青海高寒区典型植被地表径流及氮磷流失特征

研究自然降雨下青海高寒区典型植被地表径流与氮磷流失规律及其影响因素,可为青海高寒区植被建设及水土保持研究提供科学依据.该研究以青海高寒区青杨林、祁连圆柏林、青海云杉林、荒草地、华北落叶松林典型植被为研究对象,采用径流小区结合室内试验分析研究不同植被类型地表产流及氮磷流失特征,并基于冗余分析探明影响氮磷流失的主要因素.结...

Characteristics of surface runoff and nitrogen and phosphorus loss for different vegetation covers in Qinghai alpine region of China

Soil nitrogen and phosphorus loss are closely related to a surface runoff under natural rainfall. Therefore, it is necessary to explore the mechanism behind these and influencing factors in the vegetation construction for water and soil conservation in the Qinghai alpine region of China. In this study, the typical vegetations were taken as the research objects, including Populus cathayana, Picea crassifolia,Larix, principis-rupprechii, Grass land, Juniperus przewalskii in the study area. The runoff plot combined with indoor experiment was also used to analyze the characteristics of nitrogen and phosphorus loss to surface runoff for different types of vegetation. Redundancy analysis was made to identify the main influencing factors on the loss of soil nitrogen and phosphorus. The results indicated as follows: 1) Under the condition of natural rainfall, the rainfall interception effect of different vegetation types was different, and the interception effect was affected by the rainfall. In the rainfall range of 0-50 mm, the average interception rate of each vegetation was 49.37% for Populus cathayana forest, 18.90% for Picea crassifolia forest, 9.28% for Larix principis-rupprechtii forest, 32.62% for Juniperus przewalskii, and 21.21% for Grass land. 2) There was a positive correlation between penetrating rainfall and surface runoff in the study period, while surface runoff depended greatly on the penetrating rainfall. There was also an obvious difference in the runoff reduction of different planting types. Specifically, the best runoff reduction was found in Larix principis-rupprechtii forest, whereas, the worst was in Populus cathayana forest. 3) The loss of nitrogen and phosphorus in Qinghai alpine region was relatively low, and the loss of nitrogen and phosphorus in the surface runoff was ranked in order of nitrate nitrogen>ammonia nitrogen>phosphate. The total loss of nitrogen and phosphorus in different vegetation types was ranked in the order of Populus cathayana>barren grassland>Picea crassifolia>Juniperus przewalskii>Larix principis-rupprechtii. 4) The redundancy analysis showed that the loss of nitrogen and phosphorus depended mainly on the surface runoff, saturated water content, and bulk density. Five typical vegetations can be expected to effectively alleviate nitrogen and phosphorus loss to surface runoff, where the interception and nutrient control effect of Larix principis-rupprechtii forest was the best, while that of Populus cathayana forest was the worst. Consequently, some suggestions can be given during this time to reduce surface runoff and saturated water content, while increasing bulk density for the effective reduction of nitrogen and phosphorus loss. This finding can provide a sound reference for regional vegetation construction in the future,