盐碱地人工草地土壤固氮作用强度的研究

Study on the intensity of Soil Nitrogen Fixation in the Artificial Meadow in Saline Lands

在山东无棣、天津大港、河北沧州滨海和内陆盐碱地设置田间试验，研究了人工草地（紫花苜蓿）生态系统土壤固氮作用强度。结果表明，在盐分含量０．３％以下的盐碱地建人工草地后，土壤固氮作用强度显著提高。施用磷肥的人工草地，两年后的土壤固氮作用强度可达天然草地的３倍。土壤全氮也有较大增加。研究还表明，土壤水分含量对固氮作用强度有较大影响。

Field experiments were conducted to study the intensity of soil nitrogen fixation (ISNF) of the artificial meadow (alfalfa) on saline lands of the inland and seashore at WuDi,Shan Dong; Da Gang,Tian Jin and Cang Zhou, Hebei. The results indicated that the ISNF of the artificial meadow was increased significantly in comparison with that of the native meadow when the soil salt content was less than 0. 3%. The ISNF of artificial meadow was three times as much as that of native meadow after cultivation of alfalfa with application of phosphate fertilizer for two years. As a result,the total nitrogen content in soil of the artificial meadow was increased significantly. The results also showed that the ISNF was affected significantly by soil water content.