Effect of tillage erosion on the distribution of CaCO3, phosphorus and the ratio of CaCO3/available phosphorus in the slope landscape

Little is known about the effect of tillage erosion on the distribution of CaCO3, phosphorus and changes in the ratio of CaCO3/available phosphorus (AP) in the hillslope landscape. The aims of the present study were to elucidate the mechanisms underlying changes in CaCO3 and AP concentrations induced by tillage erosion along slope transects and to reconstruct the historical changes in CaCO3 in soil layers at different landscape positions. Two adjacent slopes were selected from the Sichuan Basin, China, one with downslope tillage (Slope 1) and the other with upslope tillage (Slope 2) for 29 years. Then, consecutive downslope tillage by hoeing was applied five and 20 times on Slope 1. Under normal tillage (both downslope and upslope) conditions, CaCO3 concentrations increased exponentially with soil depth. However, the mixing effect of consecutive tillage (five and 20 tills) changed the vertical CaCO3 distribution patterns. For downslope tillage, the topsoil layer CaCO3 concentration was significantly lower at the toeslope than at other slope positions, but there were no significant differences between toeslope and other slope positions for upslope tillage. Consecutive tillage with five and 20 tills increased CaCO3 concentrations in the topsoil layer by 27.7% and 30.8% respectively compared with downslope tillage, but AP concentrations decreased by 26.1% and 29.0% respectively. Under normal tillage, AP concentrations decreased with increasing CaCO3 concentrations due to the adsorption and precipitation of AP by CaCO3, but this relationship disappeared after consecutive tillage. After consecutive tillage with five and 20 tills, the mean CaCO3/AP ratios of the topsoil layer were 93.5% and 88.4% greater than those for downslope tillage respectively, whereas there were no significant differences between downslope and upslope tillage. In conclusion, tillage is a process of CaCO3 replenishment and AP dilution in the surface layer of soil derived from carbonate-rich bedrocks.

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A Multilayer Soil Moisture Dataset Based on the Gravimetric Method in China and Its Characteristics

Journal of Hydrometeorology ◽

10.1175/jhm-d-19-0035.1 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1721-1736 ◽

Cited By ~ 4

Author(s):

Aihui Wang ◽

Xueli Shi

Keyword(s):

Soil Moisture ◽

Soil Depth ◽

Linear Trend ◽

Standardized Precipitation Index ◽

Gravimetric Method ◽

Northwest China ◽

Soil Layers ◽

Significance Level ◽

The Mean ◽

The Standardized Precipitation Index

Abstract Based on the gravimetric-technique-measured soil relative wetness and the observed soil characteristic parameters from 1992 to 2013 in China, this study derives a user-convenient monthly volumetric soil moisture (SM) dataset from 732 stations for five soil layers (10, 20, 50, 70, and 100 cm). The temporal–spatial variations in SM and its relationship with precipitation (Pr) in different subregions are then explored. The magnitude of SM is relatively large in south China and is low in northwest China, and it generally increases with soil depth in each region. The maximum SM appears in spring and/or autumn and the minimum in summer, and the SM seasonality does not vary as distinctly as that of Pr. For the top three soil layers (10-, 20-, and 50-cm levels), the linear trend analysis indicates an overall increasing SM tendency, and the mean trends (averaged across stations with trends passing a 95% significance level test) are 9.35 × 10−7, 7.37 × 10−3, and 2.45 × 10−3 cm3 cm−3 yr−1, respectively. SM memory depends on the soil depth and regions, and it has longer retention time in the deeper layers. Furthermore, the correlation between SM and antecedent Pr varies with soil depth and lag time. The antecedent Pr anomaly (1 or 2 months in advance) can be used to some extent as a surrogate SM anomaly in most regions except for in arid regions. This result is further demonstrated by the relationships between the SM anomaly and the standardized precipitation index. The current SM dataset can be used in various applications, such as validating satellite-retrieved products and model outputs.

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Thermal conductivity of sedimentary rocks in the Sichuan basin, Southwest China

Energy Exploration & Exploitation ◽

10.1177/0144598718804902 ◽

2018 ◽

Vol 37 (2) ◽

pp. 691-720 ◽

Cited By ~ 3

Author(s):

Boning Tang ◽

Chuanqing Zhu ◽

Ming Xu ◽

Tiange Chen ◽

Shengbiao Hu

Keyword(s):

Thermal Conductivity ◽

Sichuan Basin ◽

Water Saturation ◽

Thermal Structure ◽

Burial Depth ◽

Scanning Method ◽

Clastic Rocks ◽

The Sichuan Basin ◽

The Mean ◽

Thermal Conductivities

The optical scanning method was adopted to measure the thermal conductivities of 418 drill-core samples from 30 boreholes in Sichuan basin. All the measured thermal conductivities mainly range from 2.00 to 4.00 W/m K with a mean of 2.85 W/m K. For clastic rocks, the mean thermal conductivities of sandstone, mudstone, and shale are 3.06 ± 0.73, 2.57 ± 0.42, and 2.48 ± 0.33 W/m K, respectively; for carbonate rocks, the mean thermal conductivities of limestone and dolomite are 2.53 ± 0.44 and 3.55 ± 0.71 W/m K, respectively; for gypsum rocks, the mean thermal conductivity is 3.60 ± 0.64 W/m K. The thermal conductivities of sandstone and mudstone increase with burial depth and stratigraphic age, but this trend is not obvious for limestone and dolomite. Compared with other basins, the thermal conductivities of sandstone and mudstone in Sichuan basin are distinctly higher, while the thermal conductivities of limestone are close to Tarim basin. The content of mineral composition such as quartz is the principal factor that results in thermal conductivity of rocks differing from normal value. In situ thermal conductivity of sandstones was corrected with the consideration of water saturation. Finally, a thermal conductivity column of sedimentary formation of the Sichuan basin was given out, which can provide thermal conductivity references for the research of deep geothermal field and lithospheric thermal structure in the basin.

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Ring distribution patterns—diversification or speciation? Comparative phylogeography of two small mammals in the mountains surrounding the Sichuan Basin

Molecular Ecology ◽

10.1111/mec.15913 ◽

2021 ◽

Author(s):

Yanqun Wang ◽

Anderson Feijó ◽

Jilong Cheng ◽

Lin Xia ◽

Zhixin Wen ◽

...

Keyword(s):

Small Mammals ◽

Sichuan Basin ◽

Distribution Patterns ◽

Comparative Phylogeography ◽

The Sichuan Basin

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Soil Fertility Status and Soil Quality Index in Tibrekot Community Forest, Western Nepal

Indian Journal of Forestry ◽

10.54207/bsmps1000-2015-105hk3 ◽

2015 ◽

Vol 38 (3) ◽

pp. 201-208

Author(s):

Ram Sharma ◽

M.K. Gupta

Keyword(s):

Soil Quality ◽

Quality Index ◽

Soil Depth ◽

Soil Parameters ◽

Available Phosphorus ◽

Community Forest ◽

Soil Quality Index ◽

Soil Layers ◽

Fertility Status ◽

Soil Fertility Status

Physiochemical attributes of soil under Schima-Castanopsis forest managed by the local community as Community Forest user’s group in Lesser Himalayan meta-sedimentary zone in Hemja VDC of Kaski district, western Nepal was estimated to evaluate the soil fertility status and soil quality Index. Soil organic carbon was varied from 0.62 to 3.73 per cent and soil organic matter 1.06 to 6.41 per cent in different layers in the soils at different altitudes. The mean soil pH of all soil layers was moderately acidic. The soil acidity showed decreasing trend with increasing depths. The bulk density was increases with increasing soil depths and varied from 0.78 to 1.22 g/cm3 in different soil layers. Total nitrogen varied from 0.11 percent in lowest layer (90-120 cm) to 0.40 in top layer (0-15 cm) at different elevation. The available phosphorus in different soil layers varied from 1.48 to14.90 mg kg-1. The layer wise mean value of available phosphorus was observed maximum in lowest soil depth 90-120 cm (11.76 mg kg-1) followed by 0-15 cm layer (10.13 mg kg-1). Exchangeable potassium content under in all soil depths varied from 29.40 mg kg-1 to 72.85 mg kg-1. The layer wise exchangeable potassium content was observed maximum in 90-120 cm depth (64.17 mg kg-1) and 60-90 cm (64.05 mg kg-1) followed by 0-15 cm soil depth (58.23 mg kg-1). Differences were tested through one way ANOVA of the studied soil parameters in different altitudes and observed that they were statistically significant at 0.05 level (p = <0.05). Pearson correlation analysis among the different soil parameters in TCF were showed statistically significant at the 0.01 level (2 – tailed) and 0.05 levels (2 - tailed). The Soil Quality Index of surface layer at all altitudes was higher and varied from 0.62 to 0.76 (fair to good) as compared to subsurface layer that was ranged from 0.54 to 0.56 (fair). The SQI was decreased with increasing soil depths. An average SQI in TCF was 0.60 (fair) up to 120 cm depths.

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Soil Cover Improves Soil Quality in a Young Walnut Forest in the Sichuan Basin, China

Forests ◽

10.3390/f12020236 ◽

2021 ◽

Vol 12 (2) ◽

pp. 236

Author(s):

Liehua Tie ◽

Maosong Feng ◽

Congde Huang ◽

Josep Peñuelas ◽

Jordi Sardans ◽

...

Keyword(s):

Soil Quality ◽

Sichuan Basin ◽

Soil Cover ◽

Microbial Biomass Carbon ◽

Juglans Regia ◽

Soil Layer ◽

Biological Indicators ◽

Positive Interactions ◽

Available Phosphorus ◽

The Sichuan Basin

The soil quality index (SQI) is based on several key indicators and is used to assess soil quality. More than 250,000 ha of walnut saplings (Juglans regia L.) were planted in previous cropland areas in the Sichuan Basin, China, using a range of soil cover types that may affect soil quality with effects that are unclear. We investigated the effects of white film (WF), black film (BF), shade netting (SN), and maize straw (MS) soil cover types and an uncovered control type (CK) on soil chemical and biological indicators and the SQI in the 0–15 cm soil layer in a young walnut forest in the Sichuan Basin over a 27-month study period. The results showed that all soil cover types increased the soil organic matter (SOM), total potassium (TK), and available potassium (AK) concentrations (p < 0.05), whereas the total nitrogen (TN) and available nitrogen (AN) concentrations were greater only in soils covered by MS than in CK (p < 0.05). The available phosphorus concentrations were 64.1 and 193.2% greater in soils covered by BF and MS treatments, respectively, than in the CK (p < 0.05). The numbers of soil faunal groups (N) were 45.7, 36.4, 37.2, and 101.5% higher in WF, BF, SN, and MS, respectively, than in CK (p < 0.05); the individual numbers (S) were 92.3, 36.2, 100.8, and 154.5% greater in WF, BF, SN, and MS, respectively, than in CK (p < 0.05). The microbial biomass carbon (MBC) was 15.5, 32.3, 45.0, and 77.1% greater in WF, BF, SN, and MS than in CK, respectively (p < 0.05). Redundancy discriminant analysis revealed strong positive interactions between biological indicators (MBC, N, and S) and SOM, AN, and AK concentrations. SOM, TN, AK, S, and MBC were the minimum required variables for the effective assessment of the SQI. All four soil cover types led to an improved SQI (p < 0.05), and MS had the greatest effect on SOM, TN, AN, AP, N, S, MBC, and SQI (p < 0.05). In conclusion, all four soil cover types increased the SOM levels, TK, AK, and MBC concentrations, soil faunal diversity, and SQI. The MS treatment was the most cost-effective and efficient measure to improve soil fertility, ecological function, and overall soil quality in the studied walnut forest.

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