By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to ...By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to sample soil in depression and slope lands respectively, and classical statistical tools were applied to analyze the spatial variability character of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK), pH, and C/N. It was found that land use type was the dominant factor that effected the spatial heterogeneity of SOC, TN, TP, TK, AN, and AP. The content of SOC, TN, and AN decreased with the increase of land use intensity. Due to high fertilizer input, TP and AP in tillage fields were higher than those in the other land use types. TK had no obvious change trend among various land use types. Topographic factors had a significant effect on SOC, TN, TP, AN, AP, AK, and pH. Habitat factor was the dominant factor that effected AK. Altitude factor was the dominant factor for pH. However, all of these factors had no significant effect on C/N. Tillage practice had important effect on soil nutrients loss and soil degradation in the fragile karst ecosystem, and the input of organic manure should be increased in this region.展开更多
Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo Cou...Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.展开更多
文摘By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to sample soil in depression and slope lands respectively, and classical statistical tools were applied to analyze the spatial variability character of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK), pH, and C/N. It was found that land use type was the dominant factor that effected the spatial heterogeneity of SOC, TN, TP, TK, AN, and AP. The content of SOC, TN, and AN decreased with the increase of land use intensity. Due to high fertilizer input, TP and AP in tillage fields were higher than those in the other land use types. TK had no obvious change trend among various land use types. Topographic factors had a significant effect on SOC, TN, TP, AN, AP, AK, and pH. Habitat factor was the dominant factor that effected AK. Altitude factor was the dominant factor for pH. However, all of these factors had no significant effect on C/N. Tillage practice had important effect on soil nutrients loss and soil degradation in the fragile karst ecosystem, and the input of organic manure should be increased in this region.
基金the financial support by IGCP 661, CAGS Research Fund (Grant No. YYWF201725)the National Natural Science Foundation of China (Grant No.41571203)+1 种基金the Ministry of Science and Technology of China (Grant No. 2016YFC0502403-2) the Bureau of Science and Technology of Guangxi (Grant No. 2014GXNS FAA118280)
文摘Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.