Ecological Studies on Crop Community Cultivated under the Intercropping Systems.

研究了不同间作制度下作物群落的生态特征，并对玉米、高粱和大豆间作安排对作物产量的影响进行了3年的研究。在玉米、高粱和大豆间作中，光是起重要作用的因素，因为随着各组分作物冠层有效光量的减少，在开花和成熟阶段，净同化率和叶面积指数均下降，从而导致作物生长速度下降。在开花中期和成熟期，消光系数(K)与叶面积指数呈负相关。2 .在间作条件下，K值普遍升高，表现出截光特性的恶化，而密播则通过使叶片更加直立来降低K值。通过对间作和单作各组成作物产量的比较，观察到三种类型的种间竞争，即相互合作、相互抑制和补偿。采用土地当量比对间作与单作的生产力进行比较，间作的生产力相当高，均在1.10以上。这意味着间作比单作产量更高。大豆与玉米、高粱间作显著降低了单株荚果数和节间长度等性状。但间作的荚果螟害率较低。

The studies were carried out to elucidate the ecological characteristics of crop community grown under the various intercropping systems, and effects of the intercropping arrangement of maize, sorghum, and soybean on crop yields were also investigated over a 3-year period.1. In the intercroppings including maize, sorghum, and soybean, light was a factors which played a important role, because with the decrease of light available in the canopy of each component crop, net assimilation rates, and leaf area indices and consequently crop growth rates decreased at the flowering and ripening stages.2. There was a negative correlation between light extinction coefficient (K) and leaf area indices at the mid flowering or ripening stages. K value increased commonly under the intercropping conditions in showing the deterioration in light intercepting characteristics, however dense cropping was supposed to bring the decrease of K value by making the leaves more upright.3. Three types of inter-species competition were observed by comparing the yields of each component crop cultivated in the intercropping and sole cropping, that is, mutual cooperation, mutual inhibitation, and compensation.4. Land equivalent ratios were used to compare the productivity of the intercropping and sole cropping, and they were considerably high, showing more than 1.10 in the intercropping. This means that the intercropping gave more yields than the sole cropping.5. Some characters of soybean such as number of pods per plant and internode length were significantly reduced when soybean was intercropped with maize and sorghum. However, a less percentage of grains damaged by pod borer was found in the intercropping.