Distribution Characteristics Of Soil Organic And Estimation Of Carbon Stock In The Area Of Yunfu

In order to deeply realize the change rules and characteristics of soil organic carbon, as well as the relationship between soil organic carbon and stand type, forest soil from different stand type of Luoding and Xinxing in Guangdong province is used to be object of research. Forest soil carbon from the man-made forest, the natural secondary forest and the economic forest of Luoding and Xinxing has been measured through field investigations and laboratory experiments. Carbon reserve of the area has been estimated too. The relationship between soil organic carbon and several soil physical properties,including volume weight, natural water content, capillary water holding capacity, total porosity, aeration porosity and capillary porosity, has been analyzed.Four kinds of man-made forest, eucalyptus forest, acacia forest, Chinese fir forest and Pinus massoniana forest have been investigated and studied in majority. So as to economic forest represented by cinnamon forest, herbaceous forest, oil-tea camellia, tea and several medicinal plants. 111 sampling point have been set to finish the study to the forest above.Each 38 sampling points of conifer-broadleaf mixed forests, coniferous mixed forests and broadleaf mixed forests were set respectively. 48 sampling points of eucalyptus forest,acacia forest, Chinese fir forest and Pinus massoniana forest were set totally.The research results are as follows:(1) Economic forest soil has the highest level of organic carbon content, man-made forest soil has the secondary and natural secondary forest has the lowest. Organic carbon content of three kinds of forests are as follow in descending order: economic forest(9.86g/kg)>man-made forest(9.25g/kg)>natural secondary forest(8.76g/kg). The Soil Organic Carbon Density of three kinds of forests are as follow in descending order:man-made forest(2.64g/m2)>economic forest(2.54g/m2) > natural secondaryforest(2.50g/m2).(2) Forest soil organic carbon content decreases with the soil layer gets deeper, and its descending rate gets smaller at the same time, so does the Soil Organic Carbon Density.The difference between surface mixed soil sample and any soil layer included in 0-100 cm soil layer. Vertical distribution of organic carbon is similar in the 8 kinds of forest stand.(3) Forest soil organic carbon content of the 8 kinds of forest stand as follow in descending order with the limit of 0-100 cm soil layer: Chinese fir forest(10.21g/kg)>economic forest(9.86g/kg)>acacia forest(8.97g/kg)>conifer-broadleaf forest(8.84g/kg)>Pinus massoniana forest(8.83g/kg)>broadleaf mixed forest(8.64g/kg)>coniferous mixed forest(8.64g/kg)>eucalyptus forest(8.60g/kg). And the Soil Organic Carbon Density as follow: Chinese fir forest(2.85kg/m2)>acacia forest(2.59kg/m2)>economic forest(2.54kg/m2)>Pinus massoniana forest(2.51kg/m2)>broadleaf mixed forest(2.50kg/m2)>conifer-broad leaf forest(2.48kg/m2) >coniferous mixed forest(2.44kg/m2)>eucalyptus forest(2.12kg/m2).(4) The 6 soil physical properties including volume weight, natural water content,capillary water holding capacity, total porosity, aeration porosity and capillary porosity have a significant difference with soil organic carbon content(P<0.01), but the equation of linear regression that fitted between soil organic carbon content and any soil physical properties within the six performs a low precision.(5) Except for the the Soil Organic Carbon Density doesn't have a significant correlation with 3 soil physical properties(natural water content,capillary water holding capacity and capillary porosity), the 8 soil properties including soil organic carbon content, the Soil Organic Carbon Density and the 6 soil physical properties above have significant correlation between each pair of properties.(6) The Total Organic Carbon of Luoding and Xinxing is approximately 5.59×106t.The Total Organic Carbon of the main forest types in Luoding and Xinxing is as follow:coniferous and broad leaf forest(2.01×106t) > economic forest(1.99×106t) >broad leaf mixed forest(5.05×105t)>coniferous mixed forest(4.13×105t) >acacia forest(3.20×105t)>Chinese fir forest(1.86×105t)>Pinus massoniana forest(1.34×105t)>eucalyptus forest(2.45×104t), which have a same order with area order of the 8 kinds forest. And theTotal Organic Carbon of natural secondary forest is a little higher than man-made forest.