Comparing the soil quality changes of different land uses determined by two quantitative methods

Soil quality is one of the most important environmental factors in sustaining the global biosphere and developing sustainable agricultural practices.A study was initiated in Wolong Nature Reserve,Sichuan Province,China to elucidate the soil quality changes of natural secondary succession,forest planting and agricultural practices after deforestatin in the humid mountainous region.The soil qualities of six land use types(natural forestland ,grassland,shrub land,secondary index(QI) and soil deterioration index(DI).The QI values of natural forestland ,grassland,shrub land,secondary forestland,cultivated land ,reforested land were 0.8039,0.3277,0.9127,0.6881,0.0285 and 0.3183,respectively.The DI values were 0%,-14%,12%,1%,-26% and -18% respectively.Both indexes suggested that shrub land can restore soil properties.To compare the two methods more directly,a deduced index QI‘based on QI value was developed,.The results showed that DI and AI‘ had a very high linear correlation coefficient(r=0.9775) despite the values were different .Both methods were efficient in evaluating the soil quality levels and DI was a more simple way in soil quality assessment,while QI could show more ecological meanings.     

清初“摊丁入亩”政策对环境的影响

清初“摊丁入亩”政策对清社会经济的恢复发展确实起到了促进作用,但同时对环境也构成了巨大威胁,引发了地表植被遭严重玻坏、自然灾害频繁、珍稀野生动植物大量灭绝等一系列环境问题。剖璞见玉,对今有史鉴作用。