Yones Abdoli; siroos jafari; abas Beshkar
Abstract
Introduction: The Fe forms diversity is related to parent materials, climate, soil process, biocycles, water table fluctuation, redox, organic matter and etc. in soil. The main Fe forms are Fed (extracted by dithionite citrate bicarbonate), Feo (extracted by oxalate ammonium) and Fe crystals. Feo/ Fed ...
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Introduction: The Fe forms diversity is related to parent materials, climate, soil process, biocycles, water table fluctuation, redox, organic matter and etc. in soil. The main Fe forms are Fed (extracted by dithionite citrate bicarbonate), Feo (extracted by oxalate ammonium) and Fe crystals. Feo/ Fed ratio also shows active Fe forms. Magnetic susceptibility (MS) increases when ferri-magnetite is formed due to soil processes. This characteristic (MS) changes with parent material, climate, relief, and organism. Therefore, this study was undertaken to evaluate different Fe forms and MS with soil forming factors in some gypsic soils of Khuzestan province.
Material and Methods: The study area was located in Ramhormoz and Haft-Kel regions in Khuzestan province. Soil moisture and temperature regimes were ustic and hypertermic, respectively. Soil parent material consisted of the eluvial deposit of Gachsaran and Aghajari geological formations. The soil profiles location was selected according to topography map, ETM+ Landsat satellite images, and then 14 soil pedons were dug and described according to the standard methods. All horizons or layers were sampled and 5 pedons were selected for the analysis of different Fe forms. Fed and Feowere, respectively, extracted by citrate-bicarbonate-dithionite (CBD) and oxalate ammonium, and Fe cocentration was then determined by atomic absorption spectrometry. Furthermore, MS was determined by MS2 meter Barlington Dual frequency in low (0.46 kHz) and high (4.6 kHz) frequencies. All MS were calculated for carbonates, gypsum, and OM free. These calculations were also done for Fe forms in these samples. The statistical analysis was carried out with SPSS and Pierson methods between Fe forms and MS. The Duncan’s test was used to compare the mean values.
Results and Discussion: Pedons were classified as Entisols, Inceptisols, and Aridisols soil orders. The range of clay content, pHe, ECe, CEC, OM, CCE and gypsum was 15-59%, 7.1-8.5, 0.6-58.1 dS/m, 4.2-22.4 cmol(c)/kg, 0.3-2.4%, 21.2-39.7%, and 0-78.7%, respectively. All epipedons were classified to be ochric and developed soils had cambic diagnostic horizon (Bw) in subsurface. Feo content was maximum in young soil under poor drainage, and minimum Feo content was observed for developed pedons with good drainage class. The sepedons have not been cultivated yet. Feo was maximum at surface soils in all pedons, and decreased with increasing depth. A decreasing trend was observed from surface to subsurface for Fe content in cultivated soils. This negative trend was not, however, detected in poor drainage class or pedons with lithologic discontinuity. This trend can be ascribedto more organic matter content in surface soil in comparison with subsurface soil. Organic matters increase soil acidity and therefore, Feo can not be converted to other Fe forms under this circumstance. Maximum Feo was determined under poor drainage class in low lands. In addition, Fed displayed no trend from the surface to depth at most pedons. Maximum Fed was foundin old plain and the hill slope summit. This Fed was positively strongly correlated with soil development trend. Fed had a positive association with clay content (r=0.463), and negative correlation with sand content (r= -0.411), salinity (r= -0.533), and total carbonate, gypsum and OM (r= - 0.389). Feom (Feo menerogic) was maximum in Byz (4.04 gr/kg soil) and minimum content for Feomwas found in Byb (0.29 gr/kg soil). Maximum andminimum Fedmwas measured in Cy (9.21 g/kg) and Bg2 (1.54 g/kg), respectively. The Feo/ Fed ratio was largerin young soil and decreased with time. These values decreased from the surface to depth with the range from 0.07 to 0.8. The greatest and lowest Feo/ Fedwere, respectively, observed inthe hills and the low lands. There was no significant difference in Feo/ Fed between hill and plain.
MS changed from 5 to 25.5. Maximum and minimum MS was detected in the hills and the low lands. MS decreased with depth in almost all horizons. The highest and lowestMS were, respectively, found in pedon 3 (Byb horizon) and pedon 12 in the Bw3 horizon. The MS minerogenicwas statistically significantly associated to sand content (r=0.56**) and significantly negatively correlated with total carbonates, gypsum, OM (r=-0.667**), silt content (r= -0.506) and clay content (r= -0.456). The positive relationship between sand content and MS can be explained by the effect of magnetic materials inherited from the parent materials.
Conclusion: Fed and Feo- Fed showed a close correlation with soil development. Feo/Fed ratio increased with decreasing soil age. Feo content had a positive correlation with total carbonate, OM, salinity. MS was more in older soils such as hill physiographic unit but it was low in younger soils or soils with weak drainage. MS was greatly affected by sand material size which seems to be linked to parent materials. MS showed no trend with soil development but land use, drainage and parent material largely impacted MS and different Fe forms in these gypsiferous soils.
mostafa Pajohannia; Mostafa Chorom; Siroos Jafari
Abstract
Introduction: Iron is found in different forms in the soil. In the primary minerals, iron is found as Fe3+ or Fe2+ which converted to Fe2+ and released in unsuitable reduction conditions. Minerals such as sulfide or chlorine and bicarbonate can affect and change the different forms soil Fe. FeAs these ...
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Introduction: Iron is found in different forms in the soil. In the primary minerals, iron is found as Fe3+ or Fe2+ which converted to Fe2+ and released in unsuitable reduction conditions. Minerals such as sulfide or chlorine and bicarbonate can affect and change the different forms soil Fe. FeAs these elements are abundance in groundwater or soil, they are capable to react chemically with Fe and change different Fe forms and also may deposit or even leach them by increasing its solubility in the soil. Water table fluctuation is a regular phenomenon in Khuzestan that Fe forms change under these situations. The study of Fe oxide forms and its changes can be applied for evaluation of soil development. Therefore, the aim of this study is the water table fluctuation and its quality effects, and some physio-chemical properties on Fe oxides forms in non-saline and saline soils in Khuzestan.
Materials and Methods: Soil samples were collected from two regions: saline (Abdolkhan) and non-saline (South Susa) regions. soil samples were collected from all horizons of 12 soil field studied profiles . The samples were analyzed for soil texture, pH, EC (soil: water ratio 1:5), organic carbon and aggregate stability (Kemper and Rosenau method). Fe forms also were extracted by two methods in all samples: di-tyonite sodium and ammonium oxalate extraction. Fe oxalate extracted was related to Feo (non crystal Fe) and Fed-Feo was related to Fec (crystalline Fe). The Fe content were determined by atomic absorbtion spectrophotometer (AAS). Data were analysis in SAS and Excel software and results were presented.
Results and Discussion: The results showed that texture were loamy sand to silty clay loam, OM was very poor (0.1-0.7%). The soil salinity was also 2.8-16.8 dS/m. Calcium carbonate equivalent was 38-40%. All pedons were classified in Entisols and Inceptisols according to Keys to soil taxonomy (2010). The results showed that the proportion of Fe with oxalate to di-tionite treatments was different regarding the salinity, texture, organic matters, cultivation and the water table fluctuation. The total Fe content in the middle layers had permanently increased due to the groundwater fluctuation levels and this caused the creation of mottle in this layer. All saline soils had saline subsurface water. The salinity has caused that the effective microorganisms have not been actived on the reduction processes in some profiles and the Fe deposit more in the Fe3+forms. The Fe was found more in non-crystal form in saline regions, but it was in the crystal form in non-saline regions which indicated the suitable conditions for Fe’s nodule formation. For example, when soil salinity decreased from 14.9 to 8.1 dS/m, Fec increased from 460.1 to 497.8 mg/kg soil. With increasing the amount of clay, and cultivation periods, the Fed content has also been increased. The Feo/ Fec ratio in undevelopted soils was higher than developed soils. This ratio was low in non-saline soil and was high for saline soil. this indicates that non-saline soil had more development than saline soils. The maximum amount (1.6) was belonged to saline soil and minimum was for no saline soils. With increasing in soil age, tillage periods and clay content this ratio was decreased., statistical analysis Also showed that there was significant difference between Fec and Feo in saline and no saline soils. Also, with increasing in salinity, Fec content decreased and Feo increased. aggregate stability was also increased with increasing Fec content.
Conclusions: The Feo content was more in surface of saline soil than subsurface when pedon was ponded and saturated from surface. Feo was very higher in saline soils than no saline soils. Fec had not significant difference between saline and nonsaline soils. Salinity decreased Fec and increased Feo content in soils. Feo/Fec ratio of saline soils was 4 to 5 times fold of non-saline soils. Increasing Feo/Fec ratio in saline soils and decreasing in this ratio in nonsaline soil showed that nonsaline soils had more development than saline soils. Organic matter was more effective in Feo and Fec contents in nonsaline soil than saline soils. Also, Fec content increased with increasing clay content in all horizons that this shows that mottling and more Fe concentration in nonsaline soils.
F. Ramezani; S. Jafari; A. Salavati; B. Khalilimoghaddam
Abstract
Introduction: Aspects of the physical, chemical and biological are considered. Land degradation for soil quality, or improve soil quality assessment is important.This study was conducted to evaluate soil quality indicators using quantitative models in some lands of Khuzestan province (Iran).Such studies, ...
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Introduction: Aspects of the physical, chemical and biological are considered. Land degradation for soil quality, or improve soil quality assessment is important.This study was conducted to evaluate soil quality indicators using quantitative models in some lands of Khuzestan province (Iran).Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management.
Materials and Methods: In order to evaluate the effect of crop management and cultivation on soil quality, Select several Khuzestan region and Samples were taken from the surrounding cultivated land. Physiochemical characteristics of soil samples from a depth of0-30 cm such as soil texture, bulk density (Db), mean weight diameter of wet aggregates (MWD), relative field capacity (RFC), air capacity (FA),plant available water capacity (AWC), saturated hydraulic conductivity (Ks), organic carbon (OC),electrical conductivity (EC), pH, soluble cations (Mg, Ca, Na),sodium absorption ratio (SAR), exchange sodium percent (ESP) and cation exchange capacity were determined (CEC). The soil quality was evaluated by integrated quality index (IQI) and Nemero quality index (NQI) in two data sets of soil properties including MDS and TDS. In these models, a set of characteristics that affect the quality of the soil in the form of a mathematical model incorporating and to propose a numerical quantity this number serve as general indicator of soil quality, Reflect the characteristics of the target.
Results and Discussion: The results showed that there was significant correlation between IQITDS - IQIMDS and between NQITDS -NQIMDS. The results show that the NQITDS model can be saved in compire with IQI models. This can decrease the time and costs in this method. But in some regions due to low correlation with Using a set of MDS, which comprise more limited number of soil characteristics You cannot reliably determine soil quality indicators are acceptable and should use the same set of TDS. Also, the results show that the soil was compacted due to heavy traffic, and this has reduced soil quality. The most important limiting factor of quality soil was reduced soil organic matter and porosity and increased bulk density. None of the subjects in the study area are not very stable and unstable. According to the research, increased of cultivation in most soils were clay and silt and decreased sand content. The burning of sugarcane after harvesting, can be to cause reduce organic matter, Finally, reduced the cation exchange capacity related of the soil organic matter and thus increased the bulk density of soil and reduced the soil structural stability. Decreased the electrical conductivity of the saturation extract and sodium adsorption ratio under cultivation and showed increasing trend pH of soil in all the samples. Finally reduced under cultivation soil quality. Nevertheless, we can better manage the effects can be even more improved soil quality grade. Therefore, a special management operations, such as changing the way farming, plowing, residue management, fertilizer use and the presence of organic matter the optimum, Reduce negative environmental effects such as the effect of insecticides and heavy metals... By creating a suitable building could be Prevent the destruction of the building and therefore the distribution of pores.
Conclusion: This investigation showed the efficiency of soil quality studies for the evaluation of present conditions of soil in agricultural and natural ecosystems. Therefore, these soils need to special management, such as minimum tillage or no tillage, addition of residues, and improve of aggregate stability can be applied for soil improvement quality. These strategies can improve soil prosity and, therefore, it can reduce bulk density under monocroping system. Therefore, special management practices seems essential in arid and semi-arid regions. Given the importance of soil quality in balancing the environment and the sustainability of agricultural systems, in addition to the chemical and physical factors, biological factors to take appropriate management programs and improve soil quality checked.
A. Mahjoubi; A. Hooshmand; AbdAli Naseri; S. Jafari
Abstract
Sugarcane is one of the high consumption plants that has very high drainage coefficient. Irrigation frequency of Sugarcane in the maximum of consumption month is near 5 days and drainage systems often are removing drain water more than enough from the soil. This study was carried out to investigate the ...
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Sugarcane is one of the high consumption plants that has very high drainage coefficient. Irrigation frequency of Sugarcane in the maximum of consumption month is near 5 days and drainage systems often are removing drain water more than enough from the soil. This study was carried out to investigate the impact of controlled drainage on reduction of drainage coefficient and drainage volumes in three fields of Imam Khomeini sugarcane agro- industry. Two treatments were controlled drainage with water table controlling in 70 and 90 cm depth from soil surface (CD70, CD90) and the third one was free drainage (FD) treatment. According to the results, the CD treatments significantly reduced drainage coefficient during the study, compared to free drainage treatment. Average drainage coefficient in during the study in CD70, CD90 and FD treatments was 3, 4.12 and 8.98 mm/day respectively. Controlled drainage treatments (CD70, CD90) reduced drainage coefficient by 67% and 54% respectively, compared to free drainage treatment. CD70 treatment reduced drainage coefficient by 27%, compared CD90 treatment, too. The use of controlled drainage did not limited for plant growth and did not reduce sugarcane yield. Using of this method, in addition to the economic benefits will cause decreasing river pollution load and has a positive environmental impact.
F. Moradi; B. KhaliliMoghadam; S. Jafari; S. Ghorbani Dashtaki
Abstract
The objective of this study was to evaluate the long-term effects of mechanized sugarcan cultivation on some soil physical properties in several lands of Khozestan Sugarcane Agro-Industries. According to this, the experiment was carried out statistically as a randomized complete block design at 38 points ...
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The objective of this study was to evaluate the long-term effects of mechanized sugarcan cultivation on some soil physical properties in several lands of Khozestan Sugarcane Agro-Industries. According to this, the experiment was carried out statistically as a randomized complete block design at 38 points in each of Deabal-Khazaei, Amir-Kabir, Karoon and Haft-Tapeh Agro-Industries with 5, 15, 40 and 50 years service. Measured soil variables included soil texture, electrical conductivity, sodium adsorption ratio, organic matter, equivalent calcium carbonate, acidity, bulk density (BD), resistance of soil penetration (PR) at 16.82-17.96 moisture interval at two depths 0-40 and 40-80 cm and mean weight diameter (MWD) at soil surface and 40 cm depth. The results showed that BD and PR increased with numbers of years service and also, MWD increased caused by improvement soil organic matter content. The PR values increased with depth, which achieved to the greatest value at 55 to 80 depth interval. Also, results showned that the significant effect of number of years service on BD, PR and MWD, so that BD, PR and MWD with increasing the number of years service from 5 to 50 years were increased from 1.57 to 1.7 gr/cm3, 0.98 to 1.16 MPa and 0.98 to 1.76 mm at first depth and 1.58 to 1.79 gr/cm3 and 1.29 to 2.15 MPa at second depth, respectively. Whereas, non-significant change was found in MWD related to increase the number of years service at first depth.