宁夏引黄灌区丰水年型苜蓿草田生长季地下滴灌灌溉制度研究

Research on Subsurface Drip irrigation Schedule for Growth Season Alfalfa Fields in Wet Year in Ningxia Yellow River Irrigation Area

以苜蓿草田生长季地下滴灌灌溉制度为研究目标,采用完全随机设计开展地下滴灌不同土壤含水量下限控制试验,通过对各茬次苜蓿生长、水分利用及产量指标的系统分析,采用隶属函数法进行定量评价,确定各茬次苜蓿适宜土壤水分下限指标,建立宁夏引黄灌区苜蓿草田丰水年型地下滴灌灌溉制度。结果表明:不同土壤含水量下限条件下,各处理干草产量随收获茬次的延续逐步下降,但土壤含水量下限高于田间持水率60%的各处理间产量差异达不到显著水平;苜蓿干草产量与分枝数、茎叶比、鲜草产量、耗水量相关关系极显著,与株高相关关系显著,分枝数和茎叶比对产量的影响大于株高,株高在收获的各茬中均呈现先升高再下降的2段式变化过程,分枝数随收获茬次的延续而逐步下降,茎叶比随灌溉定额的下降而逐步减少;各茬灌水量通过影响耗水量而影响苜蓿茎叶比,进而影响株高和分枝数来影响干草产量;宁夏引黄灌区丰水年型苜蓿草田生长季地下滴灌灌溉制度为:灌溉定额3410.95 m^3/hm^2,灌水17次,第一茬灌水定额230.5 m^3/hm^2,灌水4次,灌水周期7d,灌水量为922 m^3/hm^2;第二茬灌水定额276.5 m^3/hm^2,灌水3次,灌水周期7 d,灌水量为829.5 m^3/hm^2;第三茬灌水定额138.3 m^3/hm^2,灌水8次,灌水周期4d,灌水量为1106.4 m^3/hm^2;第四茬灌水定额276.5 m^3/hm^2,灌水2次,灌水量为553 m^3/hm^2;各茬次适宜的土壤含水量下限分别为田间持水率的70%、60%、80%和60%。

Taking the subsurface drip irrigation schedule for growth season alfalfa fields as the research object,this experiment adopts completely random design to carry out the soil water content lower limit control test under subsurface drip irrigation.Based on the comprehensive analysis of growth,water use and production indexes of each stubble alfalfa,the subordinate function method is adopted to carry out the quantitative evaluation to determine the suitable lower limit of soil water index of each stubble alfalfa and then set up the subsurface drip irrigation schedule for growth season alfalfa fields in wet year in Ningxia yellow river irrigation area.The results show that:under different lower limits of soil moisture content,the hay yield of each treatment decreases gradually with the increase of stubbles,but the yield difference between different treatments can not reach a significant level when the lower limit of soil moisture content is higher than 60%of field moisture holding rate;the correlation between hay yield and branch number,stem-leaf ratio,fresh yield and water consumption is very significant,and the correlation with height is significant;the effect of branch number and stem-leaf ratio on yield is greater than that of plant height;plant height in all harvested stubble shows a two-stage change process of first increasing and then decreasing,branch number decreases gradually with the continuation of harvested stubble,stem and leaf ratio decreases gradually with the decline of irrigation quota;the irrigation amount of each stubble affects the stem and leaf ratio of alfalfa by affecting the water consumption,and then affects the plant height and branch number to affect the hay yield.The irrigation schedule of subsurface drip irrigation for growth season alfalfa fields in wet year in Ningxia yellow river irrigation area is:irrigation quota 3410.95 m^3/hm^2,irrigation 17 times,the first stubble irrigation quota 230.5 m^3/hm^2,irrigation 4 times,irrigation cycle 7d,irrigation water amount 922 m^3/hm^2;the second stubble irrigation quota 276.5 m^3/hm^2,irrigation 3 times,irrigation cycle 7 d,irrigation water amount 829.5 m^3/hm^2;the third stubble irrigation quota 138.3 m^3/hm^2,irrigation 8 times,irrigation cycle 4d,irrigation water amount 1106.4 m^3/hm^2;the fourth stubble irrigation quota 276.5 m^3/hm^2,irrigation 2 times,irrigation water amount 553 m^3/hm^2;the suitable lower limit of soil moisture content for each crop was 70%,60%,80%and 60%of field moisture holding rate respectively.