Study On Response Regularity Of Water Requirement Regulation And Growth Index Of Winter Wheat In Yunnan Plateau Region

Due to the impact of the plateau landform and special climate of Yunnan Province,the space distribution of water resources is uneven,and available water resources are scarce.Coupled with the accelerated development of industrialization and urbanization in recent years,rapid increase of industrial and domestic water,and the occupation to agricultural water,the agricultural water is particularly tense in the parts area of the province.Therefore,the study of water demand regulation of daily growth period and different irrigation method from the point of view of crop physiological growth is import to explore the key storage period,to select suitable irrigation methods and to develop reasonable irrigation system.In this study,it takes full irrigation and regulated deficit irrigation,takes pot experiment of winter wheat as method,and takes the soil water content as control variate to monitor the growth indicators of each growth stages of winter wheat.The soil water content was measured by TDR.The evaporation was measured by water balance method.The correlation between the treatments and the yield was analyzed by F test and t test.Finally,the water demand regulation of winter wheat in Yunnan Plateau area was obtained.The main conclusions are as follows:(1)The total growth period of winter wheat in Yunnan Plateau is about 148 days,and the daily water requirement is 2.8mm.In the seedling stage,the water requirement of winter wheat showed oneincrease of linear regression equation.In the middle and early tillering stages,the water requirement of winter wheat showed six-time change of linear regression equation.During the period,the water demand of winter wheat reached the maximum,and the trend was unimodal parabolic shape,;in the later stage of tillering,the physiological activity decreased with the decrease of temperature,the water demand decreased,and the lowest temperature was reached before and after the lowest temperature;after entering the jointing-booting stage,the water demand of winter wheat slowly recovered and finally converged to the daily water demand.(2)Under different water stress conditions,the water demand regulation of winter wheat was significantly different.The stage of largest difference was the premetaphase of tillering stage;and the stage of medium difference was the seedling stage;the stage of the smallest difference was jointing-booting stage,heading and filling stage,and maturation stage.Among them,the differencesof treatment 1(full irrigation)and treatment 2(80% ~ 90% field capacity),treatment 3(70% ~ 80% field capacity)and treatment 4(60% ~ 70% field capacity)are not significant.It has significant difference of treatment 5(50% ~ 60% field capacity)to other treatments.(3)The growth and yield of winter wheat were significantly affected by different drought levels.During the seedling stage,when the soil water content was 60% or less of the field capacity,the winter wheat is seriously reduced;when the soil water content is 60% ~ 70% of the field capacity,the winter wheat was reduced in a certain degree;when the soil water content is more than 70% of the field capacity,the growth of wheat seedling was normal.During the tillering stage,when the soil water content was less than 70% of the field capacity,the water demand under the normal growth condition was significantly different.During the jointing-booting stage,heading and filling stage,and maturation stage,the growth of wheat was less affected by water stress,and the difference was not significant.Among them,when the growth during seedling stage and tillering stage was normal,it had no significant difference in the yield of full irrigation and the deficit irrigation with the highest soil water content irrigation.Itindicates that the soil water content during the irrigation can be kept between 80%~90% of field capacity,and thenthe yield of wheatcan be guaranteed.