Analysis Of Spatial Variability Of Nutrients In Soil And Its Feasibility To Tea Growing In Peak-Clluster Depression Areas Of Karst Region

Peak-cluster depression area of karst region were divided into four ecological areas according to artificial disturbance and characteristics of vegetation in the present study, including artificial forest area, secondary forest area, primary forest area and disturbed area. The characteristics of descriptive statistics of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK) and pH in the 4 ecological areas were analyzed to investigate the soil nutrients with classical statistic method. Futhermore, in order to research the ecological process and mechanism, the the spatial variability and spatial distribution of soil nutrients in artificial forest area were studied by geostatistics and GIS. Based on above studies, the soil feasibility to tea growing in Peak-cluster depression area of karst region was analyzed, and the application prospect of geostatistics method for researching ecological system in tea garden were also discussed. The main results were shown as follows:(1) The soils were generally presented litmusless or low alkaline reaction in the four ecological areas at average pH 7.0. The soil nutrients were affected by parent materials, vegetation type, vegetation coverage, artificial disturbance, climate, landform and physiognomy, and the content of SOC, TN and AN were mainly affected by vegetation type and vegetation coverage, increasing along with the succession of ecosystem from disturbed area to artificial forest area, to secondary forest area, to primary forest area. In addition, phosphorus and potassium were mainly affected by parent materials, however, AK were largely affected by vegetation and planting system. (2) The results of spatial autocorrelation analysis and Semivariagram analysis showed that the values of Co/Co+C of pH, SOC, TN, TP, TK were less than 25% in the artificial forest area suggesting intense spatial autocorrelation, while the values of C0/C0+C of AN, AP, AK were around 30% indicating medium spatial autocorrelation., The spatial distributions of SOC, TN and AN were shown in a similar spatial pattern, and their concentrations were affected by vegetation coverage, litter fall, landform and fertilization, increasing in block corelated to the landform altitude. In contrast, the spatial distributions of pH, TK and AK apparently affected by parent materials and artificial disturbance, were shown in crack. Moreover, TP affected mostly by vegetation coverage and fertilization, its maximum presented at the left down-slope, and decreased with the distants far from the point of maximum. However, AP distributed in a contrary spatial pattern to TP.(3) Tea with high resitance to drought and alkalescence were growen in the depression area or medium/downslope of Peak-cluster depression area of karst region. Additionally, ecosystem could be reconstructed indeed along with tea garden development by simultaneously growing tea and tree.(4) Geostatistics should be combined with GIS to analyze spatial variability and spatial distribution of ecological factors in the future research on the ecosystem of tea garden, and the ecological process and mechanism of ecological factors should be used to build and improve ecological condition of tea garden.