黄土塬区春玉米氮肥-水分-产量关系研究

土壤水分是制约我国西北干旱半干旱地区农业发展的重要因素,探寻科学合理的氮肥—水分—产量关系,对于促进区域农业持续发展有重要的理论与实践意义。在陕西省长武县的中国科学院长武黄土高原农业生态试验站进行氮肥递减试验,在传统施氮250 kg/hm~2(N6)的基础上,依次递减20%,设置CK、N1、N2、N3、N4、N5、N6 7个处理。结果表明:(1)春玉米生育期土壤耗水量随氮肥施用量的增加而增加,土壤水分亏缺主要发生在80 cm以下土层,且水分亏缺程度随施氮量增加而加重。(2)春玉米产量和水分利用率均随氮肥用量的增加呈现二次抛物线趋势变化。春玉米传统施氮量(N6,250 kg/hm~2)已严重过量,减氮20%(N5,施氮量200 kg/hm~2)可以取得较高的产量和水分利用率。2年N5籽粒产量较N6分别增加9.6%和5.8%,水分利用率提高14.5%和9.1%。因此,建议把减氮20%(N5,即200 kg/hm~2施氮量)作为试验区推荐施氮量。

Study on the Relationship Between Nitrogen Fertilizer-Water-Yield of Spring Maize in the Loess Plateau

Soil moisture is an important factor restricting agricultural development in arid and semi-arid regions of northwest China. It is of great theoretical and practical significance to explore a scientific and reasonable relationship between nitrogen fertilizer,water and yield for promoting the sustainable development of regional agriculture. At the Changwu Loess Plateau Agro-ecological Experiment Station of the Chinese Academy of Sciences in Changwu County,Shaanxi Province,a nitrogen fertilizer decline test was performed. Based on the traditional nitrogen application of 250 kg/hm² (N6),it was reduced by 20% in order. Set CK,N1,N2,N3,N4,N5,N6 seven processes. The results showed that: (1) The soil water consumption during the growth period of spring corn increases with the increase of nitrogen fertilizer application. The soil water deficit mainly occurs below 80 cm of soil layer,and the degree of water deficiency increases with the increase of nitrogen fertilizer application. (2) Both the yield and water use efficiency of spring corn showed a second parabolic trend with the increase of nitrogen fertilizer use. The traditional nitrogen application rate of spring corn (N6,250 kg/hm²) has been severely excessive,and a reduction of 20% (N5,nitrogen application rate of 200 kg/hm²) can achieve higher yield and water use efficiency. Compared with N6,N5 grain output increased by 9.6% and 5.8%,and water use efficiency increased by 14.5% and 9.1%. Therefore,it is recommended to reduce nitrogen by 20% (N5,200 kg/hm² nitrogen application rate) as the recommended nitrogen application rate.