Research Article
Soil science
jalal ghaderi; shahrokh fathi; Majid forouhar; kamal kalkhal
Abstract
Introduction: In Iran, sugar beet is the second most prominent irrigated crop after forage corn and wheat, occasionally ranking third after sugarcane in specific years. This versatile plant not only serves as a primary source of sugar but also contains essential nutrients beneficial to human health. ...
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Introduction: In Iran, sugar beet is the second most prominent irrigated crop after forage corn and wheat, occasionally ranking third after sugarcane in specific years. This versatile plant not only serves as a primary source of sugar but also contains essential nutrients beneficial to human health. Its adaptability to diverse environmental conditions allows it to be cultivated across various regions of the country. Sugar beet production plays a significant role in Iran's agricultural sector, with recent data indicating an increase in production levels over the years. However, achieving optimal performance and desired product quality requires a precise understanding of the nutritional status of sugar beet. Therefore, awareness of its nutritional condition is crucial for enhancing both quantity and quality. soil tests based on critical levels can indicate the adequacy of nutrients, but in some cases, soil testing alone is insufficient to reveal nutrient deficiencies or nutritional imbalances soil tests based on critical level may indicate the adequacy of nutrients, but in some cases, soil testing alone cannot reveal nutrient deficiencies or nutritional imbalances. Under these conditions, plant analysis leads to better identification of deficiencies as well as understanding the concentration of elements and comparing them with reference concentrations to ensure optimal plant growth. One method for interpreting leaf analysis results is the use of compositional nutrient diagnosis (CND) method. The CND method offers an effective approach for assessing the nutritional status of sugar beet plants by analyzing nutrient composition in plant tissues against standard values. Its primary objective is to identify nutritional deficiencies, optimize fertilizer use, mitigate adverse environmental impacts from excessive fertilization, and boost crop yields. This research aims to evaluate and optimize the nutritional status of sugar beet over two agricultural years in Khorasan Razavi province using the CND method.
Materials and Methods The study was conducted over two agricultural years on sugar beet crops in Khorasan Razavi province, involving 30 fields one year and 31 fields the next with varying soil properties. After selecting the fields, prior to planting and fertilizing the sugar beet, a composite soil sample was taken from each field, covering an area of one hectare and a depth of 0-30 cm. The physical and chemical properties of these samples were measured in the laboratory. Leaf sampling was performed in both years to determine nutrient concentrations, approximately 90 to 120 days after planting, using young, healthy, fully developed leaves. After washing with distilled water, the leaf samples were dried in an oven at 70°C for 48 hours, ground with an electric grinder, and then nutrient concentrations were measured. In this study, the high-yielding group in sugar beet farms was identified using the CND method through mathematical and statistical analysis and the application of the cumulative function.
Findings: Soil analysis revealed a wide range of physical and chemical characteristics among the selected fields. The findings in this province revealed that 67 %, 52.5 %, 82 %, 62 %, 59 %, and 53 % of the fields were deficient in phosphorus, potassium, iron, manganese, zinc, and copper, respectively, with an average yield of 58.5 tons/ha across all fields. Based on the average CND indices, the most limiting nutrients in low-yielding fields for macro and micronutrients were identified as follows: K (44 %) > P (34 %) > N (10 %) and Cu (27 %) > Mn (22 %) > Fe (17 %) > Zn (15 %), respectively. The Nutritional Balance Index (NBI) for sugar beet farms in this province was calculated, indicating a relative imbalance among the nutrients absorbed by this plant.
Conclusion: The findings suggest that nutritional deficiencies are a primary factor contributing to low yields of sugar beet in this region. The results indicated that to enhance performance and improve the quality of sugar beet products, special attention should be given to the fertilization of potassium, phosphorus, copper, and manganese in these fields. The findings from the selected fields suggest differences in field management practices and suboptimal use of chemical and organic fertilizers. The results of this research can be applied to enhance yield and improve the quality of sugar beet crops. Additionally, the CND method can serve as an effective tool for interpreting soil and plant analysis in plant nutrition management at sugar beet fields.
Research Article
Irrigation
Maliheh Akbari; Mojtaba Farhadzadeh; پریسا ملکی
Abstract
Abstract
The imbalance between water availability and water consumption is a critical challenge to sustainable development, particularly in water-dependent regions. This study examines the Tajan River Basin in northern Iran to evaluate the balance between water resources and sectoral water demands, focusing ...
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Abstract
The imbalance between water availability and water consumption is a critical challenge to sustainable development, particularly in water-dependent regions. This study examines the Tajan River Basin in northern Iran to evaluate the balance between water resources and sectoral water demands, focusing on agriculture, aquaculture, drinking, and environmental needs. Using hydrological data from river monitoring stations, ten years of inflow and outflow data from the Shahid Rajaee Dam (2011–2021), and regional groundwater information, the study assesses water availability under different hydrological conditions. Annual water demands are estimated at 598 million m³ for agriculture and aquaculture, 68.7 million m³ for drinking, and 100 million m³ for environmental sustainability. Available resources include regulated water from the Shahid Rajaee Dam, the flow of rivers in the middle basin, groundwater extraction, and surface water from ponds. Water availability was analyzed under three scenarios: normal, dry, and very dry years. In the first six months of the year, Shahid Rajaee Dam can supply 231 million m³ (normal), 194 million m³ (dry), and 122 million m³ (very dry). Annual contributions from ponds and wells are estimated at 12.8 million m³ and 176 million m³, respectively. Comparative analysis shows that the Tajan Basin experiences significant water shortages of 166 million m³ (normal), 231 million m³ (dry), and 324 million m³ (very dry). These findings highlight the urgent need for improved water management, better allocation strategies, and infrastructural developments to mitigate the effects of water scarcity and support long-term sustainability in the region.
Keywords: Water resources, basin, Tajan River, water uses, Shahid Rajaee Dam
1) Introduction:
Water is essential for survival, economic growth, and industrial development, and its optimal allocation is crucial for sustainable progress. Effective water management, especially in agriculture, requires understanding the dynamic relationship between water supply and consumption. This study focuses on the Tajan River Basin, aiming to evaluate and compare available water resources and their uses—agricultural, drinking, industrial, and environmental—across the Tajan Plain and the upstream basin during the exploitation season. The goal is to identify potential water shortages throughout the year. The study builds upon data and findings from a 2023 report by Pandam Company on the basin's water needs.
2) Materials and Methods:
The Tajan River is one of the important rivers of Mazandaran Province, which originates from the Hezar Jarib Mountains and flows into the Caspian Sea after passing through the city of Sari in Farahabad. The entire catchment area of this river up to the entrance to the plain with an area of about 4050 square kilometers and the Tajan Plain with an area of about 800 square kilometers, has been considered as the study area to investigate water resources and uses. In this study, long-term statistical data from hydrometric stations of the Zaremroud (Garm Rud Station), Lajim (Vastan Station), Chahardangeh (Varand Station), and Tajan (Kordkheil Station) rivers, as well as the inflow and outflow statistics of Shahid Rajaee Dam (during the ten-year operation period of 1390-1400) as the main source of water supply for the Tajan basin, have been used. For groundwater resources (wells), information obtained from the Mazandaran Regional Water Company in 1400 and basic water resource studies have been used. Regarding water ponds, the results of the interpretation of new satellite images in the form of a land use map have been used.
3) Results:
Surveys in the Tajan River Basin, including the Tajan Plain and upstream areas, reveal approximately 119,800 hectares of agricultural land, with 74,500 hectares irrigated and the rest under dry-land farming. Additionally, there are 550 hectares of fish farming ponds in the plain, mostly for warm-water species, some of which also support aquaculture. The total annual water requirement is 492 million cubic meters for agriculture and aquaculture in the Tajan Plain, and 106 million cubic meters for upstream areas. Drinking, industrial, and tourism-related water needs across Sari, Miandoroud, and Kiasar counties total 7.68 million cubic meters per year. The environmental water demand of the Tajan River is estimated at 100 million cubic meters annually. Available water sources include regulated releases from the Shahid Rajaee Dam, seasonal flows of middle basin rivers, pond water storage, and groundwater. Water availability is assessed under three hydrological scenarios: normal, dry, and very dry years. In the first half of the year, Shahid Rajaee Dam can supply 231 million m³ (normal), 194 million m³ (dry), and 122 million m³ (very dry). Annual extraction from ponds and wells is estimated at 12.8 and 176 million cubic meters, respectively.
5) Discussion and Conclusion
A comparison of the needs and available water resources shows that the amount of water shortage in the entire area (Tajan basin) in normal, dry and very dry years is 166, 231 and 324 million cubic meters, respectively. A comparison of the resources and uses of the study area shows that the amount of water shortage in normal, dry and very dry years in the Tajan Plain area is 147, 212 and 305 million cubic meters, respectively. In other words, in a normal or normal water year, there is a water shortage of about 150 million cubic meters in the irrigation network and the Tajan Plain area. Water shortage due to the reduction of available water resources, including the outlet of Shahid Rajaee Dam, leads to resource constraints and, as a result, water shortage in the lands of the Tajan Plain. In the dry water year, the water shortage was mainly due to the decrease in discharge from the Shahid Rajaee reservoir dam and the rivers of the middle basin. Therefore, in addition to the necessity of managing water distribution and scheduling, as well as improving the Tajan irrigation network, which will partially reduce the amount of damage caused by water shortage, the construction of the planned dams on the Zaremroud and Chahardangeh rivers is very important in regulating the monthly discharge.
Research Article
Soil science
Omid Eghbali; Hojat Emami; Reza Khorasani
Abstract
Introduction
Agronomic management is a set of field practices that not only influence plant growth and yield but also affect the soil physical, chemical, and biological properties. The selection the crop species and cropping systems -monoculture or crop rotation-significantly affects soil attributes ...
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Introduction
Agronomic management is a set of field practices that not only influence plant growth and yield but also affect the soil physical, chemical, and biological properties. The selection the crop species and cropping systems -monoculture or crop rotation-significantly affects soil attributes and plays an important role on enhancing nutrient cycling, increasing organic matter content, reducing erosion, and ultimately promoting the sustainability of agricultural ecosystems. Therefore, an appropriate cropping strategy can be regarded as a key strategy for sustainable soil management. Evaluating soil quality through physical, chemical, and fertility indicators provides a comprehensive knowledge of soil status, which is essential to develope effective management strategies and long-term planning for sustainable land use. This study was performed to assess soil quality under alfalfa cultivation and to compare with a maize–wheat rotation in a single cropping season.
Materials and Methods
This study was conducted during the 2020–2021 cropping season at the research farm of Ferdowsi University of Mashhad, located in Khorasan Razavi Province, northeastern Iran. Two adjacent fields with different agronomic management systems were selected: (i) alfalfa (Medicago sativa L.) monoculture, which had been continuously cultivated for several years without rotation, and (ii) a maize–wheat (Zea mays L.–Triticum aestivum L.) rotation system, a typical cereal-based cropping pattern in the region. These different systems were chosen to evaluate the long-term effects of continuous legume cultivation versus crop rotation on soil quality attributes. The experimental design was a randomized complete block design (RCBD) with three replications. Soil samples were collected after the harvesting the crops and taken from three depths (0–10, 10–20, and 20–30 cm). 11 soil properties including pH, electrical conductivity (EC), calcium carbonate equivalent (CCE), total nitrogen (TN), available phosphorus (P), available potassium (K), mean weight diameter (MWD) of soil aggregates (both wet and dry methods), soil structure stability index (SI), saturated hydraulic conductivity (Ks), and organic carbon (OC) were measured. The minimum data set (MDS) was identified using principal component analysis (PCA). Subsequently, the soil quality index (SQI) was calculated based on both the total data set (TDS) and the minimum data set (MDS).
Results and Discussion
Using the Minimum Data Set (MDS) approach, the number of soil properties was reduced, and the most important variables were selected. Among the principal components (PCs), only those with eigenvalues greater than one were retained. For both alfalfa and the maize–wheat rotation, four components explaining more than 80% of the total variance were selected. In alfalfa, the selected variables included organic carbon, total nitrogen, calcium carbonate equivalent, and mean weight diameter (MWD) of wet and dry sieving. In the maize–wheat rotation, the selected variables were organic carbon, electrical conductivity (EC), calcium carbonate equivalent, and MWD under wet and dry sieving. Regarding the EC in the rotation system reflects probabily the influence of evaporation and fertilization practices on soil salinity. Evaluation of the Soil Quality Index (SQI) among the different soil depths and two agronomic management systems revealed that soils under alfalfa monoculture exhibited higher quality compared to the maize–wheat rotation, particularly in the surface layer (0–10 cm). These findings emphasize the crucial role of continuous plant cover in maintaining soil organic matter, reducing surface erosion, facilitating nitrogen fixation through rhizobial symbiosis, improving soil aggregate stability, and enhancing soil biological activity in perennial systems such as alfalfa. These processes may improve nutrient availability and foster long-term soil sustainability. Soil depth significantly influenced SQI trends. The decline in SQI with increasing depth in the maize–wheat rotation reflects reduced biological activity and limited nutrient availability in deep layers, whereas soils in alfalfa system had the relatively higher SQI values even at deep depths, indicating the potential of deep-rooted legumes to enhance subsoil quality through extended root penetration and associated biological processes.
Conclusion
This study revealed that alfalfa monoculture considerably enhanced soil quality compared to the maize–wheat rotation, particularly at the soil surface (0–10 cm). The most important soil properties improved soil quality were organic carbon, total nitrogen, calcium carbonate equivalent, and aggregate stability (MWD). The presence of continuous plant cover, biological nitrogen fixation, and reduced tillage in alfalfa cultivation played vital roles in increasing soil organic matter, reducing erosion, and improving soil structural stability. The application of the Minimum Data Set (MDS) approach proved to be a reliable, efficient, and cost-effective method for soil quality evaluation. These findings highlight the potential of perennial legume-based systems, such as alfalfa, to enhance soil quality and sustainability in semi-arid agroecosystems. Long-term monitoring of soil quality and alfalfa monoculture is recomended for sustainable land management.
Research Article
Soil science
Mina Alipour Babadi; Mojtaba Norouzi Masir; Abdolamir Moezzi; Afrasyab Rahnama Ghahfarokhi; Mehdi Taghavi Zahedkolaei
Abstract
Introduction:
Iron (Fe) is a critical micronutrient essential for plant metabolic processes. However, in calcareous soils with high pH, Fe availability is severely restricted due to its precipitation as insoluble forms, leading to Fe deficiency and yield reduction in many crops. This limitation highlights ...
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Introduction:
Iron (Fe) is a critical micronutrient essential for plant metabolic processes. However, in calcareous soils with high pH, Fe availability is severely restricted due to its precipitation as insoluble forms, leading to Fe deficiency and yield reduction in many crops. This limitation highlights the need for alternative strategies to enhance Fe uptake efficiency in plants. Recent studies suggest that Fe aminochelates (complexes of Fe with organic ligands such as amino acids) can significantly improve Fe availability and uptake in alkaline soils. Fe deficiency is especially problematic in arid and semi-arid regions, where calcareous soils dominate and conventional Fe fertilizers, such as FeSO₄, are often ineffective due to rapid oxidation and fixation of Fe³⁺. Insufficient Fe availability disrupts chlorophyll synthesis, enzyme activity, and overall photosynthetic efficiency, which ultimately affects plant growth, biomass accumulation, and nutritional quality. Therefore, improving Fe acquisition through more stable and bioavailable sources is crucial for sustainable crop production. Among various synthetic and natural Fe sources, Fe aminochelates have drawn attention because of their stability, solubility, and ability to resist precipitation in high-pH environments. By forming soluble Fe–amino acid complexes, these chelates enhance Fe translocation within plant tissues and promote physiological functions even under Fe-limiting conditions. Given this potential, the present study was conducted with the following objectives: (i) to evaluate the effect of fertigation application with Fe aminochelates and FeSO₄ on the distribution of Fe chemical fractions in the solid phase of calcareous soil, (ii) to analyze the correlation between soil Fe fractions and Fe content/uptake in sunflower (Helianthus annuus L. cv. Oscar), and (iii) to establish a comparative efficacy framework for Fe sources in calcareous soil-plant systems under fertigation management.
Materials and Methods:
A field experiment was carried out using a randomized complete block design (RCBD) with three replications. The treatments included: (1) control (without any Fe fertilizer), (2) FeSO₄ at 20 kg ha⁻¹, (3) Fe-glycine [Fe (Gly)2] aminochelate at 4 L ha⁻¹, and (4) Fe- methionine [Fe(Met)₂] aminochelate at 4 L ha⁻¹. Fertilizers were applied through irrigation (fertigation). At the end of the growing season, soil samples were collected and analyzed for pH, DTPA-extractable Fe, and Fe chemical forms in the solid phase using the modified Tessier sequential extraction method. The measured Fe fractions included exchangeable (EXC-Fe), organically bound (ORG-Fe), carbonate-bound (CAR-Fe), Fe/Mn oxide-bound (OX-Fe), and residual (RES-Fe). Additionally, Fe concentration in sunflower seeds and leaves and also seed Fe uptake were quantified.
Results and Discussion:
Application of Fe aminochelates significantly affected Fe dynamics in the soil and improved Fe nutrition in plants. Both [Fe(Gly)₂] and [Fe(Met)₂] treatments resulted in a significant decrease in soil pH compared to control and FeSO₄, which likely enhanced Fe solubility. The DTPA-extractable Fe content increased by 28.5% and 35.2% in [Fe(Gly)₂] and [Fe(Met)₂] treatments, respectively, relative to the control. These treatments also increased seed Fe concentration by 5.1% and 7.5%, and seed Fe uptake by 66.6% and 86.7%, respectively. The distribution of Fe chemical fractions in the soil followed the order: residual > Fe/Mn oxides > carbonate-bound > organically bound > exchangeable. Fe aminochelates, especially [Fe(Met)₂], significantly enhanced the relative proportion of EXC-Fe and ORG-Fe while decreasing the proportion of CAR-Fe compared to both control and FeSO₄. Furthermore, DTPA-extractable Fe exhibited strong positive correlations with EXC-Fe (r = 0.87**) and ORG-Fe (r = 0.84**) fractions. Among the different forms, EXC-Fe (r = 0.72**) and ORG-Fe (r = 0.69**) showed significant positive correlations with seed Fe concentration, indicating their critical role in Fe bioavailability and plant uptake. These findings support the hypothesis that [Fe(Met)₂], due to its greater stability and chelation strength, improves Fe mobilization and provides a renewable pool of bioavailable Fe in the soil system. Thus, Fe aminochelates can contribute to improved nutrient acquisition and enhanced crop quality under Fe-deficient calcareous conditions.
Conclusion:
This study confirms the superior efficacy of Fe aminochelates, particularly [Fe(Met)₂], over conventional FeSO₄ in enhancing Fe bioavailability in nutrient-deficient, calcareous soils. The significant shift in Fe fractions towards more labile pools (EXC-Fe and ORG-Fe) and the strong correlations between these pools and plant Fe uptake underscore the potential of aminochelates to create a more plant-available Fe reservoir. Therefore, the use of Fe aminochelates represents a viable and efficient strategy to correct Fe deficiency and improve crop nutritional quality in calcareous soils, contributing to more sustainable micronutrient management practices.
Research Article
Soil science
Narges Pordel; Jaafar Hosseinzadeh; Mehdi Heydari; Reza Omidipour
Abstract
Forests are recognized as one of the most vital components of terrestrial ecosystems, playing a multifaceted role in maintaining environmental equilibrium, supporting biodiversity, regulating climate, conserving water resources, and providing a wide range of essential ecosystem services. The long-term ...
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Forests are recognized as one of the most vital components of terrestrial ecosystems, playing a multifaceted role in maintaining environmental equilibrium, supporting biodiversity, regulating climate, conserving water resources, and providing a wide range of essential ecosystem services. The long-term sustainability and productivity of forest ecosystems are closely linked to the quality of the soil and the inherent biological potential of the site in which the forest stands. These two critical factors—soil quality and site potential—are, in turn, profoundly shaped and affected by various environmental parameters, including geomorphological characteristics such as topography and elevation, the density and structure of vegetation or canopy cover, as well as anthropogenic influences stemming from land use changes, deforestation, and other human activities. In light of these considerations, the primary objective of this research was to conduct a detailed, quantitative evaluation of soil quality and site potential indices within the semi-arid Zagros forest regions. The study specifically focused on analyzing the impacts of key variables such as elevation gradients, slope orientation (aspect), and the density of canopy cover. In addition to the empirical assessment of these factors, the research employed advanced spatial analysis techniques and geostatistical tools to develop a reliable spatial prediction model. This model aims to enhance our understanding of spatial variability in forest conditions and provide a scientific basis for implementing more informed, effective, and sustainable forest management and restoration strategies tailored to the unique ecological context of the Zagros Mountains.
Materials and Methods: The study was conducted in the Zagros forests (Shalam Mountain, east of Ilam) within an elevation range of 1500 to 2150 meters. Sixty forest stands were selected across three elevation classes (lower, middle, and upper), two slope aspects (north-facing and south-facing), and two canopy cover classes (less than and more than 25%). Soil samples were collected from a depth of 0–15 cm in each stand, mixed, and their physical and chemical properties were analyzed in the laboratory. The Soil Quality Index (SQI) was calculated using the SQI-2 standard model based on normalization and weighting of selected soil properties. Site quality was estimated using a logarithmic model of tree height to log tree age ratio for Persian oak (the dominant species). For spatial structure analysis, variograms were fitted using spherical, exponential, Gaussian, and linear models, and the best model was identified for each index. Interpolation and spatial mapping were performed using ordinary kriging, simple kriging, universal kriging, co-kriging, and inverse distance weighting (IDW). The accuracy of these methods was evaluated using the mean standardized root mean square error, and the most accurate method for each index was determined.
Results: The findings showed significant differences in soil quality between north- and south-facing slopes across all elevation classes. The highest soil quality (0.84 ± 0.01) was found in densely canopied, north-facing mid-elevation stands, while the lowest (0.60 ± 0.03) was in open-canopy, south-facing upper elevation stands. Site quality also decreased with increasing elevation. Its highest value (25.26 ± 2.08 m) was recorded in densely canopied, north-facing lower elevation stands, and the lowest (16.51 ± 0.79 m) in open-canopy, south-facing upper elevation stands. Statistical analysis revealed a generally positive and significant correlation between soil quality and site quality, which was stronger on south-facing slopes. Regression analysis confirmed this relationship. Variogram modeling indicated that the spherical model best fit soil quality, while the exponential model was most suitable for site quality. Interpolation accuracy assessments showed that ordinary kriging was the most accurate method for soil quality, and universal kriging was best for site quality.
Conclusion: The study comprehensively demonstrated that both soil properties and overall site quality within the Zagros forests are significantly influenced by key environmental variables, including topographical features, the extent of canopy cover, and variations in elevation. The interrelationship between the two assessed indices—soil and site quality—is statistically significant, and the strength of this relationship fluctuates in response to differing ecological conditions, particularly on south-facing slopes, which are more exposed to solar radiation and drier microclimates. The results of the analysis underscore the necessity of incorporating both soil attributes and broader environmental characteristics when evaluating the biological productivity and ecological potential of forested regions. Moreover, observed differences in the spatial distribution patterns and the structure of the variogram models emphasize the critical importance of selecting appropriate and context-sensitive spatial modeling techniques. These findings not only provide a robust scientific basis for ongoing ecological assessment and environmental monitoring but also offer valuable guidance for implementing targeted forest restoration strategies and developing long-term, sustainable management plans tailored to the unique conditions of the semi-arid Zagros forest ecosystems.
Research Article
Soil science
RASOUL MIRKHANI; FARHAD MOSHIRI; ALI GHAFFARINEJAD; HAMED REZAEI
Abstract
Introduction: Soil quality plays a very important role in crop production. Quantitative and rapid assessment of soil quality provides the possibility of timely evaluation of the effect of management methods, including fertilization management, on soil conditions. In order to study the state of soil quality, ...
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Introduction: Soil quality plays a very important role in crop production. Quantitative and rapid assessment of soil quality provides the possibility of timely evaluation of the effect of management methods, including fertilization management, on soil conditions. In order to study the state of soil quality, it is necessary to use characteristics that represent dynamic soil quality that are sensitive and effective to land use changes and various management practices. In order to investigate the effects of the combined use of organic and chemical fertilizers on soil quality, this research was conducted in the form of randomized complete blocks in 9 treatments and three replications in the Alborz province.
Materials and Methods: This research was conducted in the form of randomized complete blocks in 9 treatments and three replications in plots with an area of 200 square meters in the Alborz province. Fertilizer treatments include: 1) fallow, 2) control (without using fertilizer), 3) application of nitrogen, ,phosphorus and potassium fertilizers based on soil test, of soil and water research institute (SWRI) 4) application of 20 tons of cow manure every two years + application of 75 % of the recommended amount of nitrogen + application of 50% of the recommended amount of phosphorus and potassium, 5) application of 20 tons of compost every two years + application of 75 % of the recommended amount of nitrogen + application of 50 % of the recommended amount of phosphorus and potassium, 6) annual application of 20 tons of cow manure + application 75% of the recommended amount of nitrogen, 7) annual application of 20 tons of compost + application of 75 % of the recommended amount of nitrogen, 8) annual application of 20 tons of cow manure, 9) annual application of 20 tons of compost. After sampling the soil at the end of each crop and measuring the properties of pH, electrical conductivity, soil organic carbon, available phosphorus and potassium, bulk density, mean weighted diameter, cumulative soil quality index (SQI) and nemero quality index (NQI) were calculated. Finally, changes in soil quality indicators due to different management practices of organic and chemical fertilizers were evaluated.
Results and Discussion: According to the results, there was a significant difference between the treatments in the studied indices in all years, which indicated the effect of different treatments on soil quality. Furthermore, no significant differences were observed between the years. In the second and third years, the highest wheat yield in the studied treatments was related to treatment 7 (annual application of 20 tons of waste compost + application of 75% of the recommended nitrogen amount) with values of 3833 kg/ha (first year), 6733 kg/ha (second year) and 5211 kg/ha (third year). This resulted in increases of 44%, 105%, and 131% compared to the control treatment (without fertilizer) in the first, second, and third years, respectively. The combined application treatments of organic and chemical fertilizers (4, 5, 6 and 7) had a significant increase compared to the chemical fertilizer application treatment (treatment 3) and the organic fertilizer application treatment (treatments 8 and 9). Moreover, There was no significant difference between the combined application treatments of organic and chemical fertilizers (treatments 4, 5, 6 and 7). In addition, all treatments had a significant increase compared to the control treatment (treatment 2), which indicates the effect of the combined application of organic fertilizers with chemical fertilizers in improving soil quality and wheat yield. In the third year, there was a significant correlation between yield and soil quality indices (p<0.01), which indicates the effect of increasing soil quality due to increasing organic matter and chemical fertilizers on increasing wheat yield.
Conclusions: The results showed that there was a significant difference between the treatments in the studied indices, but there was no significant difference between different years. The combined application treatments of organic and chemical fertilizers significantly increased wheat yield compared to the chemical fertilizer application treatment and the organic fertilizer application treatments, while there was no significant difference between the combined application treatments of organic and chemical fertilizers. In addition, all treatments also had a significant increase compared to the control treatment (without fertilizer). In the third year, there was a significant correlation between wheat yield and soil quality indices.
