模拟稻田生态系统对农村污水中磷的消纳

The Simulation of Sequestration of Rural Sewage Phosphorus in Rice-based Ecosystems

通过模拟试验研究了垄作、平作以及在不同施肥水平下,稻田生态系统对农村污水中磷的消纳效果。结果表明：TDP（总水溶性磷）浓度为2.0 mg/L的污水加入1 d后,稻田田面水中DRP（溶解态活性磷）和TDP浓度分别降低了22%-36%和6%-27%;3 d后,DRP和TDP浓度分别降低了73%-89%和53%-66%。各处理田面水中DOP（溶解态有机磷）浓度在污水加入后均迅速上升,3 d后达到峰值0.21-0.30 mg/L;7 d后DOP浓度平均降至0.11 mg/L。田面水中磷素的形态特征,在水稻生长发育前期,田面水中TDP主要以DRP形式存在,在水稻生长发育中期DRP和DOP的含量基本相同;在水稻生长发育后期DRP的百分含量又有升高的趋势。各处理田面水中CODcr,BOD5在污水加入后均迅速上升,3 d后达到峰值（CODcr为64.2-90.0 mg/L,BOD5为2.09-2.76 mg/L）,7 d后CODcr,BOD5降至较低水平（CODcr平均为35.0 mg/L,BOD5平均为0.76 mg/L）并保持较长时间,但是在水稻生长发育后期CODcr有上升的趋势。相关分析表明田面水中DOP与BOD5之间存在良好的线性关系,达到极显著水平。

Through a simulation test, the sequestration of rural sewage phosphorus in the rice-based ecosystems under ridge tillage, conventional tillage and different levels of fertilizer was studied. It was found that 1 day after the sewage （the total dissolved phosphorus concentration is 2.0 mg/L） was added, the DRP （dissolved reactive phosphorus） and TDP （total dissolved phosphorus） in surface water were reduced 22%-36% and 6%-27% respectively; and 3 days later , the DRP and TDP were reduced 73%-89% and 53%-66% respectively. The DOP （dissolved organic phosphorus） had a rapid rise after the sewage was added, 3 days later, they all reached the peak values （0.21-0.30 mg/L） ; but 7 days later, the mean of DOP was reduced to 0. 11 mg/L. At the early stage of rice growth, the main characteristics of phosphorus forms in surface water was DRP, and DRP percentage was basically similar as DOP at medium-term of rice growth, but the DRP percentage rised at he late stage of rice growth. The CODcr and BOD5 in surface water rised rapidly after the sewage was added, 3 days later, they all reached the peak values （CODcr were 64.2-90.0 mg/L, BOD5 and were 2.09-2.76 mg/L） ; 7 days later, the CODcr and BOD5 were reduced to lower levels and kept a long time, but the CODcr rised at he late stage of rice growth. Correlation analysis showed that there was a good linear relationship between BOD5 and DOP, and reached a very significant level.