Showing 8 results for Soil Characteristics
F. Noorbakhsh, S. Hajrasuliha, G. Emtiazy,
Volume 5, Issue 3 (10-2001)
Abstract
The urease enzyme plays an important role in the efficient use of urea fertilizer and some environmental risk assessment. Urease activities in 20 different soil samples of arid to semi-arid regions of Isfahan Province were determined and their correlations with some soil physical, chemical and biological characteristics were studied. Urease activities range from 5.3 to 79.2 µg NH4
+ g
-1 soil 2hr
-1.
Results indicated that soil organic carbon was significantly correlated with urease activity (r=0.899***). None of sand, silt and clay percentages were significantly correlated with urease activity. Total nitrogen was significantly correlated with urease activity (r=0.797***). Electrical conductivity of saturated paste extracts were also negatively correlated (r=-0.499*) but sodium adsorption ratio (SAR), pH, equivalent calcium carbonate and cation exchange capacity failed to be correlated significantly with urease activity. No significant correlations were found between urease activity and total bacteria (on nutrient agar) or total fungi (on potato dextrose agar), but the bacteria that could colonize urea-agar media were significantly correlated with urease activity (r=0.47*). Multiple stepwise regression analysis showed that organic carbon accounted for most of the variation in urease activity.
E. Zandi Esfahan, S. J. Khajedin, M. Jafari, H. Karimizadeh, H. Azarnivand,
Volume 11, Issue 40 (7-2007)
Abstract
In order to determine the reciprocal relationship between the important characteristics of soil and the growth of Haloxylon ammodendron (C.A. Mey) plant in segsi plain of Isfahan., ordination method was used. The study was performed through the stratified random sampling and the regions were separated according to the plant age and physical physiognomy, then 10 samples of Haloxylon ammodendron (C.A. Mey) of the same age were selected in each region. Meanwhile, factors such as height, canopy cover area, canopy cover perimeter, canopy cover diameter, and basal area were considered. Also, 30 profiles from viewpoint of growth situations in 10 different regions were dug. Soil characteristics such as : pH, Ec, total soluble Ca2+ and Mg2+, Cl-, CO3--, HCO3-, SP%, CaCO3%, CaSO4%, organic matter%, total nitrogen percentage, phosphorous, Na+, K+, SAR, and hardpan depth were measured. Data was analyzed using ordination method. According to the results, samples of the same age showed significant differences in plant features. Other results showed that physical characteristics such as depth of hardpan from soil surface, SP%, and chemical characteristics such as salinity, alkalinity and total nitrogen had the highest effect on qualities of this kind of plant. In other words, the results mentioned above showed the important role of Haloxylon ammodendron (C.A. Mey) in sharp increase of salinity and alkanity in it's stratum.
A. H. Gharehsheikhloo, M. R. Vahabi, H. R. Karimzadeh ,
Volume 14, Issue 53 (10-2010)
Abstract
The purpose of this study was to compare the physical and chemical characteristics of soils covered with vegetation and soils without vegetation in Dagh-e- Sorkh Ardestan area.To achieve the goal, first the vegetation was classified using physiognomic method, and for each vegetation type, the distinctive area was specified for soil and vegetation sampling. Vegetation sampling was done by stratified random sampling. Alongside pursuing the case, twenty two soil physical and chemical factors were investigated also for each growth type and area without vegetation. In the next step, to investigate the similarities and dissimilarities of the soils of desert areas by means of PC-ORD software, the cluster analysis was performe. After simplifying the one-way ANOVA, the most important soil factors which were effective in causing differences in the area’s soils were identified. Results show that the soils of area covered with vegetation differed much from the soils without vegetation physically in such a way that, the soil texture became heavier and gravel percentage became less in the areas without vegetation. Regarding the chemical characteristics, the frequencies of sodium, magnesium, calcium and chlorines and electrical conductivity were highly different. Because of topographic condition of land without vegetation, runoff is directed to this place and deposits salts there. Also, high groundwater level and capillary flowing salts are the important reasons for the salinity of this place. These are the limiting factors for the vegetation establishment in the desert areas of Ardestan.
H. Shirani , E. Rizahbandi, H. Dashti, M.r. Mosaddeghi, M. Afyuni,
Volume 15, Issue 55 (4-2011)
Abstract
Organic matters are the most important factors that affect soil compactability and physical characteristics. In order to study the effect of pistachio waste on physical characteristics of two soils, a factorial experiment was conducted in a completely randomized design with three replications in a greenhouse. The treatments included pistachio waste at 4 levels (0, 3, 6 and 9 w/w %) and two types of soil texture (silty clay loam and sand).The results showed that the bulk density of sandy soil was decreased at high levels of waste application before compaction but had no significant effect on the bulk density of clay soil. The penetration resistance of both soil types was decreased by pistachio waste application. Soil water holding capacity increased and moisture curves shifted up for higher levels of organic matter application, while compaction curve reciprocally shifted into the lower levels by incorporation of wastes into the soils. At higher levels of organic matters, maximum bulk density was decreased and critical moisture was increased specially in fine texture soil. After compaction, the application of pistachio waste significantly reduced penetration resistance in silty clay loam soil relative to control but in sandy soil its effect on penetration resistance was only significant at maximum level (9 %).
A. Khanamani, H. Karimzadeh, R. Jafari,
Volume 17, Issue 63 (6-2013)
Abstract
Soil characteristics are the most powerful factors in desertification phenomenon. The purpose of this study was investigating soil characteristics as indices for evaluating desertification intensity. The most important indicators of the soil that affect desertification were selected in the present study. Soil samples were taken from Segzi desert vicinity located in the east of Isfahan city with surface area of 112,167 ha. Soil indices such as Soil texture, soil gypsum percentage, the content of HCO3-1, electrical conductivity (EC), pH, the percentage of the organic matter, the content of the soil sodium, chloral and sodium absorption ratio (SAR) were selected. All of these indices were calculated on the thirty four soil samples. After ensuring of the normality of the samples by Klomogrov-Smirnov test, the mentioned indices were imported into GIS for delineating soil characteristics maps. To delineate distribution maps of each soil indice, inverse distance weighting and ordinary and discrete Kriging methods were applied, and appropriate method was selected. Each layer was scored based on MEDALUS model, and the final characteristic maps were then generated using soil geometric mean indices. Results showed that the affected areas of the average, severe and very severe classes of desertification were calculated about 66000, 45650 and 517 ha, respectively. The results also revealed that the indices of the organic matter, soil gypsum percentage, electrical conductivity and SAR were the most influential indicators, which affected desertification in the study area.
A. Hosseinpur, M.h. Salehi, F. Khaefi,
Volume 20, Issue 77 (11-2016)
Abstract
Potassium (K) fixation in soil is an important process which affects the availability of K to plants. There is limited information on K fixation capacity (PFC) of soils in Chahar Mahal & Bakhtiary province. This study was carried out with the aim of determining PFC and its relation with soil characteristics in 10 samples of surface soils in Chahar Mahal & Bakhtiary province. PFC was determined by adding six different levels of K by using KCl salt and measuring cation exchange capacity (CEC) in mineral, organic and clay fraction of soils. The results showed that the CEC in the mineral, organic and clay soils changes from 16.02-19.38, 1.71-3.27 to 29.3-39.8 cmol+/kg consequently. Potassium availability index (PAI) in the soils changes from 0.36 to 0.7 and Potassium fixation index (PFI) changes from 0.29 to 0.63. According to the results PFI and PAI showed significant correlation with whole and mineral fraction of the soil CEC, clay percent, pH and CaCO3 percent. The results of this study also showed that fixation of K fertilizer in the studied soils plays an important role in K dynamic of soil and K availability to plants.
S. A. M. Mirmohammady Maibody, S. Dybaie, H. Shariatmadari, N. Baghestani,
Volume 21, Issue 2 (8-2017)
Abstract
The adaptability of Haloxylon appilium to adverse environmental conditions and especially its capability for an appropriate establishment in saline and desert soils has introduced this plant as a suitable means for biological methods to stabilize sand dunes, control erosion and prevent desertification in arid regions. In order to evaluate the ecophysiological characteristics of Haloxylon appilium some characteristics of soils under the long term establishment, survival and development of this plant and ion composition of this plant growing in Yazd province in thirty two growing trees of similar ages and traits within 8 locations of Chah Afzal and Ashkezar were investigated and their height (H), crown diameter (CD) and the above ground biomass index (Yi) were measured. Also, after cutting the trees from their collars, soil profiles were dug underneath the tree locations and soil samples were taken at depths of 0-30, 30-60, 60-90 and 90-120cm from four sides of each profile. The samples were then analyzed for Electrical Conductivity (EC), pH and Cl, Na, Ca, Mg, K concentrations in 1:5 soil to water extracts. The results showed statistically significant differences in soil parameters between the two regions, except for pH and Mg concentrations. The ion concentration of the plants in the two regions showed statistically significant differences for only Cl in shoots and Ca in roots. Based on the plant growth indices the Chah Afzal and Eshkezar regions were respectively evaluated as suitable and unsuitable for Haloxylon appilium growth. In spite of a higher salinity, the higher Ca and K concentration and lower Na/K ratio of Chah Afzal soils may explain the better plant performance in this region against Eshkezar, however, comprehensive researches on application of Ca and K fertilizer are needed to confirm this hypothesis
B. Farid Giglou, R. Ghazavi,
Volume 22, Issue 3 (11-2018)
Abstract
In this research, a regression model was introduced to study the mechanisms of the formation of gullies in the Quri Chay watershed, northern Ardebil province (Moghan Plain); this was done through investigating the effective factors of geo-environment and soil characteristics on the gully erosion. For this purpose, 17 gullies were randomly assigned through field surveys. Mapping and recording the morphometric of the selected gullies were performed by GPS positioning after seven rainfall events. The catchment-upper area of each gully was determined and its related physical parameters were calculated in order to investigate the effect of the physical characteristics of the catchment. Soil sampling was also done at the head of each gully at two different depths (30-30 and 60-30 cm) in order to determine the physical and chemical characteristics of the soil. According to measurement of the morphometric characteristics of the gully and soil characteristics through multivariate analysis of the data, a suitable regression model was developed for the longitudinal development of erosion after determining and calculating environmental factors related to the upper catchment of the gullies. The results of the correlation matrix between the longitudinal extension of the gully and the factors investigated indicated that the factors related to the physical characteristics of the beside watershed (area, perimeter, main stream length and average width of the catchment, main stream slope), gully morphometric characteristics (mean of gully cross section, the gully expansion area, and the gully average width) and soil characteristics (geometric mean of the aggregates diameter, lime, organic matter percentage) affected the formation and expansion of gully erosion in the Quri chay catchment. The results of regression analysis showed that the longitudinal expansion of the gully was mostly influenced by the area around each gully and the percentage of organic matter, which resulted in pressure on the rangeland and the loss of vegetation, which increased runoff and accelerated the lengthwise expansion of the gully. Also, the increase in the area of the beside catchment the gullies is known as one of the factors influencing the length of the gully, due to the high volume of runoff entering the head cut section; so it is necessary to manage runoff in the gully with the large beside catchment.
