نشریه تحقیقات کاربردی خاک
سال چهارم شماره 2 (زمستان 1395)

Cation Exchange Capacity (CEC) is an important characteristic of soil in absorption and desorption of nutrient and potential of heavy metals hazard and some of organic contamination. Knowing spatial patterns of CEC for sustainable management of ecosystems, has special importance. hence, the main objectives of this research was to evaluate, recognize and introduce the best interpolation methods for prediction of CEC in some of Guilan province soils. 153 points of surface soil in depth 0-15 cm were sampled and were measured clay, Organic carbon and CEC. Interpolation methods including kriging, cokriging, fuzzy kriging and regression kriging have been done using GIS. Results showed that the hybrid methods including regression kriging and fuzzy kriging, respectively with RMSE values of 1.02 and 1.2, significantly reduced the error of prediction compared with the other methods. In addition, between these two mentioned methods, the regression kriging had more efficiency in prediction of CEC. The results also revealed that increasing the number of data by means of the best pedotransfer functions (created by ANFIS) will enhance the accuracy of prediction. In general, combination of the best pedotransfer functions with the best interpolation method increased the accuracy of CEC prediction in the study area.

In order to perform this research, a greenhouse experiment was conducted in a completely randomized design with three replications. Treatments were involved: inoculation of Mentha peparata L. with 5 plant growth promoting (PGP) and arsenic-resistant isolates and control (without use of inoculant). Results revealed that inoculation of Oregano with superior isolates had significant effect on proline concentration. The greatest accumulations of proline (0.23 µg g-1FW) was observed in plants inoculated with AHG-6 isolate. The application of PGP isolates significantly increased chlorophylla, b, total chlorophyll content, chlorophyll index and carotenoids proportions compared with control. The inoculation of Mentha peparata L with PGP isolates has no significant effect on the plant phosphorus concentration. The utilization of all PGP microorganisms notably propagated the shoot magnesium concentration compared with control. Whereas only AHG-5 and AHG-6 significantly increased the root magnesium concentration. Regarding calcium and potassium, the use of PGP isolates augmented their concentration in the root and shoot, although there was no significant between some treatments and control The utilization of all PGP microorganisms notably propagated the shoot magnesium concentration compared with control. Whereas only AHG-5 and AHG-6 significantly increased the root magnesium concentration. Regarding calcium and potassium, the use of PGP isolates augmented their concentration in the root and shoot, although there was no significant between some treatments and control.

Quantitative knowledge of soil water characteristic curve is crucial for modeling water flow and transport processes in agriculture and hydrology. In this study, HYDRUS2D/3D software was used to estimate the hydraulic parameters of van Genuchten-Mualem model via inverse modeling using double-ring infiltrometers. Double-ring infiltration experiment was conducted in three sites with different soil textures (i.e., silty clay, loam and sandy loam) with three replications. Disturbed and undisturbed soil samples were also collected from three depths (0−10, 10−30 and 30−60 cm) per each soil and some soil physical properties such as bulk density, texture, initial water content and saturated water content were measured. Soil water retention curve was determined for the matric suctions lower than 100 cm H2O by sand box, and for the matric suction range 100−15000 cm H2O using pressure plate. The van Genuchten model with Mualem’s restriction was fitted to the soil water retention data by RETC software. The accuracy and reliability of the HYDRUS predictions were evaluated. The results showed that inverse estimation of soil hydraulic parameters provided a reliable alternative method for determining the soil water retention curve at horizon/field scale. The soil water retention curves obtained from the RETC fitting had very good correspondence with those derived from inverse modeling; the efficacy parameters of inverse estimation (i.e., Pearson’s correlation coefficient (r), root of mean squared differences (RMSD, m3 m-3), absolute value of mean differences (AMD, m3 m-3) and the mean difference (MD, m3 m3)) were 0.988, 0.036, 0.012 and 0.008, respectively. Also there was a good agreement between the water content values measured in the soil profile and those predicted by HYDRUS (R2= 0.936).

The plants which can be used to clean up the heavy metals contaminated soils but, for this reason may take years or even decades, because of this chemical and biological treatment uses for phytoremediation. In this study, the potential of corn (hybrid KSC. 704) for accumulation of lead was conducted as an experiment using a completely randomized design with three replications in a greenhouse experiment in a sandy loam soil contaminated with Pb. Citric acid and EDTA were used at concentrations level 0, 0.5 and 1 mmol kg-1 soil and poultry manure extract 0, 0.5 and 1 g kg-1 soil. The results showed that the effect of chelating agents on the shoots and roots Pb concentration, shoots absorption Pb and biological concentration factor (BCF) was (p

Infiltration plays an important role in surface and subsurface hydrology and it is a key factor in the rainfall and runoff equations. The use of new approaches that have no limitations of common theoretical and empirical methods to determine infiltration relationships, will minimize the necessity of time consuming and costly experiments to determine permeability values and will make it possible to estimate the functional values. In this regard, in the present study the amount of soil permeability was estimated in Behshahr plain of Galougah located in Mazandaran province, using Fuzzy Inference System (FIS), Fuzzy Clustering Algorithm (FCA) and Nero-Fuzzy (ANFIS); so that, initial soil moisture content, soil organic matter content and soil lime content were considered as input parameters, and final soil infiltration rate was considered as output parameters of the models. Finally, the results obtained by the three mentioned modes were compared to the observed values by single-ring approach. According to the achieved results, Nero-Fuzzy approach with a mean deviation of 0.0042 cm/min, BIAS value of 0.6754 cm/min, Root-Mean-Square Error of 1.2096 cm/min and correlation coefficient of 0.9233 showed the most appropriate performance to estimate soil infiltration rate among the studied models; while, Fuzzy Clustering Algorithm with a mean deviation of 0.0075 cm/min, BIAS value of 2.1165 cm/min, Root-Mean-Square Error of 2.0244 cm/min and correlation coefficient of 0.8776, and Fuzzy Inference System with a mean deviation of 0.0161 cm/min, BIAS value of 2.5042 cm/min, Root-Mean-Square Error of 2.4533 cm/min and correlation coefficient of 0.8167 were placed in the next ranks respectively. Also, the highest correlation between observed and estimated values was seen in Nero-Fuzzy model (R2=0.85), and the two other studied models including Fuzzy Clustering Algorithm (R2=0.77) and Fuzzy Inference System (R2=0.66) are at the next ranks respectively. At the end of this research providing more data of soil physical and chemical characteristics as well as permeability amounts has been recommended in order to more accurate estimation of the studied models.

Use of organic manure can improve yield of agricultural products for sustainable agriculture. This research was conducted to study the effects of Chicken manure and Potassium fertilizer on yield and uptake of some nutrients by Potato in a factorial experiment with a randomized complete block design that replicated three times for two years in Tajarak research station, Hamedan Province. The Chicken manure had four levels (0, 5, 10 and 15 T/ha) and Potassium fertilizer had three levels (0, 50 and 100 kg/ha) as Potassium sulfate. In flowering stage, shoot yield and nutrient concentrations was determined by sampling. Yield of potato tubers and nutrient concentrations of tubers were also determined after harvesting. Combined data of two years of experiment showed that the main effect of chicken manure on the potato tubers and shoot yield and also the nutrient concentrations were significant. The main effect of potassium sulfate was only significant on the copper and zinc concentrations of tubers and the shoots. Consumption of 50 kg/ha potassium sulfate made maximum concentration of copper and zinc in tubers and shoots. Use of 5 T/ha chicken manure caused the highest yield equal to 44.7 T/ha. The maximum nutrient concentrations in tubers and shoots and maximum yield of shoots was obtained with application of 15 T/ha chicken manure. Therefore, in the soil conditions similar to this research, using 5 T/ha chichen manure could cause considerable increase in tuber yield.

Gypsiferous soils comprise an important part of soil resources in arid and semiarid areas in the world and gypsum is the most common sulphate mineral in the soils of arid and semiarid areas. Accumulation of gypsum in the soils affect the most of physic-chemical, mineralogical and engineering properties of soils and in the most of cases results in serious problems for human activities. In this research, 9 soil profiles that all mostly located on the gypsiferous parent material in Nooshi Shahr region, were dug, described and sampled and their morphological, physical, chemical and mineralogical properties were determined using standard methods. Finally, soils were classified according to American soil taxonomy (2014). According to the results, gypsum content of soils varied from 62.91% in Cyy horizon of profile 1 to 2.91% in Ap horizon of profile 8 and each change in gypsum content of soils followed by variations in other properties of soils. Results showed that the soils with higher gypsum content had lighter color, lighter texture, lower values of organic Carbone and cation exchange capacity and higher values of electrical conductivity. These parameters reversely changed with decreasing of gypsum content of soils. Mineralogical studies revealed the presence of smectite, illite, chlorite, vermiculite and palygorskite as major clay minerals in these soils. The origin of illite, chlorite and kaolinite were related to the inheritance from parent material and the origin of vermiculite was related to the transformation of illite. Smectite group of clay minerals in these soils have been resulted from three origin of inheritance from parent material, transformation of other minerals (especially from illite) and neoformation. Palygorskite had pedogenic origin and has been formed in the soil via neoformation. The comparison of clay mineralogy of soils with different gypsum values revealed the presence of higher smectites in soils with higher gypsum and palygorskite was identified just in soils with higher gypsum. But, in soils with lower values of gypsum, illite and chlorite were the predominant clay minerals and palygorskite has not been identified in these group of soils. Finally, regarding to the effect of gypsum on morphological, physical, chemical and mineralogical properties of studied soils, in order to optimum use of these soils, revision in their management is necessary.

In order to evaluate the effect of Azolla compost on qualitative and quantitative parameters of the rice under PGPRs inoculated, a factorial experiment in a randomized complete block design with three replications was conducted in Guilan province. Experimental Factors including Azolla compost (0, 5 and 10 ton.ha-1) and plant growth promoting bacteria (non-inoculated, Herbaspirillum, Azospirillum). The results showed that the bacterial effect on acidic and alkaline phosphatase was significant so that the Azospirillum was superiority compared to non-inoculated treatment and Herbaspirillum. The use of 10 ton.ha-1 of Azolla compost significantly increased in activity of acid phosphatase. Interaction of Azolla compost and PGPRs on tiller numbers, plant height, grains number.panicle-1, biomass and grain yield were significant. The maximum grain yield was obtained from 10 ton.ha-1 of Azolla compost Azospirillum with 7946 kg.ha-1 that compared to the control and 10 ton.ha-1 of Azolla compost had increased 31.28 and 27.47 percent, respectively. The bacterial inoculation, increased significantly phosphorous compared with non-inoculated treatment. While the maximum amount of phosphorus and potassium was observed. 10 and 5 ton.ha-1 of Azolla compost, respectively. Thus, according to the results obtained for the maximum seed yield 10 ton.ha-1 of Azolla compost as well as Azospirillum inoculation is recommended.

The different fractions of soil metals vary considerably in their chemical reactivity and bioavailability. The distribution of metals among soil components is important for assessing the soils potential to supply sufficient micronutrients for the growth of plant. The sequential extraction procedures have been used to identify and evaluate the mobility and the availability of the metals in soil samples. Ten soil samples with a wide range of chemical and physical properties were collected from agricultural soils of Golestan province. The extractability and solid-phase fractionation of copper (Cu) in the soils was determined by two different sequential extraction procedures and then studied relationship between this fractions together and with plant uptake. Results indicated that the amounts of Cu present in exchangeable form and associated with carbonates were very small (0.3 and 0.4%, respectively). Copper in these soils was dominantly associated with mineral lattices (Tessier procedure: 80%; Singh procedure: 37%). In the remaining fractions i.e. (associated with organic matter and associated with Mn and Fe oxides), the results obtained by Tessier et al. procedure were differed considerably from those obtained by employing Singh et al. procedure. This study demonstrated that dissolution of iron oxides was incomplete during the reductive step of Tessier’s scheme, leading to an overestimation of the residual fraction. Strong and negative correlation (r=-0.692*) was found between plant Cu concentration and the Sodium hypochlorite-extractable Cu (associated with organic matter, Singh procedure) in the 10 calcareous soils, suggesting a prominent role of organic matter in the retention and bioavailability of Cu. Such relation was not observed when employing Tessier’s scheme, suggesting suitability of NaOCl for use in the sequential extraction procedures.