Journal of Soil Management and Sustainable Production
Year:2020 | Volume:10 | Issue:3|Papers Count:9

Background and Objectives: Veterinary antibiotics enter into agricultural soils through application in animal husbandry and manures where these soils could be the source of dissemination of antibiotics in soil and water habitats. Owing to increasing antibiotic applications in our country, the aim of the present study was to understanding and evaluating the consequences of mostly applied antibiotics in soil (with and without organic and mineral conditioners) on extracellular enzymes activity, alkaline phosphatase and urease, and their resistance and resilience indices as well as mean soil enzyme activity, in a 90-day incubation period. Materials and Methods: Three soil conditioners including decayed cow manure, biochar and nano-zeolite thoroughly mixed by soil samples in 2 percent (w/w) and control treatment (without conditioner) was included. Aqueous solutions of gentamicin, oxytetracycline and penicillin prepared with distilled water and added to 400g dry soil and thoroughly mixed. While mixing, water added to the soil to the moisture content of 60 percent of field capacity (0. 6 WHC). For each antibiotic treatment three concentrations including 50, 100 and 200 mg/kg plus a control treatment (without antibiotic) in three replications were evaluated. The efficiency of alkaline phosphatase and urease enzymes were assessed by p-nitrophenol and urea as substrates, respectively and the soil enzymatic efficiency, and enzymes resistance and resilience indices were calculated at three time periods 1-7, 7-30 and 30-90 days in a 90-day incubation period. Results: In treatments without conditioner application, gentamicin at 200 mg/kg concentration caused 68. 9 percent decrease in alkaline phosphatase efficiency compared to control (without antibiotic) and decreasing enzyme activity in soil treated by 200 mg/kg oxytetracycline at control (without conditioner), application of manure, biochar and nano-zeolite compared to control (without antibiotic) was 17. 5, 13. 8, 17. 5 and 16 percent, respectively. Urease enzyme efficiency at 30-90 days had an increasing trend and the highest enzyme activity recorded at this time period. Based on the results, measured enzymes had different responses, so that penicillin and oxytetracycline had not such a considerable impact of soil alkaline phosphatase activity. While, gentamicin and oxytetracycline at all applied concentrations, had significantly negative impact on soil urease activity. Considering the great responsiveness of alkaline phosphatase to gentamicin antibiotic, application of soil conditioners had no significant efficiency in improving resistance of this enzyme in gentamicin treated soils. also, application of soil conditioners had no significant impact on increasing resistance index of urease enzyme in oxytetracycline and penicillin applied soils. Results show that increasing application amount of antibiotics caused decrease in soil enzymes activity and highest enzymes resilience observed in 50 mg/kgantibiotic concentration. Also results showed that urease enzyme had the highest resilience indec in penicillin application treatments followed by gentamicin and then oxytetracycline treatments. Conclusion: Present study showed that application of conditioners, especially manure and its biochar improved soil properties and increased extracellular enzymes’ resistance, which are indicators of soil microorganisms’ function, against antibiotics, even at higher concentrations. There was difference among responsiveness of studied enzymes, so that oxytetracycline had no significant impact on soil alkaline phosphatase activity, while penicillin had no considerable effect on soil urease activity. Totally, the present study showed that application of soil conditioners could alleviate toxic impacts of antibiotics and result in increase in resistance and resilience indices of soil enzymes and improved enzymes activity and efficiency in antibiotictreated soils.

Background and Objectives: Accurate and detailed spatial soil information over the landscape is essential for the precision monitoring of land resources, hydrological applications, land use management. The present study aimed to predict the spatial prediction of SOC, CCE, Clay, Silt, and Sand in the Qorve-Dehgolan region, Kurdistan province. Materials and Methods: Qorve-Dehgolan region, with mean annual temperature and precipitation of 12 ° C and 348 mm (20-year statistical period), has soil moisture and temperature regimes xeric and thermic, respectively. A total of 145 samples were collected from the topsoil (0-30 cm) based on a random sampling pattern. Then, all of the soil samples were transferred to a soil laboratory for physicochemical analysis. Random forest (RF) as a nonparametric model and Ordinary kriging (OK) and inverse distance weighting (IDW) as an interpolation method were used for modeling the soil properties and their spatial autocorrelation. All steps of modeling for RF and interpolation methods (OK and IDW) were performed in RStudio, ArcGIS and, GS+ softwares, respectively. A total of 30 environmental covariates, including the Digital Elevation Model (DEM) derivatives in the SAGA GIS 7. 3 and Landsat 8 satellite reflective band data in the ERDAS IMAGINE softwares, were developed as environmental variables. All of the environmental covariates were resampled at resolution-30 m. The most appropriate covariates were selected according to the variance inflation factor (VIF). Modeling of soil properties was performed according to 80% and 20% of data sets, respectively for calibration and validation, and two statistics of root mean square error (RMSE) and determination coefficient (R2) was used to determine the accuracy of the models. Results: Seven variables including SAVI, EVI1, GNDVI, RVI1, DEM, Channel Network, and TPI were selected from the 30 variables prepared as the most appropriate auxiliary variables based on the variance inflation index. Four remote sensing variables include the soil adjusted vegetation index (SAVI), the green normalized difference vegetation index (GNDVI), the relative vegetation index (RVI) and the enhanced vegetation index (EVI) and three geomorphometric attributes including, digital elevation model (DEM), vertical distance to channel network and the topographic position index (TPI) were the most important parameters. The results of modeling showed that RF model for soil organic carbon variable (R2=0. 5 and %RMSE=0. 4), calcium carbonate equivalent (R2=0. 4 and %RMSE=11. 61), clay variable (R2=0. 21 and %RMSE=5. 65), the Silt variable (R2=0. 15 and %RMSE=7. 24) and, Ordinary kriging methods for sand variables with (R2=0. 14 and %RMSE=10. 26) was the most accurate than RF and IDW models. Among the semi-variogram models, the exponential model had the best performance for soil organic carbon, clay, silt, and sand percentage, with the exception of CCE which follows the spherical model. The results of spatial autocorrelation showed that for both variables CCE and Sand had a strong class and, the others had a moderate class. The highest values of the semi-variogram sill were related to the calcium carbonate equivalent and clay, and the lowest values were related to the soil organic carbon and sand contents. These results indicate that, the existence of a random pattern or weak spatial structure in the samples that used to calculate the experimental semi-variogram. Among the seven environmental covariates were used for spatial modeling of top-soil organic carbon, clay and calcium equivalent carbonate, the geomorphometric attributes such as DEM topographic position index are of the most important and NDVI, SAVI and RVI covariates were more important in predicting of sand and silt properties. Conclusion: Generally, topsoil properties had moderate and strong spatial autocorrelation, but the spatial prediction results were not highly accurate. Therefore, it would be recommended that in future studies other sampling methods like that Conditional Latin hypercube or stratified random and thematic maps such as geomorphology, geology, and soil map units as inputs for spatial modeling toward enhanced modeling performance will be used.

Background and Objectives: The soil water retention curve (SWRC), as an important hydraulic soil property, is used in modeling water flow and solute transport in the unsaturated zone of the soil. Direct measurements of SWRC are difficult, time-consuming and costly. Hence, researchers have proposed indirect methods such as pedotransfer functions to estimate soil water retention curve using readily available soil data. Over the last decades, soil spectral data as a rapid, low cost, and nondestructive method has been widely applied to estimate basic soil properties. Consequently, in this study, the feasibility of using soil spectral information in the visible and near-infrared region, as input variables for transfer functions, and evaluation its performance was investigated compared to basic soil properties in estimating soil water retention curve. Materials and Methods: A number of 100 soil samples were collected and their spectral reflectance over 350-2500 nm region were measured using a handheld spectroradiometer apparatus. Some basic soil properties such as particle size distribution, particle density, bulk density, organic carbon content and calcium carbonate equivalent, and soil moisture content at matric potentials of-10,-33,-50,-100,-300,-500,-1000, and-1500 kPa were also determined with pressure plate-membrane apparatus. Spectral reflectance curves of the samples were recorded using RS3 1 2 software on a portable computer connected to a spectroradiometer with 5 readings per soil sample. After spectral preprocessing, the correlation coefficient between absorption features of soil in each wavelength with soil moisture content at different matric potentials were investigated. Stepwise multiple linear regression was applied to derive pedo-transfer functions (PTFs) and spectral transfer functions (STFs) that uses basic soil properties and soil spectral reflectance as input, respectively. The accuracy of the proposed functions were assessed by adjusted coefficient of determination (R2 adj), normalized root mean square error (NRMSE), mean error (ME), and the ratio of performance to deviation (RPD). Results: Pedo-transfer functions (PTFs) provided more accurate estimates at the dry-end of the soil moisture curve than the wet-end, due to the high correlation of soil moisture with soil particle size distribution at the dry-end of the soil moisture curve. The results of the statistical parameters showed that the derived PTFs for estimating soil water retention at 10 to 1500 kPa matric suctions have good prediction accuracy. However, STFs also had reasonable but poorer results than the proposed PTFs in estimating the studied characteristics. Conclusion: Overall, the results of this study revealed that, despite the relatively poorer results of STFs than PTF, due to lower costs, time and field data, soil spectral data can be used as an indirect and novel method for estimating volumetric soil moisture content at different matric potentials.

Background and Objectives: Proper management and use of agricultural waste is one of the important strategies for sustainable development of agriculture in Iran. Given that most of the country is covered by arid and semi-arid lands, rapid decomposition of organic matter and its deficiency in soil is one of the problems of agriculture and natural resources, preventing the waste from being burnt and making optimum use of it can both compensate for the lack of soil organic matter and reduce environmental pollution. Considering the high durability of biochar in soil, a useful strategy for organic waste management is use of biochar on agricultural land to provide organic matter for plant growth and as a modifier to improve soil properties. Due to the expansion of pistachio cultivation in central Iran, pruning of its branches results in considerable amounts of waste annually, which is usually burned to prevent pest spread. The aim of this study was to investigate the effect of pistachio waste on growth characteristics of safflower. Materials and Methods: In order to investigate the effect of biochar on growth characteristics of safflower, an experiment was conducted in a completely randomized design with three replications. Biochar treatment prepared from pistachio wood at 500 ° C under low oxygen conditions was studied at four levels of 0, 1, 2 and 4%. by weight. At the end of the growth period, plants were collected and leaf area, leaf length and width, number of yellow, green leaves and total, internodes distance, fresh and dry weight of shoot and root, stem height, germination time from planting, relative leaf water content, Ion leakage percentage, leaf chlorophyll index, sodium, potassium and phosphorus concentration and sodium to potassium concentration ratio were measured. Data were analyzed in SAS software and mean comparisons were made using Duncan test at 5% level. Results: The results showed that the effect of biochar treatment on leaf area, fresh and dry weight of plants, root dry weight, plant height, leaf chlorophyll, ion leakage percentage, leaf relative water content, sodium, phosphorus and potassium concentration and sodium to potassium concentration ratio were significant. However, the effect of this treatment on leaf length and width indices, number of green and yellow leaves and their total, root fresh weight, internodes distance and germination time was not significant. Mean comparison showed that the highest leaf area (413. 25 mm 2), root dry weight (1. 17 g), fresh weight (3. 79 g) and plant dry weight (0. 89 g), plant height (0. 25 g). 52 cm), relative leaf water content (89. 2%), potassium concentration (2. 81%) and phosphorus (0. 24%) were obtained at the highest biochar level (4% by weight). Also, the highest leaf chlorophyll index content (53. 8%) was observed in one percent biochemical treatment and the highest ion leakage (81. 75%), sodium concentration (3. 35%) and sodium to potassium ratio (1. 63) were observed in control treatment. Conclusion: This study showed that the use of biochar can improve the morphophysiological properties and concentration of essential elements such as phosphorus and potassium in the aerial parts of safflower and in this regard, the amount of biochar consumption is important. According to Biochar analysis in terms of nutrients and carbon content, it seems that Biochar application may improve the nutritional status of these elements in soil and also increase Soil moisture storage capacity due to high content of Biochar organic carbon, it Provide a more suitable environment for plant growth and thereby improve growth indicators. Therefore, if the pistachio and other agricultural products waste are used properly as biochar, compensates a part of the lack of organic matter in the soils of dry areas and environmental pollution can be prevented.

Background and Objectives: Soil contamination by heavy metals is a serious environmental challenge and can cause problems for human and animal health globally. Most of remediation techniques to eliminate contamination from soils are very costly and deteriorate soil physical and chemical properties. The use of ornamental plants with high biomass and uptake is an innovative, economical and environmentally friendly way to remediate urban and industrial sites polluted by heavy metals. The purpose of this study was to investigate the ability of the marigold, ornamental cabbage and amaranthus to remediate cadmium contaminated soils in Zanjan province under greenhouse conditions. Materials and Methods: The present study was conducted as a factorial experiment in a completely randomized design. Experimental treatments included three types of plant (marigold (Calendula officinalis), ornamental cabbage (Brassica oleracea) and amaranthus (Amaranthus cockscomb) and soil cadmium levels (2. 2, 12. 2, 27. 2, 57. 2, 77. 2 and 102. 2 mg Cd/kg soil) which were used in triplicate. Results: The results indicate that high concentrations of cadmium in soil were toxic to plants and decreased the fresh and dry weight of the shoot and root. The highest level of soil cadmium (102. 2 mg Cd/kg soil) decreased the fresh weight of the shoot in the marigold, ornamental cabbage and amaranthus by 77, 69 and 62%, respectively, when compared to the control (zero cadmium) treatment. Also, the concentration of cadmium of the shoot in the marigold, ornamental cabbage and amaranthus, when the soil cadmium level was 102. 2 mg Cd/kg soil, increased by 39. 88, 21. 75 and 46 times, respectively, compared to the control (zero cadmium) treatment. The maximum amount of cadmium uptake for whole plant biomass was measured for marigold and ornamental cabbage when soil cadmium level was 77. 2 mg Cd/kg soil, but the highest uptake for amaranthus was calculated in treatment with 102. 2 mg Cd/kg soil. The lowest cadmium uptake was also observed in the control treatment. Translocation factors for cadmium in studying plants were higher than one and at the highest soil cadmium level (102. 2 mg cadmium per kg soil), the calculated translocation factors of plants were in the order of marigold > amaranthus > ornamental cabbage respectively. The shoot bioaccumulation factor at the soil cadmium concentration of 102. 2 mg Cd/kg soil was in the order of marigold > amaranthus > ornamental cabbage. The order of bioaccumulation factor for root at the soil cadmium concentration of 102. 2 mg Cd/kg soil was amaranthus > ornamental cabbage > marigold.Conclusion: The results showed that the translocation factor in the studied plants (marigold, ornamental cabbage and amaranthus) was more than one and the concentration of cadmium in dried tissues of aerial parts was more than 100 mg/kg. Therefore, these plants can be classified as metal accumulator plants in terms of cadmium uptake and translocation and are suitable for remediation of cadmium contaminated soils.

urban waste, environmental hazards of these wastes are on of the most important challenges in most cities that the safest way to prevent them from accumulating is to add them to the agriculture lands. This case is especially considered in countries with dry climates because of lacking organic matter in soils. Due to the high consumption of vegetables in the country and the use of sewage sludge as soil fertilizer, the risk of soil pollution for the peresence of heavy metals in soil and plant may threaten human and creature health. Consequently, studies need to be conducted to evaluate the effect of different levels of sewage sludge on of zinc (Zn), cupper (Cu), cadmium (Cd) and lead (Pb) concentration in root and shoot of radish (Raphanus sativus) and and basil (Ocimum basilicum) vegetables. Materials and Methods: This study aims to investigate the effect of domestic sewage sludge on concentration of zinc (Zn), cupper (Cu), cadmium (Cd) and lead (Pb) in radish (Raphanus sativus) and and basil (Ocimum basilicum) vegetables. A pot experiment in greenhouse was conducted at Ferdowsi University of Mashhad, Faculty of Agriculture, in 2018. The experiment was performed in a completely randomized design with three replications. Sewage sludge was consumed at five levels (0, 10, 20, 40, 80 t ha-1) during plant growth. Available form of heavy metals in soil samples was extracted by DTPA 0. 005 M solution. total concentration of heavy metals in sewage sludge and soil measured by Aqua regia method and concentration of plant metals measured by dry digestion method. Results: The results indicated that the use of the sewage sludge in different treatments levels had significant impact (P<0. 05) on the concentration on of these heavy metals in the two plants studied. increase of sewage sludge enhanced metals concentration in shoot and root rather than control plant. Particularly for Zn, in root and shoot in both plants. Increase in concentration metals in the two plants were followed Zn> Cu> Pb> Cd in both roots and shoots, The metals uptake in radish was drastically higher than basil. the value of all the metals at 10 t sludge per ha were lower than permissible concentration and at 80 t per ha were higher than permissible concentratoin for all of them. Conclusion: In general, application of different levels of sewage sludge in soil caused changes in soil chemical properties including decrease of soil pH, increase of electrical conductivity and soil organic carbon. Also, in the treatment of last level of sewage sludge, two plants were toxic and in the lowest level of treatment of sewge sludge, no toxicity and damage were observed in the plants. However, continuously application of the sludge at 10 t per ha did not plluted the plants, should be recommended cautiously As the results of the study indicate, application of the lowest level of sewage sludge should also be performed with constant precision and monitoring.

Background and Objectives: Soft computational techniques have been widely used in scientific research and engineering in recent decades. Since the measurement of hydraulic properties by direct laboratory methods is hard, time consuming and expensive, Thus, there is need to use alternative methods based on conveniently available soil properties to estimate it with less effort, time and cost. One of the new methods for estimating soil hydraulic properties, such as soil moisture characteristic curve, is non-parametric methods. This study was performed to determine the efficiency of the decision tree method in separation of effective properties in estimating soil moisture characteristic curve parameters. Materials and Methods: To perform this study, number of 72 points were selected in the village of Marghmalek and Sharekord city. Samples were collected from depth of 0-20 cm and then were transferred to the laboratory for required measurements. Some properties such as pH, EC, saturated moisture, calcium carbonate, organic matter, clay and sand, bulk density, mean weight diameter of dry aggregate, mean weight diameter of wet aggregate, geometric mean and standard deviation of particle diameter were measured in the laboratory. Also, the moisture characteristic curves were determined at 0, 1, 3, 5, 10, 30, 50, 100, 150, 1000, 1500 kPa suctions and were fitted to the van Genuchten model. The input variables were introduced into the MATLAB software in two scenarios (first scenario: pH, EC, %clay and sand, organic matter, calcium carbonate, mean weight diameter of wet and dry aggregate, bulk density, saturated moisture and the second scenario: pH, EC, geometric mean and standard deviation of particle diameter, organic matter, calcium carbonate, mean weight diameter of wet and dry aggregate, bulk density, saturated moisture) and modeled by decision tree and error estimators of cross validation and resub stitution. Evaluation statistics of each model including R2, RMSE and %RMSE were calculated. Results: The results obtained from decision tree modeling showed that the most important factors affecting moisture content in PWP suction, were saturated moisture and clay. The PWP target variable has the highest correlation in the first scenario (0. 88) and in the second scenario (0. 91) and the least error rate among the other variables and after that, FC has the highest correlation (0. 86) in the second scenario. Target variables n had the highest error rate and α the lowest correlation in both scenarios. Generally, the second scenario performed better than the first scenario by replacing the geometric mean and standard deviation of particle diameter with the percentage of clay and sand. The sensitivity analysis showed that PWP was the most sensitive among the input parameters to pH, BD, calcium carbonate and organic matter and FC was the most sensitive to geometric standard deviation of particle and MWDwet. Conclusion: In general, modeling has been successful in both scenarios. But by substituting geometric mean and standard deviation of particle diameter instead of clay and sand percentage, a better performance was obtained in estimating moisture characteristic curve variables in the second scenario.

Background and Objectives: Drought is the most important known abiotic stress which strongly affects the growth and yield of different crops worldwide. Among all the mineral nutrients, potassium (K) plays a particularly critical role in plant growth and metabolism, and also contributes to the survival of plants and adequate biomass production under various biotic and abiotic stresses, especially under drought stress. Under drought stress conditions, K regulates the stomatal opening and helps plants adapt to water deficits. In this study, the effect of phlogopite, as a potassium-rich source and a soil chemical conditioner, to help moderate the adverse effects of drought stress on barley growth and yield under greenhouse conditions was evaluated. Materials and Methods: This study was conducted as a completely randomized design with factorial arrangement and 3 replications in the hydroponic greenhouse of the Isfahan University of Technology. The growth medium was a mixture of quartz sand and phlogopite and different levels of drought stress were applied. Plants were supplied with either a complete or a potassium-free nutrient solution during the five-month growth period. At the end of the experiment, shoots and roots were harvested separately and their dry weight recorded. The amount of potassium in the extract prepared by the dry ash method was determined by a flame photometer. The percentage of potassium release from phlogopite in potassium-free nutrient solution was calculated and elemental analysis (XRF) was performed on several selected samples. Results: The shoot and root dry weight and potassium uptake of plants grown in the phlogopite containing media were higher than those in the control media. These two parameters were also higher in plants received complete nutrient solution as compared to those supplied with the K-free nutrient solution. Drought stress reduced yield and potassium uptake. The highest levels of loss of dry weight and potassium uptake were observed in plants supplied with the K-free nutrient solution under severe drought stress. There was a significant positive correlation between the shoot dry weight and K uptake and also between the root dry weight and K uptake. The results of the elemental analysis of phlogopite particles before and after application in the growth medium were consistent with the amount of potassium uptake by the plant. The highest percentage of potassium removal was observed under no drought stress conditions. In general, it looks like that the application of phlogopite alleviates the negative effects of drought stress by releasing its interlayer potassium, due to the important role of potassium in regulating stomatal opening and closing, increase photosynthesis rate and water retention in plant tissues. Conclusion: The results of this study showed that the application of phlogopite was useful as a natural and low-cost source to supply K requirement in plant growth medium to reduce the effects of the drought stress, especially in the greenhouse.

Background and Objectives: In recent years, the use of aluminum sulfate has been considered by farmers as an alternative compound to sulfuric acid due to the high risks and the need for special tools and equipment, as well as elemental sulfur due to the slowly oxidation in unsuitable conditions of calcareous soil in vineyards and agriculture lands. For this purpose, the present study was conducted to investigate the effect of aluminum sulfate and iron sulfate on the adsorption and chemical forms of zinc in a calcareous soil. Materials and Methods: The amounts of 22. 21 and 27. 8 g of aluminum and iron sulfate calculated for neutralizing of 2% of lime, respectively and were added to 500 g of soil. The samples were incubated for two weeks at 25± 1 ° C under field capacity (FC) condition, according to the kinetic experiment. At the end of incubation, adsorption experiments carried out with different initial concentration of Zn (0-300 mg L-1 Zn) with 0. 01 M CaCl2 as a background solution, Zn-extractable by DTPA method and Zn distribution by Tessier sequential extraction method were determined. Results: The results showed that adding of aluminum and iron sulfate to soil reduced and increased zinc adsorption, respectively. Nonlinear fitting of experimental showed that the Freundlich model (with highest R2 and lowest SE) was better fitted to the experimental data compared to the Langmuir, Temkin, and Doublebin-Raduskvich models, and sorption capacity factors (qmax, B, KF, qD) and sorption energy factors (KT, KL, n) decreased with application of aluminum sulfate but increased with application of iron sulfate. The sorption energy parameter (E) of Dubinin-Radushkevich was less than 8 kJ mol-1, indicating that the Zn adsorption process was physical. The sorption intensity (SI) index of zinc decreased with application of aluminum sulfate and increased with application of iron sulfate, respectively. Application of aluminum sulfate reduced the exchangeable form of zinc and increased carbonate form, while the application of iron sulfate significantly decreased the exchangeable form and increased oxide forms. Conclusion: It was concluded that application of aluminum sulfate in soil lead to transformation of the zinc from insoluble forms into more soluble forms and increased zinc bioavailability, while the application of iron sulfate decreased Zn bioavailability due to reduction of zinc sorption in the soil.