Fatemeh Karami; Masoud Bazgir
Volume 26, Issue 4 , December 2019, , Pages 953-970
Abstract
Climate and land use are two important factors which are greatly influence on soil physical and chemical properties. This research was conducted to study the effects of climate and land use on physical and chemical properties of soil in Ilam province in 2016. After initial studies, Ivan area with semi-humid ...
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Climate and land use are two important factors which are greatly influence on soil physical and chemical properties. This research was conducted to study the effects of climate and land use on physical and chemical properties of soil in Ilam province in 2016. After initial studies, Ivan area with semi-humid climate and Ganjavan with semi-arid climate in Ilam province were selected. In each region, three land uses including forest, rangeland and agricultural were considered. After field studies in each land use, five soil samples were taken from 0-10cm and 10-30cm depths and collected randomly. The results showed that the highest amount of soil lime (47.85%) and soil silt (31.75%) were obtained in semi-arid climate of Ganjvan. The soils of Ayvan as a semi-humid climate had the highest amount of clay and K available. The highest bulk density (1.87 g.cm-3) was obtained in semi-arid climate of Ganjavan under the effect of agricultural use at lower soil depth. The lowest amount of bulk density (1.08 g.cm-3) was observed in semi-humid climate of Ayvan in the soil surface depth under forest land use. The highest amount of organic matter was obtained in forest land use in semi-humid climate in Ayvan, (42.85 %) which was more than semi-arid climate of Ganjvan. Agricultural land use had the lowest amount of organic matter (4.37%). The highest amount of N (0.514%) and P (35.04 mg kg-1) concentrations were obtained in forest land use in the semi-humid climate of Ayvan. The amount of Ca and Mg concentration in subsoil solution (10-30cm) layer was higher than topsoil solution (0-10cm) layer in Ayvan. In general, by changing land use from forest to farm, the percentage of clay, organic matter, nitrogen, phosphorus, and potassium available decreased in semi-arid climates of Ganjvan. Therefore, proper land use management in semiarid climates is essential for optimal preservation of soil properties.
Mohsen Fereydoni Nasri; Esmaeel Rahbar
Volume 11, Issue 1 , September 2019, , Pages 19-32
Abbas Zarezadeh; Esmaeel Rahbar; Mohammad Abolghasemi
Volume 11, Issue 2 , August 2019, , Pages 179-190
Mohammad Javad Ahmadian Yazdi; Esmaeel Rahbar
Volume 10, Issue 4 , August 2019, , Pages 459-478
Mehdi Najafi Ghiri; Alireza Mahmoudi; Shahrokh Askari; Esmaeil Farokhnejad
Volume 25, Issue 1 , April 2018, , Pages 170-182
Abstract
Halophytes may change different soil properties and nutrients availability by organic materials addition to soil and soil conservation against erosion agents. Destroying these lands and halophytes may have an undesirable effect on environment. To study the effects of physiographic position, plant variety ...
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Halophytes may change different soil properties and nutrients availability by organic materials addition to soil and soil conservation against erosion agents. Destroying these lands and halophytes may have an undesirable effect on environment. To study the effects of physiographic position, plant variety and plant growth position (sole or under another plant) on soil properties of salt marshes, an investigation was carried out in Korsia region, Darab (Fars province). Soil samples were collected from the beneath of Tamarix aphylla and Salsola rigida (sole and under Tamarix) and between plants with triplicates in two different salt marshes with lowland and piedmont plain positions. Soil properties including particle size distribution, organic matter, pH, EC and equivalent calcium carbonates and nutrients availability including P, K, Fe, Mn, Cu and Zn were determined. Results indicated that lowland had more saline and heavier textured soil and shorter Tamarix aphylla as compared with piedmont plain. Tamarix aphylla increased organic matter, EC, P, K, Fe, Mn, Cu and Zn; however, it had no effect on soil texture and equivalent calcium carbonates. Salsola rigida increased organic matter and its effect on available Mn and Zn was more than other nutrients. Salsola rigida under short Tamarix aphylla did not change soil salinity; while Salsola rigida under long Tamarix aphylla decreased soil salinity. Generally, it seems that organic matter is the most important factor on different plant nutrients availability and soil fertility status of the soils studied. Organic matter affects mobility, precipitation or nutrient uptake by the effect on pH, chelating agent production, nutrient adsorption, and nutrient release due to decomposition and soil physical properties improvement.
Maryam Dadgar; Masoud Aliha; Enseyeh Faramarzi
Volume 18, Issue 3 , September 2011, , Pages 498-504
Abstract
Phosphorus is of macro elements for plant growth. Phosphorus compounds are almost insoluble and available phosphorous in soil is rapidly decreased. Use of phosphate fertilizers in soil has been always one of the fundamental issues in agriculture and production due to the low efficiency of phosphorus ...
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Phosphorus is of macro elements for plant growth. Phosphorus compounds are almost insoluble and available phosphorous in soil is rapidly decreased. Use of phosphate fertilizers in soil has been always one of the fundamental issues in agriculture and production due to the low efficiency of phosphorus fixation in the soil and its uptake by plants. To study the relationship between available Phosphorus and some soil features, soil sampling was performed from 0-30 cm soil depth for 110 samples in Absard. Some soil physical and chemical characteristics such as percentage of sand, silt, and clay, organic matter, calcium carbonate, soil acidity, and available phosphorus were measured and correlation between phosphorus and above soil characteristics was determined. The results showed that significant correlation (P< 0.01) was found between P and some soil properties. In addition, there was a negative correlation between and soil acidity and percentage of calcium carbonate, but a positive correlation was found between phosphorus and organic matter.
Aziz Arsham; Ali mohammad Akhund ali; Abdolkarim Behnia
Volume 16, Issue 4 , January 2010, , Pages 445-455
Abstract
Antecedent soil moisture is one of runoff and sedimentation crucial factors affected by parameters such as soil properties, topographic-, climatic-, and coverage circumstances etc. The work aimed at determining effects of soil properties and rainfall on runoff and sediment load at various antecedent ...
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Antecedent soil moisture is one of runoff and sedimentation crucial factors affected by parameters such as soil properties, topographic-, climatic-, and coverage circumstances etc. The work aimed at determining effects of soil properties and rainfall on runoff and sediment load at various antecedent moisture levels. Heavy, medium and light textured field soils were selected, exposed to a constantly intensified 80mm/hr rainfall under air-dried, air-dried to field capacity point, field capacity point and nearly saturated conditions, and two slopes of 5 and 15%. Recording runoff and sedimentation values every 2-5 min; populated values were calculated within 10, 20 and 30 min. intervals. All experiments were carried out with simulated rainfall technique in a 1×1×0.1m flume. Treatments showed most significant differences within first 10min. decreased with increasing rainfall duration. Maximum runoff coefficients increased as 2-5 folds as minimum ones with all durations. When moisture increased to field capacity point, light, medium and heavy textured soils had the lowest to the highest values of runoff coefficient, respectively. Under nearly saturated condition, increasing runoff trend decelerated with heavy textured soils and decreased to a lesser extent as compared to medium textured samples. Also, sedimentation process was consistent with runoff fluctuations. Medium textured soils showed a significant level of sedimentation under nearly saturated conditions. Runoff coefficients were unnoticeably different with 5 and 15% slopes; however, a more significant sedimentation increase occurred with 15% slope.
Gholam reza Zehtabian; Marzeyeh Tayeb; Mahshid Souri
Volume 13, Issue 4 , February 2007, , Pages 368-384
Abstract
Salinity is one of the factores affecting the reduction of soil biological potential and vegetation and finally desertification. Water is the most limiting factor for cultivation in arid and semi arid regions. Due to shortage of surface water resources, the pressure is exerted on under ground water ...
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Salinity is one of the factores affecting the reduction of soil biological potential and vegetation and finally desertification. Water is the most limiting factor for cultivation in arid and semi arid regions. Due to shortage of surface water resources, the pressure is exerted on under ground water resources. Meanwhile, over –exploitation of underground water resources and neglecting technical points in exploitation have caused the level of underground water to be dropped. This water level drop in addition to other factors causes the quality of water resources to be changed leading to increasing of salinity. This research has been carried out in kabootarkhan plain, kerman province. In order to study factors salinizing underground water resources in this basin, some baseline data were gathered. Then, sampling of profiles of soil profiles were done in the four soil units (arable lands, ferdowsi, agriculture station and kabootakhan) in the basin in three replications. The laboratory results and existing data were analyzed using SPSS software according to the randomized split-pot design. The results show that in appendage plain of the basin, irrigation with saline water resources in addition to soil texture have caused salinity to be occurred and in clay flat, irrigation has caused salinity to be declined due to the good soil texture and existence of natural drainage.
Mohammad javad Ahmadian yazdi; Esmaeil Rahbar; Orujali Karimi
Volume 14, Issue 3 , January 2007, , Pages 313-322
Abstract
A general model was developed to explain the interrelationships between soil saturation percentage, mean annual precipitation, and population density on growth and vigority of planted Haloxylon trees. Based on the model, estimated number of population density for 7 years old Haloxylon plantation in Sabzevar ...
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A general model was developed to explain the interrelationships between soil saturation percentage, mean annual precipitation, and population density on growth and vigority of planted Haloxylon trees. Based on the model, estimated number of population density for 7 years old Haloxylon plantation in Sabzevar was 309 trees per hectar; therefore, six density treatments were selected around the estimated density; two density treatments over estimated number, two under it, and existing density as the control treatment. The treatments consisted of T1=247, T2=278, T3=309, T4=340, T5=371, and existing density(control) T6=500 trees per hectar. The treatments have been compared in a Randomized Complete Block Design, with four replications, since winter of 1994. After thinning practices, height(H) and crown diameters(CD) of the remained trees were measured. This measurement was repeated during the growth period in ten years. Since the CD increment between the first and the 10th measurement was 3 times more than H increment; therefore, a size index(SI) model of the form H×(CD)2, which was constructed by trial and error, was found to distinguish the best among the 6 treatments. The growth percentage of H, CD, and SI between first and the last measurement were calculated. The analysis of variance of the growth percents showed that there is significant differences between treatments for H, CD, and SI. The highest growth belonged to T2 and lowest belonged to T6(control). The results show that optimized population density of seven years old Haloxylon stands in Sabzevar is 10% less than the estimated number based on the general model.