APPLIED SOIL RESEARCH
Year:2020 | Volume:7 | Issue:4|Papers Count:15

Biochar and hydrochar are carbonacious solid materials that produced through carbonization of biomasses, resulting in carbon sequestration and soil fertility improvement. The aim of this study was converting different biomasses including sewage sludge, poultry manure, sugar beet tailing, wheat straw, and apple wood wastes to biochar and hydrochar and investigating their chemical properties. Also, using a factorial experiment on the basis of completely randomized design with three replications, the effects of the apple wood biochar and hydrochar were studied in the presence and absence of monocalcium phosphate fertilizer on soil pH and EC and available P, K, and Na. A slow pyrolysis process with a temperature of 500 º C for 1 h was employed to produce the biochar and a hydrothermal carbonization process with a temperature of 180 º C and pressure of 11 bar for 12 h was applied to produce the hydrochar. After conversion of biomasses to biochar and hydrochar, yield percentage of the biochars and hydrochars and pH, EC, ash percentage, and concentrations of N, P, K, Ca, Mg, Na, Fe, Mn, Cu, and Zn in initial biomasses, biochars, and hydrochars were measured. The results showed that the ash percentage and elements concentrations in biomasses, biochars, and hydrochars of poultry manure and sewage sludge were greater than those of sugar beet tailing, wheat straw, and apple wood. The pH of all biochars was more than 7, and the pH of all hydrochars (except for the poultry manure-derived hydrochar) was less than 7. Application of wood biochar increased soil pH and the integration of P-fertilizer with hydrochar decreased soil pH. The soil pH and EC in presence of hydrochar were lower than those of biochar with and without P-fertilizer. The P-fertilizer had synergistic interactions with biochar and hydrochar in terms of soil available-P. The effects of biochar, hydrochar, and P-fertilizer application on soil available-potassium and sodium were not significant. Regarding the acidic pH of the studied hydrochars and increased concentrations of some nutrients in the investigated biochars and hydrochars, the applications of biochar and hydrochar accompany with P-fertilizer could be recommended in calcareous soils...

Soil organic matter (SOM) is one of the important soil quality factors and knowledge of its condition in soil, is one of the most important steps in the management of land resources and controlling soil losses. As SOM monitoring is an expensive and time-consuming task, any method which can produce high quality maps of SOM with available axillary soil data and less samples, would be a step forward in reaching the goals of sustainable agriculture. The aim of this research is to predict SOM using soft data, auxiliary data and Bayesian maximum entropy method (BME). Soil samples were gathered from the Bonab-Miandoab plain, and almost 122 samples were collected from 0-20 cm depth of surface soil. SOM and some other soil properties including soil texture, aggregate stability, and calcium carbonate equivalent were measured. Later spatial prediction of SOM was done using SOM soft data, auxiliary data and generalized linear model (GLM) using BME method. Results showed that the highest R, lowest RMSE and nRMSE with values of 0. 97, 0. 07 and 0. 12 respectively, belonged to spatial prediction of SOM with soft data and error. Results also revealed that the developed GLM model with calculated error, resulted in better R, RMSE and nRMSE in comparison to predictions with GLM model without error (R, RMSE and nRMSE improved from 0. 65, 0. 58 and 0. 55 to 0. 85, 0. 31 and 0. 29 respectively). As a conclusion, BME method has provided the possibility of merging error resulted from the use of soft data, in spatial prediction equations and through that, has helped to improve spatial prediction of SOM...

Application of various nanoparticles is increasing in different industries, including agriculture. Hence, extensive researches requires is needed to assessment of the relationship between metallic nanoparticles and dominant chemical species of the metals elements in the soil. For this purpose, a research was carried out to investigation investigate of the effects of zinc oxide nanoparticles and zinc sulfate fertilizer on zinc chemical species in the soil solution and also its correlation with concentration and uptake of zinc in wheat plant. This study was conducted in greenhouse conditions as a completely randomized design with three replications. The experiment treatments include ZnO Nanoparticles nanoparticles at three levels (100, 200 and 300 mg. kg-1), ZnSO4 fertilizer (40 kg ha-1) and Control. Some chemical properties of the soil, concentration and uptake of zinc were measured at the end of the cultivation season. Geo-Cchemical model of visual MINTEQ was used after the extraction of soil solution elements, in order to estimation of the dominant chemical species of zinc in the soil solution. The results indicated that soil solution pH, soil available zinc and DOC were influenced by the treatments. The ZnO nanoparticles significantly were decreased the soil pH. Also, these nanoparticles significantly were increased the DOC and soil available zinc. The highest amount of zinc free species (Zn2+) was obtained in treatment of zinc oxide nanoparticles at level of 300 mg. kg-1. ZnO nanoparticles and ZnSO4 fertilizer significantly were increased the Zn-DOM specie compared to control. The results also showed that a positive correlation between Zn2+ and Zn-DOM species with concentration and uptake of zinc in various parts of wheat...

In order to investigate the effects of salicylic acid and calcium on resistance chilling of pistachio seedlings, cv. Kale-Quchi, a factorial greenhouse experiment was carried out in a completely randomized design with three replications. Treatments consisted ofwere salicylic acid (0, 0. 75 and 1. 5 mM), calcium (0, 3 and 6 per thousand) and temperature (0,-2 and-4 ° C). The results showed that, leaf electrolyte leakage percentage increased with decreasing temperature to-4 ° C, but combined application of salicylic acid (1. 5 mM) and calcium (6 per thousand) decreased this important indicator of chilling by 47 percent compared to control in this temperature. Also, with decreasing temperature (from 0 to-4 ° C), the phenolic compounds, and soluble sugars and proline concentration incresed 44 and, 31 and 100 percent respectively and proline concentration more than two folds increaded compared to control seedlings. Also, the results of this experiment showed that the chlorophyll fluorescence index, total chlorophyll, carotenoids, soluble proteins and starch content decreased with decreasing temperature, but with combined application of 1. 5 mM salicylic acid and treatment ofcalcium (6 per thousand) calcium, the amount of these parameters increased these parameters compared to control. So that the content of total chlorophyll, carotenoids, protein and starch increased compared to control at 4 ° C by 87, 49, 25 and 99 percent, respectively compared to control and protected pistachio seedlings against chilling. Based on the results of this study, in chilling conditions, the combined application of salicylic acid and calcium, by improving the photosynthetic parameters and increasing osmotic regulators, decreased detrimental effects of chilling of pistachio seedlings. in chilling conditions...

Soil is the main nonrenewable natural source in the world. Soil degradation is the main threat across the globe and cause to decrease the soil ability in economical and biological production as well as environmental Instability. Therefore, the consideration of affective factors of soil degradation and determination of regional solutions has an important role in using and protecting soils. One of the suitable methods in studying the soil degradation is FAO/ UNEP method that studies different soil physical and chemical factors. The purpose of this research, therefore, was to study the soil degradation in Joupar plain by quantitative FAO/ UNEP method approach. To do this research, the 46-point sampling (auger and profile) on topographic map with a scale of 1: 25, 000 with regular network, was determined. Finally, in each land unit components, a control profiles, the sampling was done and the final classification. The chemical and physical properties of soil were determined by conventional methods. The effect of chemical properties (salinity and alkalinity) and physical properties (density, soil and water table depth) on soil degradation using the formula and weighting coefficients presented in FAO-UNEP assessment and destruction of soil was obtained. The results of this study showed that the total of 39. 2 percent of the studied lands were prone to the chemical soil degradation in which 28. 2 percent of the area were classified as very high and 1l percent classified as low risk in this regard. The total physical degrading risk of the studied lands were determined about 39. 2 percent in which 28. 2 percent of the lands classified as low risk while 11 percent were considered at medium level of degradation risk. It was also found physical properties density had the greatest impact on the destruction area...

Edible crops grown in cadmium polluted soils are the primary source of large amounts of cadmium entering the consumer body. To investigate the effect of potassium (K) and zinc (Zn) on tuber yield and uptake and accumulation of cadmium (Cd) in potato tubers, a factorial experiment in a randomized complete block design with 9 treatments and 4 replications has been carried out in 2014-15 in one of the polluted farm in the Faridan, Isfahan province. In this study, potassium sulfate (SOP) was applied at three levels (0, 150 and 300 kg ha-1) and zinc sulfate at three levels (0, 20 and 40 kg ha-1) were used. The results showed that the highest tuber yield and percentage of dry matter were 38505 kg ha-1 and 23. 14 that obtained from treatment 150 kg ha-1 SOP + 20 kg ha-1 ZnSO4 and the lowest was 24000 kg ha-1 and 19. 88 that obtained from control. The highest concentration of K in tubers was equal to 378 mg kg-1 that obtained from 300 kg ha-1 SOP + 40 kg ha-1 ZnSO4, and the lowest was equal to 210 mg kg-1 that obtained from control. The highest concentration of Zn in tubers was equal to 40 mg kg-1 that obtained from 150 kg ha-1 SOP + 20 kg ha-1 ZnSO4, and the lowest was equal to 20 mg kg-1 that obtained from control. While Cd concentration in the control was 0. 77 mg kg-1, it decreased significantly in all other treatments, and the lowest was 0. 23 mg kg-1 in both 150 kg ha-1 SOP + 20 kg ha-1 ZnSO4 and 300 kg ha-1 SOP + 20 kg ha-1 ZnSO4 treatments. According to the obtained results it can be concluded that application of K2SO4 and ZnSO4 fertilizers in the polluted farm is necessary for obtaining higher yield and is necessary for healthy crop...

Soil erosion by water is one of the most important destructive factors on the earth's surface. The slope and aspect are the factors controlling the movement of water and sediments on the surface of the slopes and have a special contribution in different soil characteristics. In general, the public relations of surface erosion and soil loss are continuous, depending on the degree and length of the slope. As the degree and length of the slope increases, the discharge and flow rate increases, and the rate of separation and transfer of particles increases as well. This study was conducted to investigate the effects of slope and aspect on soil characteristics in slopes with weak vegetation cover in Western Zanjan semi-arid region, northwest Iran. Five plateaus were surveyed on both the northern and the southern slopes with different slope percentages (9-10, 13-17, 16-22, 29-31 and 33-37 percent). Soil samples were taken from two depths (0 to 5 and 5 to 15 cm) at four positions with a distance of two meters along the slope during two replications. Finally, 160 soil samples were considered for determination of particle size distribution, organic matter and lime size distribution. The results of this study showed that the surface erosion of the studied area was strongly affected by slope and aspect of the land. In the two-meter position from the top of the slope, there was the highest degree of fine particle erosion but at the bottom of the slope, the relative frequency of fine particles was increased. The surface erosion rate in the southern slopes was on average 23% higher than that of the northern slopes. Also, the results showed that increasing the slope had an incremental effect on the amount of sand and a significant reduction effect on clay content (P < 0. 05, R2 = 0. 43)...

Zinc is one of the most critical nutrient elements limiting the plant growth. To investigate the effects of soil Zn deficiency on some physiological and morphological traits in bread wheat (Triticum aestivum L. ), a factorial experiment was conducted based on completely randomized design (CRD) with three replications in greenhouse. Zn-efficient (Bayat and Nik-nejhad) and inefficient (Hirmand and Karaj-1) cultivars were grown in Zn-deficit (0 mg kg-1 soil) and-adequate (5 mg kg-1 soil) soils. The studied traits were 1000 grain weight, number of grains per spike, chlorophyll content, grain, root and leaf Zn concentrations and some morphological traits. The results of variance analysis showed that all traits are significantly (P≤ 0. 01) affected by Zn levels and cultivars, while the interaction effects of Zn level × cultivars were only significant (P≤ 0. 01) for root, shoot and grain Zn concentrations. Mean comparisons of the interaction effects revealed that under soil Zn deficiency, the concentration of root Zn in Zn-efficient cultivars (Nik-nejhad: 59 mg kg-1, Bayat: 44. 75 mg kg-1) is significantly (P≤ 0. 01) more than those of Zn-inefficient cultivars (Hirmand: 30. 58 mg kg-1, Karaj-1: 32. 98 mg kg-1). The grain Zn concentration of Bayat (28. 82 mg kg-1) cultivar was also significantly (P≤ 0. 01) more than those of Zn-inefficient cultivars (Hirmand: 24. 95 mg kg-1 and karaj-1: 22. 85 mg kg-1). The estimation of trait decline percentage under soil Zn deficiency revealed more decrease for shoot dry weight, root and grain Zn concentrations and chlorophyll content in Zn-inefficient cultivars, compared to Zn-efficient ones. In conclusion, the results of the current study demonstrated that Zn-efficient bread wheat cultivars are able to produce more dry matter and accumulate more Zn in grains under soil Zn deficiency conditions...

Success of the phytoremediation technique depends not only on plant species, but also largely on the interactions of plant roots with the rhizosphere microorganisms. These microorganisms, especially bacteria with plant growth promoting traits, can improve efficiency of phytoremediation by helping to proper plant establishment, increasing root system growth and, consequently, increasing plant growth and enhancing heavy metal uptake. Considering the important role of soil microbial community in increasing the remediation of polluted soil with plants, this research was conducted with the aim of isolating, screening, investigating the traits of cadmium and lead-resistant bacteria and introducing superior isolates. Soil samples were taken from Cd and Pb contaminated soils of the Shahid Tondguyan oil refinery and after measuring some physical and chemical properties, heavy metals resistant microorganisms were isolated from them. Resistance to cadmium and lead was determined in the isolates, and then the ability of the superior isolates to produce phytohormones of auxin, secretion of growth inhibitor metabolites and solubilization of insoluble inorganic phosphate were evaluated. In this study, thirty microorganisms were isolated from contaminated soils. After examining the appearance of the colony, its color and margin, as well as the growth rate, at the end, 20 different isolates were selected. 70% of the studied isolates showed a very good growth in culture medium up to a concentration of 8 mM l-1 of lead and cadmium. The results of evaluation of plant growth promoting traits in the top 10 isolates in terms of resistance to heavy metals of lead and cadmium showed that all of these isolates had the ability to produce auxins and dissolve insoluble inorganic phosphates. The highest (10. 20 mg l-1) and the lowest (0. 64 mg l-1) auxin production were observed for C4 and C2 isolates, respectively. The average solubility of tricalcium phosphate by isolates was 106. 91 mg l-1. 80% of isolates had the same ability to produce siderophore. The highest rate of production of this metabolite was observed in the isolate C1 with a halo to colony ratio of 23. 3. Among 10 studied isolates, three isolates, K2, K5 and C8, were able to produce hydrogen cyanide, protease and cellulase enzymes...

Soil saturated hydraulic conductivity (Ks) can be estimated from surrogate data such as soil texture, bulk density and organic carbon and CaCO3 contents using regression (Reg-PTFs) and artificial neural networks (ANN-PTFs) pedotransfer function (PTF). Saturated hydraulic conductivity was measured by falling head method in 100 soil samples that obtained from Ardabil plain, Iran. After performing physicals and chemicals analysis on soil samples, the data were divided into two sets of training (80 samples) and validation data (20 samples). Regression models were created by SPSS software, stepwise method and neural networks models were created by Neurosolution software. Statistics criteria such as coefficient of determination (R2), root mean square deviation (RMSE) and Akaike information Criterion (AIC) were determined. Input variables in the best regression models were sand, silt and bulk density. The best neural network models were obtained from the input variables that include bulk density, geometric mean and standard deviation of soil particle size distribution. The values for R2 and RMSE in training and testing data set for the Reg-PTF were 0. 53, 0. 074 and 0. 51, 0. 052 and for the ANN-PTF they were 0. 84, 0. 04 and 0. 73, 0. 06, respectively. In this research all independent variables such as bulk density, particle density, CaCO3, geometric mean and standard deviation of the particle size distribution included as inputs for development of Reg-PTFs and ANN-PTFs. The amount of R2 and RMSE for training and testing data set equal 0. 87, 0. 036 and 0. 58, 0. 076, respectively. Results showed that the ANN-PTF (R2= 0. 84) performs better than the Reg-PTF (R2= 0. 53) in this case. It was also found that when all independent variables were used as inputs in the neural ANN-PTF the values of R2 and RMSE (0. 87 and 0. 036) have been improved in the training data set...

In order to study the effect of two organic amendments on some physical properties of three soils with different textural class, a greenhouse experiment was conducted as a factorial arrangement in completely randomized design with three replications. Treatments consisted of two types of organic materials (compost and ripe fig fruit waste), four organic material levels (zero, one, two and four % by weight) and three types of soil textural class (Loamy Sand, Loam, and Silty Clay Loam) from Maharloo, Zarghan and Shiraz areas in Fars Province, Iran. Four months after mixing the organic material with soil, some physical properties of the soil including the mean weight diameter (MWD), the final infiltration rate of water in the soil, field capacity (FC), and water evaporation from the soil surface were measured. Results showed that application of 4% ripe fig fruit waste significantly increased the average MWD, infiltration rate, FC moisture by about 32. 4, 8. 5, and 9. 02% respectively, and application of 4% compost significantly increased the average MWD, infiltration rate, and FC by about 69. 3, 5. 4, and 7. 7% respectively as compared to that of control. Moreover, application of 4% ripe fig fruit waste and compost significantly decreased the average of water evaporation from the soil surface by about 10. 9 and 22. 3 %, respectively as compared to that of control. According to the results, organic waste can be used as an amendment in soils with different textural class to improve soil physical condition. Moreover, results showed that the effect of compost in improving the physical properties of the soil was more than that of ripe fig waste...

Digital soil mapping approaches that require quantitative data for prediction are difficult to implement in countries with limited data on soil and auxiliary variables. Extensive field sampling is very labor intensive and costly that is problematic for mapping missions. On the other side, it is believed in digital soil mapping approaches that unique soil conditions (soil types or soil properties) can be associated with unique combination and configuration of environmental variables. In this study we used a Random Forest (RF) algorithm combined with classification information of 64 soil profiles and 19 environmental variables (including terrain attribute, geomorphology units, land use and vegetation cover index) to map soil classes in the part of loess plateau, Golestan Province Iran. Geomorphology, elevation, slope aspect and land use were the most important parameters in prediction of soil map in different taxonomic level. The results of accuracy assessment of RF with different entrance variables revealed that accuracy of model including overall accuracy and kappa index respectively decreased of 0. 91 and 0. 83 for great group, 0. 78 and 0. 56 for subgroup, 0. 50 and 0. 32 for family. The minimum and maximum Out of bag (OOB) estimate error rate in modeling were 32. 69% and 65. 38% for great group and soil family, respectively and the soil classes with higher frequency had the lower OOB error. The present study showed that in regions of Iran with limited data, digital soil mapping and high resolution ancillary data with smaller sample size can be led to an effective result in higher taxonomic levels...

Assessing the spatial variability trend of various soil properties is a helpful procedure to access to the efficient site-specific management of this ecosystem vital component. Aimed to investigate the spatial soil variability in lands of Zanjan University, 48 topsoil (0-25) samples were collected based on a regular grid of 250 meter. Soil samples were analyzed for some physical properties, including bulk density, available water capacity, saturated hydraulic conductivity, mean weight diameter and clay, sand, organic carbon and equivalent calcium carbonate percentage. Identifying the spatial structure of selected properties, ordinary kriging was used to estimate the values of soil properties in un-sampled locations and continuous maps were prepared. The results showed that saturated hydraulic conductivity (43. 28%) and bulk density (5. 53%) had the maximum and minimum coefficients of variations, respectively. The spherical model was performed well to describe the spatial structure of organic carbon and carbonate calcium equivalent; whereas exponential model showed the best fit to the remained soil properties. Saturated hydraulic conductivity showed a strong correlation class; whereas spatial structure of other studied properties was moderately correlated. Interpolated maps revealed that increasing clay percentage from the south to the north of study area led to the decreased contents of saturated hydraulic conductivity and increased values of available water capacity. This observation indicated that considering soil youthfulness and less-developed soil structure, most of the soil physical properties are mainly influenced by soil texture. It is also observed that cultivated crops in the south of studied area and apple trees in the north, resulted in the soil organic carbon to be increased to more than 1%, in turn, led to the significant increase in mean weight diameter of soil aggregates in these areas...

In order to study the effect of Pseudomonas putida and Glomus mosseae on accumulation of nutrient elements residual on root, straw and soil in wheat under dryland conditions, an experiment was carried out in a factorial arrangement using randomized complete block design with three replications at Agricultural Research Station of Ilam University and Sarableh Agricultural and Research, Recources Center during 2013-2014 cropping season. Experiment factors consisted of two dry land wheat cultivars (Keras Sablan and Saji) and fertilizer sources treatment including of 1-without application of phosphorus chemical fertilizer, 2-50 kg ha-1 P, 3-Pseudomonas putida (PSB), 4-Glomus mosseae (GM), 5-PSB+GM, 6-PSB+GM+25 kg ha-1 P, 7-PSB+ 25 kg ha-1 P and 8-GM+25 kg ha-1 P. Results indicated that interaction effect between cultivar× fertilizer sources had significant effect on accumulation of nutrients elements residual in root, straw and soil in dryland wheat at 1% probablity level. Application of PSB and GM caused increased in N, K, Fe and Cu in soil and the lowest N, P, K, Zn, Fe, Cu and Mg were obtaind in root and straw. The highest N, K, Fe and Cu in soil belonged to Saji cultivar× GM+25 kg ha-1 P. Root and straw had the highest N, P, K, Zn, Fe, Cu and Mg in root and straw in Keras Sabalan×check treatment (without feriilizer sources)...

Biochar is known as a widely-use amendment in improving phytoremediation efficiency through the increase of plant growth; whereas its influence (either individually or in combination with bacteria) on the reduction of heavy metals (HMs) bioavailability of soil is an important advantage. This study was planned to assess the effects of separately and combined of biochar produced by forest wood wastes of hornbeam at three levels of 0, 2. 5 and 5% of soil dry weight and Pseudomonas fluorescens bacteria on growth properties of potted white willow (Salix alba L. ) seedling in a HM contaminated soil (Pb, Cu, and Cd). The variation of bioavailability (BA) and removal efficiency (RE) indexes, and bioaccumulation (BCF) and translocation (TF) factors also were analyzed in the treatments. The experiment was conducted under greenhouse condition for a 160 days’ period. The results showed that the variation in most growth components of seedlings was significant in the separate and combined treatments. The combined treatment of bacteria-biochar (at 5% level) increased the dry weight of leaf, shoot, root and total plant about 59, 36, 142, and 85% in comparison to the control (without the biochar and bacteria). In the biochar treatments, the BA, RE (except Pb), BCF, and TF (only in 2. 5% of biochar) for Pb, Cu, and Cd were 13-57, 4-47, 29-60, and 16-33% lower than those in control, respectively. These indexes were improved by up to 191, 79, 84, and 13% in the bacteria-biochar treatment in compared to the individual application of biochar. In overall, according to our findings, the combination of biochar-bacteria led to the HMs bioavailability and improving the white willow function to eliminate soil HMs. So that, co-application of biochar and bacteria as soil amendments can increase growth parameters in white willow seedling and improve HMs bioavailability of plant in phytoremediation process...