太湖流域水稻生产的氮、磷投入阈值

The thresholds of nitrogen and phosphorus inputs for rice production in Lake Taihu area

为了探索太湖地区水稻生产中既保产量又使污染排放最小化的氮、磷投入阈值,2011-2012年在该区域开展了田间定位试验,设置6个施氮处理和4个施磷处理,研究氮磷施肥阈值与水稻产量、肥料表观利用率、污染排放风险的关系。结果表明,太湖地区水稻田产量稳定并且面源污染小的氮、磷投入阈值分别为185.18 kg/hm2和54.22 kg/hm2,在该阈值下水稻产量可保持9 000~10 000 kg/hm2,比当地推荐氮、磷用量分别减少18%和32%,既减少了投入又降低了面源污染风险。

In order to minimize the nitrogen and phosphorus drainage in Lake Taihu area and keep the reasonable rice yield, fertilization experiments were carried out in Taihu rice/wheat rotation field from 2011 to 2012. Six nitrogen input treatments and four phosphorus input treatments were set to study the relationship between the thresholds of nitrogen and phosphorus inputs and rice yield, fertilizer utilization rate and pollution drainage. The results showed that the optimum ni-trogen and phosphorus input levels were 185. 18 kg/hm2 and 54. 22 kg/hm2 respectively to achieve the least non-point source pollution and stable rice yield (9 000-10 000 kg/hm2). The nitrogen and phosphorus input levels were 18% and 32% less than local recommended fertilizer input amount, leading to the reduced investment and risk of non-point source pollution from agriculture in Lake Taihu area.