洱海流域灌水模式对稻田可溶性氮磷浓度的影响

Effects of Irrigation Patterns on Solubility Nitrogen and Phosphorus Concentrations in Paddy Field of Erhai Lake Basin

面源污染是全球水环境污染治理面临的严峻挑战之一,氮磷污染是面源污染重要的组成部分。为了探索洱海流域水稻种植较优的灌水模式以促进农业生产和减少面源污染,开展了稻田不同灌水模式施肥后地表水、土壤水和地下水的氮磷浓度变化试验研究。结果表明,相同施肥量处理下,稻田地表水中铵态氮和磷酸盐浓度在施肥后1 d达到峰值,7 d达到最低值,之后趋于相对稳定。土壤水和地下水的峰值滞后2 d。与常规淹灌模式相比,控制灌溉模式同一指标浓度总体较高,有利于提高水肥利用率,同时渗漏量较低,使得通过渗漏进入地下水中的污染物降低。

Non-point pollution is one of severe challenges of the global water pollution control.Nitrogen and phosphorus pollution are important components of non-point pollution.In order to explore an optimal irrigation pattern of rice planting in Erhai Lake Basin and to promote agricultural production and reduce non-point pollution,an experimental study on nitrogen and phosphorus concentrations in surface water,soil water and groundwater after fertilization in different irrigation patterns was carried out in paddy field.The results showed that under the same fertilizer amount,the concentrations of ammonium nitrogen and phosphate in the surface water of the paddy field reached the peak value 1 day after fertilization,and reached the lowest value 7 days after fertilization,then tended to be relatively stable.The peak value in soil water and groundwater delayed 2 days.Compared with conventional inundation irrigation pattern,concentration of the same index under controlled irrigation pattern was generally higher,which was conducive to improving utilization efficiency of water and fertilizer.Meanwhile,controlled irrigation pattern had lower seepage than conventional inundation irrigation pattern,so the pollutants entering groundwater through seepage reduced.