污水灌溉对土壤浸提液元素浓度变化影响的田间试验研究

土壤化学元素的变化趋势关系到污水灌溉农业的可持续性。该文通过田间试验，研究了冬小麦和夏玉米轮作条件下2种灌溉水质和3种灌水量对土壤浸提液元素浓度变化的影响。试验结果表明：在自然降雨条件下，大水量污灌增加土壤盐分而中、小水量污灌则降低土壤盐分。试验用污水不会导致土壤的次生碱化。土壤中的Ca、Mg、Fe和Zn含量在试验期间增加而P、Mn、Cu、Cd和Ni减小。大水量污灌增加土壤中的Na和B含量而小水量污灌则降低其含量；K的变化趋势与其相反。污灌可补充土壤中的作物营养元素K和P，但降低污水灌水定额可有效抑制盐分、B和Zn在土壤以及重金属元素在作物中的累积。

Effects of effluent irrigation on the variation of chemical element concentrations of soil extractions under field conditions

Sustainability of effluent-irrigated agriculture depends on balance of soil chemical elements. Effects of two water qualities and three irrigation quotas on the variation of soil chemical element concentrations during successive planting period of winter wheat(Tricicum aestivum L.) and summer corn(Zea mays L.) were studied under field conditions. The experimental results indicated that irrigation with effluent water at great quota increased soil salinity, but irrigation at small quota and middle quota decreased it under natural rain conditions. The effluent water used in this study could not result in secondary alkalization of soil. After one-year planting, the concentrations of Ca, Mg, Fe and Zn of soil increased but those of P, Mn, Cu, Cd and Ni decreased. Na and B of soil cumulated when soil was irrigated with effluent water at a great quota but decreased when did at a small quota; the variation of K of soil had an opposite tendency with Na and K. Effluent irrigation may supply soil with extra nutritious elements K and P for plants; however, decreasing irrigation quotas of effluent water can effectively control the accumulations of salt, B and Zn of soil or heavy metals of plants.