Better management of agricultural fields is related to valuable information which can derived from soil salinity and alkalinity maps. These maps are considered as one of the most important factors which restrict plant...Better management of agricultural fields is related to valuable information which can derived from soil salinity and alkalinity maps. These maps are considered as one of the most important factors which restrict plant growth as well as decline crops yield. The objective of this research was preparing of soil salinity and alkalinity maps in Tabriz plain over 50,000 hectares based on different techniques of spatial analysis in GIS software. For this mean, study area was divided in 1500 × 1500 m2 grid cells. Then, geographical coordinate of each grid recorded in UTM system. So, they were transferred into GPS for navigating to the exact excavation location. After soil sampling and transferring to the lab, their EC and PH were measured in saturation extract of soil samples. So, spatial distribution of soil sampling points was prepared in form of point map by GIS software. Generalization of point information to surface was performed using different interpolation algorithms and based on standards of Soil and Water Research Institute. Accuracy of interpolated maps was evaluated due to the MAE and MBE values. The results showed that the lowest observed error is related to the Spline method and therefore, this method was used for spatial modeling of salinity and alkalinity maps in the intended area. The research findings demonstrated that from total of 50,000 hectares, only 3066 hectares were without salinity and alkalinity limitation (6.1%), 9066 hectares had low salinity and alkalinity (18.1%);17,772 hectares had average limitation for salinity and alkalinity (35.6%) and the remaining 20,096 hectares had high and very high limitation for salinity and alkalinity.展开更多
Land use change causes soil disturbance and thereby considerable soil nutrients depletion and environmental impacts. This research was conducted in Halashi catchment, Kermanshah, Iran to compare the variation of soil ...Land use change causes soil disturbance and thereby considerable soil nutrients depletion and environmental impacts. This research was conducted in Halashi catchment, Kermanshah, Iran to compare the variation of soil NPK and SOC in Agricultural Lands (AL), Rangelands (RL) and Forest lands (FL). The coverage of ground surface including plant crown, stone and litter was estimated in field by using quadrate plot (1 m2). Soil sampling and the analysis were carried out for each land use during April and May, 2015. Inter-rill, rill, gully and landslide were found as the dominant erosion features. The ANOVA analysis explored no considerable differences for soil texture, pH and Electrical Conductivity (EC). High clay and silt content induced clayey and silty soil that means Soil Organic Carbon (SOC) level in the AL, RL and FL were 1.14%, 1.45% and 2.13%, respectively, showing significant (p ≤ 0.05) different from each other among them. The respective values of total N in the AL, RL and FL were 0.14, 0.14 and 0.18 mg/kg, indicating significant decrease in the AL and RL. The respective mean avails P and exch. K in the AL, RL and FL were 15.72, 11.44, 11.38;342.5, 375.0 and 374.5 mg/kg. Crop residues burning and tillage practicing cause depletion of SOC and NPK in AL, while as compared with FL, lower vegetation canopy and litter in the RL promotes soil nutrients and SOC lost due to overgrazing and converting to rain-fed lands. As a conclusion, rangeland was the intermediate site in terms of soil nutrient and SOC stock in the Halashi.展开更多
Soils are key natural resources for the Earth's system;however,human impacts,especially,soil erosion are considered serious threats.Therefore,identifying and assessing effective factors to understand erosion hot s...Soils are key natural resources for the Earth's system;however,human impacts,especially,soil erosion are considered serious threats.Therefore,identifying and assessing effective factors to understand erosion hot spots at different scales is critical to developing effective land management plans and ensuring the sustainability of the territory.This study was conducted to determine and prepare an erosion risk map,but to prioritize the survey at different scales,such as sub-basin and watershed ones.To achieve this goal,geographic information system(GIS)and remote sensing data(RS)were used combining the analysis network process method(ANP)and ICONA model(Institute for the Conservation of Nature).As study case,we selected the degraded areas of the Gorganrood watershed located in the north of Iran.The study area was obtained for very low,low,medium,high,and very high-risk classi-fications of 14.0,21.4,17.9,31.3,and 15.4%,respectively.Results from the ICONA model also indicated that 12.8,28.8,22.1,27.9,8.5,and 0.03%belong to very low,low,medium,high,very high,and without risk of erosion,respectively.According to the validation results,it was found that the accuracy of ANP and ICONA models are 0.83 and 0.80,respectively,which indicates the suitability of the models for preparing the erosion map of the region is appropriate and useful for designing land management plans.We conclude that both models can be used to develop the erosion map potential and to prioritize sub-basins if a complete database of geomorphological characteriscs and human activities are accurate previously defined.展开更多
文摘Better management of agricultural fields is related to valuable information which can derived from soil salinity and alkalinity maps. These maps are considered as one of the most important factors which restrict plant growth as well as decline crops yield. The objective of this research was preparing of soil salinity and alkalinity maps in Tabriz plain over 50,000 hectares based on different techniques of spatial analysis in GIS software. For this mean, study area was divided in 1500 × 1500 m2 grid cells. Then, geographical coordinate of each grid recorded in UTM system. So, they were transferred into GPS for navigating to the exact excavation location. After soil sampling and transferring to the lab, their EC and PH were measured in saturation extract of soil samples. So, spatial distribution of soil sampling points was prepared in form of point map by GIS software. Generalization of point information to surface was performed using different interpolation algorithms and based on standards of Soil and Water Research Institute. Accuracy of interpolated maps was evaluated due to the MAE and MBE values. The results showed that the lowest observed error is related to the Spline method and therefore, this method was used for spatial modeling of salinity and alkalinity maps in the intended area. The research findings demonstrated that from total of 50,000 hectares, only 3066 hectares were without salinity and alkalinity limitation (6.1%), 9066 hectares had low salinity and alkalinity (18.1%);17,772 hectares had average limitation for salinity and alkalinity (35.6%) and the remaining 20,096 hectares had high and very high limitation for salinity and alkalinity.
文摘Land use change causes soil disturbance and thereby considerable soil nutrients depletion and environmental impacts. This research was conducted in Halashi catchment, Kermanshah, Iran to compare the variation of soil NPK and SOC in Agricultural Lands (AL), Rangelands (RL) and Forest lands (FL). The coverage of ground surface including plant crown, stone and litter was estimated in field by using quadrate plot (1 m2). Soil sampling and the analysis were carried out for each land use during April and May, 2015. Inter-rill, rill, gully and landslide were found as the dominant erosion features. The ANOVA analysis explored no considerable differences for soil texture, pH and Electrical Conductivity (EC). High clay and silt content induced clayey and silty soil that means Soil Organic Carbon (SOC) level in the AL, RL and FL were 1.14%, 1.45% and 2.13%, respectively, showing significant (p ≤ 0.05) different from each other among them. The respective values of total N in the AL, RL and FL were 0.14, 0.14 and 0.18 mg/kg, indicating significant decrease in the AL and RL. The respective mean avails P and exch. K in the AL, RL and FL were 15.72, 11.44, 11.38;342.5, 375.0 and 374.5 mg/kg. Crop residues burning and tillage practicing cause depletion of SOC and NPK in AL, while as compared with FL, lower vegetation canopy and litter in the RL promotes soil nutrients and SOC lost due to overgrazing and converting to rain-fed lands. As a conclusion, rangeland was the intermediate site in terms of soil nutrient and SOC stock in the Halashi.
文摘Soils are key natural resources for the Earth's system;however,human impacts,especially,soil erosion are considered serious threats.Therefore,identifying and assessing effective factors to understand erosion hot spots at different scales is critical to developing effective land management plans and ensuring the sustainability of the territory.This study was conducted to determine and prepare an erosion risk map,but to prioritize the survey at different scales,such as sub-basin and watershed ones.To achieve this goal,geographic information system(GIS)and remote sensing data(RS)were used combining the analysis network process method(ANP)and ICONA model(Institute for the Conservation of Nature).As study case,we selected the degraded areas of the Gorganrood watershed located in the north of Iran.The study area was obtained for very low,low,medium,high,and very high-risk classi-fications of 14.0,21.4,17.9,31.3,and 15.4%,respectively.Results from the ICONA model also indicated that 12.8,28.8,22.1,27.9,8.5,and 0.03%belong to very low,low,medium,high,very high,and without risk of erosion,respectively.According to the validation results,it was found that the accuracy of ANP and ICONA models are 0.83 and 0.80,respectively,which indicates the suitability of the models for preparing the erosion map of the region is appropriate and useful for designing land management plans.We conclude that both models can be used to develop the erosion map potential and to prioritize sub-basins if a complete database of geomorphological characteriscs and human activities are accurate previously defined.
