稻麦两熟农田茬口衔接期养分径流流失特征

Characteristics of Surface Runoff Losses of Soil Nitrogen and Phosphorus During the Rice-Wheat-Rice Connection Periods in Intensive Rice-Wheat Rotation Field

采用田间小区定位试验研究自然降雨条件下稻麦两熟农田"稻季-麦季-稻季"茬口衔接期养分径流流失规律。结果表明:麦季常规施肥条件下麦稻茬口衔接期径流水量达77.59m3/hm2,径流侵蚀泥沙量达48.30kg/hm2,麦季少免耕处理较常规施肥处理增加径流水量达41.41%;径流水氮磷浓度分别达2.22,0.46mg/L,径流侵蚀泥沙氮磷浓度分别达1.15,1.65g/kg;麦稻茬口衔接期氮素径流流失量达227.84g/hm2,以径流水流失为主,占氮素总径流流失量的75%以上;磷素径流流失量达115.57g/hm2,以径流侵蚀泥沙流失为主,占磷素径流流失总量59%以上;麦季秸秆还田、秸秆还田减肥处理减少麦稻茬口衔接期氮素和磷素径流流失量分别达6.04%～9.74%和5.73%～11.54%,而麦季少免耕处理则增加21.75%和13.42%。

Field plot experiment was carried out to study the characteristics of surface runoff losses of soil nitrogen and phosphorus during the rice-wheat-rice connection periods in intensive rice-wheat rotation field under natural rainfall conditions. The results showed that the total volume of surface runoff water and the quantity of sediment by surface runoff reached 77.59 ma/hmz and 48.30 kg/hm2 under the conventional ferti- lization treatment（T0） during the wheat-rice connection period. And, no tillage treatment（T4） during the winter wheat growing season increased the volume of runoff water by 41. 41%, compared with TO; total nitrogen（TN）, total phosphorus（TP） concentrations in the runoff water reached 2.22, 0.46 rag/L, and, they reached 1.15, 1.65 g/kg in the sediment by surface runoff, respectively. Furthermore, under TO condi- tions, the total quantities of TN and TP losses by surface runoff reached 227.84, 115.57 g/hmz , respective- ly. Among which, more than 75% of TN loss was attributed to runoff water, and more than 59% of TP loss was attributed to the sediment by surface runoff during the wheat-rice connection period; compared with TO, rice straw application （T1）, wheat straw return and reducing fertilizer treatment （T2） during the winter wheat growing season decreased TN and TP losses by 6.04%~9.74% and 5.73%~11.54%, however, T4 increased them by 21.75% and 13. 42%during the wheat-rice connection period, respectively.