Preliminary Study On The Mechanism Of Soybean Yield Increased By The Way Of High-Ridge And Platform On Low-wet Land Of Sanjiang Plain

This thesis is one sub-project of the task named 揟he Agricultural Synthetically Development Study on Low-wet Land of Sanjiang Plain?which belongs to 搕he NinthFive Years Plan of China? Three different genotype soybeans under two treatments, which ridge-height were 40 cm and 30 cm, were adopted in this experiment, and the control was ridge farming. The object of this study was to investigate the effect of the dynamics of soil ecological environment on soybean root growth, the change of leaf area and the regulation of dry matter accumulation. The results of this thesis would provide theoretical and practical directions for the soybean production of low-wet land not only in Heilongjiang Province, but also in all over the country.The results of this experiment showed that:1.Adopting high-ridge and plafform farming could enhance the soybean yield significantly. The yields of Dongnong 7819, Suinong 14 and Hefeng 25 were all the highest by the way of high platform, and then were by the way of normal platform, and the least were by the way of ridge farming. The yield differences of Suinong 14 and Hefeng 25 treated by three different farming ways attained a very significant level of 1%, and Dongnong 7819 attained a significant level of 5%. The correlative analysis between yield components and yield showed that pods per plant of each variety had a significant positive correlation with yield under the same tillage, and the number of seeds per pod had a negative correlation with yield, and 100 seeds weight had a positive correlation with yield. It showed that enhancing pods per plant is the chief cause of the increase of soybean yield under the condition of high-ridge and platform farming.2.The analysis of soil streture and the physicochemical characteristic showed that High platform and normal platform could decrease the volume weight of soil and regulate the three phase of soil compared with control. Thus, the allocation of soil, moisture and air was more favorable. The high-ridge and platform farming could decrease soil moisture and improve the average temperature of soil. The high-ridge and platform farming could also regulate the temperature by enhancing the temperature of daytime and lowering that of night. Owing to the regulation of physical characters of soil moisture, gas and heat and the improvement of the action of soil microorganism by high-ridge platform farming, the mineral change of organic matter in soil and the transferring and releasing of N. P, K were rapidly, and thus was favorable to the soybean root growth and the accumulation of dry matter and the change of leaf area.3.By adopting high-ridge and platform farming, the soil ecological environment became better, the growth of soybean root was stimulated and root density, dry weight and nodes number were much higher than that of control. The root density, dry weight and nodes number of different soybeans at the same growth stage showed that: high platform> normal platform > ridge farming.4.The dynamics of dry matter accumulation of three cultivars all showed ~S?curve. The change tendency of Leaf Area Index (LAI) was single peak curve. Dry matter accumulation and the change of LAI of different farming ways both showed that high platform > normal platform> ridge farming. Adopting high-ridge and platform farming was better to the soil ecological environment and soybean root growth, could increase dry matter accumulation and enlarge LAI. It was a solid foundation to enhance soybean yield.