Study On Physiological Basis Of Yield And Influences On Aftercrop By Covering Film Between Furrows Cultivation In Soybean

As a major producing area of spring soybean, Heilongjiang province is also threaten with drought and it becomes as a major factor for reducing yield of soybean. Data from Meteorological Science Research Institute of Heilongjiang province indicated that 50% of 16 agro-climatic zone were arid and semi-arid which occupied 60% of the total soybean planting area of Heilongjiang province. During spring, drought is the major climate performance while it is also the stage of pod setting and seed filling for spring soybean. Therefore, to improve the production of soybean, it is important to develop dry farming and water-saving irrigation system. There are two important techniques to maintain soil moisture, one is farmland capital construction and the other is applying conservation tillage technology. For conservation tillage, cultivation technique, film mulching is one of the major approaches.The cultivation technique of covering film between furrows in soybean was proposed based on summarizing all the drought-resistance tillage in past years by Daxijiang farm of 93 branch bureau in Heilongjiang province, and referring the research results of other crops in water saving and temperature increasing by film mulching. The purposes of this study were to verify yield-increasing effect of the covering film between furrows cultivation technique in soybean and to definite the proper time to remove plastic film and to find suitable planting area, and to reveal yield physiological basis and it's influence on aftercrop by covering film in soybean. In this study, high photosynthetic efficiency soybean variety Heinong 40, high yield variety Suinong14, high yield strain Heihe97-1271, Maize variety, Haiyu6 and wheat variety Bari were used as research materials. The treatments included covering film between furrows, uncovering film between furrows, differing the time of film uncovering, the volume of used plastic film, the size of used plastic film, and no-covering film between furrows as control. Yield physiological basis and influence on aftercrop by covering film between furrows cultivation in soybean were studied, followed was the results.1. Covering film between furrows technique in soybean was adapted to extend at arid and semi-arid area. It was an effective cultivation technique to increase yield.in those area and the optimum time to uncovering plastic film was at R₅ stage. The range of yield increase was changed by drought degree, general yield increase was 13.55%-25.4%, and the net profit was 22.45-66.95 Yuan. The effects on protein and fat contents should be studied later. 2. The photosynthetic rate of soybean by covering film between furrows was higher than that of control at different growth stage. The light saturation was increased by 15.4% than that of control, and CO₂ compensation point was lower than that of control. The leaf area index, photosynthetic potential, net photosynthetic rate and nitrogen fixation ability were higher than that of control. Biomass and economic yield were also higher. For Heinong40, the biomass and economic yield by covering film between furrows was increased 27.4%-34.6% and 21%-25.4% respectively.The reason was that leaf photosynthetic capacity, nitrogen fixation ability and group photosynthetic productivity were increased, leaf aging was delayed. It was beneficial to synthesize photosynthate and distribution reasonably, and the yield was increased. Therefore, the physiological basis of yield increase by covering film between furrows in soybean was that the photosynthetic capacity of group and single leaf, nitrogen fixation ability and group photosynthetic productivity were improved, which improved to accumulate and distribute photosynthate, and led to higher yield.3. The field exhibition experiment used Heinong40 by Covering film between furrows cultivation, The soil temperatures of different layers were higher than that of control before sealing ridge,the soil temperature was changed during daytime and growth stage, ant maturity have not been advanced .Soil relative water content was increased , soil bulk density was decreased and the number of soil microorganism was increased. The content of soil available N, available P, available K became higher while the soil pH was decreased slightly. The results could be concluded that there are significant effect on soil ecological and yield physiological basis by covering film between furrows to increase soybean yield.4. After one year of covering film between furrows cultivation in soybean, the growth stage, agronomic characters, main diseases, kernel traits, quality traits and yield of maize variety Haiyu6 were not influenced significantly. It indicated in principium that there was no negative affecting to aftercrop maize by one year of covering film between furrows in soybean.5. Growth of wheat Bari was influenced by the time of film application and the size of be-left plastic film. Leaf area index at jointing stage, booting stage and filling stage were decreased. Soil moisture and soil capacity were decreased also, which made the soil too loosed to conserve the air and then the yield was decreased. So the best way to solve the problem was to develop degradable properties film .6. The results suggested to extend the technology of covering film between furrows in soybean in Heilongjiang province. The soil ecological effects was improving by covering film between furrows in soybean and the photosynthetic capacity of group and single leaf, the nitrogen fixation ability and the group photosynthetic productivity were improved as well, then it was helpful to accumulate and distribute photosynthate. By comprehensive effect of all these factors the yield of soybean was increased significantly. That was the physiological basis of yield increase by covering film between furrows in soybean.Study on physiological basis of yield and influences on aftercrop by covering film between furrows cultivation in soybean...