Journal of Soil Management and Sustainable Production
Year:2014 | Volume:4 | Issue:1|Papers Count:15

Because of high organic matter content of Histosols, they have a thin capillary fringe that would lead to strong soil structure. Soil structure is referred to as aggregate stability which affects crop production. The objective of this study was to determine the distribution of organic carbon, total nitrogen, carbohydrates and calcium carbonate in different-sized aggregates and to investigate the role of these compounds on aggregate stability in two soil types of Histosol. In each region 3 soil profiles were studied (0-120 cm, at each 20 cm interval) and sampling was carried out. Results showed that in both types of Histosols in all depths, larger aggregates contained more organic carbon, total nitrogen and carbohydrate content than the smaller aggregates, while the smaller aggregates contained more calcium carbonate. Studying the independent role of the studying properties on aggregate stability in two soil types implies on positive role of organic carbon (r=0.48, r= 0.25; P=0.01), total nitrogen (r=0.62, r=0.44; P=0.01) and carbohydrate (r=0.51, P=0.01; r=0.23, P=0.05 hot-water soluble; r=0.52, r=0.63; P=0.01 acid soluble) and negative role of calcium carbonate (r=-0.79, P=0.01; r=-0.23, P=0.05) on soil structural stability. Investigating the Pearson correlation coefficients in different-sized aggregates resulted in different outcomes on the role of these elements. The relative importance of each of the studying properties in conjunction with other properties on the soil structural stability revealed the positive influence of total nitrogen in two soil types, positive effect of acid soluble carbohydrate in soils of Shahrekord and negative effect of other properties in two soil types.

Nowadays, application of superabsorbents is one of the strategies to combat water deficiency in arid and semiarid regions. This study was carried out to investigate the effects of two polymers on temporal variability of suction, porosity distribution and available water of two contrasting soils. The experiments were done as factorial based on complete randomized design, with three replicates. The treatments were included of Tarawat and Stockosorb polymers, each at five levels (0, 2, 4, 6 and 8 g/kg) and two soils (loamy sand and sandy loam). Moisture content at different suctions and temporal variability of moisture during two weeks were measured. Result showed that for greater amounts of the polymers, the required days to reach the corresponding suction increased, significantly. Also, the influence of polymers on increasing soil moisture was more effective at higher suctions. Overall, the application of polymers particularly tarawat led to a significant increase in moisture retention, especially for the loamy sand soil. Application of Tarawat and Stockosorb in loamy sand soil led to higher increase in capillary porosity, whereas in sandy loam soil resulted in higher increase in aeration porosity. For sandy loam soil, the highest rate of Tarawat and Stockosorb resulted in 1.9 and 1.6 folds increase in available water compared to the control. The increase for loamy sand soil was 3.3 and 3.7 folds, respectively. With respect to available water, Stockosorb was more efficient polymer for loamy sand soil, whereas Tarawat found to be more suitable for sandy loam.

Considering the importance of wind factor in wind erosion, it can be used as one of the major factors in determining the power of the wind erosivity. Extreme wind speed estimation is usually important in many fields of environmental studies such as climatology, hydrology, agricultural management and structure designing. Therefore it is important to estimate distribution function of wind velocity. Wind speed data are however often not available or attainable in short term period. To solve this problem, Linear moments analysis was used in this research. This method can determine the regional distribution function in a region, which in turn reduces the statistical uncertainty in the stations with short term period data. Monthly averages of maximum daily wind speed of 26 meteorological stations in Yazd province were used for regional analysis in this research. Based on L-moments analysis, the study area is divided to five homogeneous wind speed regions. The results indicated by statistical tests discordancy measure, heterogeneity measure, goodness of fit measure showed that the Generalized Logistic (GLO) distribution model was the best regional distribution models for 3 homogeneous regions.

Phytoremediation is one the methods to decontaminate soil which uses green plants to remove of soil pollutants. Low availability of soil heavy metals limits plant efficiency for phytoremediation. Therefore, in order to increase the availability of cadmium (Cd) by Lepidum Sativum, an experiment was conducted in four variables including: cow manure, compost, urea fertilizer and resistant bacteria into heavy metals with three different levels in soils which is contaminated with cadmium using 50 mg kg-1 as cadmium chloride (CdCl2.H2O). Cadmium concentration was analyzed by Atomic absorption and Taguchi method has been used in this experiment. Results showed that cow manure, urea fertilizer, Cd- resistant bacteria and compost in the order of importance had a significant effect on the cadmium shoot concentration of Lepidum Sativum and Cd soil solution concentration as well. Also results indicated that optimum Cd uptake by the shoots was observed in treatments of 40 g kg-1 of cow manure, 0.05 g kg-1 of urea fertilizer, inoculates of three types of bacteria (CC3, CC4, CC5) and 10 g kg-1 of compost fertilizer and in the soil solution resulted to: 10 g kg-1 of cow manure, 0.15 g kg-1 of urea fertilizer, inoculates of two types of bacteria (CC1, CC2) and 20 g kg-1 of compost fertilizer. So, according to the results, cow manure had the most contribution to increase phytoremediation efficiency in Lepidum Sativum.

In order to study the phosphorus and zinc interactions on two different cultivars of soybean, a pot experiment was conducted in north of Qaemshahr, Iran, in 2011. The altitude was 65 m asl. and soil texture was silt loam. The factorial experiment was arranged in a completely randomized design with three replications. Factors tested included three levels of phosphorus (0, 50 and 100 mg/kg), from super phosphate triple source, three levels of zinc (0, 5 and 10 mg/kg), from zinc sulphate source and two soybean cultivars, Telar (BP) and Sari (JK). Results showed that application of 5 mg/kg of zinc sulphate led to increasing trend in pod per main stem, pod per plant, filled pod per plant, and grain per pod. Application of 10 mg/kg, however, resulted in maximum reduction in root dry weight. On the other hand 100 mg/kg phosphorus increased the shoot biomass, pod per main stem, pod per plant, and filled pod per plant as well as the highest increase in root length and dry weight. JK produced the highest shoot biomass while pod per plant, grain per pod, and root dry weight were higher in BP cultivar.

In order to improve soil fertility, increase nutrient uptake and plant health, use of useful soil organisms is the best scientific method that help balance the stability of soil as a living system. In order to evaluate the effect of mycorrhizal fungi, Thiobacillus thiooxidans and sulfur fertilizer on growth and yield of corn’ a field experiment was arranged in a factorial based on completely randomized design with three replications. Mycorrhizae and Thiobacillus thiooxidans were at two levels (with (M1 and T1) and without (M0 and T0) inoculation) and three levels of sulfur (S0: 0 kg.ha-1, S1: 250 kg.ha-1 and S2: 500 kg.ha-1). Results showed that inoculation of mycorrhizae, Thiobacillus thiooxidans, and sulfur application decreased soil pH and increased grain yield, grain number per ear, stem height, weight of 100 grains (except mycorrhizae) and biological yield significantly compared to control plants. The interaction of sulfur and Thiobacillus thiooxidans was significant on all traits studied except for biological yield. Interaction of mycorrhizae and Thiobacillus thiooxidans on soil pH decrease and on stem height increase were significant.

Heavy metals (HMs) such as lead (Pb) enter the soil through various pathways and affect soil quality. HMs decline population, activity, and efficiency of soil microorganisms. The objective of this study was to evaluate the effect of soil Pb contamination on population, activity and functionality of microbes in a sterilized soil inoculated with species of Glomus fungi including G. intraradices, G. mosseae and G. fasciculatum and species of Pseudomonads bacteria including P. putida, P. fluorescens, and P. aeruginosa. Various concentrations of Pb (0, 250, 500 and 1000 mg Pb kg-1 soil) were uniformly added to the sterilized soil and after soil inoculation with the microbes Centaurea (Centaurea cyanus) was grown. This study was carried out under greenhouse condition as a randomized complete block design and in three replications. Results showed that soil bacterial population, root colonization, root dry weight substrate induced respiration and microbial carbon biomass decreased significantly (P£0.05) as soil Pb concentration increased. Metabolic quotient (qCO2) increased by increasing the soil Pb concentration for both the microbial treatments. However, this increase was higher in the bacterial treatment compared to fungal treatment. Results indicated higher effect of Pb contamination on the bacteria and the fungi were more tolerant. Therefore, soil Pb contamination with decreasing the growth of plant and declining of population, activity and functionality of soil microbes results in degradation of soil biological quality.

Some unsustainable issues in agricultural systems is related to soil quality during the time. Therefore conservation and retaining soil quality should be regarded in management operations and land use. In order to study the effect of some conditioners on soil physical quality, an experiment was carried out as a completely randomized design in a saline-sodic soil. Experimental treatments included 10 ton/ha of compost (MC), vermin-compost (VC), poultry manure (PM), and gypsum powder together with untreated treatment (control) in 3 replications.6 months after application of studied treatments, soil quality was determined by 3 approaches i.e. sustainable index (SI), cumulative rating (CR), and scoring functions. The results showed that soil quality based on sustainable index, cumulative rating, and scoring functions as a result of soil conditioners has been improved. According to SI approach, the highest increasing value was noted in MC treatment and it has a significant difference with other treatments (P<0.05). The lowest value of CR (i.e. the highest degree of soil quality improving) was obtained from MC treatment, but it has no significant difference with VC treatment (P<0.05). The highest value of scoring function was obtained in VC treatment and its difference with other treatments was significant. Although studied conditioners have caused the considerable improvement of soil quality but with regard to sodicity of studied soil, it seems that simultaneous addition of these conditioners will be more effective than their individual application into soil in improving soil quality.

Due to the role of Artichoke in blood cholesterol and sugar reduction as well as antioxidant properties, it is widely cultivated and used. Importance of plant feeding in one hand and environmental contamination by chemical fertilizers on the other hand, forced human to think about clean agriculture. To find the possibility to remove the limitation of microbial contamination and heavy metals, sewage sludge can be used as rich source of mineral and organic matter in plant feeding. In the present study, it has been tried to find the role of zeolite in heavy metal capturing beside the feeding value of sewage sludge. The experimental was complete randomized block containing two treatments of sewage sludge (design 15%, 20%, and 25%) and zeolite (0, 5%, 10% and 15%) with three replications. Results indicated that, using sewage sludge had an influence on some parameters including plant biomass and some qualitative indexes such as chlorogenic acid and total phenols. Contrary to that, a reduction in the content of caffeic acid and total flavonoid was observed. Zeolite had no significant effect on parameters involved in leaf yield and quality. Zeolite significantly (at 5%) reduced the rate of Lead and Cadmium of root. The lowest amounts of root Cadmium and Lead were observed in plants treated with 10% zeolite. Finally it can be concluded that, if it is possible to reduce the limitations of sewage sludge in plant feeding, sewage sludge could be a good fertilizer and zeolite could be a good agent to inactive the heavy metals in root rizosphere.

Symbiotic biological nitrogen fixation (BNF) is beneficial for increasing yield of legums, reduction of production expenses, increment of soil fertility, and prevention of underground water pollution. In the first stage of this study, the symbiotic effectiveness (S.E.) of 31Sinorhizobium isolates with alfalfa plant was evaluated. The results indicated that 27% was very efficient, 23% efficient, 16% relatively efficient and 36% non efficient. The SR42 and SR40 were the most and least effective isolates on alfalfa, respectively. Isolates SR8, SR14, SR15, SR26, SR51, SR52 and SR75 were effective on alfalfa plant as well. According to the results obtained from evaluation of effective indices in symbiosis, SR42 isolate was chosen and then in a greenhouse experiment the effect of co-inoculation Sinorhizobium isolate (SR42) and two plant growth-promoting rhizobacteria including P. fluorescens P9 and P. fluorescens P52 (isolated from canola and pistachio rhizosphere, respectively) on nodulation, nitrogen fixation, plant biomass weight and uptake of some elements was investigated. The results showed that application of PGPRs significantly increased shoot dry weight, nodulation number and total N uptake in Alfalfa inoculated with Sinorhizobium sp. SR42.

Fluorescent pseudomonads are one of the most important plant growth stimulating bacteria in different plant rhizosphere. In this research, 40pseudomonas fluorescence and pseudomonas putida isolates, isolated from wheat and canola root were, identified and their growth promoting qualities were evaluated. Application of studied isolates in tubes containing sterile sand, in comparison with control treatment led to increase in shoot dry weight (53.7%), root dry weight (47.8%), root length (21.6%), shoot length (17.7%), shoot wet weight (52.5%), root wet weight (56.5%), the ratio between dry shoot and dry root (20.3%) and ratio between wet shoot and dry root (up to 20.3%). The application of 14 superior isolates in greenhouse condition compared to control treatment resulted in increscent shoot wet weight (30.2%) and shoot dry weight (27.5%) and also nutrition uptake including nitrogen (30.2%), phosphorus (28.2%), potassium (25.8%), iron (100.2%), manganese (70.8%) and copper (70.3%). The results indicated that Fluorescent pseudomonads inoculation plays a vital role in increasing growth indices and nutrition uptake in canola.

This study was conducted to investigate the effect of arbuscular mycorrhizal fungi and PGPR on lead and cadmium uptake by tomato plant. For this, a greenhouse experiment in a complete randomized block design (CRBD) with three replications was conducted. The treatments were microbial treatments in four level (B0F0, B1F0, B0F1 and B1F1) and four levels of lead and cadmium (Pb0, Pb250, Pb500 and Pb1000), (Cd0, Cd50, Cd100 and Cd200). The results showed that effect of microbial, lead and cadmium treatments on the concentration of these elements in shoot, root and their transferring from root to shoot was significant (p£0.01). The highest concentration of cadmium was related to interaction of fungi with cadmium (100 mg Kg-1) treatment, so that the cadmium concentration in shoot and Translocation Factor in this treatment was 5.62 and 14.05 times of its concentration in control (no inoculation) respectively. Lead concentration in the root was in average 18.92 times its concentration in shoot. This amount for cadmium was 3.09. The results of mean comparisons related to main effects of microbial treatments showed that cadmium uptake in all of microbial treatments are higher than control (no inoculation) while, microbial treatments didn't have such an effect on lead transfer from soil to plant.

The use of fungicides in agriculture can have harmful effects on soil organisms. An important group of soil organisms are plant growth-promoting rhizobacteria that can be used as biofertilizer. In this research in order to evaluate the effects of Vitavax â-34 fungicide on growth and survival of Pseudomonas putida and Azospirillum brasilense, two experiments were conducted in in vitro and pot conditions. The first test was designed in a factorial experiment based on completely randomized design with time, use and non-use of fungicide factors in three replications. Results of wheat seeds treatment with fungicide and bacterial inoculants used, revealed that the use of Vitavax â-34 fungicide declined the population of viable Pseudomonas putida and Azospirillum brasilense on seeds of wheat and time had significant impact on the bacterial population reduction. In 120 minutes bacterial populations were reduced about 100 times in the presence of fungicide compared to its absence. Results for wheat cultivation showed that in the presence of fungicide, the rhizosphere and endorhizosphere population of Pseudomonas putida increased (approximately 10 and 8 times respectively) whereas, Azospirillum brasilense rhizosphere and endorhizosphere population decreased (about 2.5 and 2.3 times repectively). However, this decrease was less than the reduction of the bacterial population on seeds treated with fungicide. Evaluation of vegetative parameters of wheat indicated that the use of Vitavax â-34 fungicide had no significant effect on plant growth.

Plant analysis is a useful and practical tool in monitoring orchards nutritional status, recommending fertilizer rates and increasing fertilizer efficiency, provided that chemical analysis results are correctly interpreted. Diagnosis and recommendation integrated system (DRIS) is a comprehensive approach for interpretation of plant analysis results which does not have limitations of the critical value approach (CVA) and sufficiency range approach (SRA). The aim of this study is to establish DRIS norms to interpret the results of peach tree leaf analysis. Leaf samples were collected from 61 peach orchards throughout the province during July of 2009 and 2010 and analyzed for N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu concentrations. On the yield basis of 30 Kg/tree, the peach orchards were divided into two groups of low (32 orchards) and high (29 orchards) yielding populations. An information databank with 7000 records including orchards yield and foliar nutrients concentration was developed.45 expression forms, based on the greatest variance ratio (SB/SA) and the foliar concentration of nutrients during growth stage, were presented as the best reference DRIS norms for peach trees, using the Microsoft ExcelÔ software. Average of nutrients concentration as a reference values for N, P, K, Ca and Mg and Fe, Mn, Cu and Zn were obtained 2.46, 0.24, 2.29, 2.03 and 0.56%, and 132.7, 32.5, 14.5 and 42.9 mg/kg, respectively. The Indices DRIS for the 9 nutrients were also calculated. The defined DRIS norms are applicable for the nutritional disorders diagnosis of peach trees.

This study focuses on the effect of organic matter as well as potassium on some soil properties and onion yield at the field conditions. For this purpose, an experiment was carried out as factorial in a completely randomized block design with three replications. The treatments were included of poultry manure, alfalfa residue (each at 10 t/ha) and control together with two levels of potassium as K2O (0 and 250 kg/ha). The results showed that in comparison with the control, the application of poultry manure and alfalfa residue resulted in yield increase of about 57.7 and 40.9%, respectively. On average, the onion yield for the potassium treatment was 7.8% higher than that of the untreated one. Moreover, due to the application of organic matters particularly poultry manure, significant increases in organic carbon and absorbable phosphorous were observed, while for the potassium treated soil no significant increase was found. Following the application of poultry manure and alfalfa residue, 129.8 and 80.2% increases in soil organic carbon and 104.8 and 51.9% increases in absorbable phosphorous were obtained, respectively.