نشریه مدیریت خاک و تولید پایدار
سال چهارم شماره 3 (پیاپی 9، پاییز 1393)

This study was conducted to investigate the type and origin of clay minerals via several profiles in Lordegan hilly lands. The profiles were located in two kinds of land uses including forest and dry farm at different slope positions as sampling sites. The soil saples were collected from two depths of soil horizons to indicate CEC, soil texture, OC%, calcium carbonate equivalent, X-ray diffraction and micro-morphological study via undistributed soil sampling. The results illustrated that the dominating clay minerals are Illite، Smectite, Chlorite and Chlorite-Smectite as mixed minerals. According to the result, the origin of minerals in both land uses and different slope positions is inheritance from parent material. These minerals are mostly apparent in lower positions of the slope especially rain feed. Thin sections investigation of some horizons in the both land use in different slope positions showed that there was no difference regarding the kind of soil voids and C/F ratio between two sampling sites. (including land use and slope positions). Complex packing voids, Vugh and planar voids were the most dominant voids of these profiles. The observed b-fabric in all horizons was crystallitic and soil structure in back slop was subangular blocky. In all horizons of rain feed land use except for shoulder and back slop, clay films and calcite coatings were observed.

An option for improving soil physical, chemical and biological properties and carbon sequestration is by increasing organic carbon (OC) input through recycling of crop residues and organic manures. The objective of this study was to determine the degradation of some plant residues and the influence of application of plant residue on different chemical and biological forms of OC in soil. The sampled soil from the top 30-cm layer of an agricultural land treated with mild alfalfa, wheat and sawdust residues, at a rate of 20 g kg-1 (dry weight basis) and incubated in field capacity and lab temperature conditions. After 1, 20, 60 and 120 days of incubation a portion of each soil were taken for analysis. The experiment was considered a completely randomized design as factorial in three replicates. The factors were residues type and the passing time of incubation. Biomass C increased in all treatments significantly. Plant residue application increased cold water and hot water extractable OC significantly. They were relatively lower in sawdust treatment compared to alfalfa and wheat treatments in 1st day of soil incubation. Both of fulvic acid and humic acid in soil increased in plant residue treatments compared to those in control. However this increase was greater for humic acid especially in late stages of soil incubation. The study of changes of different chemical and biological fractions of OC during soil incubation and their correlations revealed that microbial secreted C and biomass C had coherence with cold water and hot water extractable OC.

Phosphate solubilizing bacteria are a group of plant growth promoting rhizobacteria (PGPR) that increase growth and yield of plant by enhancing insoluble phosphates. In this study, a greenhouse experiment was carried out to investigate the effect of Phosphate solubilizing bacteria and phosphorous fertilizer on the yield and chemical components of Sesame. This experiment was conducted in factorial based on completely randomized design with three replications including five Levels of phosphorous fertilizer (0, 100, 200 and 400 kg/Ha of triple superphosphate and 1200 kg/Ha of phosphate rock) and three bacterial levels (inoculation with two Phosphate solubilizing Fluorescent Pseudomonad, B1 and B2 and non-inoculated). Results showed that inoculation of Sesame with B1 and B2 isolates significantly increased the dry weight, Index, chlorophyll and uptake of P, Fe, Zn, Cu and Mn in comparison to the control. Also fertilizer application significantly increased dry weight, Index of chlorophyll, P uptake and some of nutrient elements. Results was also indicated that application of 100 kg/ha triple superphosphate along with the B2 isolate were significantly increased nutrient uptake parameters in the sesame plant. Hence it may decrease phosphorus fertilizer consumption and subsequently the pollution due to the high levels of fertilizer application.

Micromorphology is the branch of soil science that is concerned with the description, interpretation and, to an increasing extent, the measurement of components, features and fabrics in soils at microscopic level. The advantage of micromorphology is that, in micromorphological studies the soils are studied in their natural and undisturbed form and so, one can follow the processes that take place in a low rate. In this research, in order to study the micromorphic properties of saline-sodic soils in the west of Urmia Lake, four soil profiles were studied. The profiles were described and classified using standard methods. Disturbed soil samples were used for physic-chemical analysis and thin sections were prepared from undisturbed and oriented samples and were studied using polarizing microscope. According to the results, the most of studied soils were apedal and their voids were mainly vughs and channels. These soils were vughy, channel and massive microstructure and their b-fabric were mainly crystallitic. The micromorphic pedofeatures in these soils were illuvial clay coatings, accumulations salts as discontinues coatings of cubic and suhedral halite crystals on voids and aggregates, continues halite coatings and halite infillings in vughs and channels, calcium carbonate accumulations as typic nodules, infillings and coatings, redoximorphic accumulations as nodules in the groundmass and coatings on voids and skeletal grains, and finally, organic coatings as black films on peds and in some cases mixed with groundmass of the soil.

Mycorrhizal status of pistachio seedling in Kerman province in regard to region and some soil properties and also symbiotic potential of Sorghum, clover and onion isolates with pistachio seedling were evaluated in this research. 72 samples of pistachio nurseries and 67 samples of Sorghum, clover and onion farms were gathered from Kerman province and mycorrhizal colonization percent of their roots were determined after clearing with KOH and staining with Tryphan blue. All soil samples were analyzed for EC and pH and then for soil texture of samples with different colonization percent. The result showed that all of samples had mycorrhizal symbiosis and the colonization percent was varied from minimum 33 to maximum 97 percent. The colonization percent of Kerman, Mahan and Bardsir samples was related mainly to 75-100% range, but 25-50% for Zarand samples. Based on regression test, there was a significant relation between soil texture and pH (α=5%) and also EC (α=5%) with colonization percent. The colonization percent were decreased significantly in soil salinity more than 4 dS/m. Inoculation of pistachio seedling with 20 mycorrhizal isolates of pistachio, sorghum, onion and clover plants via a greenhouse experiment showed that all isolates had colonization potential of pistachio roots after 60 days and colonization percent was varied from minimum 63 to maximum 88 percent. Inoculation of Pistachio seedlings with selected isolates had significant effect on most vegetative index of seedlings in compare to control treatment.

Soil erosion models are useful tools to predict runoff, sediment and soil erosion in watersheds. Although, the SWAT model is used for evaluating runoff discharge and the long-term effects of management operation on water, sediment and agricultural chemical yields in the large watersheds, in this research, its efficiency was investigated in monthly runoff simulation for Tuyserkan watershed (with an area of about 3800 ha) and also the effect of soil map scale on the simulation results was studied. In order to study the effect of soil map scale, SWAT model was run with three different map scales (1:40000, 1:250000 and 1:1000000), in which all input models (such as land use map, digital elevation map, number of simulations and effective primary parameters in simulation results) were same, except soil map scale. The SWAT model calibration and uncertainty analysis for each scale in a period of 1998 to 2008 were taken using SUFI-2 program. The values of statistical indices (R2, Nash-Sutcliffe coefficient, p-factor and r-factor) for each of the three map scales were virtually the same. It seems that the key factor in determining the impact of soil map scale on the SWAT results, is not scale number of the studied map, but soils diversity plays an important role on the results of the model.

Biological methods based on using soil beneficial microorganisms’ potentials for creating symbiosis relationship with plants by modifying genetic structure of plants resulting in improving nutritional status and crops quality. This study was conducted in order to investigate the effect of Piriformospora indica inoculation on root colonization and uptake and transportation of phosphorus, zinc and iron by two wheat cultivars (Nicknejad and Azadi) in sterile sand-perlite (2:1 v/v) pot medium. The greenhouse experiment was conducted as a factorial, completely randomized design with three replications. Inoculation of P. indica increased chlorophyll a, b and total chlorophyll concentrations of Nicknejad cultivar, however had no significant effect on the mentioned index in Azadi cultivar. P. indica inoculation resulted in increase and decrease of iron concentration in shoot and root parts of Nicknejad cultivar, respectively. Despite of no significant effect of P. indica on root zinc concentration of Nicknejad cultivar, this fungus played an important role in increasing zinc concentration in the shoot of this cultivar. P. indica resulted in increase of zinc concentration in the root of Azadi cultivar but, had no significant effect on shoot zinc concentration. Phosphorus concentration in shoot and root of Nicknejad cultivar inoculated with P. indica, increased. Inoculation of P. indica resulted in increase of phosphorus concentration in shoot of Azadi cultivar but, had no significant effect on phosphorus concentration of root. In general, Nicknejad cultivar is proposed as a high compatible cultivar with the P. indica in order to enhancing nutrient uptake and thus improving yield quality.

This research was conducted on polluted soil near the lead and zinc factory in Zanjan province through which the effects of two organic and three mineral sources were examined on heavy metals fixation in randomized experiment design. Experimental treatments includes bagasse and rice husk in three levels: 1.25, 2.5 and 5%, zeolite in three levels: 5%, 10% and 15%, phosphate rock in three rates: 1%, 3% and 5%, triple superphosphate in three ratios: 0.0075, 0.015 and 0.3% accompanied with control treatment. The incubation period was performed in filed capacity moisture. After the incubation period the heavy metals concentration in soil were measured and the radish was planted. After harvesting the shoot the concentration of lead, zinc, iron and manganese in the shoot of radish were measured. The results of data Analysis of Variance showed that treatments had significant effect on reduction of iron, manganese and lead concentration in soil (extractable by nitric acid) and radish shoot. The most effective treatment on reduction of soil iron concentration was in the second level of rice husk. In manganese and lead concentration reduction was the third level of zeolite. The least concentration in radish shoot was observed in third level of bagasse treatment (460.7mg/kg), Manganese in third level of zeolite treatment (370mg/kg) and lead (14.43 mg kg⁻¹) in third level of rice husk. According to the organic and zeolite treatment on heavy metal fixation in soil and reduction of plant uptake this treatment can be used to amend the lead polluted soil.

The phosphate solubilization capability of actinomycetes has recently attracted interest but the mechanism and medium composition effect involved in this process was not clarified. Seven actinomycete isolates were characterized and their phosphate solubilizing activity, phytate degradation, siderophores, indole acetic acid (IAA) and hydrogen cyanide (HCN) production were investigated. Additionally, all isolates were evaluated as plant growth promoters to maize in pot experiment. Our results showed that the selected isolates were able to solubilize tri-calcium phosphate (TCP) only when synthetic minimum medium (SMM-agar) was supplemented with ammonium nitrate. Similarly, TCP solubilizing activity in liquid cultures was also observed (from 11 to 216 μgml-1) when medium was supplemented with ammonium nitrate and this behavior was strongly associated with a pH reduction. Phytate degradation (1.7-95%), indole acetic acid production (6.26 to 27.81 μg ml-1) and siderophore production (1.24 to 2.45 Halo to clony ratio) was observed in all strains, but no isolates produced HCN. Significant increase in maize shoot height, fresh weight, dry weight and P uptake (P<0.05) was observed in inoculated plants compared to uninoculated control. Streptomyces sp. 47 showed the best plant growth promotion performance while plants inoculated with Streptomyces sp. 50 showed a remarkably higher P uptake. Both strains were considered as suitable potential inoculants for increasing early maize growth and P uptake.

Plants are the most sources for cadmium enters to human food and this element in food regime may be a serious threat to human health. Thus, the effect of Azotobacter inoculum (Azotobacter chroococcum), mycorrhiza fungi (Glomus intraradaices), zinc sulphate and urea on cadmium Convertation and growth parameters of fenugreek medicinal plant (Trigonella foenum gracum L.) in cadmium polluted soils were evaluated. This experiment conducted in randomized complete block design with three replications at the research greenhouse of Shahrekord University. Eight fertilizer treatments included control (without fertilizer), urea, urea+ zinc sulfate, urea+ Azotobacter, urea+ mycorrhiza, urea + zinc sulfate + Azotobacter, urea + zinc sulfate + mycorrhiza, urea + zinc sulfate + mycorrhiza + Azotobacter. The results indicated that the highest of plant height, leaf fresh weight and shoot fresh weight of the aboveground of fenugreek were obtained in urea+ Azotobacter but it didn’t have a significant difference with that of the urea + zinc sulfate + mycorrhiza. Also, the lowest cadmium concentration (0.09 mg/kg) was produced in urea+ Azotobacter and urea + zinc sulfate + mycorrhiza (P≤0.05). Appliction two biofertilizers sources plus zinc sulfate in compared to chemical fertilizer treatments had appropriate vegetative growth and fairly cadmium concentration. In conclusion, Azotobacter application for fenugreek production in addition to increase yield and can be effective in preventing of cadmium transmission in the human food regime as well as.

Demand for water resources in different parts of the world, necessitate the use of wastewater. In using wastewater the soil health must be considered. This study was carried out at Green Space Zob Ahan in the years 1382 to 1385. In this study, the effects of urban and industrial wastewater irrigation on some chemical properties of soil for three years by using five different irrigation treatments were examined. The treatments were as follows: surface irrigation (FI), surface drip irrigation (SDI), subsurface drip irrigation in 30 cm depth (SDI30), Sub surface drip irrigation in 60 cm depth (SDI60) and irrigation procedures babbler (BI). At the end of the experiments, solid samples were taken of the soil of zero to 30, 30 to 60 and 60 to 90 cm depth in order to measure the heavy metal. Lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn) and manganese (Mn) were measured by using atomic absorption in soil samples. Results showed that the density of heavy metals in urban and industrial wastewater is in an allowable range and heavy elements of soil are not limiting factor. And also concentration of heavy metals was higher in the zone of wastewater injection and as whole treatments SDI60 and BI respectively had the highest and least amounts of heavy metals.

Growth of B. japonicum isolates at different concentrations of herbicide used on soybean was studied as factorial experiment arranged in a completely randomized design with three replications. Isolates B1, B6, B43 and 0, 0.125, 0.25, 0.5, 1, 2, 4, 8 and 16 folded of the recommended doses of trifluralin, metribuzin and imazethapyr herbicides were considered as factors. Isolates population trends over time and colony forming unit (CFU) data at different herbicide concentrations were fitted using the Gompertz and four parameters logistic models, respectively. Results showed that Max. B1, B6 and B43 isolates population grown in YMB at 28 C were 4.77 × 109, 4.54 × 109 and 4.43 × 109 cell/ml, respectively. In addition to, isolates population doubled during 10.76, 11.55 and 12.51 hours and reached to their mid log phase in 26.14, 25.72 and 27.20 hours after incubation at 28 C. Using four parameters dose - response logistic models revealed metribuzin> trifluralin > and imazethapyr herbicides order affecting on B. japonicum population isolates. Mean estimated EC50 values for metribuzin, trifluralin and imazethapyr herbicides were 13, 7 and 4 mg. L-1 which were 6 to 10 times more than herbicides recommended doses.

To evaluate the effect of application of municipal solid waste compost (MSWC) on the accumulation of heavy metals of lead, nickel and cadmium in the soil under maize cultivation, a factorial experiment in base randomized complete block design (RCBD) with four different amounts of municipal solid waste compost (zero, 15, 30 and 60 tons ha-1) and time (compost applied once or twice) was performed with three replications. The results showed that (MSWC) significantly increased total and DTPA extractable lead and nickel in soil in all treatments (P≤0.01), so that the concentrations of total and DTPA extractable lead in the treatment of 60 tons ha-1 was increased 1.38 and 1.89 times in compared to control. These increasing for nickel were obtained 1.27 and 4.21 times respectively. In all treatments the amount of cadmium was less than atomic absorption detection limit. The effects of (MSWC) apply replication times on accumulation of total lead and nickel in soil also was significant (P≤0.01), so that as compared with control for total Ni 4.4 and total Pb 2.7 percent was increased. In relevance with the accumulation of metals in maize, the results indicated that root uptake higher concentrations of these metals than shoots. This accumulation for nickel was more than lead (P≤0.01).So that concentration of lead and nickel root was increased 1.9 and 2.9 times in 60 tons ha-1 second year treatment in compared to control. Transfer factor was obtained 0.302 for Pb and 0.284 for Ni.

Sorption reactions in many heterogeneous systems are important. Adsorption is a time dependent process and knowing the adsorption rate is essential for designing, evaluating and recovering the adsorbents. At the present study, an ammonium adsorption kinetic experiment by some soils series of Golestan provice, which is varying in mineralogical and textural properties was conducted using solution containing 100 mg/l of ammonium chloride at the times of 0.25 to 384 h. Kinetic models were used to fit the experimental data, namely, zero-order, first-order, pseudo-second-order, simplified Elovich, parabolic diffusion and power function models. The results of adsorption kinetic study showed that ammonium is adsorbed fast within the first hours, but with elapsing the time, it will be slow. The most ammonium adsorption was in Karasou soil and the lowest one was observed in the Houttan soil 2. According to coefficients of determination (r2) and standard errors of estimate (SE) for equations, the rates of ammonium adsorption in all soils were described well by the pseudo second order, power function and simplified Elovich equations. The constant of speed rate of second-order equation (kg mg−1 h−1) for soils varied from 0.0063 (Kordkoy 2) to 0.0374 (Houttan 2) with an avg. of 0.0179. Ammonium uptake data plotted on a linear parabolic diffusion equation showed a discontinuity in slope at 8 hr. This could indicate the presence of two different mechanisms or different adsorption sites with different rate constants which are controlled adsorption process.

The location of extracellular enzymes with the soil architecture and their association with the various soil components affects their catalytic potential. Amidohydrolases including L-glutaminase, L-asparaginase, Urease, Amidase and L-aspartase play important roles in mineralization of nitrogen. This study was conducted to: investigate aggregate distribution of L-glutaminase, L-asparaginase and Urease in different ecosystems including Gisum forest, Delvara forest. A wet sieving procedure was used to separate soil aggregate into classes of >2, 1-2, 0.5-1, 0.25-0.5 and 0.1-0.25; Soil amidohydrolases which are thought to be of different origins were measured in the separated aggregates as well as soil organic C (SOC). Results indicated that in the Gisum forest, pine standing has resulted in increasing SOC content. Moreover, the activity of L-glutaminas and Urease were similar in the both standings, but the activity of L-asparaginase was greater in the maple standing compared to the pine standing. The enzyme activities enhanced as the aggregate size increased in both pine and maple standings. In the Delvara oak forest, the enzyme activities showed to be highly sensitive to management practices, while enzyme activities and organic carbon decreased significantly as cultivation practiced in the Delvara ecosystem. This study showed that soil management practices, including tillage would enhance the mass fraction of either small macroaggregate or microaggregates and therefore would significantly affect soil biological and biochemical properties, which may lead to changes in nitrogen cycling, including N mineralization in soil aggregates.

In this research, the spatial distribution of Fe, Cu, Zn and Mn on agricultural lands of Golestan province were evaluated using different interpolation methods such as, Kriging, Inverse Distance Weighted, Local Polynomial, Inverse Multiquadric and Radial Basis Function. Thus, 505 soil samples were provided from fields during 2008 and micronutrients rates were measured for each sample. The performance criteria for evaluation the used method were Mean Absolute Error (MAE), Mean Bias Error (MBE) and Root Mean Square Error with the Cross Validation method. The results showed that Inverse Multiquadric and Kriging (Exponential and Spherical models) were the best methods to estimate Fe and Mn. Kriging and Local Polynomial were also found as the most suitable and unsuitable methods for estimating Cu, respectively. Inverse Distance Weighted method with power one, had the highest precision (MAE=0.304 and MBE=0.002) for estimation of Zinc rate in this area. Semivariograms nalysis indicated that Mn and Cu were best fitted to a spherical model.

In order to study the effect of low-molecular-weight organic acids (LMO) on phosphate rocks solubility for direct use in agricultural activities, a factorial experiment was conducted at completely randomized design in three replication. LMO acids were acetic, salicylic, malic, oxalic and citric at five concentration levels (0.5, 1, 2, 5 and 10 mM) and a control (no acid), on two phosphate rocks (RP) including igneous of Yazd (RPi) and sedimentary of Yasooj (RPs). Results showed that use of low-molecular-weight organic acids caused to release large amounts of phosphorus from both phosphate rocks. Among organic acids, citric and oxalic were more effective than others. Citric acid increased soluble P from 21 to 487 μg/L in RPi and oxalic acid increased soluble P from 36 to 400 μg/L in RPs. With increasing concentration of organic acids from 0 to 10 mM, soluble P increased significantly in both phosphate rock. Soluble P increased from 21 to 888 μg/L in RPi and from 36 to 546 μg/L RPs. The sufficiency level of soluble P for most plants (200 μg/L) was found in the 0.5 and 5 mM of LMO acids for RPi and RPs, respectively. It is concluded that the release of phosphate from RP was affected by types and concentrations of organic acids and composition of RP.