[Changing characteristics of organic matter and pH of cultivated soils in Zhejiang province over the last 50 years].
By comparing the current quality investigation data of cultivated soils in Zhejiang province with the past data, changing characteristics of organic matter and pH value of the soils in this province over last 50 years were analyzed. The results showed that content of organic matter and pH value of the cultivated soils changed greatly during past 50 years, and the changes varied with historical periods and soil types. From 1958 to 1980s, accumulation of soil organic matter was obvious, soil organic matter increased averagely by 40.34%, and the mean pH increased slightly by 0.05 of pH unit. From 1980s to 2008, the mean content of organic matter in paddy soils decreased by 5.58%. The changes of soil organic matter varied with distribution zones of the paddy soils. The mean content of organic matter of paddy soils in valley plain increased with time, and those in plain with water network, hilly area and coastal plain decreased with time. The mean contents of organic matter in fluvio-aquic soil and coastal saline soil in the year 2008 were 29.48% and 14.60% respectively higher than those in 1980s. As compared with those obtained at 1980s, the cultivated soil in this province have been significantly acidified in the past thirty years, the mean pH value declined by 0.25 of pH unit, and the decline of pH value of paddy soils was greater than those of fluvio-aquic soil and saline soil. Changes in fertilization structure and conversion of paddy fields to upland were thought as main causes of the changes in both soil organic matter and pH value.
Institute of Soil and Water Resource and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. mkzhang@zju.edu.cn
Ming-Kui
MK
Zhang
Institute of Soil and Water Resource and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Yue-Chang
YC
Chang
D000383:Agriculture; D002681:China; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000032:analysis*; D012275:Oryza; D012987:Soil / Q000737:chemistry*; D014867:Water
D009930:Organic Chemicals; D012987:Soil; D014867:Water