Journal of Soil Management and Sustainable Production
Year:2014 | Volume:4 | Issue:3|Papers Count:17

Clearly, clay minerals with their particular characteristics are considered as soil active part. Without recognizing soil clay mineral, recommendation on plant nutrition, soil conservation. Soil mechanical properties would not be accurate. In addition to soil physical and chemical studies which lead to recognition of soils, soil micromorphology caused to better judge me soil condition. 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 samples were collected from two depths of soil horizons to determine 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. 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 rainfed 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 was sampledsoil from the top 30-cm layer of an agricultural land treated with mild (d<2 mm)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 120days 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. Microbial biomass carbon (MBC) increased in all treatments significantly. It increased to the highest values in soil treated with alfalfa (0.472 g kg-1) and wheat (0.372 g kg-1) straws in20th day of soil incubation. But it increased slowly and continuously in sawdustamended soil during incubation. The application of plant residue especially alfalfa and wheat straws in soil increased cold water (CW) and hot water (HW)extractable OC significantly. They were 1.75 and 7.15 g kg-1 in alfalfa straw treated soils and 1.13 and 4.40 g kg-1 in wheat straw treated soils respectively in 1st day of soil incubation. They were significantly higher than those in sawdust treated soil(1.07 and 2.92 g kg-1 soil). Although fulvic acid fraction increased significantly in soil treated with alfalfa and wheat straws in early stages of incubation, but thead dition of plant residues did not increase soil fulvic acid in late stages of soilincubation. The increase of humic acid was only significant in alfalfa treated soil. Itincreased the highest value in alfalfa treated soil (5.04 g kg-1) in 120th day of soilincubation. The study of changes of different chemical and biological fractions of OC during soil incubation and their correlations revealed that MBC had high dependence and coherence with fulvic acid, CW and HW 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 also indicated that application of 100 kg/ha triple superphosphate along with the B2 isolate 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 physico-chemical analysis and thin sections were prepared from undisturbed and oriented samples and were studied using polarizing microscope. According to the results, most of the studied soils were apedal and their voids were mainly vughs and channels. The microstructures of these soils were vughy, channel and massive and their b-fabric were mainly crystallitic. The micromorphic pedofeatures in these soils were illuvial clay coatings, accumulations salts as discontinuous coatings of cubic and suhedral halite crystals on voids and aggregates, continueous 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 (a=5%) and also EC (a=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 has resulted in improving nutritional status and crops quality. This study was conducted 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 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 enhance 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: 12.5, 25 and 50 g per kg of soil, zeolite in three levels: 50, 100 and 150 g per kg of soil, phosphate rock mine of asfordi in three rates: 10, 30 and 50 g per kg of soil, triple superphosphate in three ratios: 75, 150 and 300 g per kg of soil accompanied with control treatment. The incubation period was performed at 18-25 ºC and in field 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 (ANOVA) showed that treatments had significant effect on reduction of iron, manganese and lead concentration in soil (extractable by nitric acid) and radish shoot (P<0.01). The most effective treatment on reduction of soil iron concentration was in the second level of rice husk. The reduction in manganese and lead concentration was observed in the third level of zeolite. The lowest concentration in radish shoot was observed in third level of bagasse treatment (460.7 mg/kg), manganese in third level of zeolite treatment (370 mg/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 mgml-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 mg 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 in 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 concentration and growth parameters of fenugreek medicinal plant (Trigonella foenum gracum L.) in cadmium polluted soils were evaluated. This experiment was 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 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). Application of two biofertilizers sources plus zinc sulfate compared to chemical fertilizer treatments had appropriate vegetative growth and fairly cadmium concentration. In conclusion, Azotobacter application for fenugreek production in addition to increase in yield, can be effective in preventing cadmium transmission in human food regime.

Demand for water resources in different parts of the world, necessitates 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 2001 to 2004. 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 following: surface irrigation (FI), surface dripirrigation (SDI), subsurface drip irrigation in 30 cm depth (SDI30), Sub surface dripirrigation in 60 cm depth (SDI60) and Bubbler irrigation (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) weremeasured using atomic absorption in soil samples. Results showed that the concentration of heavy metals in urban and industrial wastewater is in an allowablerange and heavy elements of soil are not a limiting factor. And also concentration of heavy metals was higher in the zone of wastewater injection and as wholetreatments SDI60 and BI respectively had the highest and least amounts of heavy metals.

Growth of B. japonicum isolates at different concentrations of herbicide used insoybean 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, 8and 16 folded of the recommended doses of trifluralin, metribuzin and imazethapyrherbicides 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, isolatespopulation doubled during 10.76, 11.55 and 12.51 hours and reached to their midlog phase in 26.14, 25.72 and 27.20 hours after incubation at 28 C. Using fourparameters dose - response logistic models revealed metribuzin>trifluralin>andimazethapyr herbicides order affecting on B. japonicum population isolates. Meanestimated EC50 values for metribuzin, trifluralin and imazethapyr herbicides were13, 7 and 4 mg.L-1 which were 6 to 10 times more than herbicides recommended doses.

In this study effects of amounts and times of replication of municipal solid waste compost (MSWC) on the concentration of heavy metals Pb, Ni and Cd, in soil and maize plant (Zea mays L.) were evaluated. For this purpose an experiment was performed in a factorial randomized complete block design (RCBD) with two factors, different amounts of municipal solid waste compost (0, 15, 30 and 60 t ha-1) and number of replication times (one or two years) with three replications in Shahed university research farm. 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 t ha-1 compared to control 1.38 and 1.89 times was increased. These concentrations for nickel was 1.27 and 4.21 times, respectively. In all treatments amount of cadmium was less than those determined by atomic absorption. The number of application time of MSWC had significant effect on concentration of lead and nickel in soil (P≤0.01) so that treatments that received MSWC two consecutive years, accumulated more than those of one time. This increasing for total Ni and Pb was obtained 4.4 and 7.2 percentage respectively. The results from accumulation of heavy metals in maize indicated that root could uptake these metals more than shoots. This accumulation for nickel was more than lead (P≤0.01) So that concentration of lead and nicke in root in 60 t ha-1 second year treatment, compared to control, increased 1.9 and 2.9 times respectively. Transfer factor was 0.302 for Pb and 0.284 for Ni and this factor had a gradual variation for lead, but it was quite evident to nickel.

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 on some soils series of Golestan province, which are different in mineralogical and textural properties was conducted using solution containing 100 mg l-1 of ammonium chloride at the time period 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 highest ammonium adsorption was in Ghareh soo 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) to0.0374 (Houttan 2) with an avg. of 0.0179. Ammonium uptake data plotted on alinear parabolic diffusion equation showed a discontinuity in slope at 8 h. This could indicate the presence of two different mechanisms or different adsorptionsites with different rate constants which control the 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 was evaluated using different interpolation methods such as, Kriging, Inverse Distance Weighted (IDW), Local Polynomial and Radial Basis Function. Thus, 505 soil samples were collected from fields during 2008 and micronutrients rates were measured for each sample. The performance criteria for evaluation of the used method were Mean Absolute Error (MAE), Mean Bias Error (MBE) and Root Mean Square Error (RMSE) 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. Semivariogram analysis indicated that Mn and Cu were best fitted to a spherical model. Result of zoning showed that amounts of these elements were lower in north and east regions of province.

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 mg/L in RPi and oxalic acid increased soluble P from 36 to 400 mg/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 mg/L in RPi and from 36 to 546 mg/L RPs. The sufficiency level of soluble P for most plants (200 mg/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.