人工湖对沽源退化草地土壤碳、氮、磷的时空影响

在退化草地上建造人工湖泊,可以使人工湖泊与毗邻退化草地形成近湿地生态系统,从而可能改善毗邻退化草地的生态环境,积极影响退化草地土壤中养分的流动,加快退化草地的修复。本研究分析了人为建造人工湖泊后3年内（2014年、2015年、2016年）湖泊毗邻的退化草地土壤碳氮磷在离湖距离（10 m、60 m、100 m、150 m、250 m、600 m）上的时空动态变化。结果如下：距离上,土壤有机碳、全氮、全磷在上层土壤（0～10 cm和10～20 cm）中与距离有显著（P<0.05）的线性关系,呈逐渐降低的趋势,说明在建湖3年这个短时期内,土壤养分（有机碳、全氮、全磷）形成了一个近湖效应,即靠近湖的养分含量高。年际间,自建湖后土壤全磷随着年数的增加在各个土层均显著降低。土壤养分（有机碳、全氮、全磷）在建湖初期2014年在距离上特异性较大,经过建湖3年后,2016年时在距离上的特异性减弱。这些结果表明,人工湖影响毗邻退化草地土壤中养分流动,尤其在距离上有显著的影响并表现出一定的规律性。建湖对毗邻退化草地的养分产生一定的影响,表明人工湖对放牧草地产生一定的积极效应。

Temporal and Spatial Effects of Artificial Lakes on Soil Carbon,Nitrogen and Phosphorus in Guyuan Degraded Grassland

The construction of artificial lakes on degraded grasslands can form adjacent wetland ecosystems with surrounded grasslands, which could improve the ecological environment of adjacent grasslands, positively affect the nutrients flux in degraded grassland soil, and accelerate the restoration of degraded grasslands. The temporal and spatial dynamics of soil carbon, nitrogen and phosphorus at different distances (10 m, 60 m, 100 m, 150 m, 250 m, 600 m) from the lake at 2014, 2015 and 2016 (first three years after the construction of artificial lakes) were analyzed. The results were as follows:when compared among the distances, there is a significant (P<0.05)linear relationship between soil organic carbon, total nitrogen and total phosphorus in the upper soils (0~10 cm and 10~20 cm). It shows a tendency to decrease gradually with the increase of distance from the lake. It shows that in the short period of 3 years, soil nutrients (organic carbon, total nitrogen and total phosphorus) formed a "near-lake effect". Thus is, the nutrient content near the lake is higher. When compared among years, soil total phosphorus decreased significantly in all soil layers with the increase of years. The distinctness of soil nutrients among distances was very significant at the initial construction stage (2014) of the lake, but this difference became weak after three years. These results indicated that the artificial lake affected the soil nutrients flux of adjacent degraded grassland, especially reflecting in the distance,which showed certain regularity among distances. The effect of artificial lake on the nutrients of the adjacent degraded grassland indicates that the artificial lake has certain positive effects on grazing grassland.