Showing 42 results for Land Use
H. R. Moradi, M. Bakhshi Tiregani , S. H. R. Sadeghi,
Volume 16, Issue 62 (3-2013)
Abstract
Climate situation changes over a year cause changes in some soil characteristics and soil sensitivity to erosion. Investigation of these changes and how they impact on erosion can be of particular importance. This study investigated changes in Sediment Productivity and soil factors affecting these changes in Tiregan rangeland located in Daregaz city in Khorasan Razavi province. In this study, using the position of the upper and lower hillside of eastern and western aspects, the sampling with rain simulator was performed. Characteristic features of sediment yield including runoff threshold, runoff volume, sediment and turbidity were measured. Soil samples were taken from each sample rain simulation and features of the initial moisture content, bulk density, electrical conductivity, pH and organic matter were measured. Sample was collected with the same intensity and duration of the instrument with fixed locations, and was repeated in four seasons. In order to obtain the position and orientation of each of the parameters in the data obtained at different seasons, the combined analysis of variance test was used. The effect of each of these parameters and the difference between them were evaluated using the Tukey test, and the graphs in 2007 Excel software were plotted. The results showed that all the parameters of sediment yield during the year have significantly changed. The maximum amount of sediment production rates occurred in autumn and was gradually reduced. Its decreasing in both winter and spring can be attributed to vegetation in the area.
Majid Vahdatkhah, Mohammad Hady Farpoor, Mehdi Sarcheshmehpoor,
Volume 17, Issue 64 (9-2013)
Abstract
Study of land use effects on soil quality indicators leads to sustainable management and preventing progressive land degradation. The TM (1987) and ETM+ (2000 and 2005) data were used to study land use change effects in Mahan-Joopar area on soil quality indicators. Fifty random soil samples from 0-30 cm depth of each land use were taken using provided maps. Organic matter, microbial respiration potential, bulk density, pH, EC, and soil texture were investigated as soil quality indicators. Eight land uses including fruit orchards, woodlands, pistachio orchards, cultivated, barren, bare land, fallowed, and haloxylone land were detected. Results showed overall accuracies of 89.4, 95.2, and 91.7 % with kappa coefficients of 85, 92, and 88% for maps provided in 1987, 2000, and 2005, respectively. Generally, the investigated quality indicators showed that woodlands, fruit orchards, cultivated land, and pistachio orchards enhanced soil quality better than other land uses.
F. Maghami Moghim, A. Karimi, Gh. Haghnia, A. Dourandish,
Volume 17, Issue 65 (12-2013)
Abstract
The quantity and variability of soil organic carbon (SOC) is one of the most important indices to determine the effect of land use changes on the soil quality. Regarding long-term changes from rangeland to dry farming in the Roin area of North Khorasan, the objectives of this study were to investigate the effect of long-term land use changes on the SOC in different slope faces and use SOC as an index to make a proper decision about the future of land use in this area. 140 soil samples were taken from 0-15 cm soil depth of back slope position of north-, south-, west- and east-facing slopes of rangeland, dry farming, alfalfa dry farming and garden in 7 points. 14 soil samples were taken from irrigated farming, too. The results showed that garden and irrigation farming with averages of 2.03 and 0.78% have the maximum and minimum SOC content. The average of SOC content in rangeland was 1.40% that decreased by land use change to 1.04 and 1.27% in dry farming and alfalfa dry farming, respectively. SOC content in southern slope aspects showed a significant difference compared to other slope aspects. The most SOC content occurred in east aspects. It seems that after long-term land use changes, the SOC content have equilibrated to environmental and land use conditions. The average SOC content in different slope aspects except south one changed from 1.4% in rangeland to 1.11% in dry farming and 1.32% in alfalfa dry farming, which are a suitable value for semiarid regions. In conclusion, to protect land from degradation and considering this fact that dry farming is the main income of the people in the study area, it is recommended to stop dry farming on south aspects and continue on east, north and west aspects with conservation practices.
H. R. Owliaie, M.najai Ghiri,
Volume 17, Issue 65 (12-2013)
Abstract
Paddy soils provide the staple diet for nearly half of the world's population. The formation of the Anthrosols is induced by tilling the wet soil (puddling), flooding and drainage regimes associated with the development of a plow pan and specific redoximorphic features. The aim of this study was to evaluate the effects of long-term rice cultivation on physico-chemical properties and clay mineralogy of soils of three rice farms and compare the results with adjacent virgin lands in Yasouj region. Paddy soils exhibited larger contents of clay, organic carbon, saturation percentage, cation exchangeable capacity, cation exchange activity classes, electrical conductivity and lower content of calcium carbonate equivalent compared to non-paddy soils. This land use showed higher proportions of Feo, Fet and lower content of Fed. No such differences were noticed with the type of clay minerals in both land uses. Paddy soils contained greater amount of smectite, particularly in the surface horizons. Smectite in paddy soils exhibited lower layer charge and higher degree of crystallinity compared to non-paddy soils. Transformation of illite and chlorite to expandable minerals is a possible mechanism for lower amounts of these minerals in paddy soils.
H. Kashi, H. Ghorbani, S. Emamgholizadeh, S. A. A. Hashemi,
Volume 18, Issue 67 (6-2014)
Abstract
Change in land use and tillage practices has great influence on soil physical and chemical properties. The present study has focused on the effects of converting undisturbed soil to agricultural lands. Chemical and physical soil properties, infiltration, cation exchange capacity (CEC), electrical conductivity, pH, bulk density, porosity, sodium, potassium, total Ca + Mg, organic matter percentage, sodium adsorption ratio (SAR) and lime percentage were measured using standard frequently used methods. Fifty soil samples from agriculture land and other 50 soil samples from undisturbed land were collected from 0 – 30 cm depth and different statistical analysis were performed. Agriculture land is Cultivated for more than 20 years. The results showed that change in land use from undisturbed to disturbed soil did not significantly changed soil organic matter content. Also, soil electrical conductivity showed a huge increase whereas pH showed non-significant changes due to land use change. Unlike pH, SAR, organic matter percentage and lime percentage, some other soil parameters showed significant decrease in quality through land use change. Correlation coefficients of the effective factors were calculated to explain the main reason for lowering soil quality. The results showed that sodium in EC bulk density in porosity and CEC sodium and Ca+Mg in SAR EC in soil infiltration and Ca+Mg in organic matter showed the most correlation.
H. Mahmoudzadeh, M. Sheklabadi, A. A. Mahboubi,
Volume 18, Issue 68 (9-2014)
Abstract
Organic carbon pools and carbon lability directly affect soil biological, physical and chemical characteristics. Besides, capacity of self-organization of soil is related to the organic carbon pools. Sand size fraction (> 50 µm) organic matter is more labile than silt+clay size fraction organic matter. Assessment of this organic carbon variation can be a suitable index to determine soil quality. The aim of present study was to evaluate the impact of land use change on particle size fractions of organic carbon and carbon pool index. In September 2010, soil samples were collected from the three major land use types including wetlands around the lake, wetlands converted to wheat, and alfalfa cultivations. Soil samples were collected from the 0-30, 30-60 and 60-90-cm depths in each of land use. According to the results of particle size fractionation of organic carbon in 0-30-cm layer, the highest and lowest amounts of sand size fraction organic carbon were obtained in wetland (67.01 g.C.kg-1soil) and wheat land use (24.57 g.C.kg-1soil), respectively. Land use change from wetland to alfalfa and wheat caused a decrease of silt+clay size fraction organic carbon in 0-30-cm by 48.39 and 45.14 t.C.h-1, respectively. In the 30-60-cm layer of cultivated land, soil organic carbon storage in silt+clay size particle was more than sand size fraction organic carbon. Results showed that carbon pool index in alfalfa, and wheat land was decreased by 50 and 60% compared to wetland, respectively. And carbon management index in alfalfa and wheat was declined by 44.90% and 66.70%, respectively.
R. Karimi, M. Hassan Salehi, F. Raiesi,
Volume 18, Issue 69 (12-2014)
Abstract
Improper use of rangelands may lead to their destruction. Therefore, the conversion of these degraded rangelands to agricultural lands and other land uses may improve their soil quality. The purpose of the present study was to evaluate the impact of cultivation in the degraded rangelands on some soil characteristics in Safashahr region of Fars province. Four land uses including the rangeland with sparse vegetation (degraded rangeland), the rangeland converted to agricultural land over 17 years, the agricultural land converted to apple orchard for 4 years and also to an apple orchard for 40 years were selected. Samples were randomly taken from each land use at two depths (0-20 and 20-50 cm) with five replications. The results revealed that land use change significantly increased organic matter and MWD in both soil depths. Bulk density and water dispersible clay increased in agricultural land and new orchard while a decrease was observed for old apple orchard. It is suggested the traditional farming to be replaced with new cultivation methods like minimum tillage and no tillage. Overgrazing of the rangelands must also be avoided.
N. Parsamanesh, M. Zarrinkafsh, S. S. Shahoei, Weria Wisany,
Volume 18, Issue 70 (3-2015)
Abstract
Reduction of quality and soil productivity due to organic carbon losses is one of the most important consequences of land use changes, that creates irreparable effects on the soil. To evaluate the land use effect on the amount of soil organic carbon in Vertisols, Sartip Abad series with extent of 1850 hectare in south of Bilehvar area in Kermanshah province was studied by using the completely randomized block design in factorial experiment with 10 repeats in farmland and grassland, some soil physical and chemical properties in two Lands compared with each other. The results showed that the soil organic carbon in surface horizons of grassland has been more than farmland and accordingly increase the amount of sequestrated carbon in grassland. No significant differences were found in the amount of soil organic carbon in lower horizons of two lands. Due to land use change from grassland to farmland, noticeably increase in Bulk density, Nitrogen, Acidity, soil Electrical Conductivity and decrease the organic carbon percent and the soil organic material. Pedutorbation, clay amount (higher of 50%), numerous small subsoil, and stable structure are the important factors in saving the organic carbon of vertisols that can reduce the effects of land use changes on organic carbon amount. Generally, it can be conclude that: the land use changes not only can create the severe damage on soil physical and chemical properties but with the carbon losses and more release of greenhouse gases exacerbate the pollution of environment which endangers the life in a earth planet.
W. Zarei, M. Sheklabadi,
Volume 18, Issue 70 (3-2015)
Abstract
The aim of the study was to investigate the effects of land use on soil quality parameters using multivariate statistical analysis. Soil samples (0-25 and 25-50 cm depths) were taken from three land uses in forest area of Marivan including forest, rangeland, and cultivated land. Soil characteristics of pH, EC, sand, silt, clay and CaCO3 content, water-stable aggregates and their organic carbon content were measured. Principal component, cluster and discriminant analyses were used to evaluate the soil quality. Principal component analysis classified soil properties into five factors. The most important factors were soil aggregates organic carbon content and aggregate stability indices. Schematic distribution of factors and also cluster analysis showed the same pattern. Soil aggregates organic carbon content, water-stable aggregates and aggregate stability indices were the most sensitive factors to land use changes. These soil properties and factors had the same pattern in forest and rangeland, but significantly reduced in the cultivated land use. Land use change from forest to cultivated land resulted in significant decrease of aggregates organic carbon content, water-stable aggregates and also an increase of pH. The results showed the usefulness of multivariate statistical methods for integration of the soil properties and determination of different soil quality indices.
F. Parsadoust, Z. Eskandari, B. Bahreyninejad, A. Jafari Addakani,
Volume 19, Issue 71 (6-2015)
Abstract
Evaluation of chemical and biological indicators of soil in different land uses could be helpful in sustainable range management, preventing degradation of soil quality trend. This study was conducted in Friedan in Isfahan province in 2010 to compare chemical and biological indicators in three land uses (rangeland, degraded dry land and dry land), during two growing seasons (May and September) in three slopes (0-10, 10-20, 20-30 %). Nitrogen, phosphorus, potassium, organic matter, cation exchange capacity and microbial soil respiration were measured. Results showed that all measured characteristics except potassium decreased over an increase in the slope. Maximum values of phosphorus, organic matters, cation exchange capacity and soil respiration were obtained in pasture (28.4 mg/kg, 0.62%, 20.38 cmol/kg, 33.2 mgC/day, respectively)but potassium maximum rate was seen in dry land form (406.8 mg/kg).The effect of season on all measured parameters was significant except for N, while the highest amounts of phosphorus, potassium, cation exchange capacity and soil respiration (28.7 mg/kg, 377.3 mg/kg, 19.6 cmol/kg and 25.9 mgC/day, respectively) were seen in May and the highest organic matter rate (0.68%)in September. The results of this study showed that an increase in the slope, poor range management, and the end of the growing season could be major factors degrading the soil quality indices and soil productivity.
M. Mokhtari, A. Najafi,
Volume 19, Issue 72 (8-2015)
Abstract
Land use classification and mapping mostly use remotely sensed data. During the past decades, several advanced classification methods such as neural network and support vector machine (SVM) have been developed. In the present study, Landsat TM images with 30m spatial resolution were used to classify land uses through two classification methods including support vector machine and neural network. The results showed that SVM and neural network with the total accuracy of 90.67 % and 91.67% are superior. SVM had a better performance in separating classes with similar spectral profiles. In addition, SVM showed a better performance in delineating class borders in comparison with neural network method. In summary, both SVM and neural network showed satisfactory results but the method of support vector machine proved better with a difference of 1% and 2% in overall accuracy and kappa coefficient, respectively. This was an expected outcome because SVMs are designed to locate an optimal separating hyperplane, while ANNs may not be able to locate this separating hyperplane.
A. Talebi, F. Souzandehpour, M. T. Dastorani, A. A. Karimian, M. Soltani,
Volume 19, Issue 72 (8-2015)
Abstract
Land use is one of the basic factors for controlling the hydrologic behavior of watersheds. Therefore, it is generally assumed that land use change is the cause of variation in hydrological dynamic of watersheds. In this paper, the land use effect in present and optimum conditions on sedimentation of watershed was studied using GIS and applying the HEC-HM model in Shoor-Shirin watershed in Fars province. Land use map was provided based on curve number map, and this map was considered as the important factor for HEC-HM model. The results showed that the estimated sediments in two different conditions were completely different. In fact, the estimated sediment in the optimum condition was 12% less than the current land use. This means that land use change and land use type play important roles in decreasing or increasing the peak flow and erosion.
S. Youneszadeh Jalili, M. Kamali, P. Daneshkar Arasteh,
Volume 20, Issue 78 (1-2017)
Abstract
Integrated management of watershed basins depends on deep knowledge of basic concepts such as the arrangement of lands and their uses. Location and distribution of agricultural land use help to balance water resources in the watershed basins. In this research with the help of satellite images of Landsat 5 and 8, and the method of maximum likelihood classification algorithm, land use types of water, barren areas and salt lands, and irrigated agriculture were studied in the Urmia watershed in the years 2010 and 2013.Then applications of modis images and product Urmia watershed land cover for years 2010 and 2012 were compared and finally modis and Landsat land covers in 2010 were compared. Results showed that the area of irrigated farmlands of Urmia basin has increased in the years between 2010 and 2013; while, the water zone has declined. Comparison between modis and landsat in 2010 showed that modis can estimate irrigated lands and water zone better than barren areas. The kappa coefficient for years 2010 and 2013 in Landsat images are 0/77 and 0/87, respectively.
M. Zarea Khormizi, A. Kavian, K. Soleimani, K. Nosrati,
Volume 21, Issue 2 (8-2017)
Abstract
Obtaining information about relative importance of sediment sources and their contributions on sediment production and thus identification of on-site critical areas is required for implementing soil and water conservations and sediment control programs. For this reason, in this study 35 geochemical tracers and organic carbon were measured in 45 samples of sediment sources and in 11 watershed sediment samples to determine the sediment deposit contribution of each land use as sediment resources in Kond watershed of Tehran province. Based on the results of Kruskal-Wallis test, from among 35 measured traces, 10 tracers including Al, As, Be, Ca, Mo, P, Pb, S, Zn and OC had ability to discriminate sediment sources with less than 1% confidence level. Then, 5 tracers: OC, S, P, Zn and As were selected as optimum composite using Discriminant Function Analysis (DFA) with 0.000 confidence coefficient that had distinguishing capability of sediment sources by 97.8% correct assignation. Finally, the results of multivariate mixing model showed that contribution means of orchard, range and residential were 1.54, 14.27 and 84.18% in sediment production, respectively. Also, the sum of squares of the error was 0.33. The results of this study can be used in selecting an appropriate method for sediment control in studied area.
E. Chavoshi, M. Afyuni, M. A. Hajabbasi,
Volume 22, Issue 2 (9-2018)
Abstract
This study covers a large agricultural and industrial area of Isfahan province, including three types of land use, i.e., agricultural, uncultivated, industrial and urban types. A total of 275 samples from surface soil (0-20 cm) were collected and water soluble fluoride concentrations of them were measured. The spatial structure of water soluble fluoride in the soils was determined by omnidirectional variogram in the GS+ software. The spatial distribution of water soluble fluoride in the soil was mapped by employing the point kriging method in the SURFER software. The results showed that the mean of the water soluble fluoride concentration in Isfahan soils (0.85 mg L-1) was higher than the mean world soils (0.53 mg L-1). The water soluble fluoride showed moderate spatial dependence, indicating that the spatial variability of water soluble fluoride was mainly controlled by intrinsic and extrinsic factors. The mean water soluble fluoride concentration was significantly higher in agricultural and urban areas, as compared with the uncultivated land. This could be due to application of phosphate fertilizer in agricultural areas and the atmospheric fallout of fluoride from the industrial sources such as steel factories. According to the generated kriging map, the higher concentration of fluoride was mainly recorded around the Zayande Rood River and in the central and western parts of the study area.
A. Ashraf Amirinejad, S. Ghotbi,
Volume 22, Issue 2 (9-2018)
Abstract
The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and shoulder slope positions, in Miandar and Vidjanan catchments. Soil physical properties such as soil texture and particle size distribution, soil hydraulic conductivity, bulk density, mean weight diameter of aggregates, water holding capacity, and the soil organic carbon content were measured. The results showed that land use change of the forest to agricultural lands resulted in a sharp decline in the soil organic matter (52%) and an increase in silt and sand percentage and soil bulk density. Also, deforestation decreased the mean weight diameter of aggregates (from 0.39 to 0.14 mm in Miandar) and clay percent. It caused a reduction in the total porosity followed by a decrease of soil water holding capacity, and a decrease in the saturated hydraulic conductivity (from 10.34 to 1.86 cm/h), as well. In general, the results proved that the land use change from forest to agriculture severely decreased soil physical quality and its productivity.
A. Norouzi, M. Ansari, M. Moazami, N. Asgharipour Dasht Bozorg,
Volume 23, Issue 3 (12-2019)
Abstract
In recent decades, land use changes have been one of the most important environmental issues worldwide. This study was carried out to investigate and analyse land use changes in dust sources of south and south-east Ahwaz and surrounding lands using remote sensing technique. Firstly, based on the standard precipitation index (SPI), the years 1986, 2002 and 2016 were selected as years with near normal situation. In the next step, land use maps of the study area were extracted using a Landsat satellite images and supervised classification methods. MNDWI index was used to increase the accuracy of image classification. In order to evaluate the efficiency of each method, the overall accuracy and kappa coefficient were used. Finally, to investigate land use change a post-classification comparison method was employed. According to research findings, in the first period (1986-2002), the area of vegetation, wet land with vegetation and water bodies have increased by 419%, 219% and 40.7%, respectively, in contrast, the area of barren and poor range has reduced by 36.6%. One of the major causes of these changes is human factors such as population growth and climate variables such as proper amounts of precipitation. In the second period (2002-2016), the area of wet land with vegetation, water bodies and vegetation has been decreased by 94%, 49.3% and 46.7%, respectively; in contrast, barren and poor range land has been increased by 45.4%. Recent droughts increase the temperature and incorrect and non-principled management of water resources has been effective in reducing green cover and water bodies and increasing in bare land. The results show that, during the three decades, built-up land has been increased by 157%, while River bed has decreased by 28.8%. These results indicate a total degradation in the region due to climate change and human activities.
A. R. Vaezi, Sh. Karimi, M. Foroumadi,
Volume 23, Issue 4 (12-2019)
Abstract
Rainfall erosion is the first type of water erosion on the land which is affected by various factors such as land use change and previous rainfall. This study was carried out to investigate the influence of previous rainfalls on the process of rainfall erosion in two marl soils (pasture and that changed to agriculture) under the simulated rainfall. Toward this goal, aggregate samples with the diameters of 6 to 8 mm were randomly collected from the marl areas in the west of Zanjan. Soil aggregates were packed into 48 boxes with the dimension of 30×40 cm to examine the effects of eight rainfall durations with three replications. Eight simulated rainfalls with the duration of 0, 7, 14, 21, 28, 35, 42 and 49 min and a constant intensity of 40 mm h-1 were used in the experiment. The soils were exposed to another simulated rainfall with 40 mm h-1 in terms of intensity for 15 min to study the rainfall erosion processes. The results showed that the aggregate breakdown was significantly affected by the previous rainfalls in the pasture soil (P<0.01), while there was no significant difference among the previous rainfalls in the case of agriculture soil. Soil compaction and particles splash were significantly affected by previous rainfalls (P<0.05). Aggregate breakdown and particles splash were 1.41 and 1.31 times bigger than their values in the pasture soil. This study, therefore, revealed that the land use change in the mal areas increases the soil vulnerability to rainfall erosion processes. The rate of rainfall erosion processes in each rainfall event depends on the amount of previous rainfall. Increasing aggregate break down and soil water content by the previous rainfall could significantly influence the splash erosion rate in a marl soil.
S. Mehri Babadi, M. Afyuni, Sh. Ayoubi,
Volume 24, Issue 1 (5-2020)
Abstract
For sustainable soil management, the effects of slope position and land use change on soil and water resources are essential. In this research, three land uses including degraded pasture, drought and apple gardens were selected to determine the effect of slope position and land use on some physical and chemical properties of soil in the Koohrang area of Chaharmahal and Bakhtiari province. Each of the applications was divided according to the position of the slope, and from three applications and organic matter (OM), saturated hydraulic conductivity (Ks), water repellency (RI), dispersible clay (DC) and weighted average aggregate diameter (MWD) were studied as the physical and chemical properties of soil. The results showed that Ks had the greatest coefficient of variation. Also, the results of the mean comparison revealed that all of the measured physical and chemical properties had a significant difference in different slope applications and positions at 5% level. In general, the garden and the base position of the slope had better qualitative conditions than other land uses and slope positions. Rangeland degradation and change in the use of pasture from dryland cultivation led to a decrease in soil quality, which could reduce soil utilization and exhaust some of the land from the production cycle. The results of the correlation between chemical and physical properties of soil showed that in general soil organic matter had the highest correlation with other parameters.
M. Pajoohesh, M. Mohammad Yousefi, A. Honarbakhsh, H. R. Reyahi Bakhtyari,
Volume 24, Issue 1 (5-2020)
Abstract
In order to plan and manage the land and its changes, it is necessary to identify and evaluate the factors affecting it. Land use / cover changes are one of the main factors in global environmental change that is defined as a change in the type of land use; it is one of the major factors changing hydrologic flow, land erosion and destruction of biodiversity. The main purpose of this study was to assess the trends of land use changes in Beheshtabad Watershed of Chaharmahal and Bakhtiari Province with an area about 3847 square kilometers by using remote sensing and GIS during a 25-year period. In this research, first, analyzing and pre-processing the satellite images of Landsat 5 TM sensors from 1991 and 2008 were done, and Landsat 8 of OLI sensor of 2016 was applied. Then, by using the hybrid classification method, 5 land use classes including pasture lands, urban-building lands, agricultural lands, garden lands and bare lands, land use maps for the three time periods were prepared. The overall accuracy of the obtained land use maps for 1991, 2008 and 2016, was 92.17%, 94.29% and 93.41%, respectively, indicating the acceptable accuracy of the maps. Then, the process of land use change and the contribution of each land use classes and the percentage of changes in each land use class were determined in two study periods. The results of this study showed some changes occurred in the studied watershed. The total area of pasture lands during two periods indicated the decreasing trend, but urban-building and garden lands during two periods represented the increasing one. Agricultural lands during the first period indicated the decreasing trend and during the second period showed the increasing trend, while bare lands during the first period showed the increasing trend and during the second period, reflected the decreasing trend. In general, it should be noted that in the Beheshtabad watershed, we could see an increase in the replacement of pastures by urban-building class, rainfed agriculture, gardens, and bare lands, the incidence of destruction in the region.
