In order to study the effect of different green manure plants on SOIL organic matter and NITROGEN in salinity condition, an experiment was conducted in Randomized Complete Block Design with 4 replications. The treatments included plants white clover (Trifolium repens), vetch (Vicia peregrine), vetch (Vicia sativa), sorghum (Sorghum bicolor) and turnip (Eruca sativa) which were watered with natural saline water from Urmia lake (SOIL salinity: 2.7 dS m-1). Changes in SOIL nutrient elements and NITROGEN mineralization were measured during different time periods after plant residues incorporation in SOIL. The results indicated that sorghum green residues resulted in the highest amount of fresh and dry weight of shoot and root, yield (38800 kg/ha) and organic carbon (0.93%). No significant differences were obtained among the remaining plants for organic carbon. The highest SOIL NITROGEN content was observed in white clover (0.11%). The plants white clover (0.11%) and vetch (0.10%) resulted in higher total NITROGEN in corresponded SOIL samples following five months residues incorporation. The C/N ratio decreased significantly after 3 and 5 months incorporation of white clover, vicia and vetch in SOIL. Ammonium N (NH4-N) and nitrate N (NO3-N) content were achieved to the highest amount in vetch, white clover and sorghum, respectively. It was concluded that sorghum and white clover could be introduced as proper green manure for salinity condition because of higher yield and biomass, increasing the amount of SOIL organic carbon, lower amount of C/N and increasing SOIL total and mineral NITROGEN.

Detection of dispersed and blind mineral deposits is an important aim in the mineral exploration. Detailed exploratory operations such as drilled boreholes which are performed for exploration of mineral deposits in the depth caused high cost and risk. In this research, a new scenario based on spectral analysis of geochemical data has been utilized for prediction of MINERALIZED zones in the depth without any additional cost. The variations of MINERALIZED elements from the surface to the depth are predicted and delineated by using this approach based on surface geochemical data. This proposed approach is the state-of the-art application of two-dimensional Fourier transformation (2DFT) for geochemical image processing. This approach which is named frequency coefficient method (FCM) has been defined based on the behavior of elements in the frequency domain. In this study, the FCM shows two Pb and Zn MINERALIZED zones at the surface and moderate depth and a non-MINERALIZED zone at the profound depth in Chichakloo Pb–, Zn mineralization. Finally, the results of FCM have been validated and confirmed by the results of drilled boreholes and geophysical surveys.

A field experiment was conducted to examine the effects of different depths of NITROGEN (N) fertiliser placements on N accumulation, remobilisation and NO3--N content in SOIL of rainfed wheat. NITROGEN was applied on the surface (D1) and in the 10 cm (D2), 20 cm (D3) and 30 cm (D4) SOIL layers from 2010 to 2012. Compared with D1 and D2, D3 and D4 treatments obtained significant higher N distribution amounts in grain and N accumulation amounts at maturity. D3 and D4 treatments increased the N accumulation amount of vegetative organs at anthesis and at maturity. D3 treatment resulted in significantly higher N translocation amounts from vegetative organs to grains compared with D1 and D2 treatments and had no significant difference with D4 treatment. Compared with the D1 and D2, D3 and D4 treatments obtained significant higher NO3--N contents in the 20 cm to 120 cm SOIL layer at anthesis from 2011 to 2012. However, D3 treatment showed no significant differences with D1 and D2 treatments at maturity in terms of the NO3--N contents in the 40 cm to 100 cm SOIL layer. D4 treatment produced the highest NO3--N contents in the 40 cm to 140 cm SOIL layer. Grain yield, N uptake efficiency, apparent N recovery efficiency, N agronomic efficiency and N partial factor productivity were significantly increased by D3 and D4 treatments. These results suggest that the D3 treatment facilitates the best wheat production and highest efficiency among all treatments.

Biochar is a black solid containing stable carbon with many positive effects on the physical, chemical, and biological properties of SOIL. One important positive effect of biochar on SOIL is its contribution to nutrient (e.g., NITROGEN) mobility and dynamics in SOIL. Negatively charged on the surface, biochar is capable of adsorbing and storing ammonium ions (NH4+) and small NITROGEN-containing organic molecules. It also releases NITROGEN into the SOIL to change the carbon to NITROGEN ratio (C/N), whereby the mineralization-immobilization balance of NITROGEN is affected. Moreover, biochar indirectly affects SOIL NITROGEN cycle and dynamics by changing such SOIL properties as pH, cation exchange capacity, electrical conductivity, organic carbon, biological activity, nutrient availability, porosity, ventilation, and water relations, among others. It is through these changes that water, air, and nutrients are provided to make SOIL a suitable habitat favorable to SOIL microorganisms that help improve biological fixation of NITROGEN. Biochar also reduces N2O emission, as a greenhouse gas, from the SOIL by reducing SOIL NITROGEN sublimation. In general, biochar has a synergistic interaction with NITROGEN and can enhance NITROGEN use efficiency to reduce NITROGEN fertilizer consumption. However, only scant knowledge is presently available on SOIL NITROGEN changes induced by biochar, especially in calcareous SOILs. Further research is needed to investigate the effects of biochars produced from different types of biomass under different temperatures on the mobility and availability of nutrients, especially NITROGEN, in calcareous SOILs.

Human demand for food and energy has led to major changes in the level of active NITROGEN (N) released to the atmosphere. N addition experiments are a reliable way for investigating the effect of extra N deposition on target ecosystems. The present study was carried out to investigate in the effects of an artificial N deposition on the SOIL biochemical properties of a 20-year-old oak (Pinus radiata) plantation in Hyrcanian forests in the north of Iran. Twelve plots of (20 m × 10 m) were established in the study area. Four N treatments were considered: zero (control), 50 (low), 100 (medium) and 150 (high) kg N ha− 1 year− 1. N in the form of NH4NO3 solution was manually sprayed onto the plots monthly for one year. Analysis of variance showed that SOIL characteristics at NITROGEN treatment and different seasons and interaction of season and treatment had significant differences (P value <0. 01). In this regard and at the end of the simulation period, the lowest SOIL pH was observed in high treatment (6± 0. 3) and highest in control treatment (6. 8± 0. 3). The highest amount of total NITROGEN was observed at high N treatment (0. 55± 0. 02). But in relation to K and P concentrations, the control treatment (368± 2. 7) (12± 1. 6) had highest and high N treatment (266± 3) (6. 6± 0. 7) had lowest concentration of P and K, respectively. In this study, due to the increase in nitrate content obtained by adding ammonium nitrate in the NITROGEN simulation process, nitrate becomes saturated in the SOIL and mobile in the SOIL, and then leaching with base cations and decreasing SOIL pH.

Assessment of interactive effects of salinity and NITROGEN deficiency is of great importance for optimal management of SOIL and water resources in arid and semi-¬arid regions. The objective of this study was to model canola (Brassica napus L.) response to salinity under NITROGEN deficiency conditions. For this reason, the SOIL fertility models including Liebig- Sprengel (LS) and Mitscherlich- Baule (MB) that are originally proposed for nutrient deficiency were derived such to account for simultaneous salinity and NITROGEN deficiency. To obtain the required data and to assess the proposed models, an extensive experiment was conducted by different levels of salinity and NITROGEN. The experimental treatments were consisted of five levels of none saline water, 3, 6, 9 and 12 dSm-1 and four NITROGEN levels of 0, 75, 150 and 300 mgKg-1. Some statistics including maximum errors, root mean square error, modelling efficiency, coefficient of determination and coefficient of residual mass were used to evaluate the three proposed models. Results of these statistical analyses indicated that the proposed LS-based model can provide better estimates for relative grain yield in different NITROGEN levels. The proposed MB-based model, in the salinity levels of irrigation water and interaction of salinity and NITROGEN levels provided better results. It can be concluded that the proposed models can predict the interactive effect of salinity and NITROGEN deficiency reasonably well.

Biological and chemical changes in rhizosphere following organic residues as well as manures application are important processes which influence NITROGEN mineralization and nutrients bioavailibity in SOILs. This study was done to evaluation of organic residues effect on growth, NITROGEN supply and rhizosphere characteristics of corn and sunflower plants in greenhouse experiment using sewage sludge (SS), poultry (Pl), cattle (Ct) and sheep (Sh) manures. The results showed plants acquired significantly more N, P, K, Ca, Mg, Fe, Mn, Zn and Cu in SS treatment than other manures. Sunflower in comparison with corn plants showed higher N, P, K, Ca and Cu uptake, which can be attributed to its higher nutrient-uptake efficiency. The highest MINERALIZED NITROGEN in rhizosphere and non-rhizosphere SOIL were achieved in Pl (214.8 mg kg-1) and SS (227.5 mg kg-1), respectively.MINERALIZED N in particular nitrate was observed at high concentration in rhizosphere compared to nonrhizosphere SOIL, which indicate higher microbial activity including nitrificators and high mineralization processes in sunflower rhizosphere. Net NITROGEN mineralization (Nm) in rhizosphere was higher than that in nonrhizosphere which the microbial population in corn and sunflower rhizosphere were 3.7 and 2.3 times higher than non-rhizosphere SOIL, respectively. Treatments applied with SS showed the highest microbial activity compared to other organic residues. At rhizosphere, net NITROGEN mineralization was occurred in Pl and SS treatments whereas Ct and Sh applied SOIL showed NITROGEN net immobilization. Except for SS, all applied residues showed net immobilization in non-rhizosphere SOIL. The highest total MINERALIZED N (MINERALIZED N exist in SOIL and absorbed N by plants) were as fallows in treatments: Pl>SS>Sh>Ct.

Introduction SOIL texture is one of the most influential characteristics that affects the decomposition and retention of SOIL organic matter, as it directly or indirectly impacts the SOIL's physical, chemical, and biological properties. SOIL clays play an important role in SOIL organic matter stability. Organic matter adsorbed on phyllosilicate clays is more resistant to microbial decomposition than organic matter that has not interacted with any mineral. Exchangeable cations through the influence of physical and chemical characteristics of the SOIL probably cause changes in the absorption and retention of organic matter. In previous studies, the effect of SOIL texture on organic matter retention has been investigated, but the impact of clay type and exchange cation has not been investigated. This study aimed to examine the effect of different contents of vermiculite and zeolite clays and exchange cations on the mineralization of organic NITROGEN.   Materials and Methods A factorial experiment was conducted in a completely randomized design with three replications to study the effect of the type and content of clay and the type of exchange cations on organic NITROGEN dynamics. Experimental treatments include two types of clay (vermiculite and zeolite), four different levels of clay (0, 15, 30, and 45%), and three types of exchangeable cations (Na+, Ca2+, and Al3+). The experiment included 24 treatments and three replications. There were total of 72 experimental units. Artificial SOIL of 50 grams was prepared separately according to the amount and type of clay and the type of exchange cation. "Next, alfalfa plant residues were added to all samples at a rate of 5% w/w. After inoculating and air-drying the samples, the moisture content was adjusted to 60% of the field capacity (FC) using distilled water. To prevent excess water from affecting the final moisture readings, the samples were first air-dried, and then sufficient distilled water was added to each sample to achieve 60% of FC. The samples were then kept in the dark for 60 days at a temperature of 23 °C. Distilled water was added and sealed to the bottom of the incubation jars to keep the moisture content of the SOIL samples constant during incubation. The percentage of MINERALIZED NITROGEN, microbial biomass NITROGEN, and the activity of acid and alkaline phosphatase and cellulase enzymes were determined in the prepared samples. The data were analyzed using ANOVA, and the means were compared using Duncan's Multiple Range Test (DMRT). Before applying ANOVA, the data's normality and variance homogeneity were checked using Kolmogorov- Smirnov and Levene tests, respectively. The SPSS software (Windows version 25.0, SPSS Inc., Chicago, USA) and SAS software (version 9.4, SAS Institute Inc., Cary, NC) were employed for data analysis.   Results and Discussion The results of variance analysis of the data showed that the effect of the type and content of clay and the type of exchangeable cation on the percentage of MINERALIZED NITROGEN, microbial biomass NITROGEN, and the activity of acid and alkaline phosphatase and cellulase enzymes were significant (p< 0.01). The results revealed that, regardless of the duration of the samples, with the increase in the amount of clay, the percentage of inorganic NITROGEN and the activity of enzymes decreased, but the NITROGEN of microbial biomass increased. The highest percentage of inorganic NITROGEN was obtained 60 days after incubation of the samples and in clays saturated with calcium, and the lowest amount of these attributes was obtained 15 days after incubation of the samples and in clays saturated with aluminum. The results showed that NITROGEN mineralization increased with the samples' incubation time. Also, the highest percentage of MINERALIZED NITROGEN, microbial biomass NITROGEN, and enzyme activity were observed in SOILs with vermiculite.   Conclusion The increase in the incubation duration enhanced the percentage of inorganic NITROGEN. The percentage of MINERALIZED NITROGEN and microbial biomass NITROGEN was higher in SOILs with vermiculite than in SOILs with zeolite. Moreover, regardless of the incubation duration of samples, with increasing clay content, the percentage of MINERALIZED NITROGEN and enzyme activity decreased, but with increasing clay NITROGEN content, microbial biomass increased. The highest and lowest amounts of MINERALIZED NITROGEN and NITROGEN of microbial biomass were measured in SOILs with calcium and aluminum, respectively. The results showed the effect of the clay type and content and the exchangeable cation type on organic NITROGEN dynamics.

SOIL organic carbon (SOC) is a principal component in SOIL quality assessment. Knowledge of SOC and total NITROGEN (TN) stocks are important keys to understand the role of SOC in the global carbon cycle and, as a result, in the mitigation of global greenhouse effects. SOC and TN stocks are functions of the SOC concentration and the bulk density of the SOIL that are prone to changes, influenced by land use changes, and SOIL erosion processes. This study has evaluated SOC and TN stock under different land use types and SOIL erosion types at catchment scale. SOC and TN stocks were measured in 112 different sampling sites of four main groups of land use/SOIL erosion: rangeland/surface erosion, orchard/surface erosion, dry-farming land/surface erosion, and rangeland/strea mbank erosion at Hiv and Zidasht catchments, Iran. The results showed that SOC and TN stock under all land use and erosion groups was significantly different. SOC and TN stock was greatest in the orchard land use and the total SOC stock for the 20 cm SOIL layer under different land uses and erosion types varied for Hiv in order of orchard/surface erosion (46), rangeland/surface erosion (31), and rangeland/stream bank erosion Mg/ha (p<0.005). For Zidasht, the variance was, in order: orchard/surface erosion (43), dry-farming land/surface erosion (23), rangeland/surface erosion (23), and rangeland/streambank erosion 22 Ton/Hector (p<0.005). The TN stock has the same trend in all studied land use and erosional groups. Therefore it was concluded that rangelands were affected by erosion, with a subsequent decreasein productivity level. These results can be useful as a scientific basis for selecting the proper SOIL erosion control methods as a simple, low-cost approach to mitigate SOC and TN loss.