西南桦人工林土壤养分含量变化规律研究

通过对西南桦人工幼林土壤肥力６年的定位监测，结果表明：西南桦人工林在幼林期基本不会导致土壤有机质、氮素、有效Ｐ含量下降，但会导致土壤有效Ｋ含量下降。ＧＭ（１，１）模型预测：在今后５年内，西南桦人工幼林的土壤有机质和有效Ｐ含量总趋势为上升；土壤全Ｎ和有效Ｎ含量变化不大；土壤有效Ｋ含量则明显下降。因此，在营林生产中只要在定植５年以后适当施用钾肥，就可防止林地土壤有效Ｋ的下降。

Study on Change Law of Soil Nutrient Content in Betula alnoides Plantation

The results of 6 years'position determination on soil fertility of Betula alnoides young plantation indicates the siviculture of Betula alnoides will cause the decrease of available potassium content instead of the contents of organic matter,nitrogen and available phosphate in the juvenile stage.The forecast of GM(1.1)model is the following points.Within the future 5 years,the contents of organic matter and available phosphate of the soil of Betula alnoides plantation will show the tendency of increase totally, the contents of total nitrogen and available nitrogen will basically be stable,the content of available potassium however will decrease obviously.In the sivilculture production,applying potassium fertilizer 5 years after field planting can avoid the content decrease of available potassium in the soil of Betula alnoides plantation.