施用方式对赤红壤坡地上污泥铜随径流迁移的影响

Effect of application method on copper transport by runoff from sloping lateritic red soils amended with sewage sludge

  • 摘要: 研究了以撒施、撒施+草和穴施方式施用于赤红壤坡地上污泥中的Cu在人工降雨条件下随径流的迁移情况。结果表明, 污泥撒施后的前期(1 d和18 d)径流中混匀样总Cu(MTCu)、静置样总Cu(STCu)、颗粒态总Cu(TPCu)、悬浮态总Cu(TSCu)和可溶性总Cu(TDCu)浓度和流失量均达到峰值, 其中MTCu、STCu浓度和流失量峰值分别为1 674.9 mg·L-1、105.4 mg·L-1和21.59 mg·m-2、1.32 mg·m-2, 分别是穴施和撒施+草对应峰值的4.2~13.7倍和5.4~24.9倍; 此后Cu浓度和流失量均逐渐降低。与撒施相比, 撒施+草径流中各形态Cu浓度和流失量削减率可分别达72.8%~91.7%和91.4%~97.1%, 穴施对应削减率则可分别达78.2%~89.9%和68.6%~82.9%。撒施、撒施+草和穴施MTCu径流流失系数分别为0.83%、0.03%和0.26%, 穴施和撒施+草均可有效防止污泥Cu的流失, 但以撒施+草效果最好。颗粒相Cu是Cu流失的重要形式。

     

    Abstract: The effects of different application methods of sewage sludge on Cu transport by runoff from sloping plots in lateritic red soils were investigated under simulated rainfall conditions. When the sludge is broadcasted and mixed with surface soils, the concentrations and loss of MTCu (total Cu in mixed sample), STCu (total Cu in settled sample), TPCu (total particulate Cu), TSCu (total suspended Cu) and TDCu (total dissolved Cu) in runoff are highest on the 1st and 18th day after application. The peaks of concentration and loss of MTCu, STCu are 1 674.9 μg·L-1, 105.4 μg·L-1 and 21.59 mg·m-2, 1.32 mg·m-2, which are respectively 4.2~13.7 and 5.4~24.9 times of corresponding peak values under hole-application and broadcast-application with hay mulch. After that, both the concentration and loss of Cu gradually decrease with the treatment time. Broadcast-application with hay mulch reduces Cu concentration in runoff by 72.8%~91.7% and Cu loss via runoff by 91.4%~97.1%, compared with the broadcast-application alone. Cu concentration in runoff and Cu loss via runoff reduce by 78.2%~89.9% and 68.6%~82.9% respectively under hole-application, compared with those under broadcast-application. MTCu loss coefficients via runoff are 0.83%, 0.03% and 0.26% for broadcast-application, broadcast-application with hay mulch and hole-application. Hole-application, but especially broadcast-application with hay mulch, is effective for controlling Cu loss by runoff. Particle-bound Cu is the major form of Cu loss via runoff.

     

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