| In order to provide a theoretical basis and technical support for summer soybean cultivation with high yield and water saving.The field experiments were conducted in summer soybean(Heihe 43) field with 4 drip irrigations: 3000 m3·ha-1(W1),3600 m3·ha-1(W2),4200m3·ha-1(W3),4800 m3·ha-1(W4)by using of randomized block experimental design to study the effect of different drip irrigation on phot osynthetic characteristics, dry matter accumulation,distribution and transportation,nutrient absorption characteristics, yield and quality of summer soybean in north Xinjiang. The main results as follows:1. Effect of drip irrigation on the photosynthetic characteristics:both LAI and SPAD during the whole growth stage were in following order: W3>W4>W2>W1,From flowering stage to graining stage, with the increasing irrigation,net photosynthesis rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),water use efficiency of leavs(WUEL) and stomatal limitation value(Ls)increased firstly, and then decreased, intercellular CO2 concentration(Ci) showed in reverse.2. Effect of drip irrigation on distribution of pod and seed: with the increase of the drip irrigation quota,the plant height, average internode length, position of pod setting and bottom pod height increased,and there was significantly negatively correlated(R =-0.998) between plant height and stem diameter;in addition, affected by irrigation amount,the proportion of the number of pods and seeds per plant declined in lower layer while increased in the upper layer, but had little influence on middle layer.3. Effect of drip irrigation on dry matter accumulation,distribution and nutrient absorption characteristics:the dry matter accumation,N,P2O5 and K2 O of summer soybean were fitted by using the Logistic equation. The accumulation amounts of dry matter per plant of summer soybean showed increased first and then decreased with the increasing of drip irrigation,and the same as N,P2O5 and K2 O content of summer soybean.The fastest accumulation rate of total dry matter of summer soybean was from 49.5 to 53.0 days after the emergence,and the rapid growth period of total dry matter accumulation was from 30.3 to 31.9 days,the maximum average accumulation rate was about 0.48 g·plant-1·d-1, the fast accumulation rates of N,P2O5 and K2 O were 47.1 to 49.9 d,44.8 to 45.1 d and 44.6 to 46.1 d after the emergence,the rapid accumulation period were 31.7 to 36.4 d,22.2 to 22.4 d and 28.7 to 31.46 d,respectively,and the average absorption intensity were 26.35,8.15 and 9.30 mg·plant-1·d-1.4. Effect of drip irrigation on water use efficiency,yield and quality:the relationship between yield and drip irrigation amount at heading was a quadratic curve,and t he yield was highest in W3(3741.23 kg·ha-1),which higher 30.42%,13.98% and 8.44% than W1,W2 and W4,respectively,reached a significant difference in level p<0.05.The irrigation water use efficiency had no significant difference between treatment W1,W2 and W3,but all of them were higher than treatment W4. The grain protein was increased with the increasing of drip irrigation while decreased on the fat content, the correlation relationship between fat and grain protein content was negative(R=-0.77), and total contents of protein and fat was highest in W3(53.03%). |
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