Informatics Publishing Limited

Qiuju Wu ¹, Linhua Wang ¹, Faqi Wu ¹

Affiliations
1 Northwest A & F University, College of Resource and Environment, Shaanxi, Yangling, 712100, CN

Abstract

The objective of this laboratory study was to assess the effects of soil crusts and tillage treatments on soil erosion in the Loess Plateau of China. The simulated rainfall storms at 40 mm/h, 60 mm/h and 80 mm/h rates were applied to the soil boxes set to a 17.6% slope, two soil surface conditions (crusted and uncrusted soil surface) and two tillage types (contour tillage and straight slope) were used to investigate the resulting runoff rate and sediment yield. Results show that the runoff rates were greater and total soil loss was lower in crusted than uncrusted soils. Contour tillage treatment resulted in smaller runoff rate and total soil loss than straight slope treatment. Rainfall intensity, soil crusts and tillage treatments had very significant (p < 0.001) effects both on total runoff yield and soil loss. The combined effects of rainfall intensity and tillage treatment on total runoff yield and soil loss were much more significant (p < 0.01) than the other combined effects (p < 0.05). Rainfall intensity had a greatest correlation with the total runoff yield while tillage treatments had a greatest correlation with the total soil loss. As a result, the tillage treatments in the Loess Plateau can reduce the impact of soil crusts on soil erosion effectively.

Keywords

Rainfall Intensity, Runoff Rate, Soil Crusts, Soil Loss, Tillage Treatment.

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Jianing Zhang ¹, Min Xu ¹, Faqi Wu ¹

Affiliations
1 College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, CN

Abstract

Agricultural soil quality evaluation is essential for economic success and environmental stability in Loess gullied hilly region of China. The objective of this study was to develop a suitable soil index from the existence soil indices which were suitable for Loess gullied hilly region of China. A simplified indicator system of soil quality evaluation has been established. Selected soil parameters include aggregation rate, soil organic matter, total N, available P, available K, CaCO₃, catalase and invertase. The proposed simplified soil quality index incorporates all important properties of soils mainly physical, fertility and healthy, which are able to give adequate information on the soil quality status. Match analysis showed a high linear correlation between simplified indicator system and original indicator system. In conclusion, the proposed simplified indicator system for soil quality evaluation of different land-use type will help soil quality evaluator to study and describe the current quality status.

Keywords

Soil Quality, Simplified Indicator System, Loess Gullied Hilly Region.

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Xinlan Liang ¹, Pei Lu ², Longshan Zhao ¹, Jia Wu ³, Faqi Wu ¹

Affiliations
1 College of Natural Resources and Environment, Northwest Agriculture and Forestry University, Yangling 712100, CN
2 Institute of Soil & Water Conservation, Northwest Agriculture and Forestry University, Yangling 712100, CN
3 Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Shaanxi 710004, CN

Abstract

Soil erosion is a complex and dynamic process. Correspondingly, as one of the main factors of soil erosion, Soil surface roughness (SSR) is also complex and dynamic in the process of soil erosion. Soil erosion process was divided into four stages: before the rain (S₀), splash erosion stage (S₁), sheet erosion stage (S₂), rill-gully erosion stage (S₃). The objective of this research is to make it clear how soil erosion affects SSR in detail through evaluating the changes of SSR in different soil erosion stages. Soil beds were operated by four different tillage systems to shape four different surface conditions: artificial shallow ploughing (ASP), artificial deep ploughing (ADP), contour ploughing (CT), and no tillage treatment as (CK). Thirty six experiments were conducted under simulated rainfall. Several indices including the standard deviation (S_d) of soil surface elevation, SSR, and the chain method index C_r' were measured before and after each rainstorm. The result shows that: For ASP, ADP, and CP tillage systems, in splash erosion stage, all the, S_d SSR, and Cr' decrease significantly; in sheet erosion stage, S_d, SSR, and C_r' continue to decrease but the quantity of change is small; in rill-gully erosion stage, S_d, SSR and C_r' increase obviously. For CK, all the S_d, SSR, and C_r' increase all the time. This means splash erosion and sheet erosion can decrease SSR, but the degree is different. Rill-gully erosion can increase SSR, make soil surface rougher than before.

Keywords

Rill-Gully Erosion, Sheet Erosion, Soil Surface Roughness, Splash Erosion, Simulated Rainfall.

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