玉米行距对大豆/玉米间作产量及种间竞争力的影响

为明确大豆/玉米间作体系中玉米最佳种植行距,通过设置5个间作玉米种植行距(D10:10 cm、D20:20 cm、D45:45 cm、D60:60 cm、D70:70 cm),研究不同玉米种植行距对作物产量、体系生产力、种间相对竞争力的影响。结果表明:玉米行距改变不影响间作产量优势,土地当量比(land equivalent ratio,LER)均大于1;随玉米行距的增加,间作大豆产量随之下降,间作玉米产量随之升高,系统生产力(system production,SP)随之提升;间作玉米行距改变显著影响了间作大豆的结荚数和单株粒数,单株结荚数从D10处理的38.5荚·株-1下降为D70处理的15.8荚·株-1,单株粒数从D10处理的66.6粒·株-1下降为D70处理的26.4粒·株-1;随玉米行距的增加,间作玉米穗粒数呈现先增加后减小的趋势,D60处理穗粒数最大,达606粒;间作玉米行距改变显著影响了种间相对竞争力,随间作玉米种植行距的增加,大豆相对于玉米的竞争力Asm逐渐弱化,竞争力平衡点出现在D45处理,采样期平均Asm为0.01。因此,综合考虑间作体系产量,作物产量和种间竞争力,D45处理为大豆/玉米间作体系间作玉米的最佳行距配置。

Effect of row spacing of maize on yield and interspecific competition of crops in soybean/maize intercropping system

In order to propose a reasonable row spacing of maize in the soybean/maize intercropping system, a field experiment was conducted to investigate the effect of row spacing of maize on system productivity and interspecific competition, by performing five maize row spacing treatments (D10: 10 cm, D20: 20 cm, D45: 45 cm, D60: 60 cm, D70: 70 cm). The results showed that the intercropping advantage was not affected by maize row spacing, for that the land equivalent ratio (LER) was more than 1. As row spacing increased, the yield of intercropped soybean decreased, whereas that of maize increased, resulting in higher the system productivity. The pod numbers and grain numbers per plant of intercropped soybean were significantly affected by row spacing, pod numbers per plant decreased from 38.5 pods·plant^-1 under D10 to 15.8 pods·plant^-1 under D70, grain numbers per plant of soybean decreased from 66.6 grains·plant^-1 to 26.4 grains·plant^-1. As row spacing increased, the grain numbers per spike of intercropped maize increased firstly and then decreased. It was highest when maize row spacing was 60 cm, having 606 grains per spike. Maize row spacing also significantly affected interspecific competition. D45 was more reasonable for maize row spacing in soybean/maize intercropping system, considering system productivity and interspecific competition.