Effect Of Land Use Change On Soil Quality

Soil quality is defined a capacity of a soil within landscape to sustain, biologicalproductivity, maintain environmental quality, and promote of plant and animal health.Land use change profound impacts on soil quality. In this paper, based on the data ofsoil quality survey of Wujiang Municipality conducted in 2003, the content of soilnutrients and Cd, Pb, Hg, As, Cr under six different land use patterns were analysed,including paddy field, orchard, vegetable field, woodland, dry land and mulberry yard.comparison between the content of soil organic carbon under six different land usepatterns in 2003 and the date of soil fertility survey in 1982 were conducted, a soilsynthetic soil quality index was also introduced to calculate the soil quality indexunder different land uses patterns. The results were listed as follows:1, In the past 20 years the land use patterns in Wujiang Municipality havechanged greatly, this change deeply influenced the soil properties and quality. In 2003,on the whole the soils in Wujiang were little acid, pH from 6.40±0.38 to 5.40±0.55now, and the trend of acid was in Tailake region. The available phosphorous in Paddyfield were significantly lower than. the other five land use patterns. As a result,controlling the phosphorous output form vegetable field mulberry yard and other dryland might be more significant to control the non-point pollution in Tailake region.2, Along with the industrial development, the declining of cultivated acreage inWujiang resulted in the tendency of soil topsoil organic carbon pool reducing. It hasbeen more than 20 years since the second soil general survey in 1982 to 2003, thecultivated acreage reduced to 31086.67 hm², it made the decrement of the soil surfacelayer organic carbon pool to be 14.32×10⁵ t. Among the six major land use patterns,paddy had a higher SOC (soil organic carbon) density and an increased SOC densityover that in 1982 by (0.17±0.07) tC·hm^-2·cm^-1. As a whole result, increased topsoilSOC stock in the present paddy soils amounted to 1.8·10³ tC. Comparatively, land useas paddy field could be considered as a option land use for carbon stock enhancement.3, pH, the soil organic carbon, the total nitrogen, the available phosphorus, the available potassium and Hg, As, Pb, Cr, the Cd five kinds of heavy metals, took theseas appraisal factors, using the soil quality idenx (SQI) to calculate the soil qualitycomposite index under land use. The composite index respectively is: paddy field 0.61±0.08, mulberry yard 0.46±0.06, kale yard 0.43±0.09, dry land 0.45±0.14,orchard0.38±0.10, woodland 0.39±0.07. Obviously under the six landuses the paddy fieldtiled performance figure is remarkably higher than others, the soil quality difference isnot obvious between other five land use.Therefore, the change of land use patterns influenced soil quality. Paddy field asa traditional land use pattern in Tailake region is not only a pattern which cansequestrate more carbon; but also it was a best land use pattern for protecting soilquality. Thus, no matter for the food safety or the protection of ecologicalenvironment protecting paddy field ecosystem is important.