Effects Of Sowing Date On Growth Period Characters, Yield And Quality Of Different Soybean Varieties In Pattern Of Wheat/Corn/Soybean Intercropping

The effects of sowing date on the growth duration, the photosynthetic characteristics of leaves, accumulation of dry substances, the soluble carbohydrate and nitrogen metabolism, the yield and quality of different soybean varieties were studied by using early-maturing variety, middle-maturing variety and late-maturing variety in experimentation. The principal results were shown as follows:1. These characteristics of growth period of different soybean varieties in intercropping were obviously affected by sowing date. The effect of sowing date on duration from planting to maturation was more remarkable than the effect of different varieties. When the sowing date was postponed, the duration from planting to flowering and the symbiotic period were shortened. The growth stage of early -maturing variety was less than that of late-maturing variety. The growth duration of soybean in intercropping displayed significant linear correlation with meteorological factors, and daily mean temperature and sunshine duration were major factors.2. These photosynthetic characteristics of leaves of different soybean varieties were obviously affected with sowing date. The LAI, the chlorophyll content and photosynthetic rate of seedling in late-maturing breed were the highest, but the value of chlorophyll a/b was the fewest. When sowing date was postponed, the LAI and the value of chlorophyll a/b were obviously decreased, but the chlorophyll content and photosynthetic rate of seedling were increased in B3.3. The accumulation, distribution and transformation of dry matter were obviously affected with sowing date and varieties of soybean in intercropping. Firstly, when sowing date was postponed, the time reaching to the maximum dry matter accumulation rate was shortened; and the maximum dry matter accumulation rate, the average dry matter accumulation rate, dry matter yields, percentage of leaf, the rate of dry matter transferred from stem and branches and weight of pod in maturation were declined, but the growing rate of pod was promoted. Secondly, it was late-maturing breed that could achieve the highest dry matter yields, attain the maximum the average dry matter accumulation rate, reach the supreme rate of dry matter transferred from stem and branches, be the first-rate of dry mater accumulation of pod and the highest weight of pod in maturation.4. The effects of sowing date on soluble sugar content, nitrogen content and their contribution to pod of different soybean varieties were obviously in intercropping. When sowing date was postponed, the peak of soluble sugar content, translating and its...