Study On Soil Quality Change Characteristics Of Rubber Forest In Xishuangbanna

The planting of rubber forests in Xishuangbanna,Yunnan Province provides indispensable strategic materials and scarce resources for China's national defense and economic construction.However,the expanding rubber forest area has significantly reduced the proportion of tropical rain forest in this region.And the original ecological structure is changed,which has a serious impact on the soil in this area.As a result,soil water conservation capacity,biodiversity and soil quality are decreased.And with the increase of rubber plantation area,the soil quality decreasing is more and more serious,which has become an important factor of environmental deterioration in Xishuangbanna.Thus,the study on the change of soil quality caused by rubber plantation is the key to alleviate the deterioration of regional environment,restore and improve the soil quality in Xishuangbanna.Therefore,in this study soil samples from the main rubber plantation areas in Xishuangbanna are collected systematically,the mainly physical and chemical indexes of soil are tested.Soil comprehensive quality indexes and eco-chemometrics method are been used.The characteristics of soil quality change and its influencing factors of rubber plantation are studied.The change mechanism of soil quality of rubber plantation in Xishuangbanna is revealed.The main conclusions are as follows:(1)The soil bulk density of Xishuangbanna rubber forest increased with the increase of forest age,while the total soil porosity and soil bulk density showed the opposite trend,and the natural water content showed medium-sized forest> young forest> mature forest.The soil of Xishuangbanna rubber forest is acidic,soil organic carbon,total phosphorus,alkali nitrogen and available phosphorus decrease with the growth of forest age,while total nitrogen,total potassium and available potassium show up with the growth of forest age.Age forest> young forest> mature forest.(2)The soil quality of Xishuangbanna rubber forest was evaluated by the soil comprehensive quality index method.The results showed that the soil quality of the Xishuangbanna rubber forest was 0.440,and the soil quality of Naban River was 0.440,followed by Yao District,Manpa Village,Machuang Village and Xiaomo Highway.Dakar Laozhai and Guangnai.With the change of altitude,the soil quality is 1050m>950m>750m>550m>650m>850m.With the increase of forest age,the soil quality showed young forest > middle-aged forest > mature forest,and the soil quality of rubber forest in different soil layers was different.(3)The ecological stoichiometry of Xishuangbanna rubber forest soil varies with region and altitude,but for rubber forest age,C/N decreases with the growth of forest age,N/P and C/P with forest age.The growth is on the rise,but N/P<14 indicates the lack of N element in the soil of Xishuangbanna rubber forest.(4)The soil quality of Xishuangbanna rubber forest was significantly positively correlated with soil total porosity,organic carbon and available phosphorus(P<0.01),and positively correlated with total phosphorus and available potassium(P<0.05).The results of this study can provide a scientific basis for the improvement of soil quality in Xishuangbanna rubber forest and the sustainable use of forest resources and sustainable use of land resources in tropical regions of China.