海河流域水稻田氮磷地表径流流失特征初探

选取海河流域水稻田作为研究对象,在自然降雨条件下通过田间实测方法研究其氮磷元素地表径流流失特征。结果表明,氮磷元素流失率分别为0.7%和0.6%,流失负荷分别为4.77kg.hm-2和2.08kg.hm-2。在详细分析试验结果后,找出影响氮磷地表径流流失量的因素,其中颗粒态氮是农田径流流失的主要形式,并与径流量成明显正向相关,而磷素流失量则受施肥量和径流量双重影响,影响规律较氮素更为复杂,尚需进一步研究。进而得出结论：在北方干旱少雨的气候影响下,地表径流并非海河流域农田种植作物氮磷元素流失的首要途径。

Preliminary Study on Characteristics of Nitrogen and Phosphorus Runoff Losses from Rice Fields in Hai River Basin,China

Runoff is one of the major mechanisms for nutrient loss from crops.However,it has been studied less in North China than in South China where there is much more runoff.Therefore,to better understand the loss of nitrogen（N） and phosphorus（P） in runoff,we studied runoff from paddy rice in a typical agricultural county in the Hai River basin.Using event monitoring in the field,we studied the characteristics of runoff losses under natural rainfall conditions.N losses were 4.77 kg·hm-2 and its loss rate was 0.7% of applied fertilizer.P losses were 2.08 kg·hm-2 and its loss rate was 0.6% of applied fertilizer.As expected N losses were positively co-related to amount of runoff and mainly consisted of particulate nitrogen.P losses were affected by amount of fertilizer applied and runoff,however due to its complexity（of P）,the influence had to be further studied.Due to rainfall scarcity in North China area,runoff loss was not the primary problem for nutrient losses from paddy rice in the Hai River basin.