Pub Date : 2020-12-30DOI: 10.4236/ojss.2020.1012031
N. Arrebei, Mohamed Sabir, M. Naimi, M. Chikhaoui, D. Raclot
Over the last decades, estimation of soil erosion using empirical models has long been an active research topic, especially because they are useful to establish watershed management plans. Nevertheless, their application over large areas in a data-scarce Mediterranean region is still a challenge given the furrowed and steep nature of landscapes as well as the aggressiveness of the semi-arid climate. The main purpose of this research was to identify the spatial patterns of erosion and deposition in Nekor river basin (Northern Morocco) using two models: the Revised Universal Soil Loss Equation for Complex Terrain (RUSLE3D) and the Unit Stream Power-based Erosion Deposition (USPED). The two models were evaluated using existing annual soil loss rate measurements. As a result of the RUSLE3D application, about the 73% of the Nekor basin ranges between moderate and extreme risks of erosion, while according to USPED estimation, only 50% of the basin ranges between moderate and extreme risks of erosion. The analysis shows that the mean annual soil erosion rate for both models ranges between 60 and 65 t⋅ha−1⋅year−1 while the mean annual deposition rate is 38 t⋅ha−1⋅year−1. The current results confirmed those coming from previous soil erosion studies, which estimated annual soil loss rates in Nekor river basin between 50 and 70 t⋅ha−1⋅year−1. This study also provided valuable guidance on where to implement soil protection measures.
{"title":"Assessment of Soil Erosion with RUSLE 3D and USPED in the Nekor Watershed (Northern Morocco)","authors":"N. Arrebei, Mohamed Sabir, M. Naimi, M. Chikhaoui, D. Raclot","doi":"10.4236/ojss.2020.1012031","DOIUrl":"https://doi.org/10.4236/ojss.2020.1012031","url":null,"abstract":"Over the last decades, estimation of soil erosion using empirical models has long been an active research topic, especially because they are useful to establish watershed management plans. Nevertheless, their application over large areas in a data-scarce Mediterranean region is still a challenge given the furrowed and steep nature of landscapes as well as the aggressiveness of the semi-arid climate. The main purpose of this research was to identify the spatial patterns of erosion and deposition in Nekor river basin (Northern Morocco) using two models: the Revised Universal Soil Loss Equation for Complex Terrain (RUSLE3D) and the Unit Stream Power-based Erosion Deposition (USPED). The two models were evaluated using existing annual soil loss rate measurements. As a result of the RUSLE3D application, about the 73% of the Nekor basin ranges between moderate and extreme risks of erosion, while according to USPED estimation, only 50% of the basin ranges between moderate and extreme risks of erosion. The analysis shows that the mean annual soil erosion rate for both models ranges between 60 and 65 t⋅ha−1⋅year−1 while the mean annual deposition rate is 38 t⋅ha−1⋅year−1. The current results confirmed those coming from previous soil erosion studies, which estimated annual soil loss rates in Nekor river basin between 50 and 70 t⋅ha−1⋅year−1. This study also provided valuable guidance on where to implement soil protection measures.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"631-642"},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48692359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.4236/ojss.2020.1012028
C. Chauvin, Manon Trambolho, M. Hedde, D. Makowski, H. Cérémonie, A. Jiménez, C. Villenave
Nematodes have been used as bioindicators of soil quality for more than 20 years, and have been shown to have good potential for assessing the impact of heavy metal pollution on soil. They provide information about the biological condition of soil and can reveal dysfunctions linked to the presence of contaminants. In the case of contamination by multiple pollutants, bioindicators can reveal synergistic toxic effects (or “cocktail effects”) on organisms living in soil. These impacts are not revealed by the individual measurement of each pollutant. As the effects of heavy metals on nematode communities are not fully known, identifying reliable nematode-based parameters is not straightforward. Currently, knowledge gaps limit the operational use of these types of indices by soil managers. In this study, we performed a meta-analysis on the results of 37 studies from different countries to reveal general trends regarding the effect of multiple types of heavy metal pollution on soil nematode communities and indices. Based on the contamination level of each metal and using known toxicological threshold values, we defined four contamination classes to categorize soil polluted by heavy metals: normal concentration (c0), low contamination (c1), high contamination (c2), and very high (c3) contamination. The most sensitive nematode parameters, showing a strong relationship with the level of soil pollution, were the structure footprint, community footprint, abundance per trophic group (plant feeders, bacterial feeders and omnivores/predators) and taxonomic richness: all these parameters decreased with increased contamination. Our findings showed that fungal-feeding nematodes were relatively insensitive to metal contamination of soil and actually had a higher abundance in the very high contamination class (c3).
{"title":"Soil Nematodes as Indicators of Heavy Metal Pollution: A Meta-Analysis","authors":"C. Chauvin, Manon Trambolho, M. Hedde, D. Makowski, H. Cérémonie, A. Jiménez, C. Villenave","doi":"10.4236/ojss.2020.1012028","DOIUrl":"https://doi.org/10.4236/ojss.2020.1012028","url":null,"abstract":"Nematodes have been used as bioindicators of soil quality for more than 20 years, and have been shown to have good potential for assessing the impact of heavy metal pollution on soil. They provide information about the biological condition of soil and can reveal dysfunctions linked to the presence of contaminants. In the case of contamination by multiple pollutants, bioindicators can reveal synergistic toxic effects (or “cocktail effects”) on organisms living in soil. These impacts are not revealed by the individual measurement of each pollutant. As the effects of heavy metals on nematode communities are not fully known, identifying reliable nematode-based parameters is not straightforward. Currently, knowledge gaps limit the operational use of these types of indices by soil managers. In this study, we performed a meta-analysis on the results of 37 studies from different countries to reveal general trends regarding the effect of multiple types of heavy metal pollution on soil nematode communities and indices. Based on the contamination level of each metal and using known toxicological threshold values, we defined four contamination classes to categorize soil polluted by heavy metals: normal concentration (c0), low contamination (c1), high contamination (c2), and very high (c3) contamination. The most sensitive nematode parameters, showing a strong relationship with the level of soil pollution, were the structure footprint, community footprint, abundance per trophic group (plant feeders, bacterial feeders and omnivores/predators) and taxonomic richness: all these parameters decreased with increased contamination. Our findings showed that fungal-feeding nematodes were relatively insensitive to metal contamination of soil and actually had a higher abundance in the very high contamination class (c3).","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"579-601"},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43819048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-30DOI: 10.4236/ojss.2020.1012030
Eman F. A. Awad-Allah
Water is essential for the existence of all living forms on the earth, and the kinds and amounts of vegetation occurring on various parts of the earth’s surface depend more on the quantity of water available than on any other single environmental factor. Therefore, the need for the non-subjective, diagnostic assessment tools for water status measurements of plants and soils is indispensable to avoid water shortage problems and achieve sustainable development goals (SDGs) of agricultural sector. The best measure of the energy status of water in plants and soils is the water potential (Ψw), which has the advantage of being physically defined and the force that causes water movement. There are many different instruments that have essential roles for measuring water status of plant, for example, Pressure Chamber, Isopiestic Psychrometer, Pressure Probe, and Osmometers. Each had the ability to indicate not only the water status of various parts of plants and soils but also the forces used to move water from place to place. Nowadays, speaking plant approach (SPA) identifies the optimal crop cultivation conditions based on the physiological status of the plants. The physiological status information from a living plant can be achieved by using a chlorophyll fluorescence imaging robot, which is a powerful tool for early detection of drought stress in plants under practical production greenhouse conditions. Moreover, recently thermal imaging and remote sensing technology are both feasible for precise irrigation guidance and precision water management.
{"title":"Indispensable Measuring Techniques for Water Relations of Plants and Soils: A Review","authors":"Eman F. A. Awad-Allah","doi":"10.4236/ojss.2020.1012030","DOIUrl":"https://doi.org/10.4236/ojss.2020.1012030","url":null,"abstract":"Water is essential for the existence of all living forms on the earth, and the kinds and amounts of vegetation occurring on various parts of the earth’s surface depend more on the quantity of water available than on any other single environmental factor. Therefore, the need for the non-subjective, diagnostic assessment tools for water status measurements of plants and soils is indispensable to avoid water shortage problems and achieve sustainable development goals (SDGs) of agricultural sector. The best measure of the energy status of water in plants and soils is the water potential (Ψw), which has the advantage of being physically defined and the force that causes water movement. There are many different instruments that have essential roles for measuring water status of plant, for example, Pressure Chamber, Isopiestic Psychrometer, Pressure Probe, and Osmometers. Each had the ability to indicate not only the water status of various parts of plants and soils but also the forces used to move water from place to place. Nowadays, speaking plant approach (SPA) identifies the optimal crop cultivation conditions based on the physiological status of the plants. The physiological status information from a living plant can be achieved by using a chlorophyll fluorescence imaging robot, which is a powerful tool for early detection of drought stress in plants under practical production greenhouse conditions. Moreover, recently thermal imaging and remote sensing technology are both feasible for precise irrigation guidance and precision water management.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"616-630"},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41492173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils degradation is one of the constraints in food security achievement in Benin. This study aimed at assessing the effect of cropping systems and slope on soil physical and chemical properties in the watershed of Kpacomey located in the Aplahoue district. Soil samples were collected from three parallel transects along the slope. Sampling was carried out under different treatments combining cropping systems (Maize-Cassava, pure Palm grove, Palm grove-Maize-Cassava and Teak Plantation) along with slope levels (low slope, medium slope and high slope degree). The impact of cropping systems and slope on soil properties was assessed by determining the physical and chemical parameters. The cropping systems significantly (p 3) was recorded under the Palm grove-Maize-Cassava cropping system while the highest (1.47 g/cm3) was obtained with pure Palm grove cropping system. Root biomass was more abundant (0.28%) with the pure Palm grove cropping system. However, root biomass was significantly (p 0.05) on the effect of cropping systems and slope. Moreover, cropping systems resulted in significant effects (p < 0.05). Soil organic matter and soil-assimilated phosphorus content were significantly influenced by the effect of the slope. These findings indicated that cropping systems and slope are significant drivers in soil degradation in the Kpacomey watershed and bringing out cropping systems that best aim at soil conservation.
{"title":"Variation of Physical and Chemical Properties of Soils under Different Cropping Systems in the Watershed of Kpocomey, Southern Benin","authors":"A. Kouelo, Alohoutade Finagnon Mathieu, Avakoudjo Julien, Akplo Tobi Moriaque, Agodo Lambert, Agonvinon Mahugnon Socrate, Houngnandan Pascal, A. Anastase, Amadji Guillaume Lucien, Saïdou Aliou","doi":"10.4236/ojss.2020.1011026","DOIUrl":"https://doi.org/10.4236/ojss.2020.1011026","url":null,"abstract":"Soils degradation is one of the constraints in food security achievement in Benin. This study aimed at assessing the effect of cropping systems and slope on soil physical and chemical properties in the watershed of Kpacomey located in the Aplahoue district. Soil samples were collected from three parallel transects along the slope. Sampling was carried out under different treatments combining cropping systems (Maize-Cassava, pure Palm grove, Palm grove-Maize-Cassava and Teak Plantation) along with slope levels (low slope, medium slope and high slope degree). The impact of cropping systems and slope on soil properties was assessed by determining the physical and chemical parameters. The cropping systems significantly (p 3) was recorded under the Palm grove-Maize-Cassava cropping system while the highest (1.47 g/cm3) was obtained with pure Palm grove cropping system. Root biomass was more abundant (0.28%) with the pure Palm grove cropping system. However, root biomass was significantly (p 0.05) on the effect of cropping systems and slope. Moreover, cropping systems resulted in significant effects (p < 0.05). Soil organic matter and soil-assimilated phosphorus content were significantly influenced by the effect of the slope. These findings indicated that cropping systems and slope are significant drivers in soil degradation in the Kpacomey watershed and bringing out cropping systems that best aim at soil conservation.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"501-517"},"PeriodicalIF":0.0,"publicationDate":"2020-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45984214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-30DOI: 10.4236/ojss.2020.1011027
Kenneth Ray Olson, L. Cihacek
The destruction of the South Vietnamese rice (Oryza sativa L) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret; however, it received little media attention in the United States. Republic of Vietnam and United States (U.S.) militaries began destroying food crops (rice) in November of 1962 primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on 100,000 ha of mangrove forests and about 300,000 ha of rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Six Rainbow herbicides, commonly called Agent Orange, Agent Green, Agent Pink, Agent Purple, Agent White, and Agent Blue, were sprayed on wetlands, rice paddies, forests, mangroves, bamboo and military base perimeter fences to defoliate jungle vegetation, reveal guerilla hiding places and destroy the food supply of enemy troops. South Vietnamese farmers, U.S. and Republic of Vietnam military personnel, and communist insurgents were exposed to these herbicides with immediate and longer term impacts on personal health, civilian household food security and population-wide famine. Agent Blue (cacodylic acid, C2H2AsO2,) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the U.S. at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas including the Mekong Delta. Today arsenic contaminated rice and groundwater are growing concerns as neither naturally occurring arsenic nor anthropic arsenic have a half-life and cannot be destroyed. Anthropic arsenic has remained in the Mekong Delta environment for the last 60 years and added to persistent As contamination in water supplies, sediments and soils. Water soluble arsenic primarily leaches into the soil root zone and the groundwater or is carried by floodwater into adjacent waterways or volatilized under anaerobic rice paddy conditions as gaseous arsine. The health of 15 million Vietnamese people living in the Mekong Delta is at risk from the combination of manufactured and natural As in drinking water and food supply. The As in the contaminated rice paddy soil, sediment and water is up taken by fish, shrimp or by crop vegetation and trace amounts can end up in the food supply (rice grain) or be bioaccumulated by the fish, shrimp and birds which when eaten were bioaccumulated in the Vietnamese people. It is urgent that elevated As concentrations in water supplies and agricultural products be identified and mitigated through better run-off control and groundwater management; improved ri
{"title":"The Fate of Agent Blue, the Arsenic Based Herbicide, Used in South Vietnam during the Vietnam War","authors":"Kenneth Ray Olson, L. Cihacek","doi":"10.4236/ojss.2020.1011027","DOIUrl":"https://doi.org/10.4236/ojss.2020.1011027","url":null,"abstract":"The destruction of the South Vietnamese rice (Oryza sativa L) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret; however, it received little media attention in the United States. Republic of Vietnam and United States (U.S.) militaries began destroying food crops (rice) in November of 1962 primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on 100,000 ha of mangrove forests and about 300,000 ha of rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Six Rainbow herbicides, commonly called Agent Orange, Agent Green, Agent Pink, Agent Purple, Agent White, and Agent Blue, were sprayed on wetlands, rice paddies, forests, mangroves, bamboo and military base perimeter fences to defoliate jungle vegetation, reveal guerilla hiding places and destroy the food supply of enemy troops. South Vietnamese farmers, U.S. and Republic of Vietnam military personnel, and communist insurgents were exposed to these herbicides with immediate and longer term impacts on personal health, civilian household food security and population-wide famine. Agent Blue (cacodylic acid, C2H2AsO2,) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the U.S. at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas including the Mekong Delta. Today arsenic contaminated rice and groundwater are growing concerns as neither naturally occurring arsenic nor anthropic arsenic have a half-life and cannot be destroyed. Anthropic arsenic has remained in the Mekong Delta environment for the last 60 years and added to persistent As contamination in water supplies, sediments and soils. Water soluble arsenic primarily leaches into the soil root zone and the groundwater or is carried by floodwater into adjacent waterways or volatilized under anaerobic rice paddy conditions as gaseous arsine. The health of 15 million Vietnamese people living in the Mekong Delta is at risk from the combination of manufactured and natural As in drinking water and food supply. The As in the contaminated rice paddy soil, sediment and water is up taken by fish, shrimp or by crop vegetation and trace amounts can end up in the food supply (rice grain) or be bioaccumulated by the fish, shrimp and birds which when eaten were bioaccumulated in the Vietnamese people. It is urgent that elevated As concentrations in water supplies and agricultural products be identified and mitigated through better run-off control and groundwater management; improved ri","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49620550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-20DOI: 10.4236/ojss.2020.1010024
M. Amin, Md. Zulfikar Khan, Tutul Laskar, S. Rabbi
Land use change and cropping patterns are important factors for controlling carbon sequestration in soils and they may also change the relative importance of different mechanisms of soil organic matter stabilization. The study was conducted to investigate the state of carbon sequestration in soil aggregates under different cropping patterns of Khulna, Jessore and Chapainawabganj districts in Bangladesh. Thirty-six soil samples were collected from (0 - 100 cm depth) above mentioned regions of three physiographic regions: Ganges Meander Floodplain, Ganges Tidal Floodplain and High Barind Tract. The texture of the samples varied within three soil texture groups, Silt Loam, Silty Clay Loam and Silty Clay. The highest NSI value (0.89) was found under Wheat-Fallow-T. Aman cropping pattern in Silty Clay soils (sample No 15) and lowest value (0.59) was found Vegetables/Mustard-Fallow-T. Aman cropping pattern in Silt Loam soils (sample No 17). The highest value (735.20 mg•kg−1) of active C was observed under Chickpea/mustard-T. Aman (Sample No 31) and the lowest value (619.23 mg•kg−1) was found in case of Wheat-Fallow-T. Aman cropping pattern (Sample No 30). The highest SOC stock (1.62 Kg C m−2) was found in Silty Clay Loam soil under Mungbean/Ash gourd-T. Aman cropping pattern (Sample no 4) and the lowest SOC stock (0.35 Kg C m−2) was found in Silt Loam soil under Cauliflower/Pumkin/Spinach-T. Aman Cropping pattern (Sample No 2). Soil organic carbon associated with different size aggregates was the highest (3.14%) under Mungbean/Ash gourd-T. Aman (Sample No 20) and was the lowest (0.36%) under Cauliflower/Pumkin/Spinach-T. Aman cropping pattern (Sample No 2). Organic carbon content in aggregate size ranges > 2000 μm (SOC1), 2000 - 250 μm (SOC2), 250-53 μm (SOC3), and 2000 μm, 2000 - 250 μm and 250 - 53 μm, aggregates. Significant positive correlations were found between SOC stock and SOC1, SOC stock and SOC2, SOC stock and SOC3, SOC stock and SOC4.
土地利用变化和种植模式是控制土壤固碳的重要因素，它们也可能改变不同土壤有机质稳定机制的相对重要性。本研究旨在调查孟加拉国Khulna、Jessore和Chapainawabganj地区不同种植模式下土壤团聚体的固碳状态。从上述三个自然地理区域（0-100 cm深度）采集了36个土壤样本：恒河弯曲洪泛平原、恒河潮汐洪泛平原和高巴林域。样品的质地在三个土壤质地组内变化，即粉质壤土、粉质粘土壤土和粉质粘土。NSI值最高（0.89）是在Wheat-Flow-T下发现的。在粉质粘土（样品编号15）中发现了Aman种植模式，最低值（0.59）为蔬菜/芥末-Fallow-T。粉质壤土中的阿曼种植模式（样品编号17）。活性C的最高值（735.20 mg•kg−1）出现在鹰嘴豆/芥末-T。Aman（样品编号31），在Wheat-Flow-T病例中发现最低值（619.23 mg•kg−1）。阿曼种植模式（样品编号30）。在Mungbean/Ash gourd-T下的粉质粘土壤土中发现了最高的SOC存量（1.62 Kg C m−2）。在花椰菜/南瓜/菠菜-T下的粉质壤土中发现了Aman种植模式（4号样品）和最低SOC存量（0.35 Kg C m−2）。Aman裁剪图案（样品编号2）。与不同粒径团聚体相关的土壤有机碳在绿豆/灰沟-T条件下最高（3.14%）。Aman（样品编号20），在花椰菜/南瓜/菠菜-T下最低（0.36%）。阿曼种植模式（样本2）。骨料粒径中的有机碳含量范围>2000μm（SOC1）、2000-250μm（SOC2）、250-53μm（SOC 3）以及2000μm、2000-25μm和250-53µm骨料。SOC存量与SOC1、SOC存量与SOC 2、SOC存量和SOC 3、SOC存量及SOC 4呈正相关。
{"title":"Carbon Sequestration in Soil Aggregates under Different Cropping Patterns of Bangladesh","authors":"M. Amin, Md. Zulfikar Khan, Tutul Laskar, S. Rabbi","doi":"10.4236/ojss.2020.1010024","DOIUrl":"https://doi.org/10.4236/ojss.2020.1010024","url":null,"abstract":"Land use change and cropping patterns are important factors for controlling carbon sequestration in soils and they may also change the relative importance of different mechanisms of soil organic matter stabilization. The study was conducted to investigate the state of carbon sequestration in soil aggregates under different cropping patterns of Khulna, Jessore and Chapainawabganj districts in Bangladesh. Thirty-six soil samples were collected from (0 - 100 cm depth) above mentioned regions of three physiographic regions: Ganges Meander Floodplain, Ganges Tidal Floodplain and High Barind Tract. The texture of the samples varied within three soil texture groups, Silt Loam, Silty Clay Loam and Silty Clay. The highest NSI value (0.89) was found under Wheat-Fallow-T. Aman cropping pattern in Silty Clay soils (sample No 15) and lowest value (0.59) was found Vegetables/Mustard-Fallow-T. Aman cropping pattern in Silt Loam soils (sample No 17). The highest value (735.20 mg•kg−1) of active C was observed under Chickpea/mustard-T. Aman (Sample No 31) and the lowest value (619.23 mg•kg−1) was found in case of Wheat-Fallow-T. Aman cropping pattern (Sample No 30). The highest SOC stock (1.62 Kg C m−2) was found in Silty Clay Loam soil under Mungbean/Ash gourd-T. Aman cropping pattern (Sample no 4) and the lowest SOC stock (0.35 Kg C m−2) was found in Silt Loam soil under Cauliflower/Pumkin/Spinach-T. Aman Cropping pattern (Sample No 2). Soil organic carbon associated with different size aggregates was the highest (3.14%) under Mungbean/Ash gourd-T. Aman (Sample No 20) and was the lowest (0.36%) under Cauliflower/Pumkin/Spinach-T. Aman cropping pattern (Sample No 2). Organic carbon content in aggregate size ranges > 2000 μm (SOC1), 2000 - 250 μm (SOC2), 250-53 μm (SOC3), and 2000 μm, 2000 - 250 μm and 250 - 53 μm, aggregates. Significant positive correlations were found between SOC stock and SOC1, SOC stock and SOC2, SOC stock and SOC3, SOC stock and SOC4.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"459-485"},"PeriodicalIF":0.0,"publicationDate":"2020-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49475814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-20DOI: 10.4236/ojss.2020.1010025
Eman F. A. Awad-Allah, I. Elsokkary
Iron (Fe) is a vital element for the survival and proliferation of all plants; therefore, Fe-biofortification by the application of chemical and organic fertilizers is being as an effective approach to fight hidden hunger retards the growth and development of crop plants. Two experiments were carried out to investigate the effect of potassium and exogenous organic acids on iron uptake by two different plants: one is monocotyledon, maize (Zea mays L.) and the second is dicotolydon pea (Pisum sativum L.) grown under controlled conditions. The seedlings were grown in sand culture in a greenhouse experiment and irrigated with one-tenth strength modified nutrient solution of Hoagland and Arnon as a base solution (pH 7.5), containing different iron treatments (0, 1, and 5 ppm as FeSO4·7H2O) combined with potassium nutrition (0, 5, 10, and 50 ppm as K2SO4). After 30 days, the best interaction treatment was selected for further experiment including 5.0 ppm Fe as FeSO4.7H2O and 50 ppm K as K2SO4 in combination with 1 × 10-5 mole/liter of one of the following organic acids: Citric acid, Oxalic acid, Formic acid, Acetic acid, Propionic acid, Tartaric acid, Succinic acid, Fumaric acid, Malic acid, Glutamic acid, besides the free organic acid nutrient solution as a control. Results revealed that the interaction between 5.0 ppm Fe and 50 ppm K was the best interaction treatment for increasing biomass production and iron uptake of maize and pea seedlings under applied condition. Furthermore, exogenous application of organic acids improves uptake and translocation of nutrient such as iron, potassium and phosphorus by the maize and pea plants. In conclusion, potassium nutrition and exogenous organic acids have the potential to stimulate Fe-uptake of monocot and dicot plants and mediate iron-biofortified crops.
{"title":"Influence of Potassium Nutrition and Exogenous Organic Acids on Iron Uptake by Monocot and Dicot Plants","authors":"Eman F. A. Awad-Allah, I. Elsokkary","doi":"10.4236/ojss.2020.1010025","DOIUrl":"https://doi.org/10.4236/ojss.2020.1010025","url":null,"abstract":"Iron (Fe) is a vital element for the survival and proliferation of all \u0000plants; therefore, Fe-biofortification by the application of chemical and \u0000organic fertilizers is being as an effective approach to fight hidden hunger \u0000retards the growth and development of crop plants. Two experiments were carried \u0000out to investigate the effect of potassium and exogenous organic acids on iron \u0000uptake by two different plants: one is \u0000monocotyledon, maize (Zea \u0000mays L.) and the second is dicotolydon pea (Pisum sativum L.) grown under controlled conditions. The seedlings were grown in sand culture \u0000in a greenhouse experiment and irrigated with one-tenth strength modified \u0000nutrient solution of Hoagland and Arnon as a base solution (pH 7.5), containing \u0000different iron treatments (0, 1, and 5 ppm as FeSO4·7H2O) \u0000combined with potassium nutrition (0, 5, 10, and 50 ppm as K2SO4). \u0000After 30 days, the best interaction treatment was selected for further \u0000experiment including 5.0 ppm Fe as FeSO4.7H2O and 50 ppm \u0000K as K2SO4 in combination with 1 × 10-5 mole/liter of one of the following organic acids: \u0000Citric acid, Oxalic acid, Formic acid, Acetic acid, Propionic acid, Tartaric \u0000acid, Succinic acid, Fumaric acid, Malic acid, Glutamic acid, besides the free \u0000organic acid nutrient solution as a control. Results revealed that the \u0000interaction between 5.0 ppm Fe and 50 ppm K was the best interaction treatment \u0000for increasing biomass production and iron uptake of maize and pea seedlings \u0000under applied condition. Furthermore, exogenous application of organic acids \u0000improves uptake and translocation of nutrient such as iron, potassium and \u0000phosphorus by the maize and pea plants. In conclusion, potassium nutrition and \u0000exogenous organic acids have the potential to stimulate Fe-uptake of monocot \u0000and dicot plants and mediate iron-biofortified crops.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47414639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-10DOI: 10.4236/ojss.2020.109020
H. Cotler, L. Merino, S. Martínez-Trinidad
Forests improve the livelihoods and resilience of communities in diverse ways. In particular, soils provide important environmental services for communities in addition to performing many essential ecological functions in forest ecosystems, such as nutrient uptake, organic matter decomposition, water storage, and provision of anchorage for plant growth. The sound management of forest soils, although often disregarded, is a key element of sustainable forest management. From 2002 to 2016 the Forest Soil Conservation and Restoration Sub-Program was designed and implemented by the National Forest Commission (CONAFOR) in Mexico. Forests in Mexico have high biological diversity and are often owned, governed, and managed by communities or, in some cases, community forestry is practiced. Despite the importance of periodic monitoring to ensure that policies are both effective and suitable for diverse conditions and decision making, the policies implemented by this program were not evaluated during its years of operation. Therefore, in the present study, we aimed to identify the deficiencies of this policy as well as opportunities based on a review of the official information available on the Forest Soil Conservation and Restoration Sub-Program of CONAFOR during the 2002-2016 period and interviews with key informants. In addition, we aimed to highlight experiences that may be useful for similar soil conservation policies in tropical forest regions. The identified limitations ranged from conceptual problems such as policy weakness and lack of understanding of local drivers of soil degradation to an overly rigid implementation of soil conservation measures across diverse forest ecosystems and socio-ecological contexts. These deficiencies had several unintended outcomes: perhaps the most relevant was the inability of forest communities to build capacities for soil conservation. Another important limitation was the complete lack of monitoring of the program and its outcomes, which could have prevented its poor results. Finally, a lack of transparency in the distribution and determination of funding was noted. In conclusion, the hierarchical approach of this policy appears to have compromised its long-term efficacy.
{"title":"Forest Soil Management: A Mexican Experience","authors":"H. Cotler, L. Merino, S. Martínez-Trinidad","doi":"10.4236/ojss.2020.109020","DOIUrl":"https://doi.org/10.4236/ojss.2020.109020","url":null,"abstract":"Forests improve the livelihoods and resilience of communities in diverse ways. In particular, soils provide important environmental services for communities in addition to performing many essential ecological functions in forest ecosystems, such as nutrient uptake, organic matter decomposition, water storage, and provision of anchorage for plant growth. The sound management of forest soils, although often disregarded, is a key element of sustainable forest management. From 2002 to 2016 the Forest Soil Conservation and Restoration Sub-Program was designed and implemented by the National Forest Commission (CONAFOR) in Mexico. Forests in Mexico have high biological diversity and are often owned, governed, and managed by communities or, in some cases, community forestry is practiced. Despite the importance of periodic monitoring to ensure that policies are both effective and suitable for diverse conditions and decision making, the policies implemented by this program were not evaluated during its years of operation. Therefore, in the present study, we aimed to identify the deficiencies of this policy as well as opportunities based on a review of the official information available on the Forest Soil Conservation and Restoration Sub-Program of CONAFOR during the 2002-2016 period and interviews with key informants. In addition, we aimed to highlight experiences that may be useful for similar soil conservation policies in tropical forest regions. The identified limitations ranged from conceptual problems such as policy weakness and lack of understanding of local drivers of soil degradation to an overly rigid implementation of soil conservation measures across diverse forest ecosystems and socio-ecological contexts. These deficiencies had several unintended outcomes: perhaps the most relevant was the inability of forest communities to build capacities for soil conservation. Another important limitation was the complete lack of monitoring of the program and its outcomes, which could have prevented its poor results. Finally, a lack of transparency in the distribution and determination of funding was noted. In conclusion, the hierarchical approach of this policy appears to have compromised its long-term efficacy.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47020643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-10DOI: 10.4236/ojss.2020.109019
M. Ngom, Pape Ibrahima Djighaly, N. Diagne, M. Ndour, Ganna Ndong, D. Ngom, Mariama Ngom, S. Ngom, Sergio Svistoonoff
Soil salinization is one of the major causes of land degradation. In Senegal, this phenomenon continues to grow, making soils unsuitable for agriculture. To rehabilitate salty lands, one of the recommended strategies is the use of salt-tolerant plants. Among them, plants of Casuarinaceae family form a relationship with symbiotic microorganisms such as arbuscular mycorrhizal fungi and nitrogen fixing bacteria. It has been shown that symbiotic microorganisms play an important role in the establishment of tolerant plants in saline conditions (Djighaly et al., 2018). They improve plant performance and reduce transplant shock under salt stress conditions (Diagne et al., 2014). These microorganisms can be used as biofertilizers. However, inocula containing symbiotic microorganisms are either too expensive or unavailable in many developing countries. The aim of this study is to test alternatively affordable and low-tech solutions to promote symbiotic interactions such as Casuarina crushed nodule, Casuarina rhizosphere soil and Casuarina leaves compost that may contain symbiotic microorganisms and also nutrients such as N and phosphorus. Two species of Casuarina (Casuarina equisetifolia L. and Casuarina obesa Miq.) were grown in the greenhouse on sterile soil to which an amendment was added (Casuarina crushed nodules, Casuarina Rhizospheric soil or Casuarina leaves compost). Plants were subjected to saline stress. After four months of cultivation, they were harvested and morphological and physiological parameters were determined. Results showed that inoculation with Casuarina crushed nodules, Casuarina rhizospheric soil and Casuarina leaves compost improved growth, total dry biomass, total chlorophyll and proline contents of C. equisetifolia and C. obesa plants in salt stress condition. These positive effects were more important in C. obesa plants amended with Casuarina leaves compost. This study shows that Casuarina leaves compost can play an important role in the rehabilitation of saline soils by improving Casuarina trees performance in saline conditions.
{"title":"Effect of Casuarina Crushed Nodules, Rhizospheric Soil and Leaves Compost on Salt Tolerance of Casuarina equisetifolia L. and Casuarina obesa Miq.","authors":"M. Ngom, Pape Ibrahima Djighaly, N. Diagne, M. Ndour, Ganna Ndong, D. Ngom, Mariama Ngom, S. Ngom, Sergio Svistoonoff","doi":"10.4236/ojss.2020.109019","DOIUrl":"https://doi.org/10.4236/ojss.2020.109019","url":null,"abstract":"Soil salinization is one of the major causes of land degradation. In Senegal, this phenomenon continues to grow, making soils unsuitable for agriculture. To rehabilitate salty lands, one of the recommended strategies is the use of salt-tolerant plants. Among them, plants of Casuarinaceae family form a relationship with symbiotic microorganisms such as arbuscular mycorrhizal fungi and nitrogen fixing bacteria. It has been shown that symbiotic microorganisms play an important role in the establishment of tolerant plants in saline conditions (Djighaly et al., 2018). They improve plant performance and reduce transplant shock under salt stress conditions (Diagne et al., 2014). These microorganisms can be used as biofertilizers. However, inocula containing symbiotic microorganisms are either too expensive or unavailable in many developing countries. The aim of this study is to test alternatively affordable and low-tech solutions to promote symbiotic interactions such as Casuarina crushed nodule, Casuarina rhizosphere soil and Casuarina leaves compost that may contain symbiotic microorganisms and also nutrients such as N and phosphorus. Two species of Casuarina (Casuarina equisetifolia L. and Casuarina obesa Miq.) were grown in the greenhouse on sterile soil to which an amendment was added (Casuarina crushed nodules, Casuarina Rhizospheric soil or Casuarina leaves compost). Plants were subjected to saline stress. After four months of cultivation, they were harvested and morphological and physiological parameters were determined. Results showed that inoculation with Casuarina crushed nodules, Casuarina rhizospheric soil and Casuarina leaves compost improved growth, total dry biomass, total chlorophyll and proline contents of C. equisetifolia and C. obesa plants in salt stress condition. These positive effects were more important in C. obesa plants amended with Casuarina leaves compost. This study shows that Casuarina leaves compost can play an important role in the rehabilitation of saline soils by improving Casuarina trees performance in saline conditions.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49336147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-10DOI: 10.4236/ojss.2020.109018
Fredrick M. Mngube, R. Kapiyo, Paul Aboum, D. Anyona, G. Dida
The interactive and cumulative effect of temperature and rainfall on land cover change is a priority at global, regional and local scale. This study examined changes in six land cover categories (forestland, grasslands, shrub land, bare land, built-up areas and agricultural lands) in four sub-catchments (Amala, Nyangores, Talek and Sand River), of the Mara River basin over a 30-year period (1987-2017) and made predictions of future land cover change patterns. Landsat Imageries of 90 m resolution were retrieved and analyzed using ArcGIS 10.0 software. Relationship between NDVI, temperature and precipitation was determined using Pearson’s correlation coefficient, while Markov chains analyses were performed on different land cover categories to project future trends. Results showed low to moderate (R2 = 0.002 to 0.6) trends of change in NDVI of different land cover categories across all sub-catchments. The greatest change (R2 0.34 to 0.5) was recorded in bare land in three of the four sub-catchments studied. Precipitation showed a strong positive correlation with built-up areas, forestlands, croplands, bare land, grasslands and shrub lands, while temperature correlated strongly but negatively with the same land cover categories. The change detection matrix projected significant but varying changes in land cover categories across the four sub-catchments by 2027. This study underscores the impact of changing climatic factors on various land cover categories in the Mara River basin sub-catchments, with different land cover categories exhibiting strong positive sensitivity to high precipitation and low temperature and vice-versa.
{"title":"Subtle Impacts of Temperature and Rainfall Patterns on Land Cover Change Overtime and Future Projections in the Mara River Basin, Kenya","authors":"Fredrick M. Mngube, R. Kapiyo, Paul Aboum, D. Anyona, G. Dida","doi":"10.4236/ojss.2020.109018","DOIUrl":"https://doi.org/10.4236/ojss.2020.109018","url":null,"abstract":"The interactive and cumulative effect of temperature and rainfall on land cover change is a priority at global, regional and local scale. This study examined changes in six land cover categories (forestland, grasslands, shrub land, bare land, built-up areas and agricultural lands) in four sub-catchments (Amala, Nyangores, Talek and Sand River), of the Mara River basin over a 30-year period (1987-2017) and made predictions of future land cover change patterns. Landsat Imageries of 90 m resolution were retrieved and analyzed using ArcGIS 10.0 software. Relationship between NDVI, temperature and precipitation was determined using Pearson’s correlation coefficient, while Markov chains analyses were performed on different land cover categories to project future trends. Results showed low to moderate (R2 = 0.002 to 0.6) trends of change in NDVI of different land cover categories across all sub-catchments. The greatest change (R2 0.34 to 0.5) was recorded in bare land in three of the four sub-catchments studied. Precipitation showed a strong positive correlation with built-up areas, forestlands, croplands, bare land, grasslands and shrub lands, while temperature correlated strongly but negatively with the same land cover categories. The change detection matrix projected significant but varying changes in land cover categories across the four sub-catchments by 2027. This study underscores the impact of changing climatic factors on various land cover categories in the Mara River basin sub-catchments, with different land cover categories exhibiting strong positive sensitivity to high precipitation and low temperature and vice-versa.","PeriodicalId":57369,"journal":{"name":"土壤科学期刊(英文)","volume":"10 1","pages":"327-358"},"PeriodicalIF":0.0,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48752300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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