城市污水再生水灌溉对黑麦草生长及土壤磷素转化的影响

Effect of reclaimed municipal wastewater on ryegrass growth and soil phosphorus conversion

为了进一步明确城市污水再生水的农业利用价值,在温室条件下采用盆栽试验方法种植黑麦草,以自来水(clean water,CW)灌溉为对照,分别进行全再生水(reclaimed municipal wastewater,RW)和混合再生水(自来水+再生水,CW+RW,1∶1)灌溉处理,研究了再生水灌溉对黑麦草生长和土壤磷素的转化特征。结果表明,城市污水再生水灌溉显著增加了黑麦草地上部和根系的生物量,CW+RW处理黑麦草地上部和根系生物量在播种55 d后分别较对照(CW)增加18.92%和6.42%,RW处理分别增加26.79%和10.55%;黑麦草地上部磷含量分别显著增加8.48%和10.93%。再生水灌溉土壤全磷含量变化不大并有减少趋势,但土壤速效磷含量CW+RW和RW处理分别较对照(CW)增加29.15%和43.80%;CW+RW和RW处理显著增加了土壤有机磷组分中的活性有机磷和中活性有机磷,与对照CW相比,其中活性有机磷增幅分别为50.30%和81.57%,中活性有机磷增幅分别为7.66%和13.68%;也显著增加了无机磷组分中的Ca2-P和Ca8-P,CW+RW和RW处理Ca2-P含量由对照的12.90 mg·kg-1分别增加到16.42 mg·kg-1和15.49 mg·kg-1,与对照相比,增幅分别为27.29%和19.38%,Ca8-P增幅分别为19.94%和16.03%。再生水灌溉显著降低了土壤pH并显著增加了土壤有机质含量,这可能是增加土壤磷活性的原因之一。再生水灌溉对提高土壤磷素利用率有促进作用。

Ryegrass was irrigated with reclaimed municipal wastewater （RW）, 1 ： 1 clean water and reclaimed municipal wastewater （CW＋RW） and clean water （CW） as the control in the pot experiment in a greenhouse to study the effects of reclaimed municipal wastewater on ryegrass growth, conversion characteristics of soil phosphorus and the implications for agricultural production in China. The findings suggested that in comparison with the control, reclaimed municipal wastewater significantly increased aboveground and root biomass of ryegrass. While CW＋RW increased aboveground and root biomass by 18.92% and 6.42%, RW increased these parameters by 26.79% and 10.55%, respectively. CW＋RW and RW increased P concentration in aboveground rye-grass by 8.48% and 10.93%, respectively. Reclaimed municipal wastewater irrigation apparently reduced total soil P concentration. Olsen-P concentration was significantly increased, respectively, by 29.15% and 43.80% under CW＋RW and RW treatments. CW＋RW and RW also increased active organic phosphorus concentration by 50.30% and 81.57%, respectively. They, however, increased moderately active inorganic phosphorus by 7.66% and 13.68%, respectively. Ca2-P concentration was enhanced under CW＋RW and RW treatments, increasing from 12.90 mg·kg-1 of the control to 16.42 mg·kg-1 and 15.49 mg·kg-1 with increment of 27.29% and 19.38%, respectively. CW＋RW and RW also increased Cas-P concentration by 19.94% and 16.03%, respectively. Reclaimed municipal wastewater irrigation increased soil P activity by decreasing soil pH and significantly increasing soil organic matter content. Reclaimed municipal wastewater irrigation was definitely improved soil phosphorus utilization efficiency.