| The Jinghui Canal irrigation Area is located in the middle of Guanzhong Plain of Shaanxi Province,which is one of nine irrigated areas in Guanzhong Plain and plays an important role to supply irrigation water to maintain high yield and stable production of Guanzhong Plain.With the improvement of irrigation technology and the expansion of planting area,the effective irrigation area and facility irrigation area of theJinghui Canal irrigation Area have been greatly improved.That has provided new development opportunities for the agricultural development in Guanzhong.Whereas,the most of the irrigation area is by means of surface irrigation,and the channel facilities have been in disrepair for a long time.The utilization rate of the field water is low,and the deep water leakage is serious,which causes more loss of water as well as restricts the sustainable development of agriculture here.In order to solve the problems above,this paper sets the length of three kinds of irrigation fields in the Jinghui Canal Irrigation Area with the length of 80 m(L80),120 m(L120)and 240 m(L240),and the width of all is 3m.The dynamic changes of soil water content before and after irrigation,and the distribution of soil water content in winter wheat and summer maize were studied under different lengths of field.Field water consumption and crop coefficient in different growth stages of winter wheat and summer maize were calculated.The main research results of this paper are:(1)Under the conditions of this experiment,the length of the field has a great influence on the spatial and temporal distribution of soil moisture,and the longer the field,the higher the average soil water content of the 2 m soil layer after single irrigation in winter wheat and summer maize.In the meantime,the long field(240 m)has serious leakage during the jointing stage of winter wheat,which is not conducive to water conservation.(2)After irrigation of all kinds of field,the average soil moisture content of the 2 m soil layer at different locations along the length of the winter wheat-summer maize was different.Under the same length of field,the rule of average soil moisture content of the 2 m soil layer of L80 and L120 after the irrigation in the period of winter wheat and summer maize is: the head of field > the middle of field > the end of field,but the rule of L240 is inconsistent.The rule of average soil moisture content of the 2 m soil layer is L80 < L120 < L240.(3)The water consumption per unit area in the field of winter wheat and summer maize increased with the increase of the length of the field.The water consumption in the field of winter wheat was L80(68.98 mm in seedling stage,126.40 mm in wintering period,275.77 mm in jointing stage,471.15 mm in growth period)< L120(74 mm in seedling period,133.50 mm in wintering period,292.13 mm in jointing stage,499.63 mm in growth period)< L240(90.75 mm in seedling stage,160.40 mm in wintering stage,354.27 mm in jointing stage,605.42 mm in growth period).The field water consumption of summer maize is L80(86.40 mm in seedling stage,178.63 mm in jointing stage,515.60 mm in growth period)< L120(93.67 mm in seedling stage,196.57 mm in jointing stage,536.23 mm in growth period)< L240(123.87 mm in seedling period,234.87 mm in jointing period,597.89 mm in growth period).(4)The total evapotranspiration of winter wheat during the growth period of Jinghuiqu Irrigation Area was 390.99-435.50 mm,and the crop coefficient increased first and then decreased.The crop coefficient in winter wheat seedling stage was 0.35-0.38,and the wintering period was 0.63-0.67.The jointing period was 1.15-1.21,the heading period was 1.28-1.34,and the maturity period was 0.49-0.53,which is related to the number of days after sowing.The total evapotranspiration during the growth period of summer maize in Jinghuiqu Irrigation Area was 357.62-369.01 mm,and the crop coefficient increased first and then decreased.The crop coefficient in summer maize seedling stage was 0.43-0.47,and the jointing stage was 0.79-0.83.The tasseling period was 1.29-1.35,and the maturity period was 0.73-0.80,which is related to the number of days after sowing.(5)The 2-year field experiment showed that under a certain length of growth,during the growth period of the crop,The field water use coefficient of winter wheat was seedling stage(L80 was 0.530,L120 was 0.516,L240 was 0.423)< Wintering stage(L80 was 0.650,L120 was 0.612,L240 was 0.530)< Jointing stage(L80 was 0.753,L120 was 0.698,L240 was 0.543).Field water use coefficient of summer maize was seedling stage(L80 was 0.595,L120 was 0.575,L240 was 0.454)< Jointing and tasseling period(L80 was 0.668,L120 was 0.625,L240 was 0.558).The field water use coefficient L80(0.525-0.774)was significantly higher than L120(0.508-0.723)and L240(0.420-0.578)during different growth stages of crops. |
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