马尾松苗木施肥效果研究

在有磷素底肥的基础上，充足的氮磷配合追肥能显著提高马尾松苗木的高径生长量、生物量和质量；追施单－氮肥，苗木的生物量和质量仍较高；减少追施氮肥量可显著降低直径生长和叶、茎、根的干物质及苗木质量；追施单－磷肥，苗木的生长和质量都进一步下降；既无基肥又很少追肥的，苗木生长和质量最差．施氮结合磷肥能显著提高植株氮磷营养水平，全苗或叶部的氮含量与Ｉ级苗率及全苗的或叶、茎部的干物质呈极显著的正相关，与苗高、地径生长及根干物质呈显著的正相关；全苗或叶部的磷含量与全苗的或叶、根部的干物质及苗木质量也呈显著的正相关关系．试验前土壤缺氮但供磷中等的情况到试验结束时并无变化，只有土壤代换性钙含量显著提高，是为例外，暗示在培育马尾松壮苗中追施足够的氮肥是必要的，施氮时配合施磷有利进一步提高肥效，单施磷则大多成了无谓的消耗．

A Study on the Effects of Masson Pine Seedlings Fertilization

The results of a study on masson pine seedlings fertilization carried out in Xietan Nursery in Shouning, Fujian, in 1994, showed that the best growth and quality of the seedlings were found in plots treated by applying base fertilizer of superphosphate followed by top dressing urea combined superphosph-ate during growth season. Diameter and biomass of seedlings were reduced singni-ficantly by lowering N application rate. The growth of seedings had lesser response to the application of P applied single alone. The worst growth of seedlings were found in the plots treated by no base fertilizer but few top dressing of N and P fertilizers. The levels of N and P nutrients in tissues of seedlings were significantly increased by adding N combined P fertilizers. There were significant positive correlation between the N content of leaves or total seedling and the growth of height and diameter of seedlings, as well as the percentage of first grade seedlings.