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Liu Y.-J.,Huazhong Agricultural University | Liu Y.-J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Liu Y.-J.,CAS Institute of Soil and Water Conservation | Hu J.-M.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | And 5 more authors.
Catena | Year: 2016

Roads play a significant role in altering hydrological processes. Roads cause more erosion to be generated from the hillslope for both road-concentrated flow and rainfall. In this study, six treatments (Natural Restoration, Grass, Grass & Shrub, Sodded Strip, Grass & Farmland, and Farmland) were used to recolonize hillslope plants on a newly built unpaved road. Rainfall simulation (rainfall intensity of 90mmh-1 and 120mmh-1) and scouring simulation (scouring flow rate 15Lmin-1 and 20Lmin-1) tests were conducted to identify the effects of plants on soil erosion. In the rainfall simulation test, Grass & Shrub was more effective at reducing hillslope erosion than the other treatments, and Grass & Shrub also had a lower runoff coefficient, soil detachment rate, and higher efficiency in trapping runoff and sediment. The hydrological responses of all of the tested plots in the scouring test were much faster than in the rainfall simulation, as indicated by the lower lag time to runoff generation. The hillslope erosion in the scouring test was significantly higher than in the rainfall simulation. The water-stable aggregate, saturated hydraulic conductivity, vegetation cover, root length density, and root weight density were important factors that conditioned the runoff generation and sediment yield from the hillslope in both experimental tests. In the scouring test, in infiltration improvement and flow erosivity reduction, Grass was more effective at trapping runoff and sediment because of its dense well-developed system of fine roots. Therefore, except for an immediate surface cover, in the areas where the hillslope has a risk of road-concentrated flow scouring, the enhancement of topsoil roughness was also very important in weakening the impact of road-concentrated flow on the hillslope. © 2015 Elsevier B.V.


Zheng H.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Zheng H.,CAS Institute of Soil and Water Conservation | Yang J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Yang J.,CAS Institute of Soil and Water Conservation | And 8 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

The study is aimed to identify the law of how soil property and peanut growth respond to soil and water conservation (SWC) tillage in order to provide a scientific basis for preventing soil erosion, improving soil fertility and increasing peanut yield in red soil sloping land. The impacts of three types of SWC tillage practices, namely vetiver grass hedgerows (VH), straw mulching (SM) and vetiver grass hedgerows plus straw mulching (VH+SM), on soil property and peanut yield were examined and compared with conventional tillage (CT) through a long-term located experiment in sloping land of red soil. Results showed that after five years of the experiment, VH+SM and SM treatments could still promote the growth of stem, leaf, root and fruit of its in peanut flowering and podding periods, and created significant peanut yield increments of 460.65 kg/hm2 and 761.11 kg/hm2 with increasing rates of 6.19% and 20.32%, respectively, compared with CT. Although VH treatment had no obvious influence on promoting peanut growth and yield, its effect on reducing erosion was remarkable, and thus its comprehensive benefit were still better than that of CT. The three SWC tillage practices all improved the chemical properties of soil to some extent compared with CT. Among them, VH+SM treatment exhibited the best performance, and increased the soil organic matter, total nitrogen and available phosphorus contents by 36.81%, 64.03%, and 43.50%, respectively. Under VH+SM tillage practice, the soil microaggregate (with diameter less than 2 μm) content and the total amount of main microbial population were significantly higher than those under CT, indicating that soil physical structure and microbial activity were improved. Hence, the SWC tillage practices were fit for sustainable agricultural development in arid sloping land of red soil in South China. Especially, the combination mode of vetiver grass hedgerows plus straw mulching had outstanding effect on improving soil quality and crop yield. © 2016, Chinese Society of Agricultural Machinery. All right reserved.


Liu Y.-J.,Huazhong Agricultural University | Liu Y.-J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Liu Y.-J.,CAS Institute of Soil and Water Conservation | Hu J.-M.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | And 5 more authors.
Catena | Year: 2015

Roads play a significant role in altering hydrological processes. Roads cause more erosion to be generated from the fillslope for both road-concentrated flow and rainfall. In this study, six treatments (Natural Restoration, Grass, Grass & Shrub, Sodded Strip, Grass & Farmland, and Farmland) were used to recolonize fillslope plants on a newly built unpaved road. Rainfall simulation (rainfall intensity of 90mmh-1 and 120mmh-1) and scouring simulation (scouring flow rate 15Lmin-1 and 20Lmin-1) tests were conducted to identify the effects of plants on soil erosion. In the rainfall simulation test, Grass & Shrub was more effective at reducing fillslope erosion than the other treatments, and Grass & Shrub also had a lower runoff coefficient, soil detachment rate, and higher efficiency in trapping runoff and sediment. The hydrological responses of all of the tested plots in the scouring test were much faster than in the rainfall simulation, as indicated by the lower lag time to runoff generation. The fillslope erosion in the scouring test was significantly higher than in the rainfall simulation. The water-stable aggregate, saturated hydraulic conductivity, vegetation cover, root length density, and root weight density were important factors that conditioned the runoff generation and sediment yield from the fillslope in both experimental tests. In the scouring test, in infiltration improvement and flow erosivity reduction, Grass was more effective at trapping runoff and sediment because of its dense well-developed system of fine roots. Therefore, except for an immediate surface cover, in the areas where the fillslope has a risk of road-concentrated flow scouring, the enhancement of topsoil roughness was also very important in weakening the impact of road-concentrated flow on the fillslope. © 2015 Elsevier B.V.


Liu Y.-J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Liu Y.-J.,CAS Institute of Soil and Water Conservation | Yang J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Yang J.,CAS Institute of Soil and Water Conservation | And 6 more authors.
Journal of Hydrology | Year: 2016

Land cover and rainfall regime are two important factors that affect soil erosion. In this paper, three land cover types – grass cover, litter cover and bare land – were employed to analyze surface runoff, subsurface flow and sediment loss processes in relation to the rainfall regimes in the red soil region of China. Five rainfall regimes were classified according to 393 rainfall events via a k-means clustering method based on the rainfall depth, duration and maximum 30-min intensity. The highest surface runoff coefficient and erosion amount were found on bare land in all five rainfall regimes, and the lowest were found on grass cover. The litter cover generated the highest subsurface flow rate, followed by the grass cover; the lowest was on bare land. For grass cover and litter cover plots, rainfall events of rainfall regime IV which had the longest duration, greatest depth and lowest intensity had the highest surface runoff coefficient, soil erosion amount and subsurface flow rate. For bare land, storm rainfall events of rainfall regime V had the highest intensity, lowest depth and duration, had the highest surface runoff coefficient and soil erosion amount, but the lowest subsurface flow rate. The highest subsurface flow rate of bare land happened in rainfall regime IV. Surface cover was urgently needed to reduce soil erosion. When the lands under dense surface cover, more attention should be paid to rainfall events that of long duration, high depth but low in intensity which commonly occurred in spring. The interactions of surface–subsurface flow and its effects on soil erosion and nutrient loss were worth considering in the red soil region. © 2016 Elsevier B.V.


Mo M.,CAS Institute of Soil and Water Conservation | Mo M.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Xie S.,CAS Institute of Soil and Water Conservation | Xie S.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | And 4 more authors.
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2016

Hilly red soil region of southern China is characterized by thin soil layer susceptible to erosion during the period of concentrated precipitation and frequent rainstorms. Thus, non-point source pollution of nitrogen carried by runoff in development of agriculture and forestry on slope land poses a threat to the water environment. In this paper, vertical layered output characteristics of nitrogen carried by runoff on red-soil slope were analyzed in three treatments, which were Bahia grass planting, hay mulching and bare land respectively, under three natural precipitation events which happened before, after and one year after spreading fertilizer with the use of Drainage Lysimeter. The results showed that output amounts of TN through surface runoff in three treatments decreased gradually from bare land, hay mulching to grass planting, and output amounts of TN through interflow and underground runoff were ranked in descending order, from hay mulching, bare land to grass planting. Under condition of rainstorm, underground runoff was main carrier for layered output of TN in runoff on red soil slope, accounting for 55.28%~95.30%. Nitrogen loss was not only reflected in surface runoff, accounting for 0.12%~42.16%, more of which was also reflected in interflow and underground runoff. Soil and water conservation measures such as vegetation covering and dry litter mulching could help dissolved inorganic nitrogen infiltration. © 2016, China Water Power Press. All right reserved.


Zheng H.J.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Zheng H.J.,CAS Institute of Soil and Water Conservation | Zuo J.C.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | Zuo J.C.,CAS Institute of Soil and Water Conservation | And 6 more authors.
Plant, Soil and Environment | Year: 2016

Stable isotope15N tracer technique was used in combination with artificial rainfall simulation to study the influence of interflow and surface-flow on nitrogen (N) migration loss of soil-plant systems on typical red soil sloping uplands. This study also investigated the utilization efficiency of fertilizer N during different peanut plant growth stages. The results indicated that soil N loss was predominantly via interflow and erosive sediment. Fertilizer N loss during the initial growth stage was mainly through surface runoff, while that occurred as interflow increased from less than 5% to around 16% during the middle and late growth stages. The loss of fertilizer N through surface runoff, erosive sediment and interflow accounted for over 18% of the total N application. The utilization rate of fertilizer N by peanut plants was around 45% through its life cycle, and that 70% of N absorbed by this plant derived from the soil. This highlighted the importance of adopting effective methods to reduce nutrient loss through interflow and surface-flow, the need to increase the utilization rate of fertilizers, and the importance to maintain soil fertility at a relatively high level. © 2016, Czech Academy of Agricultural Sciences. All rights reserved.


Wang T.,Huazhong Agricultural University | Yu B.,Huazhong Agricultural University | Liu Y.,Huazhong Agricultural University | Liu Y.,Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

Unpaved rural roads are thought to be one of the major sources of sediment in small watershed. Measurements of erosion from unpaved roads in rural regions will be taken to improve our ability to predict the delivery of sediment and its effects on water quality. Road surface shape is an important parameter of the road micro-structure. The road surface shape change the erosion features and play a great role in altering the runoff-sediment transportation processes of the road system. In this paper, 4 typical road surface shapes in rural regions of China were chosen to study the impact of surface shape on road erosion. Soil was sampled from rural road surface. After air dried and sieved through a 2 mm screen, soil was filled in a soil bin with the bulk density of 1.65 g/cm3, which was the most common soil bulk density of unpaved road in study area by field survey. The surface of soil was shaped in convex, lateral, flat, and concave to simulate 4 common road surface shapes. The slope of lateral pavement was set to 4°, and the radian of arch pavement (including concave and convex) was set to 0.1. All of the simulated roads were tested in treatments with 3 slopes, which were 5°, 10° and 15°. American SPRACO cone nozzles were used in rainfall simulation with the vertical height of 4.75 m from the ground. The rainfall intensity was 60 mm/h, and the rainfall duration was 45 min. Runoff and sediments were collected in every 3 min. The runoff coefficient, soil loss rate and a set of hydraulic parameters such as Reynolds number, Froude number and Manning's roughness coefficient were calculated after experiment. The results showed that the runoff was generated rapidly on road surface. High bulk density of pavement soil led to less infiltration and larger runoff coefficient. The initial runoff-yielding time of all types of roads was in 30 s, and the runoff coefficient was greater than 70%. The impacts of shapes on sediment production were much higher than that on runoff generation, so the capability of shapes in changing the hydrological characteristics of the road surface flow was much more important to sediment. The concave road received the highest soil loss rate due to the highest flow velocity and erosivity. Totally speaking, the flow pattern on concave was determined as torrent flow while that on convex and lateral road was subcritical flow. The eroded sediment particle sizes on convex and lateral were much smaller than that on concave and flat. The soil erosion on convex road was the lightest for the micro-structure on erosion controlling. The sensitivities of concave and flat road to slope degree were higher, and sediment production and flow erosivity had great enhancement with the increasing of slope degree. Differences of road surface shapes led to different erosion characteristics. Optimized combination of different road shapes and "road-canal" can reduce the impacts of road construction on the surroundings in the future road design to the most extent. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

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