杨树不同土壤立地条件施肥效应的研究

EFFECTS OF FERTILIZATION IN THE DIFFERENT SITE TYPES OF SOIL FOR POPLAR TREE

在湖北省江汉平原选择有代表性的３种土壤立地，进行南方型杨树氮、磷、钾常规肥料多点施肥试验（１９９１～１９９５）。结果表明：施氮肥能显著促进杨树生长，单施磷、钾肥效应均不好；平原粘湿土壤还呈显著负效应，只宜单施氮肥；平原冲积土、湖区沉积土立地均以氮＋磷混施效应最佳。优化施肥量：平原粘湿土立地按４００ｋｇＮ／ｈｍ２、平原冲积土立地按２００ｋｇＮ／ｈｍ２＋１００ｋｇＰ２Ｏ５、湖区沉积土立地按１００ｋｇＮ／ｈｍ２＋１００ｋｇＰ２Ｏ５／ｈｍ２，折算成尿素和过磷酸钙。５年提高蓄积生长量３５％～７５％，纯增益６０００～１１０００元／ｈｍ２。

A test of the effects of fertilization was done with fertilizing the ordinary N, P, K elements from 1991～1995 in several experimental areas selected from three representative site types of soil in Jianghan plain, Hubei Province. The results shows: Overall significant effects of single N element; Overall bad or not better effects of single P or K element, even a significantly negative effect in wet clay soil of the plain(site Ⅰ) which is only suitable for single N element; The best effect of mixed N and P elements in the plain alluvial soil (site Ⅱ) and sedimentary soil in the lake region(site Ⅲ); The best application rate(total):400kg N/hm 2 for site Ⅰ; (200kg N+100kg P 2O 5)/hm 2 for site Ⅱ; (100kg N+100kg P 2O 5)/hm 2 for site Ⅲ; fertilizers are urea for N, calcium superphosphate for P 2O 5, respectively; 35%～75% increment in growing stock, which is equal to increasing 6～11 thousand yuan/hm 2 in total within five years(1991～1995).