Water and Soil

Abstract Introduction Water is a primary and fundamental need for survival, industrial development, and economic prosperity. In other words, the key to development depends on the expansion of water resources and their optimal use. To achieve this, the correct allocation of water resources to different uses based on priorities is of great importance (Loucks and Van Beek, 2017). Any management planning to control water consumption in the agricultural sector requires a correct understanding of the mutual influence of variables controlling water resources and consumption on each other in order to ensure optimal provision of agricultural water needs and also to ensure the improvement of the economic situation of farmers (Veysel, 2024). The purpose of this study is to examine and compare available water resources and uses, including agricultural, drinking, industrial, and environmental needs, for the Tajan River basin, including the two parts of the Tajan Plain and the river basin up to the entrance to the plain during the exploitation season, in order to determine the possible shortage of water supply in different months. It is worth mentioning that the results presented in the report on the study of water resources and needs of the Tajan River Basin (Pandam Company, 1402) were used to prepare this article.   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 enJulye 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.   Results The results of the surveys show that in the entire study area, including the Tajan River basin to the entrance to the plain and the lands of the Tajan Plain, there are about 119,800 hectares of pure agricultural land in the form of irrigated and dry-land cultivation, of which 74,500 hectares are irrigated and the rest are dry-land cultivation. There are fish farming ponds with a total area of 550 hectares in the Tajan Plain, which are generally related to warm-water fish. Also, some of the ponds located in the area are used for aquaculture. The total water requirement of the Tajan Plain area (agriculture and aquaculture) is 492 million cubic meters, and in the upstream lands (the Tajan basin to the entrance to the plain), this requirement is estimated to be 106 million cubic meters. The total drinking, industrial and tourism drinking needs of the region (Sari, Miandoroud and Kiasar counties) are 7.68 million cubic meters per year. The estimated environmental demand of the Tajan River is also equivalent to 100 million cubic meters per year. Available water resources for various uses include the regulated water flow of the Shahid Rajaee Dam, the seasonal flow of the rivers in the middle basin, dam water storage, and groundwater resources. To compare uses with available water resources, three comparison levels including normal, dry, and very dry water years have been used. The volume of water that can be extracted from the Shahid Rajaee Dam in the first six months of the year for normal, dry, and very dry water years is 231, 194, and 122 million cubic meters, respectively. The volume of water that can be extracted from ponds and wells located in the area are estimated to be 12.8 and 176 million cubic meters per year, respectively.   Discussion and Conclusion A comparison of water needs and available resources indicates that the total water shortage in the Tajan Basin is 166, 231, and 324 million cubic meters in normal, dry, and very dry years, respectively. Similarly, in the Tajan Plain area, the shortages are estimated at 147, 212, and 305 million cubic meters for the same conditions. 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. The reduction in available water resources, including decreased outflow from the Shahid Rajaee Dam, leads to resource constraints and consequently causes water shortages 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.

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. 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. 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 in the first year and 31 fields in the second year, 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.   Result 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. The results showed that the average yield across all fields was 58.5 tons per hectare, and the median yield of 70.9 tons per hectare was used as the threshold to distinguish between fields with favorable and unfavorable nutritional status. Based on the mean CND indices, 54.27% of the fields in this province were in a balanced nutritional state, while 45.43% were imbalanced. The most limiting macronutrients in low-yield farms were phosphorus (49%) and potassium (44%), while for micronutrients, the main limitations were copper (29%) and manganese (22%).   Conclusion An assessment of the nutritional status of sugar beet fields in Khorasan Razavi province reveals significant challenges in nutrient balance. Widespread imbalances, particularly in phosphorus, potassium, and copper, along with soil salinity and alkalinity, highlight the need for a revision in fertilization programs. The CND results emphasize that over 45% of fields require adjustments in fertilizer application patterns to prevent the adverse effects of excesses and critical deficiencies. Additionally, the high yield of some fields (20 farms with an average of 70.9 tons per hectare) proves that achieving nutritional balance not only improves productivity but also reduces financial resource wastage and environmental pollution. The CND method, as a precise tool, enables the detection of nutritional imbalances even in cases where soil nutrient concentrations appear optimal. Therefore, it is recommended that management programs based on soil testing and modern diagnostic methods like CND, along with consideration of local conditions (salinity and lime content), be implemented to ensure sustainable sugar beet production in the region.

Abstract Introduction 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, this 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 were 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.

Abstract Introduction Iron (Fe) is an essential micronutrient that plays a vital role in various plant metabolic processes. However, in calcareous soils with high pH, the availability of Fe is greatly limited due to its precipitation into insoluble forms, resulting in Fe deficiency and reduced crop yields. 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 of plants. Both [Fe(Gly)₂] and [Fe(Met)₂] treatments resulted in a significant decrease in soil pH compared to the control and FeSO₄, which likely enhanced Fe solubility. The DTPA-extractable, relative to the control, Fe content increased by 28.5% and 35.2% in [Fe(Gly)₂] and [Fe(Met)₂] treatments, respectively. 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.   Acknowledgements The authors would like to thank the Research council of Shahid Chamran University of Ahvaz, Ahvaz, Iran for the financial support of this research (grant number: SCU.AS1401.26962).

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, 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 with 9 treatments and three replications in the Alborz province.   Materials and Methods  This research was conducted in plots with an area of 200 square meters in the Alborz province. Fertilizer treatments included: 1) fallow, 2) control (without using fertilizer), 3) application of nitrogen, phosphorus and potassium fertilizers based on soil test, 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.   Conclusion  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, compared to the control (without fertilizer), all treatments showed a significant increase. In the third year, there was a significant correlation between wheat yield and soil quality indices.

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 of 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 understanding of soil status, which is essential for developing effective management strategies and long-term planning for sustainable land use. This study was performed to assess soil quality under alfalfa cultivation and compare it 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 two 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 harvesting the crops and were taken from three depths (0–10, 10–20, and 20–30 cm). Eleven 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 MDS.   Results and Discussion Using 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 the alfalfa and the maize–wheat rotation, four components explaining more than 80% of the total variance were selected. In the alfalfa, the selected variables included organic carbon, total nitrogen, calcium carbonate equivalent, and MWD of wet and dry sieving. In the maize–wheat rotation, the selected variables included organic carbon, EC, calcium carbonate equivalent, and MWD under both wet and dry sieving conditions. The observed EC in this rotation system likely reflects the influence of evaporation and fertilization practices on soil salinity. Evaluation of SQI across different soil depths and two agronomic management systems revealed that soils under the 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 the deep layers, whereas soils in the alfalfa system had relatively higher SQI values even at the 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 the 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 that improved soil quality were OC, TN, CCE, and MWD. The presence of continuous plant cover, biological nitrogen fixation, and reduced tillage in the alfalfa cultivation played vital roles in increasing soil OM, reducing erosion, and improving SI. The application of 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, in enhancing soil quality and sustainability in semi-arid agroecosystems. Long-term monitoring of soil quality under alfalfa monoculture is recommended for sustainable land management.