Study On Water Requirement And Water Use Efficiency Of Soybean Under The Condition Of Regulated Deficit Irrigation

Heilongjiang province is an important grain production base in China, one of the largest soybean producing areas. But the shortage of water resources, uneven distribution of rainfall, low of crop water use efficiency is the main factor limiting agricultural production in black soil region, therefore, research on water saving regulation in black soil region of Heilongjiang Province on the mechanism of rational use of limited water resources and further increase has important meaning of crop.In this paper, through the test in 2013 in Bei’an Farm Management Bureau of Heilongjiang Province, the Red Star Farm test base of the black soil region, soybean water production function and regulated deficit irrigation water consumption variation. This test adopts the potted way, in mobile rainproof shed. The soybean growth period from sowing to seedling emergence, seedling emergence into- branched, branches- blossom, Blossom- pod, Pod- drums, drum grain- grain mature 6 stages, in each growing stage 3 water treatment level, a total of 18 treatment.The soybean growth period is divided into 6 stages,including sowing- seedling emergence, seedling emergence- branched, branches- blossom, Blossom- pod, Pod- drums, drum grain- grain mature. in each growing stage 3 water treatment level, a total of 18 treatments.To set up the whole growing severe deficit, moderate deficit, slight water deficit the whole growth period of the appropriate water(moisture 80%, namely with the control treatment in different stages of different water deficit degree of contrast) and the whole growth period of abundant water treatment(moisture 90%), a total of 23 treatment.Through the study of the biological characters of soybean plant height, stem diameter of the study, analyzed the effect of different water treatments on these factors. By using the method of water balance deficit irrigation water demand in different growing stage of adjustment calculation, analysis of the soybean water requirement rules under different conditions of water supply and water use efficiency of soybean. Each growth stage under different water deficit conditions of water consumption and yield data, are fitted by Jensen model, getting the water production function suitable for the area of soybean, providing reference for soybean deficit irrigation conditions in regulating formulated under the reasonable irrigation system.The results show that:(1)Mild of Regulated Deficit Irrigation on soybean has little effect on plant height and stem diameter. Severe, moderate or high water regulated deficit can relatively inhibit the growth of plant height and stem diameter. the plant height, stem diameter and yield relationship showed that:Soybean yield increases first with the plant height, stem diameter increased as they reached the parabola apex, the plant height, stem diameter corresponding to soybean yield was the largest,After then the soybean yield with decreases with the increase of the plant height, stem diameter.(2)Soybean growth stage water consumption decreases as the order of pod bearing-pod filling、pod filling-maturity、branch-blossom、germination-branch、seeding- germination. Pod setting- pod filling stage has the lagest water consumption,seedinggermination was minimum.(3)The yield and water use efficiency first increases with increasing water consumption, while up to 62.5kg·pot-1, the water use efficiency reach the maximum value,Then the water use efficiency declined with the water consumption continues to increase, The yield increases to maximum with the water consumption to 84.76kg·pot-1, later than the maximum water use efficiency, then, production, water use efficiency decreased with the increase of water consumption.(4)Soybean seeding- germination stage is not suitable for light regulated deficit irrigation;germination-branch is suitable for that; branch-blossom and blossom-pod bearingnotsuitable for regulate deficit irrigation;at pod bearing-pod filling stage slight water deficit is conducive to the improvement of yield and water use efficiency;pod filling-maturity stage should maintain sufficient moisture gradient, not suitable for regulated deficit irrigation.(5)Establishment the soybean crop water production function model, analysis of relationship between water consumption and yield of soybean based on Jensen model,and to determine the sensitivity of soybean in different growth stages of water. Combined with the results of the analysis of the various stages of soybean for water sensitivity is: pod bearing-pod filling, blossom- bearing-pod, pod filling-maturity, branch-blossom, seeding- germination, germination-branch.In the background of lack of water resources, agricultural irrigation water is limited and the increasing demands for food,study of soybean water production function and regulated deficit irrigation water inconsumption,and to use the limited irrigation water resources to achieve maximum benefit efficiency is critical to the black soil area and provide favorable guarantee for water-saving high-yield.