地下水浅埋区重度盐碱地滴灌不同种植年限对土壤酶活性的影响

Effects of Different Planting Years on Soil Enzyme Activities in Saline-sodic Soil with Shallow Water Table Under Mulch-drip Irrigation

为了解在地下水浅埋区重度盐碱地上长期覆膜咸水滴灌对土壤酶活性的影响,文章通过时空转化的方法研究了覆膜咸水滴灌种植枸杞1年、2年和3年的盐碱地土壤碱性磷酸酶、脲酶和蔗糖酶活性的变化及土壤酶活性在0～40 cm土壤剖面上的分布特征,并利用数学方法探求土壤酶活性与土壤环境因子之间的相关分析,同时以试验地附近未种植的盐碱荒地作为对照。结果表明3种土壤酶活性均随土壤利用年限的增加而增大,经过3年种植后,土壤碱性磷酸酶、脲酶和蔗糖酶活性分别从未经滴灌种植时的1.29、0.73和7.23μg/(g.h)增加到14.5、4.48和158.1μg/(g.h);在水平和垂直方向上,土壤碱性磷酸酶和脲酶活性在覆膜滴灌种植后均随水平距离和土层深度的增加而减小,蔗糖酶在各方向波动性较大,没有明显规律;土壤酶活性在滴头下方的空间分布表明,在作物生育期结束时,各年限处理土壤酶活性在剖面均呈以滴头为圆心的椭圆形分布,自滴头向外径向减小;土壤酶活性与土壤环境因子之间的相关性随着土壤利用年限的增加而提高,可以作为土壤环境指标表征盐碱土土壤质量,覆膜滴灌3年后,影响土壤酶活性的主要是土壤养分。

To provide the theoretical basis for reasonable exploitation and sustainable utilization of saline-sodic soil, the changes and distributions of soil enzyme activities as well as their relationships with principal soil environmental factors were investigated in saline sodic soils planted in different planting years （1a, 2a, 3a） under mulch-drip irrigation, while the uncropped saline waste land adjacent to the experiment site was taken as the control （CK）. The method of time-space transformation was used in the experiment design. The result showed that the activities of alkaline phosphatase, ureasc and invcrtasc increased with planting years, increased from 1.29, 0.73, and 7.23 μg/（g·h） respectively of the new bed to 14.5, 4.48, and 158.1 μg/（g·h） respectively of the bed planted for three years; soil alkaline phoshatase and urease activities decreased with increasing lateral distance and soil layer depth to the dripper after soils being planted while the variation of soil invertase activities was not obvious. The distributions of soil enzyme activities in soil profiles under mulch-drip irrigation were like ellipse, and soil enzyme activities increased radially. Rclationship between soil enzyme activities and principal soil environmental factors increased as planting years increased. ARer planting for three years soil available nutrients were the primary factors which influenced soil enzyme activities.