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本实验是于1972年至74年在美国北卡罗林纳洲选择山地和平原不同环境的两片十一年生火炬松(Pinus taeda Q.)林,各建立七个试验小区,研究施肥对火炬松林木生长,对林木叶片所含氮、磷、钾浓度,对林地菌根类型和数量的影响。根据两片试验林地资料综合,结果如下: 1.施肥对菌根数量的影响。每公顷施用氮肥56公斤和112公斤时,两年内平均,施肥小区的菌根数比对照区少14—20％;在施肥后的头6个月,施肥小区的菌根数比对照区少40％;在施肥后的第二年,施肥小区和
In this experiment, we selected two Pinus taeda Q. forests in different environments in the mountainous and plains of North Carolina from 1972 to 1974. Seven experimental plots were set up to study the effects of fertilization on the growth of Pinus taeda forest trees , On the nitrogen, phosphorus and potassium content of forest leaves, the type and quantity of forest mycorrhiza. According to the comprehensive data of two experimental forests, the results are as follows: 1. Effect of fertilization on the number of mycorrhiza. When applying 56 kg and 112 kg N fertilizer per hectare, the average number of mycorrhizal in the two years was 14-20% less than that in the control area. In the first 6 months after fertilization, the number of mycorrhizae in the area was 40 %; The second year after fertilization, fertilization and community