The experiments were conducted to explore the effect of controlled irrigation and drainage modes on water saving,as well as nitrogen and phosphorus pollutants reduction from paddy rice fields under three different modes including the slight-drought controlled irrigation and drainage (LCID),the heavy-drought controlled irrigation and drainage (HCID) and the conventional controlled irrigation and drainage (CK).The results showed that the controlled irrigation and drainage technology could effectively reduce the frequency and amount of drainage from rice fields,thereby reducing the irrigation quota.Particularly,LCID extended the irrigation interval,decreased the irrigation frequency,and improved the use efficiency of rainwater by over 20%. HCID had the most significant effects on reducing the nitrogen and phosphorus concentrations in surface drainage.The average 2-year NH4+-N,NO3– -N, and TP drainage loss were reduced by 38.88%, 62.97% and 59.23%,respectively.The overall results concluded that the controlled irrigation and drainage was an effective way to save water,reduce drainage and decrease nitrogen and phosphorus discharges compared to the single drainage.Moreover, these effects were found more satisfactory under heavier rainfalls.
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