伏牛山区陶湾流域径流、泥沙及氮磷的输出动态

Changes of Runoff,Sediment,Nitrogen and Phosphorus Exported from Taowan Watershed,Funiu Mountainous Area

以伏牛山区陶湾流域为研究对象,预测和评价了不同农业管理措施下流域径流、泥沙、氮磷等的输出动态,以便采取更为有效的管理措施。选取了5种农耕模式:传统翻耕、免耕、等高种植、留茬覆盖、免耕并留茬覆盖;5种施肥模式:现有量、85%现有量、70%现有量、50%现有量、35%现有量;5种降雨模式:干旱年、偏少年、平水年、偏多年和丰水年,得到125种模式组合。调试AnnAGNPS模型,输出125组合下的陶湾流域径流、泥沙、氮磷输出量。结果表明,免耕模式可以削减泥沙输出的34.9%,但却增加了径流、氮磷等的输出;施肥模式对径流和泥沙输出没有显著影响,但对氮磷输出呈强正相关关系(R>0.95),50%现有量的L3模式可削减81.8%氮和63.7%磷;丰水年泥沙输出量为平水年的4.7倍,但氮的输出量与平水年差异不显著,磷的输出量略高于平水年;免耕与施肥模式相结合是陶湾流域削减泥沙和氮磷输出的有效方法之一。

In this study, a typical agroforestry Taowan watershed in Funiu Mountainous area was selected to investigate the changes of runoff, sediment, nitrogen and phosphorus exports, so that the better watershed management measures could be applied. A total of 125 combinations of various management treatments in- eluding five tillage practice patterns （CT-conventional tillage, NT-no tillage, CS-contour strip cropping, RC- residue cover,NR- no tillage and residue cover）, five fertilizer patterns （L0-existing, L1-85 % of existing, L2-TOG of existing, L3-50% of existing, L4-35% of existing）, and five kinds of annual rainfall patterns （Rl-deficit, R2-Less than normal, R3-normal, R4-more than normal, R5-abundant） were evaluated. The An- nAGNPS （Annualized AGricultural NonPoint Source） model was used to predict the runoff, sediment, ni- trogen and phosphorus exported from Taowan watershed. The results indicated that conservation tillage could significantly affect the amount of sediment output, no-till could reduce sediment output by 34.9%, but increase runoff, nitrogen and phosphorus output; fertilization patterns had no effect on runoff and sedi- ment output,nitrogen and phosphorus outputs strongly positive correlated with fertilization patterns （R〉 0.95）; a sharp increase in sediment output in abundant year,it was 4.7 times than the normal year. Out- puts of nitrogen were not significant between abundant year and normal year. And phosphorus output in abundant year was slightly higher than the normal year; the L3 fertilization patterns could reduce nitrogen and phosphorus outputs by 81.8% and 63.7% ,respectively. In view of feasibility and efficiency,the combination of L3 ＋NT was found to be the best scenario as the reductions of nutrient losses and sediment yield were significantly.