فهرست مطالب

نشریه پژوهش های حفاظت آب و خاک
سال هجدهم شماره 1 (بهار 1390)

تاریخ انتشار: 1390/10/01
تعداد عناوین: 13

فارسی
English

انتخاب همه

Micromorphology of development of some loess-derived soils of western Golestan province along a climo-topo-biosequence

M. Liaghat, F. Khormali Page 1

The aim of the present study, was the micromorphological investigation of development of some loess-derived soils of Golestan province along a climo -topo- biosequence, starting from lowlands in north and ending to forest uplands in south. Four soil profiles, situated in aridic, xeric and udic moisture regimes selected for this study were located at 20 to 400m elevation above sea level. Disturbed and undisturbed samples were taken for physicochemical properties and micromorphological studies. The studied soils in north-south direction were classified as Gypsic Aquisalids (pedon 1), Typic Haploxerepts (pedon 2), Typic Calcixerolls (pedon 3) and Typic Hapludalfs (pedon 4). The results showed that soils in xeric and udic moisture regimes, had higher clay. Alfisols with udic moisture regime and forest land use, were weakly acidic, but at the semiarid climate, gypsum and calcite accumulation caused an increase in pH. In Aridisols and subsurface horizons of Mollisols, crystallitic b-fabric was dominant. Whereas Alfisols showed striated-speckled b-fabric. Subangular blocky microstructure is dominant in Alfisols, Aridisols and Inceptisols. The granular and crumb microstructure were also observed in surface horizons of Mollisols. Moreover Mollisols, showed higher porosity. Quantitative microscopic studies were done using Image Tool software and image analysis techniques. From aridic to udic moisture regime more variation in porosity were observed. In soils of xeric moisture regime, various forms of pedofeatures including calcite and Fe-Mn coatings were observed. In soils of udic moisture regime, clay coatings and clay fragments were dominant. Gypsum pedofeatures were dominant in arid soils.

Abstract View Paper Original: Persian
The effects of ground water table and rice cultivation on paddy

J. Seyyed Mohammadi Marasht, M. Akef, K. Eftekhar, H. Ramzanpour Page 33

This study was carried out to gain a better understanding of the effects of ground water table and rice cultivation on morphological and micromorphological characteristics of the soils formed on Sefidrood plateaues and upper terraces, river alluvial plain, lowland and Caspian Sea coastal plain physiographic units in the South of Rasht Sangar Dam of Guilan Province. Totally, twenty pedons, five pedons on each unit, were excavated and studied on physiographic units. One pedon on each unit was selected in order to detailed study as refrence pedon. Micromorphological and physico-chemical characteristics of the soils were studied and determined by taking undisturbed and disturbed soil samples from the horizons of described soils. Reducing conditions, soil structure damaging and formation of weak granular structure after passing several month of puddling in surface horizons were the main distinguishable characteristics of the soils. Micromorphological results showed that vugh, channel and rarely plane voids in surface horizons and vugh and channel voids in subsurface horizons occurred and were coated predominantly with ferric and organic matter components. Microstructure was weak granular in all surface horizons. Microstructure was single grain in the subsurface horizons of the Coastal plain physiographic unit and their voids were mainly simple paking. Microstructure was subangular blocky and angular blocky in the subsurface horizons of other units. Micromorphological observations of alluvial plain physiography unit soils, demonstrated the presence of iron-oxide nodules as geodic and halo with diffuse boundary, ferric masses and organo-ferran complex coating. Iron oxide nodule was not observed in lowland and coastal plain soils because of high ground water table. Clay coatings were not observed due to high ground water table and its alternative fluctuation. Clay particles in plateaues were lower than other units because of alteration and suitable aeration. The soils formed on the Sefidrood plateaues and upper terraces, river alluvial plain, and lowland physiographic units were classified as Inceptisols and the soils formed on coastal plain physiographic unit as Entisols.

Abstract View Paper Original: Persian
The evaluating of drought zoning models in various time scales case study: Sistan and Balouchestan Province

H. Ansari, M. Erfanian, M. Naderian Far Page 59

Drought is a creeping natural hazard with large extent of occurrence, causes considerable damages to different economical parts of our country. Because of the vast impact of drought, it is essential to be monitored timely and spatially. Specifically, SPI was used as drought monitoring Index of Sistan and Balouchestan province of Iran, and for zoning proposes three models (Kriging, Spline and IDW) were employed. Results showed that during last 25 years period (1981-2005), occurrence of drought has been more frequent and also lasted longer than the early years. However, the severity of drought has been reduced. It can be seen that the duration and severity of drought is more in the southern and central area than in the northern parts of the province. Cross validation technique with R2, RMSE, MDE and MAE were analyzed to assess the zoning methods. Results of ranking these criteria’s summation showed that the Kriging with Gaussian variogram, with RMSE, MDE, MAE and R2 equal to 0.546, -0.0015, 0.42 and 0.56 (the maximum correlation), respectively, and the IDW with 1 and 2 power were the best methods for drought zoning. Finally, drought’s severity maps were generated, which are useful tools to take management decisions to solve the drought crisis problems.

Abstract View Paper Original: Persian
Groundwater resources pollutant conditions in Gharesoo, Golestan Province

M. Meftah Halaghi, A. Hezarjaribi Page 81

Considering the relative good potential of ground water in Gharesoo basin, compared to surface water, quantitative and qualitative studies of ground water resources in this area is very important. Followed by the basic studies such as effective pollutant resources, the qualitative studies were done on the selected places. The test points were consisted of deep and semi-deep wells. The distribution of these stations on the basis of uniform distribution has affected the Gharesoo sub-basins and pollutant resources. Thus 57 stations were chosen for sampling. Because of small variation of qualitative parameters of ground water, sampling in both wet (Ordibehesht month) and dry periods (Mehr month) and nessesary qualitative tests of samples were done. The tests consisted of anions, cations, colliforms, EC, TDS, BOD and COD. The results indicated increased rate of pollutants toward the north west or exit point of the Gharesoo basin and this was coordinated with decreasing the depth of ground water and its direction of movement. Furthermore, in more than 90 percent of places, quality of water was suitable for agriculture and drinking. The main reasons for the low quality of water for agriculture and drinking was high EC and TDS parameters in the proximity of Gharesoo exits. On the basis of Gibbs Diagram and ratio of Ca to Mg ions (less than one), dolomite minerals are dominant.

Abstract View Paper Original: Persian
Chemical characteristic, enzyme activity of urease and alkaline phosphatase in a soil amended with sewage sludge and sewage sludge Enrichment with chemical fertilizer

S.R. Ahmadpoor, M.A. Bahmanyar, S. S. Gilani, A. Forghani Page 103

The aim of this study was to investigate the effects of different rates and periods of sewage sludge and sewage sludge enrichment with chemical fertilizer application on some chemical characteristic and enzyme activity of soil in 2008. This experiment was carried out in a randomized complete block design with three replications. The main factors was fertilizer treatments (T1= no organic and inorganic fertilizer, T2= chemical fertilizer (potassium sulfate, tripill super phosphate and urea 150, 150 and 200 Kg. ha-1 respectively), T3 and T5 20 and 40 Mg. ha-1 respectively, T4 and T6, 20 and 40 Mg. ha-1 with half T2 respectively) and the secondary factor three consecutive times of sewage sludge application (2006, 2006+2007, 2006-2008 years). Soil samples were collected from 0-20 cm depth at end of 60th day of application. Results indicated that with increasing application periods of sewage sludge the amount of soil organic matter enhanced, significantly. An increasing trend was observed in total nitrogen (TN). While mean, with increasing the rates and application periods, the amount of available K and P increased significantly. Activities of urease and alkaline phosphates improved with increasing the organic fertilizers and application periods. Maximum amount of available K, P and total N, activities of urease and alkaline phosphates were observed in 40 sewage sludge ha-1 + 1/2 chemical fertilizer treatment. Significant correlation was observed among enzyme activity, organic soil matter, TN, K and P. Therefore application of sewage sludge, by increasing the amount of O.C, TN, available P and K, caused to enhance the enzyme activity in soil.

Abstract View Paper Original: Persian
Investigating the nitrification process in two calcareous and non-calcareous contaminated soils

N. Yazdanpanah, M. Mahmoudabadi Page 123

In recent decades, human activities resulted in heavy metals accumulation in soil which is a threat to organism's health. Nitrification process is one of the important biological indices to assess soil quality. This study investigates the nitrification process with complete randomized design in two calcareous and non-calcareous soils. Different treatments of nitrogen (0 and 100 µg/g), cadmium (0, 10 and 100 µg/g) and zinc (0, 100 and 500 µg/g) with 3 replicates were applied in the laboratory conditions. The results showed that increasing heavy metals concentration, nitrification rate decreased. Inhibition effect of Cd was more than the Zn. In the presence of ammonium at the highest cadmium concentration (100 µg/g) in the calcareous and non-calcareous soils, nitrification rate decreased 78% and 92% respectively. These values in the absence of ammonium were 75% and 90% respectively. Inhibition effect of the heavy metals on nitrification in the calcareous soil was more than the non-calcareous soil. Addition of ammonium to the Cd and Zn treatments led to three fold increase in nitrification rate. However, difference between nitrate values in the two soils, in the presence of ammonium was less than that of its absence. The most decrease in pH was observed in the 100 µg Cd/g soil treatment with 1.3 unit. The findings of this research reveal that in the arid and semiarid soils, the CaCO3 can diminish the toxic effects of heavy metals on biological activities.

Abstract View Paper Original: Persian
Micromorphological investigation of mollic epipedon porosity in Mollisols of the southern Gorgan River under different land uses

M. Mirkarimi, F. Khormali, F. Kiani, M. Akef Page 181

Soil degradation that sometimes occurs as the result of land use change and its vegetation cover is a widespread environmental problem that may lead to the changes in soil structure and porosity. The aim of this study, was the qualitative and quantitative micromorphological evaluation of voids in Mollisols formed on the southern Gorgan River plain. The studied land uses consisted of natural forest, pasture, orchards and cultivated land. A soil profile was dug in each of land uses. Soil samples were collected for physico-chemical analyses in three replications and also undisturbed samples for impregnation with resin by Kubiena box. Following preparation of thin sections and study by polarized microscope, the photographs were prepared and the total porosity, diameter and area of voids were determined by Image Tool 3.0 software. The data were analysed with SAS software and LSD,s test. Results of image analysis indicated that original forest and pasture had the highest percentage of porosity and the cultivated soil had the lowest one. Moreover, because of agricultural machinery in cultivated land and soil compaction, aggregates were mainly broken which reduced the size of voids in terms of feret diameter and area compared with the natural land uses. The dominant size of voids was lower than 2μm in the cultivated land. While the variations of voids in terms of size and area of the voids larger than 500 μm2 and also presence of channels and large vughs were higher in forest and pasture than other uses. The presence of such voids can cause better extension and distribution of roots and higher water and nutrient uptake in forest and pasture.

Abstract View Paper Original: Persian

علمی مصوب

نشریه پژوهش های حفاظت آب و خاک

Water and Soil Conservation

دوماهنامه کشاورزی و منابع طبیعی

آخرین شماره | آرشیو

ISSN: 2322-2069 eISSN: 2322-2794

صاحب امتیاز:

دانشگاه علوم کشاورزی و منابع طبیعی گرگان

مدیر مسئول:

دکتر علی نجفی نژاد

سردبیر:

دکتر عبدالرضا بهره مند

تلفن نشریه: ۰۱۷-۳۲۴۳۰۵۲۲

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فهرست مطالب

نشریه پژوهش های حفاظت آب و خاک سال هجدهم شماره 1 (بهار 1390)

نشریه پژوهش های حفاظت آب و خاک

Water and Soil Conservation

نشریه پژوهش های حفاظت آب و خاک
سال هجدهم شماره 1 (بهار 1390)