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二年生草木樨是我国北方种植的主要绿肥品种。但是,有的地方种的草木樨第二年往往不返青,这是什么原因呢?两年来,我们对割草时间、土壤水分状况、播种时期三个因素对草木樨返青的影响进行了试验研究。一、返青率与割草时间及根部氮素含量的关系:1979年秋,我们分5期即8月25日、9月5日、9月15日、9月25日、10月5日进行割草,在割草同时调查各期地下、地上干物质产量,40度烘干测定含氮百分比。
Biennial vegetation is the main green manure planted in northern China. However, what is the reason why some species of grassland mulberry plants do not return to green in the second year? In the past two years, we conducted experiments on the effects of mowing time, soil moisture status and sowing time on the rejuvenation of plants and trees . First, the rate of greening and mowing time and the relationship between root nitrogen content: the fall of 1979, we divided into five periods that August 25, September 5, September 15, September 25, October 5 cut Grass, mowing at the same time in the investigation of underground, dry matter production on the ground, 40 degrees drying determination of nitrogen percentage.