Study On Land Degradation Mechanism And Dynamic Economic Losses In Yulin

Started from natural factors, human factors and socialfactors, land degradation mechanism has been deeply analyzed. And that island degradation is the process which, through intense physical (sand blownby wind, flow water) and chemical effect, goes with damage of soil structure,thinness of soil layer and loss of soil nourishment by interfering withfragile natural environment, drived by human and social factors.Based on the analysis of land degradation monitor data in year 1999and 2004, the paper has analyzed the status, spatial differences and changesof land degradation in Yulin. From the damage of land degradation, economicloss caused by land degradation can be classified into three types: directeconomic loss, indirect ecological loss, and social service loss. Thedirect economic loss mean the direct loss of land degradation, mainlyreferring to the losses caused by the bankruptcy or decline in landproductivity, including the loss of agriculture, fisheries, animalhusbandry, transport and construction sectors resulted from landdegradation; Indirect ecological loss consist of the loss of soil, lossof soil fertility, soil structure damage, loss of organic matter,biodiversity, water conservation, climate change, carbon sequestrationaddress the declining oxygen, water, losses resulted from the decline inthe groundwater level; Social service loss include health indicators loss,Landscape resources loss and amenity value loss. The paper, focusing onthe direct economic loss and indirect ecological loss, has calculated landdegradation economic losses in Yulin in year 1999 and 2004 by the methodsof alternative market, the opportunity cost, restoration costs, Shadowprojects and has analyzed the time and space changes of land degradationand its economic loss in Yulin, providing new message to understand thesituation of land degradation in Yulin.(Ⅰ) The internal reason of land degradation in Yulin was the fragilenatural conditions, and the direct reason was human irrational use andexploitation of the land. The reason, at a deeper level, was thesocio-economic, cultural and irrational policies. In other word, humanbeings, in a certain social and economic conditions, acted on the fragilenatural factors and made land development go against human existence andbring land degradation, and at the same time, land degradation causedcounterproductive impact to society, creating a vicious circle. Therefore, if we want to combat land degradation fundamentally, we must take social,economic and institutional reform, and make multi-dimensional plan offarmer participated co-ordination of various departments which fit localconditions. Meanwhile, guided by the thought of integrated ecosystemmanagement, we should abandon unreasonable regulations and policies,improve the legal system, and make human activities rational. Only in thisway can we effectively prevent and combat land degradation, and ultimatelyachieve sustainable development.(Ⅱ)The economic loss by land degradation in Yulin was very severe.The direct loss in year 1999 was 1180909.32×104 Yuan, and indirect loss319664.6×104, total 1500573.92×104 Yuan; In the year of 2004, the directloss was 551315.92×104 Yuan and indirect loss was 286845.5×104yuan,total 838161.42×104 Yuan. Compared with the year of 1999, the loss wascut down 662412.5×104 in 2004, meaning that Yulin has made remarkableachievements in combating land degradation since 1999.(Ⅲ) As to the types of direction loss, in year 2004 Aeolian loss≥Waterdamage loss≥salinization loss in Yulin, As to the degree of degradation,moderate degradation loss≥mild degradation loss≥severe degradationloss≥very severe degradation loss, compared with the year of 1999, verysevere degradation loss was reduced, mild degradation loss and severedegradation loss was added. From land use types, in year 2004 farmlandloss≥forest loss≥turf loss, compared to the year of 1999, farmland losswas decreased heavily due to the very severe degradation of farmlanddisappearing.(Ⅳ) From the spatial distribution of degradation loss degree,, theloss density in six counties exception of Jia county in north is greaterthan the six counties in south, and it also shows Aeolian loss is higherthan water in Yulin.