scholarly journals Soil Chemical Properties under Various Land-Use Types in the Karst Area with a Case Study in Shibing County of China

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Shizhen Xiao ◽  
Jianghu He ◽  
Cheng Zeng ◽  
Jialu Wang
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Quality ◽  
Paddy Field ◽  
Human Activities ◽  
Karst Area ◽  
Karst Region ◽  
Nutrient Contents ◽  
Land Use Types ◽  
Pear Orchard

The effects of different land-use types on the pH, organic carbon, total nutrient, and available nutrients of soil in the 0–30 cm and 30–60 cm layers were studied using the gray relational analysis method. The research area is located in Baiduo village in the dolomite karst region and Shiqiao village in the limestone karst region of Shibing County, Guizhou Province, China. The land-use types investigated included shrubland, forest, grass slope, dryland, paddy field, pear orchard, and flue-cured tobacco field. The contents of organic carbon, total nitrogen, alkaline hydrolysable nitrogen, and available potassium, as well as the pH of the soil in the dolomite shrubland, were higher than those in the limestone shrubland. The total potassium, total phosphorus, and available phosphorus contents of soil in the limestone shrubland were higher than those in the dolomite shrubland. Among the four types of land-use most strongly affected by human activities (paddy field, dryland, flue-cured tobacco field, and pear orchard), the nutrient contents (except potassium in the upper soil layer) were higher than those in the lower layer. The differences in nutrient contents between upper and lower layers were relatively small in the dryland and the pear orchard, whereas they were large for the paddy field and flue-cured tobacco field. The gray relational degree of various land-use types decreased in the following order: dolomite shrubland > forest > grass slope > pear orchard > limestone shrubland > paddy field > dryland > flue-cured tobacco field. The dolomite shrubland had the best soil quality, while the flue-cured tobacco field had the worst. Of the four types of land use most strongly affected by human activities, pear orchard had the best soil quality. This study can provide reference for soil nutrient management and sustainable management in karst areas.

Occurrence characteristics of organic carbon and phosphorus in fissured soil under different land use types in Karst area

2020 ◽  
Vol 40 (21) ◽  
Author(s):  
岑龙沛，严友进，戴全厚，焦权，胡刚，高儒学，伏文兵 CEN Longpei
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Karst Area ◽  
Land Use Types ◽  
Occurrence Characteristics

Soil organic carbon and nutrients content at different land use types in the karst region of Northwest Guangxi

2014 ◽  
Vol 39 (6) ◽  
pp. 655-659
Author(s):  
Xi-juan SONG ◽  
Ke-lin WANG ◽  
Shu-juan LIU ◽  
Zhao-xia ZENG ◽  
Rui XUN
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Karst Region ◽  
Land Use Types

scholarly journals The Grain for Green Project May Enrich the Mercury Concentration in a Small Karst Catchment, Southwest China

Land ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 354
Author(s):  
Rui Qu ◽  
Guilin Han
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Southwest China ◽  
Karst Area ◽  
Karst Region ◽  
Native Vegetation ◽  
High Porosity ◽  
Grain For Green ◽  
Land Use Types ◽  
Grain For Green Project

The Chinese project, better known as the Grain for Green Project (GGP), has changed the land-use type in the karst area of Puding county, Guizhou province, southwest China, and this study is aimed at evaluating the Hg distribution and determining factors in soils after the land-use change. A total of ten soil profiles were selected in the typical karst region, and the land-use types were divided into native vegetation land (NVL), farmland (FL), and abandoned farmland (AFL). Total Hg concentration under different land-use types increased in the order: NVL (average 63.26 μg∙kg−1) < FL (average 71.48 μg∙kg−1) < AFL (average 98.22 μg∙kg−1). After agricultural abandonment for four to five years with a cover of native vegetation in the AFL, a higher concentration of Hg compared to the other two land-use types indicate that the Hg accumulation in soil results from vegetation restoration of AFL due to land-use change. Soil organic carbon (SOC) and macro-aggregates were highly correlated to Hg concentration in this study. Macro-aggregates can provide a stable condition for Hg due to the thin regolith and high porosity in the karst region. A high proportion of macro-aggregates can reduce the mobility of Hg in the karst area. Intense tillage can significantly reduce the formation of macro-aggregates in FL, but the macro-aggregates in AFL were recovered as well as those in NVL, resulting in the accumulation of Hg.

scholarly journals Effects of Contemporary Land Use Types and Conversions from Wetland to Paddy Field or Dry Land on Soil Organic Carbon Fractions

2020 ◽  
Vol 12 (5) ◽  
pp. 2094
Author(s):  
Di Zhao ◽  
Junyu Dong ◽  
Shuping Ji ◽  
Miansong Huang ◽  
Quan Quan ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Constructed Wetland ◽  
Paddy Field ◽  
Heavy Fraction ◽  
Light Fraction ◽  
Paddy Fields ◽  
Dry Land ◽  
Natural Wetlands

Soil organic carbon (SOC) concentration is closely related to soil quality and climate change. The objectives of this study were to estimate the effects of contemporary land use on SOC concentrations at 0–20 cm depths, and to investigate the dynamics of SOC in paddy-field soil and dry-land soil after their conversion from natural wetlands (20 and 30 years ago). We investigated the dissolved organic carbon (DOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and other soil properties (i.e., moisture content, bulk density, pH, clay, sand, silt, available phosphorous, light fraction nitrogen, and heavy fraction nitrogen) in natural wetlands, constructed wetlands, fishponds, paddy fields, and soybean fields. The results indicated that the content of DOC increased 17% in constructed wetland and decreased 39% in fishponds, and the content of HFOC in constructed wetland and fishponds increased 50% and 8%, respectively, compared with that in natural wetlands at 0–20 cm. After the conversion of a wetland, the content of HFOC increased 72% in the paddy fields and decreased 62% in the dry land, while the content of DOC and LFOC decreased in both types. In the paddy fields, LFOC and HFOC content in the topmost 0.2 m of the soil layer was significantly higher compared to the layer below (from 0.2 to 0.6 m), and there were no significant differences observed in the dry land. The findings suggest that the paddy fields can sequester organic carbon through the accumulation of HFOC. However, the HFOC content decreased 22% after 10 years of cultivation with the decrease of clay content, indicating that paddy fields need to favor clay accumulation for the purpose of enhancing carbon sequestration in the paddy fields.

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