施磷水田田表排水磷素流失特征及其机制研究

Characteristic and mechanism of phosphorus export in surface drainage from fertilized rice field

通过人工排灌手段模拟雨季条件下水田田表排水,研究了水田面施无机磷肥及有机无机磷肥配施48 h后、以间隔48 h连续进行4次人工排灌的磷素流失特征及其机制。结果表明:首次排水的磷素流失形态以可溶性磷为主,而其后多次排水的磷素流失形态主要为固相磷;面施磷肥时配施有机肥能显著提高后3次排水的田表磷素流失量与流失负荷,但对4次排水累计的磷素流失总量并没有影响,而以全磷表征的磷肥表观流失率为9%～16%。

Characteristic and mechanism of P loss in surface drainage from fertilized rice field were studied by simulating intensive rainfall season. After P fertilizer broadcast 48 hours later, four events of surface drainage from plots were conducted at 48 hours interval. The primary P form in the first drainage event was dissoluble P, while particulate P was the dominant form in the subsequent three drainage events. No significant was found on the total amount of P lost from different compositions of P application, however, P loss from application of inorganic-P plus manure-P were significantly higher than from the treatment of chemical P applied only in the subsequent three drainage events. The over four drainage events, in form of total P, resulted 9%- 16% apparent loss ratios of P fertilizers.