| Light and moisture is an important environmental factor that affects the production process of crops,and its changes are bound to affect the growth,yield and water consumption of crops.Therefore,in order to investigate the effects of different light and irrigation amount on the growth,yield and water consumption of winter wheat,the experiment of controlling light and saving water in winter wheat was carried out.Four light control treatments were set up in the experiment: full light as the control group,covering off the full light of the canopy separately 8%,14% and 24%.At the same time,there are three kinds of water treatment were set up: full irrigation(field water holding capacity 70%-80%),mild deficit irrigation(field water holding capacity 60%-70%)and moderate deficit irrigation(field water holding capacity 50%-60%),the effects of different light intensity and irrigation on growth and development,yield and water consumption were researched for winter wheat.On the basis of field experiment,a simulation of winter wheat growth process was carried out using DSSAT crop model to evaluate the applicability of the model in the region.And utilization model to set up different light intensity and irrigation scenarios to simulate the yield and water consumption of wheat under different situation.Finally,the optimal light intensity and irrigation amount were determined that can balance high-yield and water-saving.The main research results as follows:(1)After light control,the canopy temperature of winter wheat decreases 2?-5 ?,the relative humidity of the canopy increases 3.3%-18.2%,soil temperature decrease 2?-3.5?,the growth process of winter wheat slows down and its growth period extension slightly;and water deficit promoted the growth process of winter wheat.(2)The leaf area index and plant height of winter wheat were decreased under light control and water deficit treatment.The greater the degree of light control and water deficit,the smaller the leaf area index and plant height of winter wheat.Moderate light control(8% light control treatment)can promote the yield(yield increase),winter wheat yield decreased under severe light control(14% and 24% light treatment);the yield of winter wheat was decreased under water deficit treatment,and the higher the degree of water deficit,the lower the yield of winter wheat.(3)0-40 cm the variation range of soil moisture content of winter wheat in soil layer was large.40-100 cm the variation of soil moisture content in soil layer was not obvious.After light control,winter wheat soil moisture content was increased,the water consumption was decreased,and the greater degree of light control,the less water consumption;when the light intensity was same,soil water content and water consumption of winter wheat were decreased with the increase of water deficit.(4)The DSSAT model has good applicability was verified in the area by field experiment data.The simulation results of the phenology,yield,the dynamic change of soil moisture and water consumption of winter wheat were good,the simulation accuracy of dynamic change of above ground biomass and leaf area index were relatively low,when the higher the degree of light control and the higher the degree of water deficit,the lower the simulation accuracy.(5)By analyzing the yield of winter wheat under light control conditions at different growth stages,it was found that light control during the heading-grouting period had the greatest impact on the yield of winter wheat,and the light control at the grain-maturation stage had the least effect on the yield of winter wheat.Different light intensity and irrigation amount were selected as a variable input parameter,and comprehensively analysis and evaluate the growth,yield and water use efficiency of winter wheat from DSSAT model.Under the precipitation conditions of 2017-2018,the combination of 10% light control degree,60 mm irrigation at the green stage and jointing stage were recommended as the optimal light control degree and irrigation pattern for the experimental area. |
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