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Mingan Shao - One of the best experts on this subject based on the ideXlab platform.
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traditional dry Soil Layer index method overestimates Soil desiccation severity following conversion of cropland into forest and grassland on china s loess plateau
Agriculture Ecosystems & Environment, 2020Co-Authors: Xiaoxu Jia, Chunlei Zhao, Yunqiang Wang, Yuanjun Zhu, Xiaorong Wei, Mingan ShaoAbstract:Abstract Due to severe Soil erosion and low crop yield, sloping croplands have been converted into forests and grasslands during the past decades on China’s Loess Plateau (CLP). The introduced exotic high-water consumption plants cause Soil water deficit that leads to the formation of dry Soil Layer (DSL). The traditional index method used to determine the existence of DSL considers only Soil hydraulic property of “stable field capacity” and fails to fully reflect the interactions between Soil water and vegetation. A new index method that considers physiological response of vegetation to drought is needed for DSL research. Here, we proposed a new method to identify and quantify the severity of DSL and compared the proposed method with the traditional method using field data for the 5 m Soil depth in typical tree (R. pseudoacacia, n = 85) and grass (M. sativa, n = 20) plantations on CLP. The number of sites detected with DSL through the new method was less than the traditional method for both species. Based on the traditional method, the level of DSL was even more severe; with mean DSL thickness of 3.2 for R. pseudoacacia and 3.9 m for M. sativa. Then for the new index method, it was only 2.4 m for both plantations. DSL formation depth was much deeper under the new method than the traditional method. Also mean plant available Soil water (PASW) stored in the identified DSL by the traditional method was ∼44.1 and 37.8 mm; accounting for 37.2 and 88.9% of total PASW in the 1–5 m Soil profile under R. pseudoacacia and M. sativa, respectively. Thus, the traditional DSL index method overestimated DSL severity as it fails to account for plant Soil water availability, especially in areas with coarser Soil texture. The proposed new index method that is based on Soil water potential is more suitable for characterization of DSL conditions under different Soil types. This is critical for application in reclamation of DSLs and optimization of vegetation cover in the study area and beyond.
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revegetation with artificial plants improves topSoil hydrological properties but intensifies deep Soil drying in northern loess plateau china
Journal of Arid Land, 2018Co-Authors: Qingyin Zhang, Xiaoxu Jia, Chunlei Zhao, Mingan ShaoAbstract:Knowledge about the effects of vegetation types on Soil properties and on water dynamics in the Soil profile is critical for revegetation strategies in water-scarce regions, especially the choice of vegetation type and human management measures. We focused on the analysis of the effects of vegetation type on Soil hydrological properties and Soil moisture variation in the 0–400 cm Soil Layer based on a long-term (2004―2016) experimental data in the northern Loess Plateau region, China. Soil bulk density (BD), saturated Soil hydraulic conductivity (Ks), field capacity (FC) and Soil organic carbon (SOC) in 2016, as well as the volumetric Soil moisture content during 2004–2016, were measured in four vegetation types, i.e., shrubland (korshinsk peashrub), artificial grassland (alfalfa), fallow land and cropland (millet or potato). Compared with cropland, revegetation with peashrub and alfalfa significantly decreased BD and increased Ks, FC, and SOC in the 0–40 cm Soil Layer, and fallow land significantly increased FC and SOC in the 0–10 cm Soil Layer. Soil water storage (SWS) significantly declined in shrubland and grassland in the 40–400 cm Soil Layer, causing severe Soil drought in the deep Soil Layers. The study suggested that converting cropland to grassland (alfalfa) and shrubland (peashrub) improved Soil-hydrological properties, but worsened water conditions in the deep Soil profile. However, natural restoration did not intensify deep-Soil drying. The results imply that natural restoration could be better than revegetation with peashrub and alfalfa in terms of good Soil hydrological processes in the semi-arid Loess Plateau region.
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regional temporal persistence of dried Soil Layer along south north transect of the loess plateau china
Journal of Hydrology, 2015Co-Authors: Xiaoxu Jia, Chunlei Zhao, Mingan Shao, Chencheng ZhangAbstract:The occurrence of dried Soil Layer (DSL) threatens the sustainable development of restored ecosystems in the Loess Plateau of China. Knowledge of the regional spatiotemporal characteristics of DSL in water-deficient regions is critical for optimal water management and vegetation restoration. This study assessed regional temporal persistence of DSL using Spearman's rank correlation coefficient (r(s)) and relative difference (RD) analyses and determined the dominant driving factors. Two DSL evaluation indices [DSL thickness (DSLT) and DSL Soil water content (DSL-SWC)] were calculated by measuring volumetric SWC of the 0-500 cm Soil Layer at 86 locations along a south-north regional transect of the Loess Plateau in 2013-2014. Based on the study, there was DSL formation at most of the sites (61 out of 86 sites) along the transect. The level of DSL was severe, with mean DSLT of 273 cm and mean DSL-SWC of only 10.8% (v/v) [field capacity (FC) = 22.5% (v/v)]. Mean DSL-SWC generally decreased from south to north, while no obvious trend was noted in DSLT along the transect. Derived r(s) values indicated a good temporal persistence of spatial patterns of DSL. Also RD analysis showed that DSL with thicker DSLT and/or lower DSL-SWC had much stronger temporal persistence, implying higher possibility for the formation of permanent DSL. The representative locations of each DSL index well represented the regional means of DSLT and DSL-SWC. This suggested that there was the feasibility of directly estimating regional patterns of DSL from theoretical temporal stability. The temporal persistence of DSL patterns was mainly controlled by Soil texture, Soil organic carbon, field capacity, mean annual precipitation, precipitation seasonal distribution (PSD) and mean annual temperature. We concluded that Soil- and climate-related factors dominated regional temporal persistence of DSL. Lower Soil water holding capacity, fewer rainfall and more concentrated PSD could intensify the formation and/or development of permanent DSL in the Loess Plateau. This is especially true under worsening global climate change conditions. (C) 2015 Elsevier B.V. All rights reserved.
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the characteristics of Soil water cycle and water balance on steep grassland under natural and simulated rainfall conditions in the loess plateau of china
Journal of Hydrology, 2008Co-Authors: Hongsong Chen, Mingan ShaoAbstract:Summary Large-scale vegetation restoration has been helpful to prevent serious Soil erosion, but also has aggravated water scarcity and resulted in Soil desiccation below a depth of 200 cm in the Loess Plateau of China. To understand the dynamic mechanism of Soil desiccation formation is very important for sustainable development of agriculture in the Loess Plateau. Based on natural and simulated rainfall, the characteristics of Soil water cycle and water balance in the 0–400 cm Soil Layer on a steep grassland hillslope in Changwu County of Shaanxi Loess Plateau were investigated from June to November in 2002, a drought year with annual rainfall of 460 mm. It was similarly considered to represent a rainy year with annual rainfall of 850 mm under simulated rainfall conditions. The results showed that the temporal variability of water contents would decrease in the upper 0–200 cm Soil Layer with the increase in rainfall. The depth of Soil affected by rainfall infiltration was 0–200 cm in the drought year and 0–300 cm in the rainy year. During the period of water consumption under natural conditions, the deepest Layer of Soil influenced by evapotranspiration (ET) rapidly reached a depth of 200 cm on July 21, 2002, and Soil water storage decreased by 48 mm from the whole 0–200 cm Soil Layer. However, during the same investigation period under simulated rainfall conditions, Soil water storage in the 0–400 cm Soil Layer increased by only 71 mm, although the corresponding rainfall was about 640 mm. The extra-simulated rainfall of 458 mm from May 29 to August 10 did not result in the disappearance of Soil desiccation in the 200–400 cm deep Soil Layer. Most infiltrated rainwater retained in the top 0–200 cm Soil Layer, and it was subsequently depleted by ET in the rainy season. Because very little water moved below the 200 cm depth, there was desiccation in the deep Soil Layer in drought and normal rainfall years.
Chunlei Zhao - One of the best experts on this subject based on the ideXlab platform.
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traditional dry Soil Layer index method overestimates Soil desiccation severity following conversion of cropland into forest and grassland on china s loess plateau
Agriculture Ecosystems & Environment, 2020Co-Authors: Xiaoxu Jia, Chunlei Zhao, Yunqiang Wang, Yuanjun Zhu, Xiaorong Wei, Mingan ShaoAbstract:Abstract Due to severe Soil erosion and low crop yield, sloping croplands have been converted into forests and grasslands during the past decades on China’s Loess Plateau (CLP). The introduced exotic high-water consumption plants cause Soil water deficit that leads to the formation of dry Soil Layer (DSL). The traditional index method used to determine the existence of DSL considers only Soil hydraulic property of “stable field capacity” and fails to fully reflect the interactions between Soil water and vegetation. A new index method that considers physiological response of vegetation to drought is needed for DSL research. Here, we proposed a new method to identify and quantify the severity of DSL and compared the proposed method with the traditional method using field data for the 5 m Soil depth in typical tree (R. pseudoacacia, n = 85) and grass (M. sativa, n = 20) plantations on CLP. The number of sites detected with DSL through the new method was less than the traditional method for both species. Based on the traditional method, the level of DSL was even more severe; with mean DSL thickness of 3.2 for R. pseudoacacia and 3.9 m for M. sativa. Then for the new index method, it was only 2.4 m for both plantations. DSL formation depth was much deeper under the new method than the traditional method. Also mean plant available Soil water (PASW) stored in the identified DSL by the traditional method was ∼44.1 and 37.8 mm; accounting for 37.2 and 88.9% of total PASW in the 1–5 m Soil profile under R. pseudoacacia and M. sativa, respectively. Thus, the traditional DSL index method overestimated DSL severity as it fails to account for plant Soil water availability, especially in areas with coarser Soil texture. The proposed new index method that is based on Soil water potential is more suitable for characterization of DSL conditions under different Soil types. This is critical for application in reclamation of DSLs and optimization of vegetation cover in the study area and beyond.
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revegetation with artificial plants improves topSoil hydrological properties but intensifies deep Soil drying in northern loess plateau china
Journal of Arid Land, 2018Co-Authors: Qingyin Zhang, Xiaoxu Jia, Chunlei Zhao, Mingan ShaoAbstract:Knowledge about the effects of vegetation types on Soil properties and on water dynamics in the Soil profile is critical for revegetation strategies in water-scarce regions, especially the choice of vegetation type and human management measures. We focused on the analysis of the effects of vegetation type on Soil hydrological properties and Soil moisture variation in the 0–400 cm Soil Layer based on a long-term (2004―2016) experimental data in the northern Loess Plateau region, China. Soil bulk density (BD), saturated Soil hydraulic conductivity (Ks), field capacity (FC) and Soil organic carbon (SOC) in 2016, as well as the volumetric Soil moisture content during 2004–2016, were measured in four vegetation types, i.e., shrubland (korshinsk peashrub), artificial grassland (alfalfa), fallow land and cropland (millet or potato). Compared with cropland, revegetation with peashrub and alfalfa significantly decreased BD and increased Ks, FC, and SOC in the 0–40 cm Soil Layer, and fallow land significantly increased FC and SOC in the 0–10 cm Soil Layer. Soil water storage (SWS) significantly declined in shrubland and grassland in the 40–400 cm Soil Layer, causing severe Soil drought in the deep Soil Layers. The study suggested that converting cropland to grassland (alfalfa) and shrubland (peashrub) improved Soil-hydrological properties, but worsened water conditions in the deep Soil profile. However, natural restoration did not intensify deep-Soil drying. The results imply that natural restoration could be better than revegetation with peashrub and alfalfa in terms of good Soil hydrological processes in the semi-arid Loess Plateau region.
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regional temporal persistence of dried Soil Layer along south north transect of the loess plateau china
Journal of Hydrology, 2015Co-Authors: Xiaoxu Jia, Chunlei Zhao, Mingan Shao, Chencheng ZhangAbstract:The occurrence of dried Soil Layer (DSL) threatens the sustainable development of restored ecosystems in the Loess Plateau of China. Knowledge of the regional spatiotemporal characteristics of DSL in water-deficient regions is critical for optimal water management and vegetation restoration. This study assessed regional temporal persistence of DSL using Spearman's rank correlation coefficient (r(s)) and relative difference (RD) analyses and determined the dominant driving factors. Two DSL evaluation indices [DSL thickness (DSLT) and DSL Soil water content (DSL-SWC)] were calculated by measuring volumetric SWC of the 0-500 cm Soil Layer at 86 locations along a south-north regional transect of the Loess Plateau in 2013-2014. Based on the study, there was DSL formation at most of the sites (61 out of 86 sites) along the transect. The level of DSL was severe, with mean DSLT of 273 cm and mean DSL-SWC of only 10.8% (v/v) [field capacity (FC) = 22.5% (v/v)]. Mean DSL-SWC generally decreased from south to north, while no obvious trend was noted in DSLT along the transect. Derived r(s) values indicated a good temporal persistence of spatial patterns of DSL. Also RD analysis showed that DSL with thicker DSLT and/or lower DSL-SWC had much stronger temporal persistence, implying higher possibility for the formation of permanent DSL. The representative locations of each DSL index well represented the regional means of DSLT and DSL-SWC. This suggested that there was the feasibility of directly estimating regional patterns of DSL from theoretical temporal stability. The temporal persistence of DSL patterns was mainly controlled by Soil texture, Soil organic carbon, field capacity, mean annual precipitation, precipitation seasonal distribution (PSD) and mean annual temperature. We concluded that Soil- and climate-related factors dominated regional temporal persistence of DSL. Lower Soil water holding capacity, fewer rainfall and more concentrated PSD could intensify the formation and/or development of permanent DSL in the Loess Plateau. This is especially true under worsening global climate change conditions. (C) 2015 Elsevier B.V. All rights reserved.
Xiaoxu Jia - One of the best experts on this subject based on the ideXlab platform.
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traditional dry Soil Layer index method overestimates Soil desiccation severity following conversion of cropland into forest and grassland on china s loess plateau
Agriculture Ecosystems & Environment, 2020Co-Authors: Xiaoxu Jia, Chunlei Zhao, Yunqiang Wang, Yuanjun Zhu, Xiaorong Wei, Mingan ShaoAbstract:Abstract Due to severe Soil erosion and low crop yield, sloping croplands have been converted into forests and grasslands during the past decades on China’s Loess Plateau (CLP). The introduced exotic high-water consumption plants cause Soil water deficit that leads to the formation of dry Soil Layer (DSL). The traditional index method used to determine the existence of DSL considers only Soil hydraulic property of “stable field capacity” and fails to fully reflect the interactions between Soil water and vegetation. A new index method that considers physiological response of vegetation to drought is needed for DSL research. Here, we proposed a new method to identify and quantify the severity of DSL and compared the proposed method with the traditional method using field data for the 5 m Soil depth in typical tree (R. pseudoacacia, n = 85) and grass (M. sativa, n = 20) plantations on CLP. The number of sites detected with DSL through the new method was less than the traditional method for both species. Based on the traditional method, the level of DSL was even more severe; with mean DSL thickness of 3.2 for R. pseudoacacia and 3.9 m for M. sativa. Then for the new index method, it was only 2.4 m for both plantations. DSL formation depth was much deeper under the new method than the traditional method. Also mean plant available Soil water (PASW) stored in the identified DSL by the traditional method was ∼44.1 and 37.8 mm; accounting for 37.2 and 88.9% of total PASW in the 1–5 m Soil profile under R. pseudoacacia and M. sativa, respectively. Thus, the traditional DSL index method overestimated DSL severity as it fails to account for plant Soil water availability, especially in areas with coarser Soil texture. The proposed new index method that is based on Soil water potential is more suitable for characterization of DSL conditions under different Soil types. This is critical for application in reclamation of DSLs and optimization of vegetation cover in the study area and beyond.
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revegetation with artificial plants improves topSoil hydrological properties but intensifies deep Soil drying in northern loess plateau china
Journal of Arid Land, 2018Co-Authors: Qingyin Zhang, Xiaoxu Jia, Chunlei Zhao, Mingan ShaoAbstract:Knowledge about the effects of vegetation types on Soil properties and on water dynamics in the Soil profile is critical for revegetation strategies in water-scarce regions, especially the choice of vegetation type and human management measures. We focused on the analysis of the effects of vegetation type on Soil hydrological properties and Soil moisture variation in the 0–400 cm Soil Layer based on a long-term (2004―2016) experimental data in the northern Loess Plateau region, China. Soil bulk density (BD), saturated Soil hydraulic conductivity (Ks), field capacity (FC) and Soil organic carbon (SOC) in 2016, as well as the volumetric Soil moisture content during 2004–2016, were measured in four vegetation types, i.e., shrubland (korshinsk peashrub), artificial grassland (alfalfa), fallow land and cropland (millet or potato). Compared with cropland, revegetation with peashrub and alfalfa significantly decreased BD and increased Ks, FC, and SOC in the 0–40 cm Soil Layer, and fallow land significantly increased FC and SOC in the 0–10 cm Soil Layer. Soil water storage (SWS) significantly declined in shrubland and grassland in the 40–400 cm Soil Layer, causing severe Soil drought in the deep Soil Layers. The study suggested that converting cropland to grassland (alfalfa) and shrubland (peashrub) improved Soil-hydrological properties, but worsened water conditions in the deep Soil profile. However, natural restoration did not intensify deep-Soil drying. The results imply that natural restoration could be better than revegetation with peashrub and alfalfa in terms of good Soil hydrological processes in the semi-arid Loess Plateau region.
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regional temporal persistence of dried Soil Layer along south north transect of the loess plateau china
Journal of Hydrology, 2015Co-Authors: Xiaoxu Jia, Chunlei Zhao, Mingan Shao, Chencheng ZhangAbstract:The occurrence of dried Soil Layer (DSL) threatens the sustainable development of restored ecosystems in the Loess Plateau of China. Knowledge of the regional spatiotemporal characteristics of DSL in water-deficient regions is critical for optimal water management and vegetation restoration. This study assessed regional temporal persistence of DSL using Spearman's rank correlation coefficient (r(s)) and relative difference (RD) analyses and determined the dominant driving factors. Two DSL evaluation indices [DSL thickness (DSLT) and DSL Soil water content (DSL-SWC)] were calculated by measuring volumetric SWC of the 0-500 cm Soil Layer at 86 locations along a south-north regional transect of the Loess Plateau in 2013-2014. Based on the study, there was DSL formation at most of the sites (61 out of 86 sites) along the transect. The level of DSL was severe, with mean DSLT of 273 cm and mean DSL-SWC of only 10.8% (v/v) [field capacity (FC) = 22.5% (v/v)]. Mean DSL-SWC generally decreased from south to north, while no obvious trend was noted in DSLT along the transect. Derived r(s) values indicated a good temporal persistence of spatial patterns of DSL. Also RD analysis showed that DSL with thicker DSLT and/or lower DSL-SWC had much stronger temporal persistence, implying higher possibility for the formation of permanent DSL. The representative locations of each DSL index well represented the regional means of DSLT and DSL-SWC. This suggested that there was the feasibility of directly estimating regional patterns of DSL from theoretical temporal stability. The temporal persistence of DSL patterns was mainly controlled by Soil texture, Soil organic carbon, field capacity, mean annual precipitation, precipitation seasonal distribution (PSD) and mean annual temperature. We concluded that Soil- and climate-related factors dominated regional temporal persistence of DSL. Lower Soil water holding capacity, fewer rainfall and more concentrated PSD could intensify the formation and/or development of permanent DSL in the Loess Plateau. This is especially true under worsening global climate change conditions. (C) 2015 Elsevier B.V. All rights reserved.
Jeff Drahota - One of the best experts on this subject based on the ideXlab platform.
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using the electromagnetic induction survey method to examine the depth to clay Soil Layer bt horizon in playa wetlands
Journal of Soils and Sediments, 2020Co-Authors: Yuan Xue, Zhenghong Tang, Jeff DrahotaAbstract:Sediment accumulation has been and continues to be a significant threat to the integrity of the playa wetland ecosystem. The purpose of this study was to determine the vertical depth to the clay Soil Layer (Bt horizon) and thus to calculate the thickness of sediments accumulated in playa wetlands. This study used the electromagnetic induction (EMI) survey method, specifically EM38-MK2 equipment, to measure the vertical depth to the clay Soil Layer at the publicly managed wetlands in the Rainwater Basin, Nebraska, USA. The results indicated that the depth to the clay Soil Layer ranges from 21 to 78 cm (n = 279) with a mean sediment thickness of 39 cm. The annual sediment deposition rate since human settlement in the 1860s was calculated to be 0.26 cm year−1. The results provided science-based data to support future wetland restoration planning and the development of decision support tools that prioritize conservation delivery efforts. Our research confirmed that the EMI technique is effective and efficient at determining the depth to the Bt horizon for playa wetlands. Additionally, these results supported previous studies and continue to indicate that a large amount of sediment has accrued in these playa wetlands within the Rainwater Basin area since settlement. Wetland restoration ecologists can use this information to prioritize future wetland restoration work that intends to remove culturally accumulated sediments above the clay Soil Layer. These findings provided a contemporary summary of wetland Soil profile information that is typically used to develop restoration plans. This research also filled the critical knowledge gap about the thickness of the upper Soils and the depth to Bt in publicly managed wetlands.
Yujie Qiu - One of the best experts on this subject based on the ideXlab platform.
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effects of revegetation on organic carbon storage in deep Soils in hilly loess plateau region of northwest china
Journal of Applied Ecology, 2012Co-Authors: Jin Zhang, Zheng Wang, Yujie QiuAbstract:Taking the Robinia pseudoacacia woodlands, Caragana korshinskii shrublands, and abandoned croplands with different years of revegetation in the hilly Loess Plateau region of Northwest China as test objects, this paper studied the profile distribution and accumulation dynamics of organic carbon storage in deep Soil (100-400 cm), with those in 0-100 cm Soil profile as the control. In 0-100 cm Soil profile, the organic carbon storage decreased significantly with the increase of Soil depth; while in deep Soil, the organic carbon storage had a slight fluctuation. The total organic carbon storage in 100-400 cm Soil profile was considerably high, accounting for approximately 60% of that in 0-400 cm Soil profile. The organic carbon storage in 80-100 cm Soil Layer had a significant linear correlation with that in 100-200 and 200-400 cm Soil Layers, and among the organic carbon storages in the five Layers in 0-100 cm Soil profile, the organic carbon storage in 80-100 cm Soil Layer had the strongest correlation with that in 100-400 cm Soil profile, being able to be used to estimate the organic carbon storage in deep Soil in this region. The organic carbon storage in 0-20 cm Soil Layer in the three types of revegetation lands was significantly higher than that in slope croplands, but the organic carbon storage in deep Soil had no significant difference among the land use types. The organic carbon storage in deep Soil increased with the increasing years of revegetation. In R. pseudoacacia woodlands and C. korshinskii shrub lands, the average increasing rate of the organic carbon storage in 100-400 cm Soil Layer was 0.14 and 0.19 t x hm(-2) x a(-1), respectively, which was comparable to that in the 0-100 cm Soil Layer in C. korshinskii shrublands. It was suggested that in the estimation of the Soil carbon sequestration effect of revegetation in hilly Loess Plateau region, the organic carbon accumulation in deep Soil should be taken into consideration. Otherwise, the effect of revegetation on Soil carbon sequestration would be significantly underestimated.
