整地施肥对尾叶桉生长及土壤性状的影响

整地施肥试验结果表明，全垦、带垦和穴垦三种整地方式以及施肥对尾叶按造林成活率和保存率均无明显的影响，成活率在９５％－９８．８％之间，保存率在９２．１％－９７．７％之间．整地能改变土壤性状，如土壤孔隙度全垦为５７．８８％。穴垦为４９．４２％；对林木生长有促进作用，但作用效果很快减少，如造林３年后的林木材积全垦、带垦分别为穴垦的１３６．４％和１２０．０％，５年后却分别下降到１１６．５％和１０８．３％．施肥可提高土壤养分，促进林木生长．造林５年后的调查结果，穴垦施肥林地的土壤有机质、速效Ｎ分别为１５．４４７ｇ／ｋｇ和４９．２３０ｍｇ／ｋｇ，林木年均树高生长为１．２５ｍ；不施肥处理的有机质、速效Ｎ分别为１０．３８８ｇ／ｋｇ和３５．７１５ｍｇ／ｋｇ，林木年平均生长量为０．３５ｍ；林木材积施肥处理的为不施肥的９．８倍．整地施肥还可提高林木叶片的养分含量．

Effect of Land Preparation and Fertilization on Growth of Eucalyptus Urophylla and Soil Properties

An experiment with fertilization and land preparation of all-ploughing, belt-ploughing and spot-ploughing was carried out in the planting of Eucalyptus urophylla. The results showed that there was no significant effect on initial survival rates (ISR) and long-term survival ratal (LSR)among the different treatments, with ISR of 95.0%-98.8% and LSR of 92.1%-97.7%. However,land-preparation exerted influence on soil propertiest.Soil porosity increased from 49.42% in spot-ploughing to 57.88% in all-ploughing. In addition, land-preparation could enhance forest growth to a certain extent, but this effect rapidly dropped. In 3-year-old forest, standing volume with all-ploughing and belt-ploughing were 136.4% and 120.0% of those with spot-ploughing respectively, but in 5-year-old forest, the corresponding figures reduced to 116.5% and 108.3%. The fertilization raised soil nutrient level and increased forest growth. A survey, in 5-year-old,spot-ploughing forest with fertilization, illustrated that soil organic matter reached 15.447g/kg, with available nitrogen 49.23 mg/kg and annual groWth of tree height 1.25m. However, in the control forest without fertilization, the soil organic matter was only 10.388 g/kg with available nitrogen 35.716 mg/kg and annual groWth of tree height 0.35m. Standing volume with fertilization was 9.8 times as much as that without fertilzation.