Canopy Evaluation Indices And Chemical Regulation Practices In Soybean Yield

The canopy characters of population are significantly relevant to yield formation of soybean. The experiment was conducted to attain definite effects on the soybean yield of different population canopy characters and chemical regulations. And the research included three parts: the first experiment was conducted to investigate canopy evaluation indices of different soybean population by field plot experiment with one variety plus five densities, ten varieties plus three densities respectively; the second sand pot experiment was conducted to determine the key regulation period of soybean growth and development of different nutrition deficiency stages; the third was conducted to investigate leaf surface chemical regulation technology of different soybean populations with three varieties, three densities and eight leaf spraying treatments. The results indicated as follows:1. There are some differences and similarities in canopy characteristics of soybean population between different cultivars. The individual indices and the population yield are lowly correlated,but the population indices and population yield are highly. The perfect individual plant traits do not mean the high yield per unit area. The experiment indicated that the canopy indices of population yield were more accurately evaluated by population indices.2. The leaf dry weight, stem dry weight, petiole dry weight, leaf area per plant, leaf area index of population and yield per plant indicated significant and highly significant positive correlation in R1 and R5 stage. The content of starch, soluble sugar, sucrose, nitrate nitrogen and free amino acids, the total activity of sucrose invertase and chlorophyll content showed significant and highly significant positive correlation with yield per plant in R1 and R5 stage. The radiation intensity in the 40-60cm layer, light transmittance at 0-10cm, 70-80cm layer and the yield per plant showed significant and highly significant positive correlation.3. In the R1 stage, the total amino acid content per unit area and yield per unit area showed positive correlation significantly. Furthermore,in the R5 stage, stem dry weight, the content of sucrose, total content of amino acid per unit area and yield per unit area were positive correlation significantly. There were significant negative correlations between the solar radiation intensity 0-20cm, 40-60 cm layers, light transmittance of 10-20cm, 50-60cm layers and yield per unit.4. The nutrition deficiency at different growth and development stage has an effect on soybean growth and metabolism to some extent. The results indicate that the critical regulation stages for plant type and yield are from VE to V3 stage because the nutrition deficiency can significantly reduce plant height yield. Furthermore, the R1 and R5 stages are the most important regulation period for soybean yield, and the nutrition deficiency can significantly decrease the yield. And the nutrition deficiency of the rest of stages will restore after nutrition applying from early and later stage. Stage nutritional deficiency has a certain effect on the plant shape, the carbon and nitrogen metabolism of soybean. However, the subsequent nutrition recovery produced the compensation effect and the evaluation indices restored. The nutritional deficiency is to the disadvantage of photosynthetic products transportation between the Source and Pool.5. The cultivar and density significantly affected the individual plant grain weight of soybean, as well as the interaction of density and chemical regulation technology. The promoting type plant growth regulator combined with the supply of inorganic nutrients can improve the yield per plant very significantly. The cultivar and density affected the population yield of the soybean per unit area significantly. The density and chemical regulation technology interaction had a significant impact on soybean yield, but does not reach significant level. Promoting type plant growth regulator and inorganic fertilizer application of nutrients can significantly improve the population yield of soybean. The effects of chemical regulation in different cultivars and different densities are different. The regulatory effects on yield per plant by chemical regulation technology and low-density populations of Kennong4 and Kanxian4 soybean was significant, as well as the population yield of Kennong4 soybean from low to high density populations.