关键词: 长期定位试验, 单施化肥, 土壤性状, 产量

Abstract: West Sichuan sub-alpine is an extension of Qinghai-Tibet Plateau to southeast China,which is covered mainly with dark coniferous forest.As a result of long-term large scale over-logging,the forests have been greatly reduced and degraded.Nowadays,the forest restoration and regeneration in the region are being highlighted.Selecting Miyaluo as a case study area and employing the methods of plot investigation,ETM image interpretation,and overlaying vegetation map with digital topography,this paper analyzed the relations between the appearance and origin of four forest vegetation types,along with their topography differentiation and spatial patterns after a large scale logging and regeneration.The results showed that the appearance of forest vegetations was significantly correlated with their origin.Old coniferous forests (OC) were primitive ones,middle-aged and young coniferous forests (MYC) were from artificial regeneration,deciduous broadleaf forests (DB) were natural secondary ones,while mixed coniferous and deciduous forests (MCD) were partly from natural secondary ones and others from the conjunct action of artificial and natural regeneration.The main cut area in Miyaluo located in the sites with elevation from 2 800 to 3 600 m,where forest restoration appeared difference among different aspects.MYC was mainly distributed on sunny and half-sunny slope,DB and MCD were distributed on shady and half-shady slope,and OC were reserved on the sites with elevation more than 3 600 m.In the process of forest restoration, the four forest vegetation types were in mosaic pattern,and the landscape was seriously fragmentized.

Key words: Long-term located experiment, Singal application of chemical fertilizer, Soil properties, Crop yield