Gao Yang, Duan Ai-Wang, Liu Zu-Gui, Shen Xiao-Jun
Institute of Farmland Irrigation Research, Chinese Academy of Agricultural Sciences, Xinxiang 453003, Henan, China.
Ying Yong Sheng Tai Xue Bao. 2008 Jun;19(6):1248-54.
Observations on the light environment characteristics in maize-soybean narrow stnp intercropping system were made in 2006 and 2007 to study the spatial distribution of photosynthetically active radiation (PAR) in intercropped crop canopy, and to analyze the effects of light environment on crop biomass. The results indicated that in early growth period, the light transmittance at the bottom of the edge rows of soybean strips adjacent to maize was higher than that of the inner rows of soybean strips, while it was in adverse for maize strips. The horizontal variation of light transmittance at the bottom of crop canopy did not vary significantly at reproductive stage, and the average light transmittance was less than 7%. In soybean strips, the daily photosynthetic photon flux density (PPFD) above inner rows canopy in early growth period was 10% higher than that above edge rows canopy, and the average light transmittance of edge rows and inner rows in 1: 3 intercropping system (treatment I1) was about 15% higher than that in 2:3 system (treatment I2), indicating that the shading of maize strips on soybean strips was more senous in treatment I2 than in treatment I1. After flowering, there was a significant difference in the daily PPFD between inner rows and edge rows of soybean strips, but no significant difference was observed between edge rows. The mean light transmittance of edge rows and inner rows of soybean strips was 27% and 38%, respectively, and there was no significant difference between treatment I1 and treatment I2, which indicated that the shading effects of maize strips on soybean strips in treatment I1 and treatment I2 were similar at reproductive stage. The biomass of inner rows of soybean strips was larger than that of edge rows, and there was no significant different between edge rows, indicating that under adequate irrigation, the effects of different narrow strip intercropping systems on crop biomass were primarily due to the changes of light environment.
2006年和2007年对玉米 - 大豆窄行套作系统的光环境特征进行了观测，以研究套作作物冠层光合有效辐射（PAR）的空间分布，并分析光环境对作物生物量的影响。结果表明，在生长前期，与玉米相邻的大豆条带边缘行底部的透光率高于大豆条带内部行，而对玉米条带则不利。作物冠层底部透光率的水平变化在生殖期差异不显著，平均透光率小于7%。在大豆条带中，生长前期内部行冠层上方的日光合光子通量密度（PPFD）比边缘行冠层上方高10%，1:3套作系统（处理I1）中边缘行和内部行的平均透光率比2:3系统（处理I2）高约15%，表明处理I2中玉米条带对大豆条带的遮荫比处理I1更严重。开花后，大豆条带内部行和边缘行的日PPFD存在显著差异，但边缘行之间未观察到显著差异。大豆条带边缘行和内部行的平均透光率分别为27%和38%，处理I1和处理I2之间无显著差异，这表明处理I1和处理I2中玉米条带在生殖期对大豆条带的遮荫效果相似。大豆条带内部行的生物量大于边缘行，边缘行之间无显著差异，表明在充足灌溉条件下，不同窄行套作系统对作物生物量的影响主要归因于光环境的变化。
