中处理ONM的周年氮肥利用最高,比处理CN提高了36.9%。综合分析,减氮与有机肥配施不仅显著降低了0~180 cm土壤硝态氮含量,大幅度提高了氮肥利用率,且有助于增加冬小麦和夏玉米的生物量及产量。

In order to improve the yield and nitrogen(N) fertilizer utilization efficiency, the field plot experiment was conducted to study the effects of N fertilizer reduction and combined application of organic fertilizer on soil nitrate N(NO3^--N) and N fertilizer utilization efficiency in the winter wheat and summer maize rotation systems. The biomass and annual yield of winter wheat and summer maize were significantly increased with the application of N fertilizer compared with no N fertilizer application(CK). And the biomass was not affected after reducing N fertilizer by 1/3 of the traditional application of N fertilizer. The anniversary yield in the treatment of reducing N fertilizer combined with applying organic fertilizer(ONM) was increased by 1.85% and 3.78% compared with the treatments of traditional application of N fertilizer(CN) and reducing N fertilizer(ON), respectively. For CN treatment, the average accumulation of soil NO3^--N(0 ~ 180 cm) during the consecutive two-seasons was 502.7 kg hm^-2, which was 2.95,2.17 and 1.56 times of CK, ONM and ON treatments, respectively. Soil NO3^--N content was decreased by 18.1%~66.7% at the summer maize season and by 37.3%~ 87.2% at the winter wheat season in the ONM treatment relative to the CN treatment. The anniversary plant N uptake was not significantly different among the treatments of CN, ON and ONM. The N fertilizer use efficiency in the ONM treatment was significantly increased by 36.9% compared with CN treatment. In conclusion, N fertilizer reduction and combined application of organic fertilizer could significantly decrease soil NO3^--N content at 0 ~ 180 cm depth, improve N fertilizer use efficiency, and increase biomass and yield of winter wheat and summer maize.