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大气氮沉降是当前全球性的环境问题,土壤动物对环境变化反应敏感,氮沉降可能显著影响森林土壤动物群落结构。从2012年5月起,在东台林场3个不同林龄(7、11、18年生)杨树人工林(黑杨派无性系I-35,Populus deltoides cv.I-35)进行野外模拟氮沉降试验,共设置5个处理,即对照、5、10、15、30 g N·m-2·a-1。在氮添加试验2年后,探讨氮沉降对不同林龄杨树人工林土壤动物群落的影响。结果表明:随林龄增加,土壤动物群落密度增加,但土壤动物类群数在11年生林最多;土壤动物密度随氮浓度的升高先增加后减少,在15 g N·m-2·a-1氮添加时达到最高值,并与土壤总有机碳、全氮显著相关;氮添加对土壤动物多样性的影响仅在11年生林表现显著,土壤动物群落多样性和均匀度随着施氮浓度增加呈下降趋势,优势度则完全相反。氮添加可能通过改变土壤营养状况显著影响土壤动物群落结构,中等浓度氮添加对土壤动物群落有促进作用,高浓度氮添加则有抑制作用。
Atmospheric nitrogen deposition is the current global environmental problem. Soil animals are sensitive to environmental changes. Nitrogen deposition may significantly affect the community structure of forest soil animals. From May 2012 onwards, field simulated nitrogen deposition was carried out on poplar plantations (Populus deltoides cv. I-35) in three different age groups (7, 11, 18 years old) Test, a total of five treatments set, that is, control, 5,10,15,30 g N · m-2 · a-1. Two years after the nitrogen addition experiment, the effect of nitrogen deposition on soil animal community in poplar plantations of different ages was discussed. The results showed that with the increase of forest age, the density of soil animal community increased, but the number of soil fauna was the largest in 11-year-old forest. The density of soil fauna increased firstly and then decreased with the increase of nitrogen concentration. At 15 g N · m -2 · a- 1 nitrogen reached the highest value, which was significantly correlated with soil total organic carbon and total nitrogen. The effects of nitrogen addition on soil animal diversity were significant only in 11-year-old forests, and the diversity and evenness of soil animal communities varied with nitrogen application rate Increasing downward trend, dominance is exactly the opposite. Nitrogen addition may significantly affect soil fauna community structure by changing soil nutrient status. Medium nitrogen addition may promote soil fauna and inhibit high nitrogen addition.