滴灌水氮对土壤残留有效氮及玉米产量的影响

通过大田试验研究膜下滴灌施用不同水氮对玉米产量及收获后土壤残留有效氮的影响,寻求适宜的水氮耦合量,为达到高产、高效与低土壤氮损失量、残留量相协调的目标提供初步理论。结果表明:1 351~1 465 m~3/hm~2的低灌水量不能有效发挥氮对产量的贡献。灌水1 400~1 800 m~3/hm~2、施氮280~290 kg/hm~2时水对产量提升速度最快而与氮无协同增产效应。灌水1 800~2 100 m~3/hm~2、施氮250~280 kg/hm~2能获得比较高的产量和水氮协同增产效应。收获后1 m土层有效氮分布为由浅向深逐层减少,不同水氮施用量主要影响40~100 cm的残留量。施氮量增加,有效氮残留量增大,用量240 kg/hm~2以内残留量增长缓慢,继续施氮增长迅速。1 351~1 465 m~3/hm~2的低灌水量下肥料氮转化为土壤氮少,残留有效氮少。1 802~2 071 m~3/hm~2的灌水量促进肥料氮向土壤氮转化,随水迁移增大了40~100 cm土壤有效氮。灌水量达2 197~2 315 m~3/hm~2后,1 m土层有效氮残留量减少、深层损失量增大。优选水氮耦合量包含于近似椭圆的区域,交集区灌水2 016~2 100 m3/hm~2,施氮228~250 kg/hm~2可作为松辽平原到内蒙古高原过渡地带膜下滴灌种植玉米的适宜水氮耦合量。

Effects of Water and Nitrogen on Maize Yield and Soil Residual Available Nitrogen Through Mulched Drip Irrigation

The field experiments were conducted to study the effect of different water and nitrogen application on maize yield and soil residual available nitrogen through mulched drip irrigation. The main objective was to determine the suitable application amount of water and nitrogen to develop a preliminary theory for the harmonious target of high yield, high efficiency, low nitrogen residues and low loss of nitrogen. Results showed that the low irrigation (1 351 – 1 465 m3/hm2) cannot effectively increase the role of nitrogen fertilizer on the yield of maize. Combined application of 280 – 290 kg/hm2 of nitrogen with irrigation of 1 400 – 1 800 m3/hm2 led to the fastest increase in maize yield, but without synergistic effects of water with nitrogen on the yield. Combined irrigation of 1 800 – 2 100 m3/hm2with 250 – 280 kg/hm2 of nitrogen obtained relatively higher yield and high synergistic effects of water with nitrogen on the yield. The residue of available nitrogen decreased from the shallow to the deep layer in the profile of 0 – 100 cm after harvest, and the quantity of water and nitrogen applied mainly affected the residue of available nitrogen in the layer of 40 – 100 cm. The residue of available nitrogen increased with the increasing nitrogen fertilizer. When the application rate was about 240 kg/hm2, the quantity of residual available nitrogen increased slowly. The residue of available nitrogen increased rapidly when the fertilizer increased to above 240 kg/hm2. The low irrigation (1 351 – 1 465 m3/hm2) decreased the conversion of fertilizer nitrogen to soil nitrogen and quantity of nitrogen residue. Enhancing the irrigation amount to 1 802 – 2 071 m3/hm2 promoted the conversion of nitrogen fertilizer to the soil nitrogen and increased the available nitrogen. When the irrigation reached about 2 197 – 2 315 m3/hm2, the nitrogen migration with water in soil profile increased and reached to deep layer of > 1 m. The quantity of optimization of water and nitrogen coupling were in an approximate ellipse area. The irrigation of 2016 – 2100 m3/hm2 with nitrogen of 228 – 250 kg/hm2 in intersection area can be used as suitable amount for planting maize under mulched drip irrigation in the transition from Song-liao Plain to the Inner Mongolia Plateau.