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采用喷施氮肥模拟氮沉降的方法,分对照(CK,不施氮)、低氮(T50,50 kg.hm-2.a-1)、中氮(T100,100 kg.hm-2.a-1)、高氮(T150,150 kg.hm-2.a-1)4个梯度对温郁金农田生态系统进行氮沉降处理,5个月后调查其田间大型土壤动物分布情况。结果表明:①调查共获得大型土壤动物19类485只,优势类群2类、常见类群8类、稀有类群9类;类群数和个体数均以0<土壤深度h≤5 cm层最高。②氮沉降改变了土壤动物个体数的表聚特征,在高浓度氮处理下土壤动物表现出向深层趋避;氮沉降降低了大型土壤动物的个体数,0T100>T150。③氮沉降对土壤动物类群数的垂直分布无明显影响,但能够减少土壤动物的类群数,0T100>T150。④各处理下的大型土壤动物的Shannon-W e iner多样性指数H′、P ielou均匀性指数J和S inpson优势度指数C基本一致,表现为T100>T50>CK>T150,表明低氮处理对大型土壤动物多样性有促进作用,而在高氮处理时表现为抑制,存在阈值作用。⑤大型土壤动物多样性与杂草地上部分鲜质量显示出较好的正相关(r=0.74),而杂草地上部分鲜质量与农作物温郁金地上部分鲜质量显示较好的负相关(r=-0.79),土壤动物对氮沉降的响应受到杂草和农作物的影响,可能是一个更为复杂的过程。
The effects of nitrogen (N CK), low nitrogen (T50, 50 kg.hm-2.a-1), medium nitrogen (T100, 100 kg.hm-2.a 1) and high nitrogen (T150, 150 kg.hm-2.a-1), respectively. After 5 months, the distribution of soil macrofauna in the field was investigated. The results showed that: (1) There were 485 species of 19 large-scale soil animal species, including 2 dominant species, 8 common species and 9 rare species. The number of species and individuals was 0 T100> T150. Nitrogen deposition has no significant effect on the vertical distribution of soil fauna, but it can reduce the number of soil fauna, while the number of soil fauna in 0 T100> T150. (4) Shannon-W einer diversity index H ’, P ielou uniformity index J and S inpson dominance index C of the soil macrofauna under each treatment were basically the same, showing T100> T50> CK> T150, indicating that low nitrogen treatment It can promote the diversity of soil macrofauna and inhibit it when treated with high nitrogen, which has a threshold effect. (5) There was a good positive correlation between the diversity of macro - fauna and the fresh weight of aerial part of weed (r = 0.74), while the fresh weight of aerial part of weed showed a good negative correlation with the fresh weight of top part of turf (r = 0.79). The response of soil fauna to nitrogen deposition is affected by weeds and crops and may be a more complicated process.