不同施氮水平下小麦/玉米套作群体产量和水氮利用

通过2018—2020年连续两年田间试验，以小麦/玉米套作群体为试验对象，研究N0、N1和N2 3个水平下（施N量分别为小麦0、120 kg·hm^-2和240 kg·hm^-2，玉米0、180 kg·hm^-2和360 kg·hm^-2）小麦/玉米套作群体产量、土地当量比与土壤水分利用的差异。结果表明：小麦/玉米套作具有明显的产量与水分利用优势，与单作相比，套作小麦产量提高21.34%~27.80%（P＜0.05），产量优势主要来源于边1行与边2行的增产，而套作玉米表现受氮肥供应的调控，在N0与N1水平下套作产量减少3.02%~11.43%，仅在N2水平下高于单作玉米；小麦/玉米套作群体的土地当量比（LER）在1.04~1.16，具有土地利用优势；在相同产量下小麦/玉米套作群体比单作群体的耗水量更少，水分利用效率更高，其中在N1水平下耗水量减少最为明显，两年内平均减少消耗47.30 mm的水分，而水分利用效率比单作系统提高2.77%~6.46%，小麦/玉米套作群体在3个施氮水平下均表现出节水与水分利用优势；套作种植还可以提高小麦和玉米的氮肥农学利用率及小麦的氮肥偏生产力，两年内套作小麦的氮肥偏生产力和氮肥农学利用率最高可达64.17 kg·kg^-1和11.17 kg·kg^-1。因此在半湿润区雨养条件下具有发展小麦/玉米套作种植模式的可行性。

Yield, water and nitrogen utilization in the wheat\|maize intercropping system under different nitrogen levels

In this study, a two\|year field experiment was conducted to explore the yield and water use efficiency of wheat\|maize intercropping system under three nitrogen application levels: N0, N1, and N2 represent 0, 120, and 240 kg·hm^-2 for wheat and 0, 180, and 360 kg·hm^-2 for maize, respectively. The yield of intercropped wheat was significantly increased by 21.34%~27.80% than that of sole wheat during both years, and the yield advantage of intercropped wheat mainly came from the yield increase of border-1-row and border-2-row. However, the yield disadvantage of intercropped maize was mainly through the decrease of border rows. The yield of intercropped maize was affected by nitrogen rates, where maximum reduction (3.02%~11.43%) for N0 and N1 levels during both years, only higher than that of sole maize under N2 level. Compared with sole maize cropping, the grain yield of inner maize was increased by 6.27%~12.68%. In the two\|year experiment period, the LER of wheat\|maize intercropping was between 1.04~1.16, which had the advantage of land use. The water consumption of wheat\|maize intercropping system was less than that of sole crops with same yield, and the maximum reduction in water consumption was observed for N1 level, and the average water consumption of the intercropping system was 47.30 mm less than that of the sole crops during both years of experiment. The water use efficiency of wheat\|maize intercropping system was increased by 2.77%~6.46% than that of sole crops during both years. The wheat\|maize intercropping system had the advantages of water saving and water use under three nitrogen application levels. Intercropping also improved the nitrogen agronomic utilization efficiency of wheat and maize and the nitrogen partial productivity of wheat. Within two years, the nitrogen partial productivity and nitrogen agronomic utilization efficiency of intercropping wheat reached 64.17 kg·kg^-1 and 11.17 kg·kg^-1. These results suggest that wheat\|maize intercropping system should be more feasible to develop under rain fed condition in semi humid area.