宁夏灌区水面植稻净化农田退水效果研究

Purification of Irrigation Return Flow by Cultivating Rice on Water Surface in Ningxia Irrigation Area

利用生物浮床技术,将水稻移栽到农田退水水面,利用农田退水进行水稻无土栽培。试验设置引入农田退水的培养池中植稻和退水沟中水面浮床植稻二种栽培方式,并以大田栽培水稻为对照,研究水稻生长状况及对农田退水的净化效果及水稻籽粒品质状况。试验结果表明:①水面浮床植稻对农田退水具有很好的净化作用。在培养池中,农田退水TN的去除率可达到90.33%,而排沟中水体处于流动状态,大多数时间水中TN处于较高的浓度;水稻生长状况退水沟中水面浮床植稻优于培养池水面植稻,退水沟中水面浮床植稻植株直接带出水体的氮素更多。②农田退水水面植稻所栽培的水稻籽粒,重金属含量低于国家的重金属污染物限量标准。③水面浮床植稻净化农田退水是一个水稻、浮床、退水等综合作用的结果,通过合理调节各个因素,创造良好的生态小环境,有利于农田退水的净化和水稻的产量形成。

With biological floating-beds, rice can be transplanted on the surface of irrigation return flow and grew in the water without soil. During the experiment, some rice was grown in pools with irrigation return flow and some was planted in the river. Rice growing in farmland was the control group. The studies on their growth status and the purification effect on NH4^＋ -N, NO3^--N, TN were in time. Nitrogen contents and heavy metal contents were examined. The result indicated that： ①The removal efficiency of rice cultivated on surface of water by floating-beds was very good. The removal rate of TN in the cultivate pools respectively reached 90.33%. In waterway, the irrigation return flow had a high concentration of TN, so rice grown better, more nitrogen can be bring out from the water. ②The heavy metal contents of rice cultivated on surface of water were less than their corresponding heavy metal pollution limits. ③Purification of irrigation return flow by plants growing in floating-beds is a comprehensive effect of rice, floating-beds and irrigation return flow. The effect of purification and production can be improved by changing factors properly.