喀斯特裸坡地地下孔(裂)隙流养分流失特征研究  

Characteristics of Nutrient Loss in Runoff of Underground Pore Fissure on the Karst Bare Slope

作　　者：李昌兰[1] 戴全厚[1] 彭旭东[1] 袁应飞 

机构地区：[1]贵州大学林学院,贵阳550025

出　　处：《水土保持学报》2016年第3期19-23,114,共6页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41461057;41061029);贵州省重大专项(黔科合JZ字[2014]2002)

摘　　要：通过人工模拟试验,研究喀斯特坡耕地地下孔(裂)隙流养分流失特征,结果表明:(1)地下产流、产沙量与雨强、地下孔(裂)隙度呈正相关关系,与坡度呈负相关关系。(2)雨强对地下径流流失浓度影响不显著,不同坡度全钾流失浓度随坡度呈波浪型变化,全磷流失浓度在缓坡(5~10°)地上径流流失浓度最大,是陡坡(15°以上)地上磷素淋失浓度的2~3倍,氮素流失浓度呈现出随着坡度增大而逐渐减小的变化趋势,地下径流全钾流失浓度与地下孔(裂)隙之间没有明显的变化趋势。(3)全钾、全磷和全氮流失量与雨强变化均呈指数函数关系,R^2分别为0.718 7,0.817 1,0.849 2;不同坡度条件下,全钾、全磷和全氮流失量随坡度的变化趋势一致,拟合曲线均为线性关系;全钾和全磷与地下孔(裂)隙度均可用指数函数拟合,全氮流失量与地下孔(裂)隙度可用幂函数拟合,地下径流中养分流失以氮素为主。The characteristics of nutrients loss in runoff of underground pore fissure on the karst bare slope were studied by artificial simulation experiments. Results indicated that ： （1） Underground runoff, sediment yield and rainfall intensity were positively correlated with rainfall intensity and underground pore fissure degree, while were negatively correlated with slope gradient. （2）Rainfall intensity had not significantly effects on the nutrients concentration of underground runoff, in which total potassium concentration changed with fluctuations for different slopes, total phosphorus concentration reached the maximum in the gentle slope （5 -10 degrees） which was 2-3 times if that in the steep slopes （over 15°） , concentration of nitrogen loss decreased with increasing of slope, total potassium concentration of underground runoff and underground pore fissure had no obvious trend. （3）There was a exponential function relationship between total potassium loss, total phosphorus loss, total nitrogen loss and rainfall intensity, and R2 were 0. 718 7, 0. 817 1 and 0. 849 2, respectively. Under different slope conditions, the loss of total potassium, total phosphorus and total nitrogen were consistent presented as linear curves with the change of slope. Relationship between underground pore fissure and total potassium and total phosphorus could be fitted by exponential functions, and the nitro- gen loss and underground pore fissure could be fit by power function. In a word, nutrient loss in under-ground runoff was dominated by nitrogen.

关 键 词：喀斯特 裸坡地 地下孔(裂)隙流 养分流失 

分 类 号：S157.1[农业科学—土壤学]