نشریه تحقیقات کاربردی خاک
سال یکم شماره 2 (زمستان 1392)

Predicting vulnerable areas to gullying, focus on conservation tasks and prevent loss of resources is very important. The study area is located in the Reyhanlou region of Chaldoran city in the northern of West Azerbaijan province. In this research 20 active gullies were selected in Reihanlu area in 2011. Boundaries of the gullies and gullies head drainage-basins were delimited with using aerial photographs (1:40000), topographic maps (1:25000) and global positioning system (GPS). Some gully properties include mean slope of gullies head drainage-basins (S, %) and gullies head drainage-basins areas (A, m2) at the point of gullies initiation were determined by Arc-GIS software with using topographic maps. The statistical analysis such as clustering classification based on gullies topographic characteristics were done by SPSS 16 software. The cluster analyses were classified gullies into three groups. The classified gullies are very similar terms of topographical characteristics including altitude, area, slope percent, slope aspect and processes involved in the development of the gully heads. The investigation of the morphological properties of gullies in the study area showed that the areas of gullies head drainage-basins are variable (2300 m2 - 109300 m2). The mean slope of gullies head drainage-basins was %25.6 (slope was between %6.5 to %43.1). The relationship between the slope (S, %) and area (A, m2) was evaluated and the exponential equation (S=3.81A0.18) to was obtained (R2=0.16). The positive sign of exponent (b) in the (S=aAb) equation also indicate that sub surface runoff is dominant on gully development. Application of S-A relation showed that it is possible to predict the location of gullies. Due to the correlation coefficient was low (R2=0.16), so can be concluded that the topographical threshold condition is not the only factor to develop the gully erosion and to determination of topographical threshold conditions for gully erosion, other factors, such as soil properties, vegetative cover should also be considered.

Soil saturated hydraulic conductivity (Ks) is an essential property in managing irrigation projects, water and solute transport modeling and for predicting unsaturated hydraulic conductivity functions. Laboratory and field measurements of Ks are time-consuming and costly especially in the large scales. Moreover, Ks is affected by different factors and thus its predicting and modeling by derived pedotrasfer functions (PTFs) or those in the literature can be useful for many purposes. This study was performedto evaluate the already existed in literature and derived PTFs for predicting Ks in Farsan and Koohrang regions, Chaharmahal-va-Bakhtiari province in the central Zagros. Undisturbed samples (volume of 100 cm3) were collected from the surface soil at 100 locations which were well distributed in the region and in different land uses. The Ks of the undisturbed samples was measured using the constant-head method in laboratory. Easily-available soil properties were also determined and PTFs for Ks prediction were derived by multiple stepwise regression. The measured Ks values were also compared with the predictions of several PTFs in the literature. Results showed that PTFs in the literature could not accurately predict the Ks in the region. Among the literature PTFs, powerful neural network model of Rosetta (SCC) was the best. The worse PTFs for Ks prediction in the studied structured soils were Brakensiek et al. (1984) PTFs. However, the derived PTFs predicted the Ks in the region better (R2=52%, RMSE=0.5 mm/h) than the literature PTFs. The findings revealed that logarithm of Ks negatively correlates with relative bulk density (relative compaction), effective bulk density, clay to carbonate content (Clay/CaCO3) and carbonate to organic matter content (CaCO3/OM) ratios and bulk density and clay interaction [ln (BD×Clay)] and has positive correlations with OM, ln(OM/Clay), very fine sand content and soil porosity. The studied soils had good structure and the structural properties had significant role in the derived PTFs. Therefore, it is suggested to include additional structural properties such as aggregate's mean diameter as a predictor for better Ks prediction in future.

Increasing carbon sequestration in soil is an efficient method to decrease concentration of atmospheric CO2 and has a considerable role in reduction of problems caused by climate change and air pollution which recently has been considered as an attractive issue for many of the researchers. In this study, capacity of carbon sequestration and it's relation with soil physical and chemical characteristics in three different sites of Khoy rangelands was investigated. In this regard, soil samples were collected from depths of 0-15 and 15-30 centimeters. The results showed that total organic carbon concentration in sites of one and two and in third site were respectively equal to 26.89, 24.66 and 18.15 tons per hectare, and the highest amount of accumulated carbon was related to first site. In all of the studied sites, highest amounts of soil organic carbon were related to depth of 15-30centimeters samples. The results obtained from stepwise regression analysis indicated that percent of nitrogen concentration, bulk density and lime content of soil were respectively the most effective factors on organic carbon content of the soil in investigated sites. Generally optimal management of rangeland ecosystems has an important role in improvement of atmospheric carbon sequestration capacity.

The plants in symbiosis with Arbuscular Mycorrhizal Fungi (AMF) can absorb more nutrients and water which increases their resistant’s against environmental stresses such as drought or salinity. It is perceived that the presence of Plant Growth Promoting Rihzobacteria (PGPR) especially Pseudomonas in the rhizosphere of these plants has probably synergistic effect with mycorrhizal fungi. This experiment was performed to study the effect of single and dual inoculation of Pseudomonas fluorescens and Glomus intraradices on nutrient uptake in tomato variety Super strain B under salinity stress. A factorial experiment based on completely randomized block design with application of Glomus intraradices (including 2 levels; with inoculation () and without inoculation (-AM)), Pseudomonas fluorescens (including 3 levels; P. fluorescens strain Tabriz P. fluorescens strain Chao and without bacterial inoculation (control)) and four levels of salinity (S1:1.56, S2: 3 S3: 6 and S4: 9 dS m-1) was done in a pot culture with 3 replications. Mixed of different salts such as NaCl, CaCl2, MgSO4 and Na2SO4 were used to make salinity levels. Salinity treatments were daily exerted after two weeks of seedling and continued for 45 days. S1 (1.56 dS m-1) EC of the nutrient solution in distilled water was used as medium. Statistical analysis showed that concentration of nutrients such as phosphorus of shoot, potassium, calcium and magnesium of root and also root Ca/Na, root and shoot K/Na in PFT was higher than PFC and control treatment significantly (P

Zeolite is one the natural minerals that has nutrition value. Providing novel compounds and formulations accordance with the sustainable/organic agriculture is one the major needs in today’s societies. In order to evaluate the effects of different levels of enriched zeolite (with organic matters and several nutrients) on dry matter yield, yield components, and nutrient uptake in two maize varieties Single Cross (SC) (704 and 260), an factorial experiment was carried out with the basis of completely randomized design with three replications and four treatments in the pots at the research greenhouse of Agronomy and Plant Breeding Department, University of Tehran, Karaj. In this experiment, enriched zeolite with nitrogen, phosphorous, potassium, and organic matter was used in four levels including 0 (control), 5, 10, and 15 percent by weight before planting. After 70 days from planting i.e. finishing vegetative stage, dry matter of root and shoot were measured as well as some other yield components including fresh weights of root and shoot, plant height, chlorophyll (SPAD), leaf area, uptake of macronutrients amounts of phosphorous and potassium, micronutrients uptake of copper and zinc. The results showed that the effect of enriched zeolite on all measured indices were significant at 1% level. Cultivar effects on other indices were significant at 1% level (p

Nowadays, the need for sustainable resources management has led to introducing new methods for classification of managed resources. The importance of plant species diversity and its management and considering to the new methods for determining management units encouraged to initiate this research. In this study, the relationship between environmental factors and plant diversity was investigated. Therefore, six key areas were selected within four landscape units. Then, in each area, soil and vegetation sampling were done along 6 100m transects. Along each transect, 10 1×1m plots were established with a distance of 10 m between the two plots. In each plot, plant species were listed and the soil samples were then collected from some of plots located in the beginning, intermediate and the end of transects from two depth i.e. 0-15 and 15-30cm. Twenty-one environmental factors were measured as well as Simpson and Shanon diversity indices. The results of Principle Component Analysis showed that soil texture, saturated humidity, particulate organic matter (carbon), carbon of macroaggregate-associated, EC, bulk density, percentage of maco-and microaggregate and, slope and elevation had the highest impact on plant diversity. In addition, the correlation results showed that sand percentage in deeper layer of soil had negative correlation and other studied factors had positive correlation with bio-environmental variations. According to our results, soil physico-chemical characteristics are enough good for ecological assessments.

To investigate the effect of lead on some physiological traits of maize (Zea mays L.) a factorial experiment in randomized completely design was carried out in the greenhouse. Treatments contained four levels Soil of Pb: [0 (control), 100, 200 400 mg/kg soil] and eight varieties of maize: (SC260, SC301, SC302, SC500, SC604, SC647, SC704 and DC370). The results showed the effect of Pb on shoot and root Pb concentrations, membrane stability index and leaf area were significant at the 1 % level. However, there was not any significant effect on leaf relative water content. The results showed that Pb concentration in the root was higher than shoot and the accumulation of lead in shoot and root increased significantly (P

Environmental risk of heavy metals is associated with the changes of their chemical forms and bioavailability in soil. Therefore, distribution of metals in chemical forms in soil need to be more studied. To investigate the effects of alfalfa green manure (2% w/w) and root activity on chemical forms of lead, zinc, copper and nickel in a lead-zinc contaminated soil, a greenhouse experiment was conducted using rhizobox systems in a split plot design, with 3 replications, two levels of green manure (0 and 2%) and 4 zone by distance from root. Sequential extraction procedure (Tessier) was also carried out to differentiate the chemical forms of heavy metals in the soil samples. Results showed that the green manure addition enhanced dissolved organic carbon concentration (DOC) and reduced pH of the soil. It also increased exchangeable, organic matter-bound fractions and bioavailability of the metals. The highest and lowest values of DOC were found in rhizosphere and bulk soil respectively. The pH value in the rhizosphere was 0.4 times lower than in the bulk soil. Oxide fraction of metals increased with distance from the root that maybe related to the change of oxide fraction to other forms. Addition of green manure to the soil increased oxide fraction and bioavailability of lead in the rhizosphere that maybe approve the change of oxide form to more bioavailable forms. The results of plant analysis showed that green manure addition reduced the concentration of lead, zinc and copper and also reduced the uptake of lead and copper in shoots of corn.

Soil is an important component of rangeland ecosystems and investigation on the effect of enclosure on soil properties can be useful in the proper management of rangeland. The aim of this study was to investigate the effects of enclosure on soil properties in Maraveh tapeh rangeland's in the Golestan province. Soil sampling was performed by systematic–randomize method and establishment of five transects in each enclosure and control site. Then, soil samples were taken randomly from three-points in two depths (0-20 and 20-40cm) of each transects. Finally in each site, five composite soil sample of each depth were obtained by mixing all soil samples of each transect. Then, some soil physical and chemical properties including pH, electrical conductivity, bulky density, soil moisture storage, soil saturation percentage, the percentage of soil organic matter, the percentage of lime, and soil texture were determined in laboratory. Data analysis was performed by independent T test. The results demonstrated that some of studied soil properties have changed significantly because of enclosure. So, the mean of soil moisture storage and the percentage of sand in soil texture have increased significantly and the mean of soil pH was decreased significantly in enclosure site as compared with control site. The results demonstrated that enclosure has had more effect on the first depth (0-20cm) as compared to the second depth (20-40cm).