渗灌管埋深与灌溉量对枣树产量和水分利用效率的影响

Effects of depth and irrigation amount of subsurface infiltration irrigation pipes on water use efficiency and yield of jujube

探寻适宜的地下渗灌埋深和蒸发皿蒸发量系数组合对旱区枣树根系生长、产量和水分利用效率的影响。采用作物-皿系数(Kcp)作为灌溉水量计算标准,设3种地下渗灌埋深D15(15cm)、D30(30cm)、D45(45 cm)和4种灌水量W0.6(Kcp=0.6)、W0.8(Kcp=0.8)、W1.0(Kcp=1.0)、W1.2(Kcp=1.2)水平的2因素的大田试验。结果表明:随着灌水量的增加,各处理在垂直方向0~100 cm和水平距离0~80 cm土层中含水率越高;随着地下渗灌埋深的增加,土壤含水率峰值均向下移动。灌水量和地下渗灌埋深对20~80 cm土层的根系分布影响较大,D30W0.6和D30W0.8处理较其他处理提高20~60 cm土层的根系干质量密度,D45W1.0和D45W1.2处理较其他处理提高60~80 cm土层根系干质量密度。D30W1.0处理有利于增加枣树枣吊长度、每吊开花数、每吊座果数、座果率以及提高产量;2017和2018年D30W0.8处理水分利用效率最高分别为4.68、5.32 kg/m^3,并且产量较D30W1.0处理降低了9.32%、5.94%,但水分利用效率分别提高了17.88%、16.41%,D30W0.8处理水分利用效率与其他处理均有显著差异(P<0.05)。通过多元回归和空间分析方法,对产量、水分利用效率与枣树灌水方式进行优化,选择适宜的灌水量和地下渗灌埋深区间分别为:370~410mm、28~33 cm。该研究结果可为宁夏干旱地区地下渗灌枣树的高产高效管理上提供依据和技术支持。

Irrigation water in Yellow River is decreasing due to global warming,the uneven distribution of rainfall,serious surface evaporation and underground leaks.Water-use efficiency has posed a great challenge in the arid and semi-arid areas,particularly on western China,such as Tongxin County,Ningxia.To meet challenge,it is necessary to explore an efficient water-saving method using the depth of underground infiltration irrigation and pan evaporation coefficient.In this study,an experiment was performed on two factors and 12 treatments in three depths of underground infiltration irrigation:D15(15 cm),D30(30 cm),D45(45 cm),and four irrigation volume:W0.6(Kcp=0.6),W0.8(Kcp=0.8),W1.0(Kcp=1.0),W1.2(Kcp=1.2),where the crop-pan coefficient(Kcp)was used to evaluate irrigation volume,and the 7-year Tongxin round jujube was selected as the subject.The field experiments were conducted from January 2017 to December 2018 in the Water-saving and Efficient Agricultural Science and Technology Park(36°50′N,105°60′E)in the dry area of Wangtuan Town,Tongxin County,Ningxia,China.The spatial and temporal changes were investigated by soil moisture,annual growth of root system,agronomic traits,yield and water-use efficiency.Then,a spatial analysis was used to search the areas,where jujube yield and water-use efficiency were better matched,and to obtain the optimal underground level,where the irrigation range was determined by the depth of infiltration irrigation and crop-pan coefficient.The test results showed that the water contents in the soil from 0-100 cm in the vertical direction,and from 0-80 cm in the horizontal was higher than others with the increase of irrigation volume,whereas,the peak of soil water content moved downward with the increase in the depth of underground infiltration irrigation.The buried depth of 15 cm or 30 cm can increase the moisture content in the soil depth of 0-40 cm,while the buried depth of 45 cm can increase that in the soil depth of 40-60 cm.The irrigation volume and the depth of subsurface infiltration irrigation have a great impact on the root system distribution of 20-80 cm soil layer.There were significant differences in the root system increments under various subsurface infiltration irrigation depths.Specifically,the D30W0.6 and D30W0.8 treatments increased the root dry density from 20-60 cm soil layer,and the D45W1.0 and D45W1.2 treatments increased that from the 60-80 cm soil layer,compared with other treatments.Two-year experiments showed that the D30W1.0 treatment was optimum to increase the hanging length of jujube,the number of flowers per hang,the number of fruits per hang,fruit set rate and yield.The highest water-use efficiency of D30W0.8 was 4.68kg/m3 in 2017 and 5.32 kg/m3 in 2018,increased by 17.88%(2017),16.41%(2018),but the yield decreased by 9.32%(2017)and 5.94%(2018),compared with D30W1.0 treatment,indicating D30W0.8 treatment was significantly different from other treatments(P<0.05).Therefore,the yield and water use efficiency(WUE)can be used to optimize the irrigation strategies for jujube trees by using multivariate regression and spatial analysis.In this case,the optimal irrigation amount and the depth of subsurface infiltration irrigation can be selected as follows:370-410 mm and 28-33 cm,respectively.The finding can provide a sound basis and technical support for high efficient management of jujube trees during subsurface irrigation in arid areas of Ningxia,China.