絮凝泥沙对中度盐渍化土壤氮素淋失及水分利用效率的影响研究

Effect of Flocculated Sediment on Nitrogen Leaching and Water Use Efficiency from Moderately Salinized Soil

氮素淋失是主要的氮肥损失方式之一,不仅降低了氮肥利用效率,同时造成水体污染严重等负面影响。黄河水滴灌中利用水梦吸附剂进行水沙分离时会产生絮凝泥沙,为了有效利用絮凝泥沙资源、实现废弃资源再利用。通过室内土柱模拟试验,探讨絮凝泥沙对中度盐渍土的水力特性、氮素淋失、pH及电导率的影响规律。试验共设5个处理,絮凝泥沙施用比例分别为0(CK)、20(T1)、40(T2)、60(T3)、80(T4)g/kg,每个处理3个重复。施用絮凝泥沙能改善盐渍化土壤的水力特性,处理T1、T2、T3、T4的持水能力随絮凝泥沙施用比例的增加呈现逐渐升高的趋势;絮凝泥沙能够有效提高砂壤土对氮素的吸持能力,随着絮凝泥沙施用比例的增大,土壤淋溶液中氮素浓度呈逐渐减小的趋势,氮素累积淋溶量也逐渐减小,处理T1、T2、T3、T4淋溶液中氮素的淋失总量较CK分别降低了3.4%、6.18%、8.06%和11.27%;絮凝泥沙对不同处理盐渍化土壤的pH值无显著影响;当絮凝泥沙使用量不超过60 g/kg时,可以降低土壤电导率值,但效果不显著。絮凝泥沙施用量为40~60 g/kg时,能够有效改变盐渍化土壤的理化性质,降低土壤氮素的淋失量,进而可提高土壤氮素的利用效率,降低地下水面源污染的风险。

Nitrogen leaching is one of the main ways of nitrogen loss,which not only reduces nitrogen use efficiency,but also causes serious water pollution and other negative effects.In the drip irrigation with the Yellow River water,flocculation and sediment are produced when Water Dream adsorbent is used to separate water and sediment.In order to effectively utilize the flocculation and sediment resources,the waste resources can be reused.This paper discussed the effect of flocculated sediment on the hydraulic characteristics,nitrogen leaching loss,pH value and conductivity of moderately salinized soil through the indoor soil column simulation test.Five treatments were set up in the experiment.The proportion of flocculated sediment was 0(CK),20(T1),40(T2),60(T3)and 80(T4)g/kg,respectively.Each treatment was repeated for three times.The results show that the application of flocculated sediment can improve the hydraulic characteristics of salinized soil,and the water holding capacity of T1,T2,T3 and T4 increases with the increase of the proportion of flocculated sediment;the flocculated sediment can effectively improve the nitrogen holding capacity of sandy loam,and the nitrogen concentration in the soil leaching solution decreases with the increase of the proportion of flocculated sediment.Compared with CK,the total amount of nitrogen leaching in T1,T2,T3 and T4 leaching solution decreased by 3.4%,6.18%,8.06%and 11.27%,respectively;the pH value of salinized soil was not significantly affected by flocculated sediment;when the amount of flocculated sediment was less than 60 g/kg,the soil conductivity value could be reduced,but the effect was not significant.When the amount of flocculated sediment is 40~60 g/kg,it can effectively change the physical and chemical properties of salinized soil,reduce the amount of nitrogen leaching,improve the efficiency of nitrogen utilization,and reduce the risk of non-point source pollution of groundwater.