污水灌溉对苜蓿生长下土壤部分理化性质的影响

Effects of Sewage Irrigation on Alfalfa Soil Partial Physical and Chemical Properties

通过盆栽试验研究了污水、再生水等不同灌溉水质对苜蓿三次刈割后土壤部分理化性质的影响。结果表明:相对于清水灌溉,污水及再生水处理能显著降低土壤pH值,增加EC值。第二次刈割时污水、再生水处理与清水相比土壤无机氮含量分别增加了63.59%和35.02%,第三次刈割时分别增加了82.18%和30.72%。与清水灌溉相比,污灌处理土壤Cd含量在三次刈割中分别增加了33%,117.65%和138.89%,再生水灌溉处理在三次刈割中分别增加了13.33%,64.71%和61.11%。根据《土壤环境质量标准》进行土壤重金属污染评价表明,在本试验期间各灌溉水质处理未引起土壤Pb污染,但未经处理的污灌处理造成了Cd污染。本研究初步说明污水采用混灌与轮灌方式可适当减缓其不利效应;再生水可作为苜蓿的灌溉用水,但其长期效应仍需进一步深入研究。

Pot experiments were conducted to study the effects of different irrigation water qualities on the partial physical and chemical properties of alfalfa soil.The results indicated that compared with fresh water irrigation（Q）,sewage（W） and reclaimed water（Z） significant decreased soil pH and increased soil EC.At the second and third clipping,W and Z irrigation increased soil inorganic nitrogen contents by 63.59%,35.02% and 82.18%,30.72% compared with Q respectively.Compared with Q,W increased soil Cd contents in three clippings by 33%,117.65% and 138.89%,and Z irrigation increased by 13.33%,64.71% and 61.11% respectively.Evaluation of heavy metal pollution in soil indicated that during the experiment period,all treatments didn＇t over soil Pb pollution threshold,but Cd was excessive according Standard Value of Soil Environment Quality of China.Accordingly,sewage after mixed or rotational with fresh water can properly decrease the adverse effects;reclaimed water can be used as a source of irrigation in alfalfa growth for a short period of time and their long-term effects should be concerned.