Distribution Characteristics Of Soil Organic Carbon Of Different Forests In Loess Plateau Of Qianyang County

In this paper, the soils of the Loess Plateau in Qianyang County plantation as theresearch object,analyzed and discussed its soil organic carbon content in the range of0~80cm depth and its distribution characteristics and available N, P, K’s content. The soilorganic carbon contents of plantations (Robinia pseudoacaia, Populus tomentosa, Platycladusorientalis) and wasteland, and the distribution characteristics and the available N, P, K’scontent were investigated in Qianyang county loess plateau in2012, in order to provide thereferences for the recovery of artificial afforestation and ecological system. After setting12sample plots, each plot selected five quadrats.by adopting S-type survey sampling method, allplots were surveyed and sampled, and totally480samples were obtained. The samples weretreated by cleaning, drying sieving and other procedures, finally, the related experimentaltreatment and then the data were made correlation analyses. The results are as follows:(1)In the investigated range of0~80cm soil layer, the soil organic carbon contents offour kinds of sample plots ranked from big to small as follows:tomentosa(4.83g·kg-1)>wasteland(3.55g·kg-1)>black locust (3.48g·kg-1)>arborvitae (3.42g·kg-1); Shows that toment-osa in improving soil carbon reserves has a significant effect. With the increase of soil depth,the soil organic carbon contents of the forests gradually reduced. And tomentosa in the carboncontent in the range of30~80cm is significantly larger than the other three plots content.(2)In the investigation of several plots, the soil bulk density size: wasteland> blacklocust> tomentosa> arborvitae, indicating the degree of loose soil makes afforestation hasbeen significantly improved.(3)Three kinds of forest soil in afforestation available N, P, K content decreasedsignificantly, and lower than the wasteland of the content. The content of organic carbon, soildensity and soil available N, P, K three kinds of nutrition elements varied significantly in thesoil layer of0~30cm (P<0.05), but no significant differences in30cm~80cm (P>0.05). In theplots, soil available N, P, K contents increased with the depth of soil and gradually reduce. (4)Soil water content increased with soil depth and gradually reduce, Poplar plantationsoil water content in the highes. It is concluded that the poplar plantation were better thanother forest species in the Loess plateau.