| During two consecutive wheat growing seasons in 2015-2016 and 2016-2017,two widely planted cultivars Tainong 18?a cultivar with bigger ears and lower tillering capacity?and Shannong 22?a cultivar with middle-sized ears and higher tillering capacity?were selected as the experimental material.Four irrigation regimes including no irrigation?W0?,each irrigation with 45 mm?W45?,60 mm?W60?,75 mm?W75?were applied.Tainong 18was planted with four densities of 135?D135?,270?D270?,405?D405?and 540?D540?plants m-2;Shannong 22 was planted with four densities of 90?D90?,180?D180?,270?D270?and 360?D360?plants m-2.Researching the effects of irrigation quantity and planting density on water consumption characteristics,grain yield and water use efficiency of wheat field were studied.The research results show that:1 Effects of different irrigation regimes and planting density on winter wheat yield and its component factorsIrrigation and planting density significantly influenced winter wheat yield and its component factors.With the increase of irrigation regimes,the spike number per unit area of Tainong 18 and Shannong 22 was increasing,kernel per spike and kernel weight were decreasing,and the grain yield was decreasing after first rising.With the increase of planting density,the spike number per unit area of Tainong 18 and Shannong 22 was increased with each irrigation regimes.But the kernel per spike and kernel weight were decreasing,the yield of two varieties of winter wheat were increasing first and then decreasing,and when the planting density of Tainong 18 was D405,Shannong 22 planting density was D270,there was no significant difference in grain yield between two varieties of winter wheat under the condition of W45 and W60.Under the condition of W0,W45,W60 and W75,when the planting density from D135?D90?to D405?D270?of two varieties,yeild gradually increased,but the output increased gradually with the increase of irrigation quantity.It is suggested that on the basis of the current recommended per irrigation that is 60 mm,by reducing the amount of irrigation and increasing planting density can achieve stable production,and with the increase in irrigation,the increasing in planting density can increases the effect of increased yield significantly weakened.The changes of the dry matter accumulation in Tainong 18 and Shannong 22 were consistent with the grain yield in different irrigation and densities.2 Effects of different irrigation regimes and planting density on water consumption characteristics of winter wheatWith the increase of irrigation regimes,the total water consumption of Tainong 18 and Shannong 22 was increased.With the increase of planting density,the total water consumption of two varieties of winter wheat was increased first and then flat after each irrigation condition.When the planting density of two varieties of winter wheat increased from D135?D90?to D405?D270?,the total water consumption increased continuously,and the total water consumption did not increase significantly when planting density increased from D405?D270?to D540?D360?.Corresponding to the treatment of W0,W45,W60 and W75,the total water consumption of two varieties of winter wheat increased from D135?D90?to D405?D270?,and the effect increased with the increase of irrigation quantity.This from the narrow sense of water-saving is obviously not want to get results.However,the further analysis shows that the increase of planting density will help to improve the utilization of soil water in winter wheat,especially for the lower layer?1-2 m?soil water.With the increase of irrigation,the soil water consumption of two varieties of winter wheat in the 0-2m soil was decreased.In the amount of irrigation is W0,under the conditions of W45,W60 and W75,when the planting density increased from D135?D90?to D405?D270?of Tainong 18 and Shannong 22,two varieties of winter wheat increased the total soil water consumption in 0-2m soil,but the proportion of soil water consumption in 0-1 m soil was decreased,1-2 m the proportion of soil water consumption in 1-2m was increased.The total soil water consumption and the proportion of 1-2 m soil in 0-2 m soil increased with the increase of each irrigation amount.3 Effects of different irrigation regiems and planting density on leaf area index of winter wheatWith the increase of irrigation,the index of leaf area of Tainong 18 and Shannong 22increased first and then decreased.Under the condition of W0,W45,W60 and W75,before joinjing stage,the two winter wheat cultivars were increased with planting density,when planting density was D540?D360?of Tainong 18,and Shannong 22 the leaf area index reached the maximum.After Jointing stage,The leaf area index of two cultivars increased with planting density was first ascending and then decreased,when planting density was D405?D270?of Tainong 18,and Shannong 22 the leaf area index reached the maximum.The results show that reasonable irrigation and close planting can help to construct efficient groups,reduce the waste of resources,and contribute to the increase of leaf area index,thus laying the foundation for high yield and high efficiency.4 Effects of different irrigation regiems and planting density on soil evaporation and soil evaporation to total evapotranspiration of farmlandWith the increase of irrigation,the evaporation rate of Tainong 18 and Shannong 22 was increasing,while the plant population transpiration increased first and then decreased with the increase of irrigation quantity.Before jointing stage,the evaporation rate of two winter wheat was decreased with the increase of planting density,while the transpiration of plant population increased.After Jointing stage,with the increase of planting density,the evaporation of two varieties of winter wheat increased with the increase of planting density.When the planting density was D405?D270?,the evaporation reached the minimum,while the plant population transpiration increased first and then decreased with the increase of planting density,and the planting density was D405?D270?.,the population transpiration reaches the maximum value.Under different irrigation conditions,the ratio of evaporation of two varieties to total evapotranspiration decreased first and then increased with increasing planting density,the proportion of winter wheat planting density of two cultivars was D405?D270?,and the treatment of each irrigation volume W45 was significantly smaller than that of each irrigation amount in the least proportion of density treatment W60 treatment,which should be closely related to the change of leaf area index,it also shows that increasing the total water consumption after planting density and irrigation is more used for plant transpiration rather than evaporation,which is beneficial to improve water use efficiency.5 Effects of different irrigation regiems and planting density on water use efficiencyWith the increase of irrigation quantity,the increase of water use efficiency under the condition of optimum planting density is reduced,the planting density treatment of two varieties of winter wheat is D405?D270?,and the W45 of each irrigation quantity is significantly higher than that of each irrigation quantity W60,mainly because of increasing planting density and decreasing irrigation quantity,the absorption and utilization of the root of winter wheat to deep soil water was increased,and the ratio of evaporation to total evapotranspiration was reduced,thus the water use efficiency was improved... |
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