三环追压非等灌对枸杞根系湿润体盐分的影响

Effect of three-ring pressure and unequal irrigation on salt content of root moist body of Lyceum Barbarum

针对新疆降水稀少、蒸发量大,土壤盐碱化面积不断蔓延,改良盐碱地用水量居高不下等问题,提出一种以作物为圆心滞后滴水的3环灌溉模式,探究其节水排盐效果.将枸杞作为研究对象,根据土壤湿润体内盐分运移规律,试验确定第1环、第2环、第3环的半径分别为5,10,15 cm.在滴水器流量为3 L/h的条件下,第1环(最内环)先开始滴水,2 h之后,其滴水产生的土壤湿润体脱盐范围超出第2环位置时,打开第2环滴水阀门;以此类推,2 h之后打开第3环滴水阀门,各环滞后滴水将根系发育范围内的盐分逐步追压至根系发育范围之外,从而达到节水排盐的效果.对晾干后土体采用剖面法取样测定不同位置的盐分含量,结果表明:环心附近的盐分少,离环心越远盐分含量越多;环心水平方向40 cm处不同深度取土检测盐分质量比:在(0,10],(10,20],(20,30],(30,40]和(40,50]cm分别为61.550,57.640,53.470,50.690和129.650 g/kg,表明土壤盐分积累在湿润体边缘,排盐效果良好;同时,试验的灌水定额为31.5 mm(315 m^(3)/hm^(2)),年总灌水量为1890 m^(3)/hm^(2),较常规滴灌条件下枸杞的年灌水量3450 m^(3)/hm^(2)节约了1560 m^(3)/hm^(2),节水效果显著.

Aiming at the problems of scarce precipitation,high evaporation,continuous spread of soil salinization area,and high water consumption in improved saline-alkali land in Xinjiang,a 3-ring irrigation mode with lagged dripping centered on the crop was proposed to investigate its water-saving and salt-drainage effect.Taking Lycium Barbarum as the research object,according to the salt transport law within the soil wetting body,the test determines that the radius of the 1st ring,the 2nd ring and the 3rd ring were 5,10 and 15 cm,respectively.Under the condition of dripper flow rate of 3 L/h,the 1st ring(the innermost loop)started dripping first.After 2 h,when the desalination ranges of the soil wetting body produced by the dripping exceeded the position of the 2nd loop,then the drip valve of the 2nd loop was opened.By analogy,after 2 h,the third loop drip valve was opened,and each loop lag drip would root development range of salts gradually chase pressure to the root development to outside the range,thereby achieving the effect of water-saving and salt discharge.The profile method was used to sample and measure the salt content at different positions of the soil after drying.The results show that there is less salt near the loop center,and the farther away from the loop center the higher the salt content.Soil samples are taken at different depths of 40 cm in the horizontal direction of the center of the ring to test the salt mass ratio:61.550,57.640,53.470,50.690,and 129.650 g/kg are taken at(0,10],(10,20],(20,30],(30,40],and(40,50]cm,respectively,which indicate that soil salts accumulate at the edge of the wetted body and the effect of salt exclusion is good.At the same time,the irrigation quota of this experiment is 31.5 mm(315 m^(3)/hm^(2)),and the total annual irrigation water volume is 1890 m^(3)/hm^(2),which is higher than that of the conventional drip irrigation conditions.The annual irrigation volume of Lycium Barbarum is 3450 m^(3)/hm^(2),saving 1560 m^(3)/hm^(2),and the water-saving effect is remarkable.