Foundation Of Soil Acidity Database And Study On Variation Of Soil Acidity In Hainan Island

Considering the phenomenon of serious soil acidifications in nowadays, this paper applied the method of spot (Wuzhi Mountain ) combining with entire areas(the whole Hainan Island area) to made a appraisal to the variation of soil acidity in the last half century and found soil acidity database.Based on the HaiSOTER, soil profile database, soil layer database and soil composition database of 50s, 80s and about 2000 were founded, respectively. Integrated soil acidity database formed after these database connected with terrain database and terrain composition database of HaiSOTER . Variation of the soil acidity in different land use field and different rainfall precipitation regions in the past half century was studied; The result showed that:1, The course of Hainan soil acidification accelerated greatly after 1980s. 2, This paper applied GIS technology to carry on space analysis for the sampling point in SOTER unit areas. The analysis results indicated that from the 1950s to about 2000, the area of strong acid soil accounted for the percentage of all SOTER unit areas that sampling point located in this period increased gradually, but the area of weak acid soil accounted for the percentage of all sampling point in SOTER unit areas in this period reduced gradually, and the area of acid soil in SOTER unit areas accounted for the percentage changed in disorder within the same period.3, Variation of the soil pH of arid farm lands in the past half century was not remarkable; The soil pH of paddy field was remarkable higher than the soil pH of same land-use pattern about 50 years ago,but not remarkable higher than that about 20 years ago; the remarkable acidification of soil in all land-use field , non-paddy field, forests and meadow took place in the past 20 or 50 years.The soil pH difference was not remarkable between the 1950s and the 1980s in any same land use field, the forests and meadow soil pH were all the lowest in those periods.4, According to every 200mm divided hainan rainfall precipitation regions, in the two areas of rainfall precipitation > 1940mm and in the area of rainfall precipitation 1540mm ~ 1740mm, the acidity of soil about 2000 declined extremely remarkably compared with the...