APPLIED SOIL RESEARCH
Year:2019 | Volume:7 | Issue:3|Papers Count:15

Wind erosion and its dust are serious danger in erodible soil degradation, environment, air pollution and human health. It is an important problem in Iran and especially in Khuzestan province. In the current research, the effect of Sporosarcina pasteurii bacteria in Tryptic Soy Broth (TSB) and sugarcane molasse as a culture media on wind erosion was investigated. The sandy soil sample was obtained from the Hamidyeh area in the Azadegan plain of Khuzestan province and the effect of time and culture media on the test was considered. The treatments were conducted with sugarcane molasse (10%) and TSB as a culture media and urea (2%) and calcium chloride as an injection solution. The experiment was carried out with the basis of completely randomized design with three replications. After 7, 15 and 30 days of injection, calcium carbonate content, penetration resistant and erodibility by wind tunnel were considered. Results showed that the highest concentrations of calcium carbonate were observed under 10% molasses treated with bacteria, which increased the percentage of calcium carbonate by 52%. The highest resistance to penetration was related to treatment 10% molasses application, which resulted in an increase of 1000 times the penetration resistance. The penetration resistance and the percentage of calcium carbonate accumulated in the soil showed a significant increase at the 5% level by LSD test, over time. The investigation of erodibility for selected samples was performed in wind tunnel with an average wind speed of 16 m/s. The amount of erosion in the sandy soil was decreased from 52% to zero, which indicates a 100% reduction in erosion. The results of this study indicate the significant role of molasses in reducing the erodibility of sandy soil and increasing the penetration strength. Thus, it can be suggested as a method to stabilize the sand.

Considering the development of industry and technology, the accumulation of environmental contaminants, especially heavy metals (HMs) in the soil lead to increasing concern about the food security. The purpose of this study was to assess the environmental risk of heavy metals using soil pollution indices. For this purpose, thirty five soil samples were taken from agricultural area in seven sites. The total and available concentration of metals extracted by Aqua Regia and DTPA were determined by an atomic absorbtion spectrometer. Geoaccumulation index (Igeo), enrichment factor (EF), pollution index (PI), contamination factor (CF), potential ecological risk (RI), and availability ratio (AR) were calculated. Mean total concentration of Cd, Pb, Zn, Ni, Co, Cu and Cr were 0. 09, 52. 3, 146, 25. 0, 4. 90, 42. 1 and 73. 1 mg/kg, and their available values were 0. 035, 5. 07, 7. 10, 0. 047, 0. 041, 3. 01 and 0. 030 mg/kg of soils, respectively. The highest values of Igeo, EF, PI, RI and AR indicators were found in Cu (1. 69), Cr (8. 70 ), cu (5. 21), Cr (43. 52), and lead (10. 87), respectively. Integrated pollution index (IPI) calculated using the average of total CF was 4. 08 indicating the higher contamination class in the area whereas IR value was in acceptable ecological range (IR= 109). Analysis of Igeo and IR data showed that Pb, Zn and Cu vary by anthropogenic activities in the area while Cd and Co values are solely affected by lithgenic factor. Agricultural inputs and urban wastewaters can be the major factor increasing of pollutants in the agricultural soils in the area. Monitoring the pollutants concentration in the agricultural soils as well as in agricultural products is essential to conserve natural resources and obtain food security.

Using of microorganisms in stress affected soils can alleviate the condition in plants. In order to assess the effects of phosphate-solubilizing microorganisms (PSB: Pseudomonas fluorescens, PSF: Aspergillus niger) and mycorrhizal fungies (M: Funneliformis mosseae (G. mosseae), Rhizophagus irregularis (G. intraradices), Rhizophagus fasciculatus (G. fasciculatum)) and their interactions on improving nutrient uptake under salinity stress condition, an experiment carried out in a randomized complete block design under greenhouse conditions. Some plant growth indicators and nutrient concentrations in plant shoot were measured at the end of growing period (70 days). The results showed the significant influence of salinity levels on phosphorous uptake, potassium, sodium, and chlorine concentrations, and shoot length. Proline accumulation in leaves (0. 96 μ mol g-1) was resulted with increasing of salinity levels. Among all microbial treatments, the maximum values of the parameters were resulted with mycorrhiza treatment, including shoot length (78. 89 cm), shoot dry weight (15. 77 g pot-1) and root dry weight (8. 47 g pot-1). Unlike shoot sodium and chlorine concentrations, leaves nitrogen and potassium contents increased in microbial inoculation condition. Leaf proline was increased by 14. 46% and 15. 85% with fungi and mycorrhizal treatments compared to control, respectively. It is inferred that inoculation of AMF drastically decreased salinity effects in compared to other phosphate-solubilizing microorganisms in corn.

Symbiotic fungies such as mycorrhiza can alleviate biotic and abiotic stresses in host plants and affect their growth, nutrition and tolerance to salinity stress. Glycyrrhiza glabra is commonly grown in Asia for medicinal purpose and fodder source for livestock. In order to assess the effect of entophytic fungi symbiosis on growth and some physiological properties of G. glabra under different levels of salinity, an experiment was conducted in a factorial design with combination of two factors, salinity levels (non-saline, 4, 8, 12 and 16 dS m-1) and symbiotic fungi (non-inoculated, inoculated with Piriformospora indica orRhizophagus intraradices) in three replicates. Results showed the decrease of root fungal colonization, shoot and root dry weight and root length, and shoot K and P content with increasing of salinity levels. Phosphorus and K utilization efficiency were decreased by increasing of salinity levels. Moreover, salinity caused a significant increase in electrolyte leakage and Na+/K+ ratio. R. intraradices colonization considerably increased tolerance index under salinity stress and decreased Na+/K+ ratio. R. intraradices inoculated plants showed greater biomass, P and K content in comparison with non-inoculated and P. indica inoculated plants. While plant inoculating with P. indica resulted in an increase in shoot dry weight at non-saline condition, and did not significantly affect other studied parameters. Results of this study indicated the ameliorating effects of arbuscular mycorrhizal symbiosis in G. glabra under salinity stress, and the utilization ability of this symbiosis in phytoremediation of salt affected soils.

The application of organic amendments is vital for poor soils of sugarcane fields in south Khuzestan. Recently, filter cake which is a byproduct of sugarcane factories rich in nutrients has received attention as a potential organic amendment. Therefore, an experiment was conducted to study the effects of sugarcane filter cake on selected soil quality indices at Haft Tape agro-industrial complex in 2014. The experiment was carried out in a randomized complete block design with three treatments including: 1-uncultivated, 2-sugarcane field with 100 kg ha-1 filter cake application for two continuous years, and 3-sugarcane field without filter cake (control), and three replications. Soil bulk density (BD), porosity (Pt), mean weight diameter (MWD) and geometric mean diameter (GMD) of water stable aggregates were determined in surface layer (0-30 cm). Moreover, the same properties as well as total organic carbon (TOC), active carbon (AC), total nitrogen (TN), available phosphorus (P) and available potassium (K), basal (BR) and induced (IR) microbial respiration, and alkaline phosphatase enzyme activity (PE) were compared in surface (0-30 cm) and subsurface (30-60 cm) of different treatments. Filter cake application resulted in significant increase in TOC (4. 1 folds), P (7. 4 folds), BR (1. 5 folds), IR (1. 9 folds), PA (1. 6 folds), MWD (2. 8 folds) and GMD (1. 2 folds), as well as a significant decrease in BD (0. 84 folds) compared to the control. The interactions of treatments and soil depth were exclusively significant for AC and TN. Available K was highest in uncultivated field (157 mg kg-1) with no significant disparity compared to filter cake treatment (135 mg kg-1). Furthermore, no significant improvement was detected in soil total porosity with filter cake application. The results suggest that short-term application of sugarcane filter is beneficial for soil quality improvement.

Application of plant residues as soil amendment is one of the most strategies to improve the physical and chemical properties of calcareous, saline and sodic soils in arid and semi-arid regions. In order to investigate the effect of plant residues application on improvement of chemical properties of calcareous, sodic, and saline-sodic soils, an incubation experiment was carried out as a factorial design with factors including soil type (calcareous, saline-sodic and sodic) and plant residues (corn, sunflower, wheat, trifolium and vicia) along with control treatment (soil without plant residues) in three replications. Plant residues were added to the soils by 2%. Treatments were incubated for 13 weeks at 25° C and 50% of field capacity moisture content. The results showed that electrical conductivity (EC), nitrogen content, cation exchange capacity (CEC), available K, iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) in treated soils with various plant residues increased significantly (P<0. 01) compared to control treatment. Application of plant residues caused a significant decrease (P<0. 01) in pH and %TNV in treated soils. The concentration of available phosphorus in treated soils with vicia, trifolium and sunflower residues increased by 39, 35 and 18%, respectively, while it decreased in treated soils with corn and wheat residues by 19 and 25% respectively. Application of plant residues increased organic carbon and urease enzyme activity as compared to control treatments to 27 and 134%, respectively. The exchangeable sodium percentage (ESP) of the studied soils decreased by 19%. It can be concluded that, application of plant residues improved the chemical properties of calcareous, sodic and saline-sodic soils, and increased the availability of nutrients. Chemical and biochemical quality of various plant residues are important in improvement of soil chemical properties.

Application of gravel for controlling evaporation is prevalent in soils of arid and semiarid regions. The objective of this field study was to investigate the interactional effects of gravel and poultry manure (PM) at different application rates on selected properties of cucumber and soil. A factorial experiment was carried out in Shabestar region based on completely randomized design with three replicates. The first factor was gravel at the rates of 0, 15, 30, 45 and 60 kg m-2 and the second was PM at the rates of 0, 250, 500, 750 and 1000 g m-2. Gravel was applied as surface mulch while PM was mixed into the top 20 cm of soil depth. Some growth indices of cucumber and soil properties were determined during and at the end of growth season. The highest rate of gravel significantly increased the yield (16. 9%) and water use efficiency (WUE) (17%) of cucumber, aggregate stability (46. 5%) and field water content (42. 8%) of soil and significantly decreased CaCO3 (15. 1%) and soil penetration resistance (59. 3%) compared to the control. The highest rate of PM significantly increased the chlorophyll index (50. 3%), yield (96. 9%), fruit dry matter (60. 3%), WUE (98%), organic carbon (64. 4%), aggregate stability (150%), electrical conductivity (EC) (287. 5%) and significantly decreased CaCO3 (27. 8%) and soil pH (12. 8%) relative to the control. Simultaneously, application of gravel and PM at the highest rate significantly increased the relative water content of leaf (14. 8 to 24. 4%) relative to the other treatments. Results showed that gravel mulch improves cucumber yield and soil physical quality by increasing water holding capacity of the soil. Also, PM at low and high rates can improve soil physical and chemical quality in the semiarid region by increasing the organic carbon and decreasing pH and CaCO3.

Nowadays, the heavy metal pollution caused by the landfill leachate becomes very serious because of their potential to impact on human health through the food chain. In this study, the effect of landfill leachate on the accumulation and selected indices of soil pollution to heavy metals (Zn, Cu, Cd, Pb, Ni, Mn) including contamination factor (CF), modifi ed degree of contamination (mCd), and modifi ed pollution index (MPI) were investigated in four different soil sites. Results indicated that soils were significantly enriched by the metals in the sequence of Zn> Cd> Ni> Cd> Cu> Mn. However, only the Cd contents exceeded the standard levels based on national and international references. Considering CF, Cd and Zn showed a high pollution class (3≤ CF< 6) in the majority of soil sites and other metals (Cu, Pb, Ni, and Mn) categorized as moderate pollution (1≤ CF< 3). Except site 1, the values of MPI were found to be moderate contamination (3 P3 > P4> P1 in different soil site under the influence of leachate probably due to the quantity and quality of the leachate. Overall, the finding of the study can provide a valuable benchmark for the design of appropriate strategies and management of those agroecosystems by both local and national managers.

Spirulinacyanobacterium (Arthrospira platensis) has a vast range of nutritional organic and inorganic substances and can be used as new material for organic cultivation of plants. In order to evaluate the effect of non-living powder of Spirulinacyanobacterium on spinach (Spinasia olerace L. ) yield and nutrient uptake and comparing the results with some organic and chemical fertilizers, a greenhouse experiment was carried out in a completely randomized design with three replications. Treatments including of control, four non-living spirulina levels (500, 1000, 2500, 5000 mg kg-1), vermicompost (10000 mg kg-1), cattle manure and sheep manure (20000 mg kg-1), chemical fertilizers: (1) 80 mg N kg-1 and 10 mg P kg-1, (2): 150 mg N kg-1 and 20 mg P kg-1 as urea and monocalcium phosphate, respectively. Results showed that the highest and lowest dry weights were obtained in 500 mg non-living Spirulina kg-1 and sheep manure respectively. The total content of nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in spinach was significantly increased with application of 500 mg non-living Spirulina kg-1as compared to control. Application of higher levels of cyanobacterium (more than 1000 mg kg-1 soil) had not significantly effect on spinach yield and some nutrient uptake. Results showed that the effect of fertilizers on some studied characteristics such as dry weight, N, P, K and micronutrient uptake was as following order: Spirulina cyanobacterium > cattle manure> vermicompost> chemical fertilizer (N and P)> control= sheep manure.

Water defi cit is the main growth-limiting factor for pistachio (Pistacia vera L. ) production in semiarid and arid soils of Iran. The objective of this study was to evaluate the effect of humic acid application on root and shoot growth characteristics, phosphorus (P) and potassium (K) uptake and photosynthetic pigments of P. vera L. seedlings under drought stress condition. This study was carried out in greenhouse condition as a factorial experiment based on a randomized complete block design with two factors including drought stress (in three levels: 80% (control), 60% and 40% of field capacity moisture content) and humic acid (in three levels including control, 1 g HA kg-1 soil and 2 g HA kg-1 soil) in three replications. Results indicated that leaf area, dry weights of leaf and stem, shoot and root dry weights, chlorophyll contents and shoot and root P content decreased by increasing of soil drought levels, while the reverse result was found in carotenoids and shoot and root K concentrations. application of humic acid leads to significant increase (P≤ 0. 05) in shoot length (17 %), leaf area (39 %) root dry weight (31 %), leaf dry weight (16 %), Stem dry weight (28 %), total plant dry weight (19 %), total chlorophyll (37 %), carotenoids (19 %), root P concentration (10 %), shoot P concentration (23 %) and K content in root (11 %) and shoot (22 %) in all moisture levels. It can be concluded that application of humic acid (especially at level of 2 g HA kg-1 soil) results in improve of the plant growth properties and tolerance to drought stress due to increase of photosynthesis pigments and enhance of shoot and root P and K contents.

Phosphorus deficiency is one of the most important problems in calcareous agricultural soils of arid and semi-arid regions. This study was conducted to investigate the phosphorus uptake and activity of acidic and alkaline phosphatase enzymes in three types of soils with different levels of available phosphorus (Qazvin1, Qazvin2 and Dizan) treated with 50 mg/kg phosphorus by using sheep manure, municipal solid waste compost and triple superphosphate under greenhouse conditions in 2015 as a completely randomized design with three replications. The results showed that the acidic and alkaline phosphatase activity in Dizan were significantly higher than other studied soils. The alkaline phosphatase activity was more 2. 7 times than acidic phosphatase in the soil. The influence of municipal solid waste compost on acidic and alkaline phosphatase enzymes activity were 82. 3 and 62. 1 p-Nitro phenol (µ g/g-1dwt h-1) and 52. 6 and 87. 6 p-Nitro phenol (µ g/g-1dwt h-1) higher than sheep manure and triple superphosphate treatments respectively. The results of soil and fertilizers interaction showed that, acidic phosphatase enzyme activity in municipal solid waste compost and triple superphosphate were more than sheep manure in Dizan soil sample. The phosphorus uptake by plant was 34. 3, 20. 9 and 65. 7 % in Dizan treated soil sample with sheep manure, municipal solid waste and control respectively. In Dizan soil residual phosphorus after harvest of wheat in triple superphosphate treatment was 33. 3, 61. 7 and 72. 4 % compared to sheep manure, municipal solid waste compost and control, respectively. According to the results the maximum phosphatase enzyme activity was obtained in treated calcareous soil with municipal waste compost.

Biochar is a carbon-rich solid material produced by heating biomass and agricultural residues in an oxygen-limited environment. However, effects of biochar in soil depend on pyrolysis temperature and type of the raw material used in its production. In order to determine the effect of biochars prepared from agricultural residues at different temperatures on soil characteristics, soil cations and anions and Na and K concentrations of corn, a factorial experiment was conducted in a completely randomized design in four replications under greenhouse condition. Treatments included biochar type (rice, cotton and canola), pyrolysis temperatures (350 and 700 ° C) and two application rates (0, 2 and 5 w/w). The results showed that all types of biochar increased soil EC values. The lowest and highest values of soil pH were observed at biochar prepared from rice and cotton residues, respectively. The soil pH was significantly increased with increasing pyrolysis temperature from 350 to 700 ° C. The highest values of soil Na+, Ca++, Mg++, Cl-and HCO3-was observed at 350 ° C. The results showed that between each three biochars type produced from crop residues (rice, cotton and canola), the highest Na concentrations of leaf and stem were recorded with addition of biochar prepared from rice residues, however, the biochar prepared from canola residues lead to the highest amount on K concentrations of leaf and stem. The pyrolysis temperature only affected the Na concentration of leaf at 5% probability level. The results showed that pyrolysis temperature and the type of feedstock material are important factors that influence the chemical properties of biochars and subsequently the soil characteristics.

Land use change from forest and pasture to Rosa damascena Mill orchard can affect many soil properties and fertility. Thirty-six surface soil samples from different land uses including forest, pasture and Rosa damascena Mill orchard were collected from Morvarid region (Darab, Fars province) to evaluate the effect of land use change on soil properties and fertility. Different soil properties, macro-and micronutrients availability and soil potassium forms were determined. Results showed that the content of organic matter, soil pH and cation exchange capacity in the orchard soil were significantly lower than those in the forest and pasture soils. The nitrogen content in the orchard soil was significantly lower than that in the other land uses, however the content of available P in the orchard soil was significantly higher than that in the forest and pasture soils (39 vs. 22 and 24 mg kg-1, respectively). The availability of manganese, zinc and copper in the orchard soil was significantly higher than those in the forest and pasture soils. The contents of exchangeable K in the forest soil (749 mg kg-1) and non-exchangeable K in the orchard soil (1344 mg kg-1) were significantly higher than those in the other land uses. Generally, farmers may change the soil properties and fertility with addition of chemical fertilizers, disturbing the soil and harvesting some aerial parts of plants. Changes in soil properties and nutrients availability must be considered in agricultural land management and the results of this research, for example the decrease in content of some macronutrients and organic matter due to the land use change from forest and rangeland to orchard, can be useful to predict the consequences of land use change in the studied region and other similar regions. It is recommended that in order to maintenance of nutrients balance in orchards, P fertilizers application should be done with more consideration and the decrease in the contents of organic matter and such macronutrients as N and K should be recompensed with organic and inorganic fertilizers application.

Soil quality is affected by the type of land use and management. Evaluation of soil quality indices is a suitable guide for adopting sustainable management practices and preventing soil degradation. The goals of this research were to explain soil variations and to determine the most important soil quality assessment indices. Therefore, totally 50 soil samples were collected from four land uses including forest, pasture, rain fed and irrigated farmlands in Lordegan watershed. Then soil characteristics consisted of soil bulk density, soil texture components, calcium carbonate equivalent, cation exchange capacity, pH, electrical conductivity, organic carbon, total nitrogen, carbon to nitrogen ratio, microbial basal respiration and mean weight diameter of aggregates were measured. Also, average monthly temperature, annual precipitation, elevation and slope of sampling points were determined. The results of principal component analysis illustrated that organic carbon, sand content, annual precipitation and elevation were the most important factors causing soil variations in the area. This method could explain 81% of soil variations in the region by creating 5 principal components. Furthermore, various kind of land uses were distinguished successfully according to a set of selected soil attributes using Discriminant Analysis. The percentage of correct classification in this analysis was 94%. The results of this study emphasize on the applicability of multivariate statistical methods in the assessment of soil quality. The individual examination for each of selected indices indicated the high quality of forest soils compared to the other land uses. However, rain fed farmlands had a poor quality situation. Therefore, achieving sustainable management in the area requires the prevention of land use change and the restoration of degraded lands for improving soil quality.

Assessing the variation of different soil properties through the land use changes may provide useful information for land managers. The present study aimed to assess the soil quality variation due to the land use changes from dense (non-degraded) to semi-dense (degraded) oak forest and then to dry-farming in Mokhtar plain located in Yasouj region. A total number of 100 surface soil samples were collected in order to analyses of the selected physicochemical soil properties. After statistical analyses, the continuous distribution maps were prepared for all soil variables using ordinary kriging and inverse distance weighting methods in ArcGIS software (ver. 10. 2; ESRI). Analyses of the average values of selected soil properties showed that after changing the land use from dense to the degraded oak forest and then to dry-farming, organic matter and CEC changed in a decreasing trend and bulk density changed in an increasing trend. Moreover, electrical conductivity, carbonate calcium equivalent and clay percentage decreased in lower contents; whereas soil pH and sand percentage inconsiderably increased. Among the soil properties, organic matter content as one of the most important soil quality indices showed a significant change with an average of 6. 74%, 3. 42% and 1. 58% in dense forest, degraded forest, and dry-farming lands, respectively. Supporting these findings, spatial distribution maps of the selected properties revealed that the most optimum soil properties were found in the southwest of the studied area, i. e. in the soils covered with dense oak forest; whereas increasing distance to the dry-farming lands in the northeast of the area, the selected soil properties were adversely changed. According to these findings, it can be stated that wide deforesting and land use change have been led to the considerable soil quality decline and therefore if deforesting will not be stopped a huge portion of the studied soils may lose their vital capabilities.