Pub Date : 2024-04-01DOI: 10.1016/j.iswcr.2024.03.003
Soil nutrients are essentially regulated by land management practices via modulating biotic element input and metabolism. The Three Gorges Reservoir Area in China was dominated by a farming landscape, but land management has become diversified over recent decades. How these restorative management practices may have affected soil nutrients is not completely understood. In this study, a space-time substitution approach was applied to evaluate soil nutrients and their stoichiometric changes in response to post-farming land management practices. Soil samples (0–10 cm, 10–20 cm, and 20–40 cm) were collected from present-day croplands, cypress plantations, eucalyptus plantations, abandoned croplands, and citrus plantations. Soil organic matter, soil organic carbon, total nitrogen, alkaline hydrolyzed nitrogen, total phosphorus, and available phosphorus were determined. The results showed that soil organic matter and total nitrogen in abandoned croplands, cypress plantations, eucalyptus plantations and citrus plantations were increased by 186% and 190%, 184% and 107%, 45% and 33%, 45% and 54%, respectively, in comparison with those of present-day croplands. Soil nutrients except for total phosphorus decreased with soil depth by exclusion of tillage mixing. Comprehensive soil nutrient index showed that abandoned croplands (0.90) and cypress plantations (0.72) exhibited favorable nutrient recovery capacity. Soil C:P and N:P ratios increased in abandoned croplands, cypress plantations, and eucalyptus plantations. Phosphorus may become a limiting factor for plant growth with prolonged recovery in abandoned croplands, cypress plantations, and eucalyptus plantations, while soil organic matter and total nitrogen deficiencies were exacerbated in citrus plantations and present-day croplands. Therefore, cropland abandonment and reforestation (particularly cypress trees plantation) are recommended options for restoring soil nutrients in the Three Gorges Reservoir Area.
{"title":"Divergent behaviour of soil nutrients imprinted by different land management practices in the Three Gorges Reservoir Area, China","authors":"","doi":"10.1016/j.iswcr.2024.03.003","DOIUrl":"10.1016/j.iswcr.2024.03.003","url":null,"abstract":"<div><div>Soil nutrients are essentially regulated by land management practices via modulating biotic element input and metabolism. The Three Gorges Reservoir Area in China was dominated by a farming landscape, but land management has become diversified over recent decades. How these restorative management practices may have affected soil nutrients is not completely understood. In this study, a space-time substitution approach was applied to evaluate soil nutrients and their stoichiometric changes in response to post-farming land management practices. Soil samples (0–10 cm, 10–20 cm, and 20–40 cm) were collected from present-day croplands, cypress plantations, eucalyptus plantations, abandoned croplands, and citrus plantations. Soil organic matter, soil organic carbon, total nitrogen, alkaline hydrolyzed nitrogen, total phosphorus, and available phosphorus were determined. The results showed that soil organic matter and total nitrogen in abandoned croplands, cypress plantations, eucalyptus plantations and citrus plantations were increased by 186% and 190%, 184% and 107%, 45% and 33%, 45% and 54%, respectively, in comparison with those of present-day croplands. Soil nutrients except for total phosphorus decreased with soil depth by exclusion of tillage mixing. Comprehensive soil nutrient index showed that abandoned croplands (0.90) and cypress plantations (0.72) exhibited favorable nutrient recovery capacity. Soil C:P and N:P ratios increased in abandoned croplands, cypress plantations, and eucalyptus plantations. Phosphorus may become a limiting factor for plant growth with prolonged recovery in abandoned croplands, cypress plantations, and eucalyptus plantations, while soil organic matter and total nitrogen deficiencies were exacerbated in citrus plantations and present-day croplands. Therefore, cropland abandonment and reforestation (particularly cypress trees plantation) are recommended options for restoring soil nutrients in the Three Gorges Reservoir Area.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 896-907"},"PeriodicalIF":7.3,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140783800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-29DOI: 10.1016/j.iswcr.2024.03.002
Land and soil resources are scarce in the Tibetan Plateau, and the region is facing ecological pressure from climate warming and increasing human activities. As a major ecological problem, gully erosion is destroying land and soil resources on the Tibetan Plateau, but related research is limited, and susceptibility areas and influencing factors are unclear. Machine learning methods are often applied to study gully initiation susceptibility, but they require a programming foundation. Therefore, the Redui watershed on the southern Tibetan Plateau with severe gully erosion was selected to evaluate the susceptibility and influencing factors of gully initiation through 12 influencing factors including topography, human activity, and underlying surface conditions, and all 2310 gully headcut sites. Two non-code nonlinear modeling methods, the categorical Regression (CATREG) and geographical detector (Geodetector) methods, were first used in the spatial modeling of gully initiation susceptibility. The results showed that the gully initiation susceptibility of the hillslope around the alluvial fan was highest. The very high susceptibility areas of the CATREG model and Geodetector model account for 18.2% and 16% of the total, respectively. The main influencing factors of gully initiation were elevation, relief, and soil type recognized by CATREG, and elevation, human footprint, and soil type recognized by Geodetector. Elevation is the primary factor controlling downstream susceptibility in both models. The primary factors in the upper and middle reaches are soil type and relief identified by CATREG. Human footprint, soil type, and distance to road are primary factors in the upper and middle reaches identified by Geodetector. The explanatory power of elevation, elevation-relief interaction, Geodetector model and CATREG model were 39%, 54%, 46.4% and 73.8%, respectively, at extremely significant levels (P < 0.001), which means that the influencing factors were well considered and that the methods have great application potential in the future.
{"title":"Modeling gully initiation by two codeless nonlinear methods: A case study in a small watershed on the Tibetan Plateau","authors":"","doi":"10.1016/j.iswcr.2024.03.002","DOIUrl":"10.1016/j.iswcr.2024.03.002","url":null,"abstract":"<div><div>Land and soil resources are scarce in the Tibetan Plateau, and the region is facing ecological pressure from climate warming and increasing human activities. As a major ecological problem, gully erosion is destroying land and soil resources on the Tibetan Plateau, but related research is limited, and susceptibility areas and influencing factors are unclear. Machine learning methods are often applied to study gully initiation susceptibility, but they require a programming foundation. Therefore, the Redui watershed on the southern Tibetan Plateau with severe gully erosion was selected to evaluate the susceptibility and influencing factors of gully initiation through 12 influencing factors including topography, human activity, and underlying surface conditions, and all 2310 gully headcut sites. Two non-code nonlinear modeling methods, the categorical Regression (CATREG) and geographical detector (Geodetector) methods, were first used in the spatial modeling of gully initiation susceptibility. The results showed that the gully initiation susceptibility of the hillslope around the alluvial fan was highest. The very high susceptibility areas of the CATREG model and Geodetector model account for 18.2% and 16% of the total, respectively. The main influencing factors of gully initiation were elevation, relief, and soil type recognized by CATREG, and elevation, human footprint, and soil type recognized by Geodetector. Elevation is the primary factor controlling downstream susceptibility in both models. The primary factors in the upper and middle reaches are soil type and relief identified by CATREG. Human footprint, soil type, and distance to road are primary factors in the upper and middle reaches identified by Geodetector. The explanatory power of elevation, elevation-relief interaction, Geodetector model and CATREG model were 39%, 54%, 46.4% and 73.8%, respectively, at extremely significant levels (P < 0.001), which means that the influencing factors were well considered and that the methods have great application potential in the future.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 747-760"},"PeriodicalIF":7.3,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140406854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1016/j.iswcr.2024.03.001
Common farming practices in sub-Saharan Africa (SSA) such as intensive and repeated tillage, complete crop residue removal, and biomass burning create risks of soil degradation. To reduce these risks, conservation agriculture (CA) uses minimal soil disturbance, crop residue retention, and crop rotation in order to reduce soil erosion, improve soil quality and crop production, and facilitate climate change mitigation and adaptation. Nevertheless, CA adoption in SSA is extremely low. This paper aims to review current practices, challenges, and constraints to the adoption of CA in SSA. Our analyses show that CA is practiced in only about 1.25% of the total cultivated area in SSA, despite two decades of efforts to promote CA adoption among smallholder farmers. Specific difficulties in CA adoption by smallholder farmers in SSA may be attributed to i) lack of locally adaptable CA systems, particularly those integrating the needs of livestock production; ii) lack of adequate crop residues for surface mulch; iii) inconsistent and low crop yields; iv) lack of smallholder CA equipment for direct sowing; v) limited availability, high cost, and inadequate knowledge associated with the use of appropriate fertilizer and herbicides; and vi) lack of CA knowledge and training. Other problems relate to the management of specific soil orders, e.g., CA implementation on steeply sloping land and poorly drained soils such as Vertisols. CA adoption by smallholder farmers is also obstructed by socio-economic factors due to smallholder farmers’ focus on short term yield increases and their lack of access to markets, loans, and education. To facilitate wider adoption by smallholder farmers in SSA, CA approaches should be downscaled to fit the existing tillage tools and the specific agroecological and socio-economic farm settings.
撒哈拉以南非洲地区(SSA)的常见耕作方式,如密集和重复耕作、完全清除作物残留物和焚烧生物质,都会造成土壤退化的风险。为了降低这些风险,保护性农业(CA)采用了尽量减少土壤扰动、保留作物残茬和轮作的方法,以减少土壤侵蚀、提高土壤质量和作物产量,并促进减缓和适应气候变化。然而,撒哈拉以南非洲地区对 CA 的采用率极低。本文旨在回顾撒哈拉以南非洲地区采用 CA 的当前实践、挑战和制约因素。我们的分析表明,尽管二十年来一直在努力促进小农户采用 CA,但在 SSA,CA 的种植面积仅占总种植面积的 1.25%。撒南非洲小农在采用 CA 方面遇到的具体困难可归因于:i) 缺乏适应当地情况的 CA 系统,特别是那些结合畜牧业生产需求的系统;ii) 缺乏足够的作物残茬用于地表覆盖;iii) 作物产量不稳定且较低;iv) 缺乏直接播种的小农 CA 设备;v) 与使用适当肥料和除草剂相关的可用性有限、成本高且知识不足;以及 vi) 缺乏 CA 知识和培训。其他问题与特定土壤的管理有关,例如在陡坡地和排水不良的土壤(如 Vertisols)上实施 CA。小农户采用 CA 还受到社会经济因素的阻碍,因为小农户注重短期增产,缺乏进入市场、获得贷款和接受教育的机会。为促进撒哈拉以南非洲地区的小农更广泛地采用 CA 方法,应缩小规模,以适应现有的耕作工具以及特定的农业生态和社会经济农场环境。
{"title":"Challenges and constraints of conservation agriculture adoption in smallholder farms in sub-Saharan Africa: A review","authors":"","doi":"10.1016/j.iswcr.2024.03.001","DOIUrl":"10.1016/j.iswcr.2024.03.001","url":null,"abstract":"<div><div>Common farming practices in sub-Saharan Africa (SSA) such as intensive and repeated tillage, complete crop residue removal, and biomass burning create risks of soil degradation. To reduce these risks, conservation agriculture (CA) uses minimal soil disturbance, crop residue retention, and crop rotation in order to reduce soil erosion, improve soil quality and crop production, and facilitate climate change mitigation and adaptation. Nevertheless, CA adoption in SSA is extremely low. This paper aims to review current practices, challenges, and constraints to the adoption of CA in SSA. Our analyses show that CA is practiced in only about 1.25% of the total cultivated area in SSA, despite two decades of efforts to promote CA adoption among smallholder farmers. Specific difficulties in CA adoption by smallholder farmers in SSA may be attributed to i) lack of locally adaptable CA systems, particularly those integrating the needs of livestock production; ii) lack of adequate crop residues for surface mulch; iii) inconsistent and low crop yields; iv) lack of smallholder CA equipment for direct sowing; v) limited availability, high cost, and inadequate knowledge associated with the use of appropriate fertilizer and herbicides; and vi) lack of CA knowledge and training. Other problems relate to the management of specific soil orders, e.g., CA implementation on steeply sloping land and poorly drained soils such as Vertisols. CA adoption by smallholder farmers is also obstructed by socio-economic factors due to smallholder farmers’ focus on short term yield increases and their lack of access to markets, loans, and education. To facilitate wider adoption by smallholder farmers in SSA, CA approaches should be downscaled to fit the existing tillage tools and the specific agroecological and socio-economic farm settings.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 828-843"},"PeriodicalIF":7.3,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140273513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-17DOI: 10.1016/j.iswcr.2024.02.002
This study examined land use/land cover (LULC) changes in Chemoga watershed of the Upper Blue Nile Basin, comprising four distinct agroecological regions: Wet Wurch, Moist Dega, Moist Weyna Dega, and Moist Kolla. We used multi-temporal Landsat images from 1985 to 2020, a hybrid classification method and the Cellular Automata-Markov model to analyze historical and predict future (2020–2060) LULC changes under business-as-usual (BAU) and land conservation (LC) scenarios. Magnitudes and patterns of spaciotemporal LULC changes were analyzed using intensity analysis. Cropland expanded across all agroecologies from 1985 to 2020, with Moist Kolla experiencing the highest increase at the expense of woodland, due the introduction of commercial farming to this hotter, less populated and inaccessible area. Moist Dega exhibited the highest allocation changes within cropland and forest, attributable to farmers’ adoption of rotational land use to rehabilitate extensively degraded cultivated lands. Under the BAU scenario, projections suggest further cropland expansion at expense of woodland in Moist Kolla and built-up areas at the expense of cropland and grassland in Moist Dega. Under the LC scenario, forest cover is expected to increase at the expense of cropland across all agroecologies. The historical and projected BAU LULC change scenario substantially increased soil erosion and reduced ecosystem services. These effects can be minimized if LC scenario is properly implemented. The agroecology-based LULC intensity analysis reveals local drivers of change and associated impacts, providing vital insights for targeted land use planning in this study watershed and other watersheds facing similar challenges.
{"title":"Agroecology-based land use/land cover change detection, prediction and its implications for land degradation: A case study in the Upper Blue Nile Basin","authors":"","doi":"10.1016/j.iswcr.2024.02.002","DOIUrl":"10.1016/j.iswcr.2024.02.002","url":null,"abstract":"<div><div>This study examined land use/land cover (LULC) changes in Chemoga watershed of the Upper Blue Nile Basin, comprising four distinct agroecological regions: Wet Wurch, Moist Dega, Moist Weyna Dega, and Moist Kolla. We used multi-temporal Landsat images from 1985 to 2020, a hybrid classification method and the Cellular Automata-Markov model to analyze historical and predict future (2020–2060) LULC changes under business-<em>as</em>-usual (BAU) and land conservation (LC) scenarios. Magnitudes and patterns of spaciotemporal LULC changes were analyzed using intensity analysis. Cropland expanded across all agroecologies from 1985 to 2020, with Moist Kolla experiencing the highest increase at the expense of woodland, due the introduction of commercial farming to this hotter, less populated and inaccessible area. Moist Dega exhibited the highest allocation changes within cropland and forest, attributable to farmers’ adoption of rotational land use to rehabilitate extensively degraded cultivated lands. Under the BAU scenario, projections suggest further cropland expansion at expense of woodland in Moist Kolla and built-up areas at the expense of cropland and grassland in Moist Dega. Under the LC scenario, forest cover is expected to increase at the expense of cropland across all agroecologies. The historical and projected BAU LULC change scenario substantially increased soil erosion and reduced ecosystem services. These effects can be minimized if LC scenario is properly implemented. The agroecology-based LULC intensity analysis reveals local drivers of change and associated impacts, providing vital insights for targeted land use planning in this study watershed and other watersheds facing similar challenges.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 786-797"},"PeriodicalIF":7.3,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139966119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-14DOI: 10.1016/j.iswcr.2024.02.001
Soil profile organic carbon (OC) and total nitrogen (TN) are influenced by topographic attributes, and land use. The visible and near-infrared (Vis-NIR) spectroscopy method can be used for the prediction of OC and TN because it is reliable, nondestructive, fast, and cost-effective. VIS-NIR soil spectral and environmental data were combined with the Partial least squares regression (PLSR) model to examine the effect of topography attributes and land use on topsoil and subsoil OC and TN stocks. After this, based on the soil depth, 114 soil samples were collected from 0 to 20 cm (topsoil) and 20–50 cm (subsoil) under three land uses, as well as OC and TN, along with several soil properties including soil particles (sand, silt, clay), pH, and bulk density in both topsoil and subsoil samples were measured. A DEM with a resolution of 30 m was used to derive the topography factors and remote sensing data was used to calculate the vegetation index. Soils (0–50 cm) under orchard land use had the highest stock of SOC (7.4 kg m−2) as well as TN (2.4 kg m−2). There was a significant increase in the organic matter stock of soils located on the south aspect (8.3 kg m−2) compared to soils located on other aspects, particularly on the north aspect (3.9% increase). Soils on the south aspect contain higher soil-water contents and lower temperatures, resulting in a decrease in the decomposition of soil organic matter. A strong positive correlation was demonstrated between topography wetness index (0.57–0.63) and topography TN stocks (0.54–0.66) as well as the highest loading score among terrain attributes, suggesting that topography is the primary factor controlling SOC stocks, particularly subsoil stocks. Additionally, we found that soils on the south-facing aspects (N aspects) had the highest spectra. Additionally, the PLSR, which showed an R2 of 0.82, a RMSE of 0.15 %, and a RPD of 0.39 indicated excellent prediction capabilities for the OC content. We concluded that the PLSR model coupled with Vis-NIR spectroscopy is able to predict topsoil and subsoil OC and N content under different aspect slopes.
{"title":"VIS-NIR spectroscopy and environmental factors coupled with PLSR models to predict soil organic carbon and nitrogen","authors":"","doi":"10.1016/j.iswcr.2024.02.001","DOIUrl":"10.1016/j.iswcr.2024.02.001","url":null,"abstract":"<div><div>Soil profile organic carbon (OC) and total nitrogen (TN) are influenced by topographic attributes, and land use. The visible and near-infrared (Vis-NIR) spectroscopy method can be used for the prediction of OC and TN because it is reliable, nondestructive, fast, and cost-effective. VIS-NIR soil spectral and environmental data were combined with the Partial least squares regression (PLSR) model to examine the effect of topography attributes and land use on topsoil and subsoil OC and TN stocks. After this, based on the soil depth, 114 soil samples were collected from 0 to 20 cm (topsoil) and 20–50 cm (subsoil) under three land uses, as well as OC and TN, along with several soil properties including soil particles (sand, silt, clay), pH, and bulk density in both topsoil and subsoil samples were measured. A DEM with a resolution of 30 m was used to derive the topography factors and remote sensing data was used to calculate the vegetation index. Soils (0–50 cm) under orchard land use had the highest stock of SOC (7.4 kg m<sup>−2</sup>) as well as TN (2.4 kg m<sup>−2</sup>). There was a significant increase in the organic matter stock of soils located on the south aspect (8.3 kg m<sup>−2</sup>) compared to soils located on other aspects, particularly on the north aspect (3.9% increase). Soils on the south aspect contain higher soil-water contents and lower temperatures, resulting in a decrease in the decomposition of soil organic matter. A strong positive correlation was demonstrated between topography wetness index (0.57–0.63) and topography TN stocks (0.54–0.66) as well as the highest loading score among terrain attributes, suggesting that topography is the primary factor controlling SOC stocks, particularly subsoil stocks. Additionally, we found that soils on the south-facing aspects (N aspects) had the highest spectra. Additionally, the PLSR, which showed an R<sup>2</sup> of 0.82, a RMSE of 0.15 %, and a RPD of 0.39 indicated excellent prediction capabilities for the OC content. We concluded that the PLSR model coupled with Vis-NIR spectroscopy is able to predict topsoil and subsoil OC and N content under different aspect slopes.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 844-854"},"PeriodicalIF":7.3,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139876070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Three-River Source Region (TRSR), China's water tower and an important ecological barrier in China, provides a considerable amount of water to the downstream regions, home to more than 500 million people. The present study focused on the assessment of hydrological components (i.e., precipitation, actual evapotranspiration, potential evapotranspiration, surface flow, baseflow, streamflow, soil moisture, snowmelt water, and terrestrial water storage), their transformation and trends along with meteorological elements (i.e., maximum temperature, minimum temperature, mean temperature, relative humidity, wind speed, and sunshine hours) in the historical and future periods. For this, the hydrological model, HEC-HMS, was applied to simulate hydrological components and Mann-Kendal to explore the trends for 1981–2015. First time, the statistical downscaling model, SDSM, was used to generate climatic data under the shared socio-economic scenario-5 (SSP585) in the region, which was applied to simulate the hydrological cycle. The assessment results showed that precipitation transformed into evapotranspiration and streamflow by 70 % and 30 %, respectively. In the region, streamflow was generated by 78 %, 22 %, and 5.6 % by baseflow, surface flow, and snowmelt. According to trend results, all climatic variables showed statistically significant trends but insignificant in all hydrological components for the historical period, except evapotranspiration. However, all hydroclimatic components were projected to increase in the future, except windspeed. For example, temperature, precipitation, evapotranspiration, streamflow, and direct flow (surface flow) will increase by 1.4 (3.3) °C, 12 (36) %, 8.5 (19) %, 25 (95) %, and 77 (473) % in 2021–2060 (2061–2100) relative to 1981–2020, which shows, the region will be hotter and wetter, with high flooding potential in the future. These results will be helpful for precise water resources planning and management in this extremely sensitive region to climate change.
{"title":"An integrative analysis of hydroclimatic elements in the three-river source region for historical and future periods: Shift toward an intensified hydrological cycle","authors":"Rashid Mahmood , Shaofeng Jia , Aifeng Lv , Mukand S. Babel","doi":"10.1016/j.iswcr.2024.01.005","DOIUrl":"10.1016/j.iswcr.2024.01.005","url":null,"abstract":"<div><div>The Three-River Source Region (TRSR), China's water tower and an important ecological barrier in China, provides a considerable amount of water to the downstream regions, home to more than 500 million people. The present study focused on the assessment of hydrological components (i.e., precipitation, actual evapotranspiration, potential evapotranspiration, surface flow, baseflow, streamflow, soil moisture, snowmelt water, and terrestrial water storage), their transformation and trends along with meteorological elements (i.e., maximum temperature, minimum temperature, mean temperature, relative humidity, wind speed, and sunshine hours) in the historical and future periods. For this, the hydrological model, HEC-HMS, was applied to simulate hydrological components and Mann-Kendal to explore the trends for 1981–2015. First time, the statistical downscaling model, SDSM, was used to generate climatic data under the shared socio-economic scenario-5 (SSP585) in the region, which was applied to simulate the hydrological cycle. The assessment results showed that precipitation transformed into evapotranspiration and streamflow by 70 % and 30 %, respectively. In the region, streamflow was generated by 78 %, 22 %, and 5.6 % by baseflow, surface flow, and snowmelt. According to trend results, all climatic variables showed statistically significant trends but insignificant in all hydrological components for the historical period, except evapotranspiration. However, all hydroclimatic components were projected to increase in the future, except windspeed. For example, temperature, precipitation, evapotranspiration, streamflow, and direct flow (surface flow) will increase by 1.4 (3.3) °C, 12 (36) %, 8.5 (19) %, 25 (95) %, and 77 (473) % in 2021–2060 (2061–2100) relative to 1981–2020, which shows, the region will be hotter and wetter, with high flooding potential in the future. These results will be helpful for precise water resources planning and management in this extremely sensitive region to climate change.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"13 1","pages":"Pages 43-66"},"PeriodicalIF":7.3,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139636526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.1016/j.iswcr.2024.01.004
Permafrost plays an important role in hydrological processes of alpine regions. The frost table in the active layer on the permafrost acts as an impermeable boundary and regulates water generation from hillslopes and its routing to streams. Past studies focused on modes or critical conditions of flow generation, rather than on the capacity of the active layer on the permafrost to recharge flow. This study aimed to characterize the role of supra-permafrost groundwater in the generation of runoff on hillslopes during the active layer thawing processes. The study focused on an alpine meadow permafrost hillslope located in the northeastern Tibet Plateau during the months of July and August in both 2021 and 2022. Hydrometeorological variables, including precipitation, air temperature, soil temperature, soil moisture, thaw depths, supra-permafrost groundwater level, and runoff generation were monitored in field. Partial Least Squares Path Modeling was selected to analyze the relations between the above variables. The results showed that infiltrated rainwater tended to move into deep thawed soil, following which the frozen layer forced horizontal transport along the hillslope. This indicated that thaw depths along the soil profile regulated the dominant runoff path. The accumulated precipitation of the previous days had a significant impact on runoff generation. There was minimal lateral subsurface flow when the saturated zone was absent, whereas lateral subsurface flow increased with increasing thickness of the saturated zone. Runoff generation on the hillslope was regulated by both thaw depths and the thickness of the saturated zone along the soil profile. This study can act as a reference for runoff generation processes of permafrost hillslopes.
{"title":"Generation of runoff in an alpine meadow hillslope underlain by permafrost","authors":"","doi":"10.1016/j.iswcr.2024.01.004","DOIUrl":"10.1016/j.iswcr.2024.01.004","url":null,"abstract":"<div><div>Permafrost plays an important role in hydrological processes of alpine regions. The frost table in the active layer on the permafrost acts as an impermeable boundary and regulates water generation from hillslopes and its routing to streams. Past studies focused on modes or critical conditions of flow generation, rather than on the capacity of the active layer on the permafrost to recharge flow. This study aimed to characterize the role of supra-permafrost groundwater in the generation of runoff on hillslopes during the active layer thawing processes. The study focused on an alpine meadow permafrost hillslope located in the northeastern Tibet Plateau during the months of July and August in both 2021 and 2022. Hydrometeorological variables, including precipitation, air temperature, soil temperature, soil moisture, thaw depths, supra-permafrost groundwater level, and runoff generation were monitored in field. Partial Least Squares Path Modeling was selected to analyze the relations between the above variables. The results showed that infiltrated rainwater tended to move into deep thawed soil, following which the frozen layer forced horizontal transport along the hillslope. This indicated that thaw depths along the soil profile regulated the dominant runoff path. The accumulated precipitation of the previous days had a significant impact on runoff generation. There was minimal lateral subsurface flow when the saturated zone was absent, whereas lateral subsurface flow increased with increasing thickness of the saturated zone. Runoff generation on the hillslope was regulated by both thaw depths and the thickness of the saturated zone along the soil profile. This study can act as a reference for runoff generation processes of permafrost hillslopes.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 775-785"},"PeriodicalIF":7.3,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139635947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-20DOI: 10.1016/j.iswcr.2024.01.003
Sana Khan, Rebecca Bartley, Anne Kinsey-Henderson, Aaron Hawdon
Daley et al. (2023a) argue that at least 10–15 years apart Digital Elevation Model (DEM) derived DEMs of Difference (DoD) surveys are needed to detect reliable geomorphic change within the gullied landscapes of the Great Barrier Reef, Australia. We acknowledge that the reliability of observed geomorphic change increases as more subtle geomorphic processes are detected with longer monitoring periods. As further good quality long-term legacy datasets become available, we encourage utilising these to improve confidence in targeting erosion rehabilitation. However, our approach to consistently apply 2–3 year DoDs to contrasting gully morphologies enabled capture of more intense geomorphic processes acting over shorter timeframes and provided valuable and timely information on (i) contrasting erosional mechanisms and erosion rates between variable gully morphologies, and (ii) rehabilitation efforts undertaken. In this paper, we take the opportunity to concisely address all the concerns raised by Daley et al. (2023a).
{"title":"Response to comment by Daley et al., on “Assessing gully erosion and rehabilitation using multi temporal LiDAR DEMs: Case study from the Great Barrier Reef catchments, Australia”","authors":"Sana Khan, Rebecca Bartley, Anne Kinsey-Henderson, Aaron Hawdon","doi":"10.1016/j.iswcr.2024.01.003","DOIUrl":"10.1016/j.iswcr.2024.01.003","url":null,"abstract":"<div><p><span>Daley et al. (2023a)</span> argue that at least 10–15 years apart Digital Elevation Model (DEM) derived DEMs of Difference (DoD) surveys are needed to detect reliable geomorphic change within the gullied landscapes of the Great Barrier Reef, Australia. We acknowledge that the reliability of observed geomorphic change increases as more subtle geomorphic processes are detected with longer monitoring periods. As further good quality long-term legacy datasets become available, we encourage utilising these to improve confidence in targeting erosion rehabilitation. However, our approach to consistently apply 2–3 year DoDs to contrasting gully morphologies enabled capture of more intense geomorphic processes acting over shorter timeframes and provided valuable and timely information on (i) contrasting erosional mechanisms and erosion rates between variable gully morphologies, and (ii) rehabilitation efforts undertaken. In this paper, we take the opportunity to concisely address all the concerns raised by <span>Daley et al. (2023a)</span>.</p></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 3","pages":"Pages 741-745"},"PeriodicalIF":7.3,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095633924000030/pdfft?md5=3b0cf699169be34cc0fddb31225adb8d&pid=1-s2.0-S2095633924000030-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139637963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-13DOI: 10.1016/j.iswcr.2024.01.002
Land suitability assessment is used in conjunction with geographic information systems to spatially model diverse aspects of soil functions, having the potential to facilitate a sustainable increase in agricultural production, reduce land degradation, or aid humans in adapting to climate change. Compared to the existing datasets, this study provides a new higher resolution geospatial assessment of the agricultural land suitability for several crops and land uses in the temperate continental climate across Europe. To model the land suitability we used geospatial data depicting seventeen eco-pedological indicators (e.g. soil texture, pH, porosity, temperature, precipitation, slope). To evaluate how the land is utilized, the suitability maps have been spatially cross-tabulated with a crop map. Over the entire study area, wheat and barley showed significant suitable land in the southern part, potatoes, and sugar beet exhibited the highest extent of suitable land in the northern parts, while corn and sunflower exhibited a much lower extent of suitable land. Water table depth, precipitation, temperature, terrain slope, soil porosity, SOC, and topsoil texture emerged as the limiting factors for agricultural suitability in the study area. Our results show that the suitable arable land does not have space left for the expansion of crops, however, we have identified regions with extensive cultivation of wheat and corn on unsuitable land with the potential for cultivation of more suitable crops such as barley, sunflower, sugar beet, and potato. It seems that one action that can enhance agricultural practices in the study area is to better allocate each cultivated crop across more suitable lands.
{"title":"Geospatial evaluation of the agricultural suitability and land use compatibility in Europe's temperate continental climate region","authors":"","doi":"10.1016/j.iswcr.2024.01.002","DOIUrl":"10.1016/j.iswcr.2024.01.002","url":null,"abstract":"<div><div>Land suitability assessment is used in conjunction with geographic information systems to spatially model diverse aspects of soil functions, having the potential to facilitate a sustainable increase in agricultural production, reduce land degradation, or aid humans in adapting to climate change. Compared to the existing datasets, this study provides a new higher resolution geospatial assessment of the agricultural land suitability for several crops and land uses in the temperate continental climate across Europe. To model the land suitability we used geospatial data depicting seventeen eco-pedological indicators (e.g. soil texture, pH, porosity, temperature, precipitation, slope). To evaluate how the land is utilized, the suitability maps have been spatially cross-tabulated with a crop map. Over the entire study area, wheat and barley showed significant suitable land in the southern part, potatoes, and sugar beet exhibited the highest extent of suitable land in the northern parts, while corn and sunflower exhibited a much lower extent of suitable land. Water table depth, precipitation, temperature, terrain slope, soil porosity, SOC, and topsoil texture emerged as the limiting factors for agricultural suitability in the study area. Our results show that the suitable arable land does not have space left for the expansion of crops, however, we have identified regions with extensive cultivation of wheat and corn on unsuitable land with the potential for cultivation of more suitable crops such as barley, sunflower, sugar beet, and potato. It seems that one action that can enhance agricultural practices in the study area is to better allocate each cultivated crop across more suitable lands.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 908-919"},"PeriodicalIF":7.3,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139637071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-06DOI: 10.1016/j.iswcr.2024.01.001
Knowing soil hydraulic properties is essential to support soil use and management practices; however, their measuring is commonly expensive and time-consuming. Thus, pedotransfer functions (PTFs) have been used to quantify physical properties such as the soil water retention curve (SWRC). SWRC relates the volumetric soil water content (θ) as a function of the matric potential (h) and plays a vital role in soil hydraulic modeling. Point-PTFs estimate key-points of the SWRC, often from measured texture, bulk density, and organic matter. This study aimed to formulate new point-PTFs to estimate θ(h) data ranging from θ(-0.1 m) to θ(-150 m) to be applied in subtropical, tropical and temperate soils. The PTF equations were derived from linear and non-linear regressions of measured soil physical properties against to the water retention data. The prediction performance of the new-formulated PTFs overcame the performance of already existing and widely-known PTFs recognized in the literature and can be, therefore, applied in soil water retention topics under a wider textural range.
{"title":"New empirical-point pedotransfer functions for water retention data for a wide range of soil texture and climates","authors":"","doi":"10.1016/j.iswcr.2024.01.001","DOIUrl":"10.1016/j.iswcr.2024.01.001","url":null,"abstract":"<div><div>Knowing soil hydraulic properties is essential to support soil use and management practices; however, their measuring is commonly expensive and time-consuming. Thus, pedotransfer functions (PTFs) have been used to quantify physical properties such as the soil water retention curve (SWRC). SWRC relates the volumetric soil water content (<em>θ</em>) as a function of the matric potential (<em>h</em>) and plays a vital role in soil hydraulic modeling. Point-PTFs estimate key-points of the SWRC, often from measured texture, bulk density, and organic matter. This study aimed to formulate new point-PTFs to estimate <em>θ</em>(<em>h)</em> data ranging from <em>θ(-0.1 m)</em> to <em>θ(-150 m)</em> to be applied in subtropical, tropical and temperate soils. The PTF equations were derived from linear and non-linear regressions of measured soil physical properties against to the water retention data. The prediction performance of the new-formulated PTFs overcame the performance of already existing and widely-known PTFs recognized in the literature and can be, therefore, applied in soil water retention topics under a wider textural range.</div></div>","PeriodicalId":48622,"journal":{"name":"International Soil and Water Conservation Research","volume":"12 4","pages":"Pages 855-867"},"PeriodicalIF":7.3,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139392772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}