Agricultural Engineering

Research Paper Plant Nutrition, Soil Fertility and Fertilizers

Evaluation of the nutrient content of soil and wheat grain due to the integrated application of chemical and organic fertilizers

Ali Reza Jafarnejadi; Farhad Moshiri; Fatemeh Meskini-Vishkaee

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2024.48100.1746

Abstract

Introduction: Arid and semi-arid areas such as Khuzestan province has highly fragile ecosystems that are characterized by low soil fertility, and high organic matter decomposition rates. Moreover, according to the FAO, around 12% of world soils and 65% of Iran's soils are calcareous and more than 20 ... Read More Introduction: Arid and semi-arid areas such as Khuzestan province has highly fragile ecosystems that are characterized by low soil fertility, and high organic matter decomposition rates. Moreover, according to the FAO, around 12% of world soils and 65% of Iran's soils are calcareous and more than 20 % of the irrigated farms in the world is affected by salinity. Since soil carbon saturation is low in saline-calcareous soils, the use of organic manure can be effective in increasing soil organic carbon and supplying essential nutrients in crop production. Applying organic manure in agriculture has been considered during the last two decades due to its high-quality products, high price, and low market availability of synthetic fertilizers, chiefly in developing countries. The manure application, both alone or in combination with inorganic fertilizers, is effective in increasing soil organic carbon (SOC) content and improve in soil fertility, microbial activity, and soil water retention capacity. Now the integrated application of organic and chemical fertilizers is inevitable for sustainable production and soil conservation. Hence, comprehension of the response of the soil and crop to applying organic and inorganic fertilizer may help to determine proper manure management strategies to enhance SOC and improve soil health and its ecosystem services. Thus, the aim of the study was to investigate the effects of different fertilizer managements on nutrient content of soil and wheat in saline-calcareous soils of Khuzestan province.Materials and Methods: To evaluate the effect of the integrated and long-term application of chemical and organic fertilizers on the nutrient content of soil and wheat grain in fixed plots, this research was carried out in Khuzestan province (Ahvaz city) in a calcareous- saline soil with silty clay texture under wheat cultivation (Barat cultivar) as a randomized complete block design in six treatments with three replications for four years (2017-2021). The treatments included T1: unfertilized control, T2: application of nitrogenous, phosphorus and potassium chemical fertilizers based on soil test, T3: application of 20 tons of cattle manure every two years + 75% of recommended nitrogen + 50% of the recommended phosphorus and potassium, T4: application 20 tons of bagasse every two years + 75% of the recommended nitrogen + 50% of the recommended phosphorus and potassium, T5: annual application of 20 tons of cattle manure + 75% of the recommended nitrogen, T6: annual application of 20 tons of bagasse + 75% of the recommended nitrogen. In treatment T2 recommended dose of P2O5, K2O, and 30 % of recommended N were applied at the time of second irrigation; the remaining N dose was applied in two splits at tillering (40 % of recommended N) and booting stages (30 % of recommended N). The organic manures were incorporated in the soil (depth 0-15 cm) a week before sowing. At the end of the growing season, wheat yield components were measured. At the end of the growth season, some soil properties involved pH, salinity and SOC, and the concentration of nitrogen, phosphorous and potassium in soil and grain wheat were determined. SAS v.9.1 statistical software and LSD test were used to compare the means of the studied treatments.Results and Discussion: The mean values of SOC varied in range of 0.60 to 0.73 %. As a result of applying treatment T2 (inorganic fertilizers application as alone), no significant difference was observed in SOC compared to the control treatment (p< 0.05). Compared to unfertilized control treatment, the SOC content were increased significantly by the use of cattle manure at T3 treatment (0.13 %), which could be attributed to the larger proportion of tenacious organic compounds in organic fertilizers than in chemical fertilizer. The highest concentration of soil available phosphorus (19.8 mg kg-1) was obtained in the integrated application of chemical fertilizer and cattle manure (T3), which is 60 and 169 % higher than those in the exclusive chemical fertilizer application (12.35 mg kg-1) and control (7.35 mg kg-1) treatments, respectively. The highest average soil available potassium concentration (253.3 mg kg-1) was also observed in T3. The results showed that the application of different fertilizer treatments was significant only on the nitrogen concentration of wheat grain (p< 0.01). The increase in wheat grain nitrogen concentration due to the application of integrated fertilizer treatments (28-38% increase compared to the control treatment) was significantly higher than the chemical fertilizers treatment (19% increase compared to the control treatment).Conclusion: Based on the results of this research, it was found that the integrated application of organic and inorganic fertilizers has a more positive effect on improving soil fertility in the long term than using them alone. Moreover, the results indicated that the use of cattle manure was more effective than bagasse manure which may be due to its lower carbon to nitrogen ratio (21.3). The integrated use of organic and inorganic fertilizers not only improve soil fertility, but also increases the efficiency of chemical fertilizer use, which reduces the basic chemical fertilizers consumption. Therefore, it is recommended to application of 20 tons of cattle manure every two years + 75% of recommended nitrogen + 50% of the recommended phosphorus and potassium (T3) in the saline-calcareous soils under wheat cultivation in arid and semi-arid climates such as southern of Khuzestan province.

Research Paper Soil Physics, Erosion and Conservation

Investigating the temporal changes in some soil quality properties in different tillage management in agricultural lands of western Golestan province

Bahareh Kiani; Farshad Kiani; Azam Rezaee; Pouneh Ebrahimi; Samaneh Mahzari

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2024.48218.1748

Abstract

Introduction: Different strategies have been proposed to sustainable soil management, including conservation agriculture. Conservation agriculture is based on four principles. Reducing plowing and soil disturbance, leaving an appropriate amount of plant residues on the soil surface, crop rotation with ... Read More Introduction: Different strategies have been proposed to sustainable soil management, including conservation agriculture. Conservation agriculture is based on four principles. Reducing plowing and soil disturbance, leaving an appropriate amount of plant residues on the soil surface, crop rotation with an economic cultivation pattern, and sustainable production of agricultural products with benefits are the basis of these four principles. The economic benefits of conservation agriculture and tillage in the early years have challenges in terms of implementation. There are few studies on the impact of the initial phase of conservation agriculture on soil nutrients and its consequences, so this study aims at the impact of Various protection management on some soil quality indicators during the initial years of implementation. Recently, farmers in Golestan province have been following the conservation agriculture in their fields without implementing a standard method and uniform instructions. Therefore, different results are obtained by implementing conservation tillage methods. In general, the economic benefits of conservation agriculture in the first year of its implementation are very controversial, and farmers think that the implementation of conservation agriculture may not be profitable due to the high consumption of herbicides and low yield, especially in the early years of its implementation.Methods and Materials: This study was conducted in Nokandeh region of Golestan province in the form of a randomized complete block experiment in three types of management including optional(minimum) tillage (MT), Conservation agriculture (CA) and conventional tillage (CT) and in 4 years. In each management, 30 soil samples were selected from the depth of 0 to 20 cm and the indicators were evaluated. Soil pH, Texture, Electrical Conductivity, Total Neutralizing Value (TNV), Soil Carbon, Total Nitrogen, Available Phosphorus and Potassium, and soil micronutrients contain Fe, Mn and Zn were evaluated using scientific methods. Data normality was also tested using the Kolmogorov-Smirnov test. The difference between the means has been calculated using Duncan's test at the confidence level of 0.01 and 0.05. SAS ver 9.4 software was used to analyze the data.Results and Discussion: he results show that the effect of tillage management on pH changes is not significant, while the effect of time on pH changes is significant at the one percent level (p ≤ 0.01). The pH in no-till in the fourth year was (7.64) and minimum tillage (7.62) and conventional tillage (7.4). The lowest pH value was in conventional tillage treatment, which decreased by 3.6 percent compared to the first year. The main decrease in electrical conductivity was observed in no-till, with a 32% decrease in soil electrical conductivity in the fourth year compared to the first year, and the minimum changes were observed in conventional tillage. The amount of organic soil in conservation agriculture and then OC was observed to increase by 47% and 17%, respectively, compared to the first year. The implementation of conservation management in different years was not significant on the amount of TNV, but the percentage of the amount of TNV was observed in tillage managements, CT > CA > CT respectively. The amount of total nitrogen has increased in MT and CA, which means a decrease in nitrogen leaching in four years. Conservation agriculture in the fourth year can increase the amount of available phosphorus in the soil by 47% compared to the first year, and the potassium element has increased by 58% in CA and 52% in MT, while the potassium content has increased by 6%. The elements of iron and zinc in MT and the amount of manganese in CA were higher. The results of the present study showed that the most important management factors affecting the initial years are the amount of soil organic matter. Soil nutrients are sensitive indicators of fertility. Changes in soil nutrients increase with a gentle slope in the initial years. And this trend is sometimes accompanied by uncertainties. There are significant aspects of water, plant, and soil interactions in nutrient cycling, etc., that are still unknown.Conclusion: The results of this study showed that although low tillage and no-till treatments improve soil nutritional and fertility indices compared to conventional tillage, the trend of changes in these indices over time is different, which may discourage farmers and promoters in the early years of implementation. Considering that different results have been obtained in this research, it seems that to achieve better and visible results by farmers, sufficient time is needed for implementation. These findings provide a practical perspective to farmers, promoters and managers to realistically pay attention to the achievements in the early years of implementation. It is suggested that in the initial years of implementation in farms with greater fragility and uncertainty, government support should be provided to reach the final sustainability of the plan.

Research Paper Land Evaluation and Suitability

Assessment and modeling of soil quality using multivariate analysis approach (Case study of rainfed agricultural land in Dezpart city)

Sina Bigdeli; Heidar Ghafari; Mojtaba Norouzi Masir; Abdolamir Moezzi

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.48357.1753

Abstract

Introduction: Today, the concept of soil quality (SQ) has been widely used to know the capacity and limitations of soils in different environmental systems. The degree of suitability of land is determined by its capacity to provide services and its flexibility against external conditions. Production ... Read More Introduction: Today, the concept of soil quality (SQ) has been widely used to know the capacity and limitations of soils in different environmental systems. The degree of suitability of land is determined by its capacity to provide services and its flexibility against external conditions. Production of plant biomass is one of the most important functions of soil in relation to food security. The share of dry land in Iran's agricultural production, especially wheat, is very significant. So that in terms of area, about half of the total area of agricultural lands, in terms of volume of production, about 10% of all agricultural products and about 30% of the country's wheat production are related to these lands. Therefore, maintaining the soil quality of these lands is very important. The main goal of this research is to model and quantify the soil quality of part of the rainfed agricultural lands of Dezpart city using integrated multivariate analysis and also to determine the minimum effective data set.Materials and methods: This study was carried out in a part of the rainfed agricultural area of Dezpart County. First, 119 soil samples were prepared using the composite method from the soil depth of 0-30 cm. Soil sampling was done in a stratified random manner to include all the different geomorphological units. The geographic location of the sampling points was also recorded. The samples were transferred to the laboratory and their chemical-fertility and physical characteristics include reaction (pH), electrical conductivity (EC), organic matter (OM), total nitrogen, available potassium, absorbable phosphorus, calcium carbonate equivalent (CCE), texture, bulk density, mean weight diameter (MWD) of soil aggregates, soil gravel content and cation exchange capacity (CEC) were measured. Then the soil quality was determined using two datasets of total (TDS) and minimum (MDS), and multivariate analysis method. In this method, by using appropriate scoring functions, a score between zero and one was considered for each member of the data set. Also, a weight coefficient was calculated for each member, and finally, the soil quality index, which indicates its degree of desirability, was obtained by three indices including Nemero (NQI), cumulative weighted index (IQI) and simple cumulative index (AQI). Finally, a spatial variation map of soil quality was prepared using the Inverse Distance Weighting (IDW) method in geographic information system (GIS) software.Results and Discussion: The results of the principal component analysis (PCA) test indicated that there are three main components that cover 78% of the total variance changes. The first component alone accounts for about 41% and the second and third components account for 25% and 12% of the total data variance, respectively. Based on the correlation analysis between soil components and characteristics, five characteristics including organic matter (OM), silt content, gravel, pH and EC were selected as MDS members. Became in the TDS collection, the highest weights related to silt and sand (0.093 and 0.095, respectively) and the lowest weight with 0.050 was assigned to bulk density (BD). In the MDS set, the highest weight was related to organic matter and silt and the lowest weight was related to pH. The soil quality of the region was generally classified as medium based on the two indexes of AQI and WQI. However, the NQI method indicated that the soil quality was low. Among the three selected indices with different functions and data sets, the weighted soil quality index with the minimum data set and nonlinear function (WQI_MDS_NL) was chosen as the superior model due to having a higher sensitivity index (or a larger standard deviation). The spatial soil quality map, which was prepared for this study, showed that approximately 50% of the lands in the region had an average soil quality and 50% had a low soil quality.Conclusion: Organic matter, silt, pH, gravel and EC are the main characteristics to determine the soil quality of the region. In addition, stability of soil aggregates, bulk density and lime are the most important limiting factors of soil quality in the region. Therefore, it is suggested to use appropriate management practices such as conservation tillage and use of organic fertilizers to improve these characteristics.

Research Paper Plant Nutrition, Soil Fertility and Fertilizers

Effect of Carbon Black and Zinc-Solubilizing Bacteria on the Chemical Distribution of Zinc in Soil under Salinity Stress

Sepideh Raeisi; Nafiseh Rangzan; Naeimeh Enayatizamir

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.48339.1752

Abstract

Introduction: Zinc (Zn) is a vital nutrient for plants, needed in small amounts for their reproductive and physiological functions. Zinc deficiency is common in soils with high pH, low organic matter, and high calcium carbonate. Soil salinity is one of the most important and common environmental stresses ... Read More Introduction: Zinc (Zn) is a vital nutrient for plants, needed in small amounts for their reproductive and physiological functions. Zinc deficiency is common in soils with high pH, low organic matter, and high calcium carbonate. Soil salinity is one of the most important and common environmental stresses in the world. The impact of salinity on the forms of zinc and its availability in soil has varied. Among the chemical forms of zinc, the soluble and exchangeable forms have the highest mobility and availability for plants; whereas the residual form, associated with the crystalline lattice of soil minerals, appears to be very inactive. Depending on the physical and chemical properties of the soil, the carbonate forms, those bound to iron and manganese oxides, and the organic forms of elements are relatively active and have the potential to be available for plants. Organic materials like carbon black can alter zinc distribution. Zinc-solubilizing bacteria enhance zinc availability by converting insoluble forms into absorbable ones. This study examines the effects of carbon black and growth-promoting bacteria on zinc forms and soil properties under varying salinity levels.Materials and Methods: In this study, to investigate the effect of carbon black and inoculation of a mixture of two bacteria on the distribution of chemical forms of zinc under salinity stress, a pot experiment with four replications was conducted as factorial with three factors: salinity (2, 5, and 8 dS m-1), carbon black (0, 4% by weight), and a mixture of two bacteria (inoculated and non-inoculated). The bacteria included Enterobacter cloacae and Bacillus sp., which were obtained from the microbial collection of the Soil Science Department at Shahid Chamran University of Ahvaz. The experiment was carried out in a completely randomized design in 2023 in the greenhouse of Khuzestan Agricultural Sciences and Natural Resources University. In 5-kilogram pots, 10 corn seeds were planted, which were reduced to 6 plants per pot after ensuring germination. Two months after planting, soil samples were taken from the pots, and after removing the roots and passing through a 2-millimeter sieve, they were transferred to the laboratory to determine the chemical forms of zinc. The sequential extraction method was used to determine the chemical forms of zinc. The fractions—exchangeable, carbonate, iron and manganese oxides, organic, and residual—were determined. The concentration of zinc in the extracts obtained from the various stages of sequential extraction of the soil was read using an atomic absorption device. Some biological properties of soil, such as microbial biomass carbon via fumigation-extraction method, catalase activity via the titration method, and soil respiration by titration of residual NaOH, were measured.Results and Discussion: The interaction effect of carbon black× inoculation× salinity on chemical forms of Zn was significant. The results showed that the inoculation of a mixture of two bacteria and addition of carbon black in soil significantly increased the soluble and exchangeable, carbonate, iron and manganese oxide, and organic forms of zinc. Inoculation of a mixture of two bacteria and carbon black to the soil at a salinity level of 2 dSm-1 resulted in an increase in EXCH-zinc from 1.02 to 1.38 mgkg-1 compared to the control, which is equivalent to a 35% increase. Inoculation of the bacterial mixture and the addition of carbon black to the soil increased all forms of zinc except the residual form. With increasing salinity level, the amounts of soluble and exchangeable, carbonate-bound, and oxide-bound forms increased, while the organic-bound form decreased. The highest amounts of microbial biomass carbon, catalase activity, and soil respiration were measured in the treatment with bacteria, carbon black, and at a salinity level of 2 dS m-1, with values of 19.9 mg-Cmic 100g-1, 0.95 mLKMnO4g-1h-1, and 70.2 mgCO2 100g-1day-1, respectively. There was a positive correlation between soil respiration and all forms of zinc, except the residual form, but the correlation between soil respiration and the residual form of zinc was negative, indicating the influence of microbial activity on different forms of zinc.Conclusion: The addition of a carbon black to the soil and inoculation of a mixture of two bacteria caused zinc to convert from residual form to soluble and exchangeable, carbonate, oxide, and organic forms, increasing the availability of zinc in accessible fractions at various salinity levels. Overall, zinc-solubilizing bacteria offer a promising solution for enhancing zinc availability in saline soils, promoting plant health, and contributing to sustainable agricultural practices.

Research Paper Soil Physics, Erosion and Conservation

Investigating the use of Reflectometry and surface soil color for separation of surfaces exposed to gully erosion

Mitra Yarahmadi; Ataallah Khademalrasoul; hadi Amerikhah

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.48065.1745

Abstract

Introduction: Soil erosion is the most prevailing form of soil degradation which is really play an important role on the mass balance index of soil particles in the watersheds. Moreover, regarding the on-site and off-site effects of erosion essentially has to measure and predict the soil loss using different ... Read More Introduction: Soil erosion is the most prevailing form of soil degradation which is really play an important role on the mass balance index of soil particles in the watersheds. Moreover, regarding the on-site and off-site effects of erosion essentially has to measure and predict the soil loss using different methods. Specifically gully erosion is a form of water erosion with the huge amount of soil dislodgement. Due to the complexity and variability of soil erosion it is necessary to apply different techniques in order to monitor the soil erosion changes. Remote sensing technology and the use of spectrometry and reflectometry basics is a suitable solution and option for monitoring coastal areas affected by erosion and deposition events, which provide high quality temporal and spatial data. Soil color is an appearance property which is meaningfully effective on soil reflectance. Generally, soils with high amount of organic matter has low reflectance because of the darkness while the light soils has high reflectance from surface (high Brightness index, BI) which is effective on soil temperature. Therefore we try to use RS and radio spectrophotometry to find a relation between soil color and its reflectance. Materials and Methods: The study area is located at Zahirieh watershed of Khuzestan province which is between Ahvaz and Masjedsoleyman cities with approximately 7100ha area. The average of rainfall is 218.6mm, the maximum temperature is 54 and the minimum is 7 degrees. Regarding the separation of erosional and depositional surfaces in the study area; first, using the visual inspection of Landsat satellite false color images, 8 regions were divided into several regions, then random sampling points were created using the random point generator tool in ArcGIS 10.4 software to implement the random sampling method within the block. Finally, 12 sampling points representing erosion surfaces and 14 sampling points representing depositional surfaces were selected and sampled to determine surface soil characteristics. Surface soil color was determined using Mansell's color book in natural daylight in two dry and moist conditions. After collecting the soil samples in air-dry moisture condition and also in wet condition, their spectroscopic analysis was done by FieldSpec3 device and this moisture condition was considered for all the soil samples of eroded and depositional surfaces. Statistical analyzes and mean comparisons were performed using SPSS 26 statistical software. Corrections of satellite images and transformations were made in ENVI 4.7 software, and visual outputs and maps were made in ArcGIS 10.4 software.Results and Discussion: Results depicted that among the evaluated soil color indicators, the dry weight parameter is significant at the level of 1%. This level of significance shows well that the Value index in the dry state can be used as an effective parameter to identify and separate erosion and deposition levels in the study area. There is a difference between the values of the statistics for red, green and blue RGB in the dry state for erosion and depositional surfaces, and these differences are also evident for the moist state. In the depositional surfaces, with the drying of the soil, blue, red, and green reflections all decrease, but this decrease is double and about six times for blue. The reduction of blue reflections in the RGB system leads to an increase in the yellowness of the color. In the case of the soils of erosion surfaces, we can see the pattern of the photo and we see the enhancement of reflections and consequently the lightening of the color of the soil when the soil is dry. According to what has been seen in the Munsell system, it seems that this issue has a direct relationship with the amount of organic matter and the ratio of fulvic acid to humic acid in the organic matter of the soil. Moreover, the results of the comparison of the average bands of Landsat 8 shows that bands 2, 3 and 4 are able to separate erosion and sedimentary surfaces at the 1% level, but thermal bands cannot be used to separate surfaces. Due to the difference in the color characteristics of erosional and sedimentary surfaces, as a result, it is possible to separate them based on reflectometric characteristics, and it is possible to separate eroded and sedimentary surfaces by using color indices.Conclusion: Due to the difference in the color characteristics of erosional and depositional surfaces, as a result, it is possible to separate them based on reflectometric characteristics, and it is possible to separate eroded and depositional surfaces by using color indices. The results showed that it was possible to model surface soil characteristics using quantified surface soil color data, and this hypothesis was confirmed by statistical investigations.

Research Paper Plant Nutrition, Soil Fertility and Fertilizers

The application of stress modifier nanoparticles on the biochemical characteristics and yield of ajwain (Carum copticum L.) under drought stress

Saeid Heydarzadeh; ahmad tobeh; Sodabeh Jahanbakhsh; salim farzaneh

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.47090.1731

Abstract

Introduction: Ajwain (Carum copticum L.) is a medicinal herb from the Apiaceae family that is widely cultivated in Europe, Iran, India, Egypt, and Pakistan. Pharmacological and clinical trials indicate that C. copticum is effective in treating pharyngitis, showcasing benefits like antioxidant, antiparasitic, ... Read More Introduction: Ajwain (Carum copticum L.) is a medicinal herb from the Apiaceae family that is widely cultivated in Europe, Iran, India, Egypt, and Pakistan. Pharmacological and clinical trials indicate that C. copticum is effective in treating pharyngitis, showcasing benefits like antioxidant, antiparasitic, expectorant, and antilithiatic effects. Although this herb can withstand damage from water stress, regular and sufficient watering will increase its yield. Inadequate water supply, particularly in terms of quantity and allocation throughout growth and developmental stages, leads to reduced achievement of the crop's intrinsic potential, eventually decreasing the farmer's production and livelihood. Water deprivation is a major limiting factor in semi-arid and arid regions, affecting all aspects of plant morphology, physiology, growth, development, and yield. Chitosan facilitates the formation of secondary compounds like polyphenolics, flavonoids, and lignin, which are beneficial for various herb species, and for the activation of herb defense enzymes. Humic acid can especially influence the growth of medicinal herbs by affecting cell membrane permeability, metabolic pathways, cellular respiration, photosynthetic efficiency, enzyme activation, and cell growth. Melatonin improves plant tolerance against various environmental stresses, including extreme temperatures, cold, salinity, chemical compounds, heavy metals, and pathogens. The use of selenium improve photosynthesis, antioxidant activity, carbohydrate accumulation, and synthesis of secondary metabolites under drought stress. Therefore, this study aims to assess the effects of stress modifiers; namely chitosan, humic acid, melatonin, and selenium on the physiological and yield traits of ajwain when exposed under water stress.Materials and Methods: A two-year field trial was performed in the 2022 and 2023 years of cultivation at the University of Mohaghegh Ardabili in Ardabil, Iran. The experimental design was factorial, using a complete randomized block design with three replications. The factors were the stress modulator treatment (MEN: melatonin, CHN: chitosan, HUC: humic acid, and SEM: selenium and CON: control) and irrigation treatments (watering at 100%, 75%, and 50% field capacity (FC) as normal, moderate deficit irrigation and severe deficit irrigation, respectively). All plots consisted of 8 rows of herbs spaced 20 cm from each other, with plants spaced 40 cm apart within each row. Seeds of ajwain (Carum copticum L.) were sown on March 20, 2022 and 2023. During the vegetative phase of ajwain, foliar spraying was applied on the leaves in the three stages at ten-day intervals, coinciding with periods of moisture stress. Weeds were carefully controlled when needed. The soil was collected from a depth of 0-30 cm, analyzed, and found to be silty clay (36% Silt, 33% Clay, 31% Sand) with an electrical conductivity of 0.37 dS /m, pH of 7.8, 1.04% of organic matter, 0.11% total N, 10.04, and 344 mg kg−1 available P and K, respectively. A 2-year investigation analysis of variance (ANOVA) was conducted operating the general linear model (GLM) (SAS 9.1.3) combining the findings from 2022 and 2023. The LSD trial was evaluated for comparing means at p < 0.05.Results and Discussion: The results showed that under normal irrigation conditions, ajwain plants sprayed with melatonin had the seed yield (733.35 kg/ha), and essential oil yield (22.11 kg/ha). The maximum absorption of nitrogen, phosphorus and potassium (3.09%, 0.40%, and 1.65%, respectively) was obtained under normal irrigation conditions and foliar spraying with melatonin. While the highest amount of total phenol and flavonoid (29.55 and 3.33 mg/g dw, respectively), DPPH radical inhibition percentage, nitric acid radical inhibition percentage, and superoxide radical collection capacity were 78.85, 67.88, and 138.47% respectively, which were observed in the conditions of severe stress and foliar spraying with melatonin. Also, melatonin foliar application improved the amount of essential oil of ajwain (3.30%) under medium stress conditions. Water stress hinders plant growth and development by impacting many physiologic processes, including nutrient absorption, stomata function, transpiration rate, sugar synthesis, hormone production, assimilation, and photosynthesis. Stressful environments were shown to accelerate the synthesis of EOs, as evidenced by the increased EO content under stress. This is likely due to the role of secondary metabolites in helping plants withstand ecological stresses. The application of MEN, CHA, HUM, and SEM directly enhanced photosynthetic pigments, improved photosynthetic efficiency, increased the concentration and activity of RuBisCo, and promoted ATP and NADPH production to enhance plant productivity. Drought stress triggers the production of secondary metabolites and essential oils, which act as protective molecules against environmental pressures. The biostimulant composition, which includes macro and microelements, vitamins, amino acids, and growth hormones, plays a crucial role in promoting plant growth, as well as the percentage and yield of essential oil. When soil moisture availability is restricted, the uptake of water, the solubility of minerals in the soil, and their absorption by roots decline, leading to adverse effects on photosynthesis and transpiration rates. In these circumstances, as previously demonstrated, the foliar application of MEN, CHA, HUM, and SEM positively influences stomatal opening adjustment and chlorophyll abundance, facilitating the growth, division, and elongation of herb root cells. As a result, foliar spraying of MEN, CHA, HUM, and SEM likely maximized this influence by reactivating various biosynthetic and biological pathways and genes that regulate secondary metabolite production, while also enhancing the glands that manufacture essential oils in the flowers and leaves of plants under water restriction. Since hydrocarbons are required as precursors for the production of phenols, an increase in their rate and concentration influences the enhancement of phenolic combinations. Applying MEN, and CHA has been shown to be beneficial in reducing the impact of free radicals and increasing the production of phenolic compounds. This effect may be related to the role of MEN, and CHA in improving antioxidant activity against ROS.Conclusion: Overall, among all the tested stress modulators, MEN and CHN emerged as valuable tools for improving growth, physiological characteristics, essential oil, and fixed production in ajwain herb. They can help reduce the detrimental impacts of water stress and establish a sustainable framework for optimizing ajwain performance even under moisture-deficit conditions in semi-arid and arid regions of Iran.

Research Paper Soil, Water and Plant Relationships

The effect of enriched biochar on the growth and physiological characteristics of forage corn (Zea mays L.) grown in arsenic contaminated soil under deficit irrigation conditions

maryam mosapour; Afsaneh Alinejadian-Bidabadi; mohammad feyzian; amir lakzian

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.46964.1729

Abstract

Introduction: Today, the use of biochar to reduce the adverse effects of environmental stress such as heavy metal stress and drought stress has increased rapidly. Biochar reduces the adsorption of these metals by plants through the adsorption of soil pollutants on its surface due to the porous system ... Read More Introduction: Today, the use of biochar to reduce the adverse effects of environmental stress such as heavy metal stress and drought stress has increased rapidly. Biochar reduces the adsorption of these metals by plants through the adsorption of soil pollutants on its surface due to the porous system and the presence of important functional groups such as carboxyl, phenolic and hydroxyl. Research has shown that by changing the surface characteristics of biochar, including specific surface area, pore volume and the content of functional groups, especially oxygen-containing groups, it is possible to increase the ability of biochar to adsorb heavy metals. Another important solution that has been started today to improve the quality of soil, agricultural products and remove pollutants is the use of nanotechnology. Today, zinc oxide nanoparticles are used in agriculture and related sectors. Zinc is a mineral element for plant growth and has beneficial and harmful effects on various aspects of plant growth. Forage corn (Zea mays) is one of the most important grains in the world and is very important in providing energy for animals. According to the studies conducted, one of the most important factors that has reduced the yield of forage corn in the world is drought stress, in addition to this, heavy metals may also be involved in this matter, so although there are various solutions to overcome the stress drought and pollution caused by heavy metals in forage corn, however, the effect of biochar enriched with zinc nanoparticles in these conditions has not been well investigated; Therefore, considering the importance of the forage corn in the human and livestock food chain, the main objective of this research is the role of biochar and biochar enriched with zinc nanoparticles in reducing the negative effects of deficit irrigation and arsenic on some morphological and physiological characteristics of forage corn.Materials and Methods: Experimental factors include 5 levels of biochar: control (no use of biochar), 0.5 and 1% by weight of plain biochar, 0.5 and 1% by weight of biochar enriched with zinc nanoparticles and three irrigation levels: control (100), 75 and 55% of Field Capacity (FC)). In this study, green walnut skin was used to prepare biochar. Zinc oxide nanoparticles were used for biochar enrichment. At first, 0.2 % of the weight of biochar was weighed from nanoparticles, and then it was brought to a certain volume with distilled water. The produced suspension was shaken overnight at room temperature. After this step, the sediment produced was washed several times and dried in an oven at 100 degrees for 12 hours. Then it was weighed according to the experimental treatments and mixed separately with the soil of the pot, which was previously contaminated with arsenic from the source of Na2HAsO4.7H2O in the amount of 50 mg/kg of soil. To determine the FC, the weight method was used, and based on the soil moisture level, the levels of 75 and 55% of the FC were calculated, and the test plants were irrigated by the weight method of the pots every other day. After the completion of the vegetative growth and before entering the reproductive growth, the samples were taken. Then some morphological and physiological traits of the plant were measured.Results and Discussion: The results showed that the application of biochar (unenriched) and enriched biochar reduced the negative effect of arsenic and deficit irrigation. So that the highest fresh weight (43.95 gr per pot) and dry weight (5.36 gr per pot) of leaves in the treatment of 0.5% weight enriched biochar, the highest, height (87.86 cm), chlorophyll a (17.52 mg/g leaf weight) and total chlorophyll (26 mg/g leaf weight) in the treatment of 1% enriched biochar and the most chlorophyll b (8.73 mg/g leaf weight), cartenoid (5.65 mg/g leaf weight), RWC (79.19%) was observed in the treatment of 1% biochar (unenriched) and control treatment (100% FC). The results also showed that the highest (17.21 mg/kg) and the lowest (11.74 mg/kg) available arsenic were in the 0.5% enriched biochar treatment and the control treatment (no use of biochar) respectively, highest zinc uptake in leaf (393.04 µ/ pot) in the treatment of 1% enriched biochar and full irrigation (100% FC) and the lowest amount (105.55 04 µ/pot) in the control treatment (no use of biochar) and severe irrigation deficiency (55% FC) was observed; While highest arsenic uptake in leaf (18.58 µ/pot) in the control treatment (no use of biochar) and severe deficit irrigation (55% FC) and the lowest amount (2.34 µ/pot) in The treatment of 1% enriched biochar and complete irrigation was observed; which can be related to the effective role of enriched biochar in reducing arsenic absorption in severe irrigation conditions.Conclusion: Considering the favorable effect of biochar in improving the growth and physiological characteristics of forage corn and reducing the absorption of arsenic at different levels of irrigation, it can be said that in soils contaminated with arsenic, the addition of biochar plays an effective role in improving plant growth in deficit irrigation.

Research Paper Design and Evaluation of Agricultural Machines

Design, construction and evaluation of a field transplanter with a biodegradable pot. Case study: Tomato transplanting

mehdi kakaei; Hossein Haji Agha Alizadeh

Volume 48, Issue 1 , April 2025

https://doi.org/10.22055/agen.2025.48835.1762

Abstract

Introduction: In developing countries, since most farmers have small plots of land, they are unable to afford expensive machinery for cultivating vegetables, so they use the manual method. In this method, on average, each worker works for about 8 to 9 hours a day. This activity causes physical fatigue, ... Read More Introduction: In developing countries, since most farmers have small plots of land, they are unable to afford expensive machinery for cultivating vegetables, so they use the manual method. In this method, on average, each worker works for about 8 to 9 hours a day. This activity causes physical fatigue, reduces work accuracy, and uneven distribution of seedlings across the field. On the other hand, during peak work, due to the high demand for human resources, there is usually a shortage of human resources. This shortage of manpower during the planting season affects the right time and the final yield of the cropTransplanting machine is used to increase productivity, uniform distribution, precision in planting, save time, and timely planting. A review of the resources of the last few years in the special planting of seedlings has given automatic feeding with determinate pot seedlings, reducing manpower, increasing the final yield and increasing the carrying capacity at the same time, and as a result, it also helps to improve the performance of semi-auto games better and also helps to improve the performance of semi-autos, reducing human intervention, and on the other hand, seedlings grown in paper pots, to mechanize the transplanting operation by improving the quality of the pot in the soil and helping to meet the conditions. Growth and organic matter in the soil are a better option. Therefore, this research aimed to develop, design and evaluate a smart seedling planting device in small farms to identify the speed of the advance operation using seedlings grown in paper pots.Materials and Methods: In this study, the physical and mechanical properties of two biodegradable pot models, an incomplete cone and a square pyramid, were evaluated for use in a transplanter in a pressure test device. According to the field data of tomato planting methods, a model with suitable dimensions for small farms was first designed using SolidWorks engineering software. Then, to build the transplanter, its frame was first built. Considering the dimensions of the device, a potting tractor model with a nominal power of 45 horsepower was used to provide driving forces due to its appropriate maneuverability in a small space and greenhouse. In this device, a furrow opener with adjustable height for working at different depths was installed at the beginning of the device. A finger covering system, soil leveler, and two-disc coverings were used to properly position the pot in the created furrow. To transfer the pots in this device to the drop tube, a turntable with a stepper motor was used to transport them at different rotational speeds, an electronic circuit to control its rotational speed, and two infrared sensors to detect and count the pots. Then, for its field evaluation, two factors, the advancing speed at three levels (0.7, 1.5, and 2.5) and the type of seedling at two levels (4 and 6 leaves) were studied in a completely randomized factorial design with three replications. The aim of designing this transplanting device is to use biodegradable pots to develop sustainable agriculture and reduce physical damage to roots during planting.Results and Discussion: The results of this study showed that the most suitable incomplete cone pot that withstands the highest force in the pressure test was used as the most suitable pot for use in the transplanter. Then, to eliminate lateral forces on the movement of the pot in the drop tube, a diagonal position in the opposite direction of movement was used. The results of the analysis of the measured data showed that the effect of the forward speed on the parameters of the percentage of uniformity of the distribution of seedlings, the percentage of changes in the planting depth, the percentage of plant deviation from the row and the percentage of physical damage was significant at the 1% level, and its effect on the parameters of the percentage of multiple planting and non-planting, acceptable and unacceptable planting was significant at the 5% level. Also, the effect of the seedling type factor on the parameters of the percentage of seedling mortality after planting and plant deviation from the row were significant at the 1% and 5% levels, respectively. The interaction effect of the factors was not significant on any of the measured parameters. Comparison of the average effects of the measured factors at the three levels of forward speed and two types of seedlings showed that all factors had equal effects at the two speed levels of 0.75 and 1.5 km/h, except for the factor of the percentage of uniformity of seedling distribution (with an average of 89.36%) at the speed of 1.5 km/h and the mortality of seedlings after planting at four leaves (with an average of 22.33%).Conclusion: Considering the physical characteristics of the biodegradable pot, the incomplete cone model was selected for use in the device. The best performance of the transplanter device at three levels of forward speed and two types of transplanting was achieved at a forward speed of 1.5 km/h and 6 leaves with the lowest percentage of plant deviation from the row, physical damage, multiple planting and non-planting, percentage of unacceptable planting, percentage of depth changes, and with the highest percentage of acceptable planting and uniform distribution.

Effect of Tillage and Planting Methods in Hill Slopes on Soil Erosion and Wheat Grain Yield under Rain Fed Conditions in Kermanshah Province

Volume 35, Issue 2 , March 2012, , Pages 1-12

Abstract

The erosion in dryland causes decrease in yield and soil quality, especially in slope lands with conventional tillage. To investigate the effects of tillage and planting methods in slope lands on erosion and yield of rain fed wheat, an experiment was conducted in 2007-2008 at Kermanshah Province. The ... Read More

Ergonomic Evaluation of the Posture of Dates Packinghouse Workers by REBA Method

Volume 37, Issue 1 , September 2014, , Pages 13-22

Abstract

This study was conducted among dates’ packinghouse workers with the objectives of a) determining of MSDs prevalence and b) evaluating level of exposure to MSDs risk factors. The results of this study can be used to develop MSDs preventive strategies in the workplace and improve workers’ health. ... Read More

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Application of gypsum and manure on improving the amount of nitrogen, phosphorus and potassium in leaves and seeds of wheat under salinity stress

Volume 36, Issue 1 , September 2013, , Pages 1-11

Abstract

Salinity limited plant growth and will decrease the yield with decrease in solution osmotic pressure, nutrient imbalance and toxicity of some specific elements. Application of amendment materials such as gypsum and cattle manure can adjust the undesirable effects and increase the nutrient elements in ... Read More

The Effects of Different Sizes of Particles of a Superabsorbent Polymer on Water Holding Capacity of Two Different Soil Textures

Volume 36, Issue 1 , September 2013, , Pages 65-75

Abstract

Superabsorbent polymers are water containers that absorb and retain large quantities of water when applied to the soil. These materials release the absorbed water, allowing the plants to consume adequate amounts of water at all growth stages. One of the best options for increasing the irrigation efficiency ... Read More

Estimating Soil Erosion and Sedimentation Using Cesium-137 Method: A Case Study (Raymaleh Watershed, Lorestan)

Volume 35, Issue 2 , March 2012, , Pages 37-54

Abstract

The rate of soil erosion and sediment yield estimation in the catchment areas is considered as an important factor for soil and water conservation practices. Due to difficulties and restrictions in common soil erosion methods, applying a high accuracy method with lowest cost and time consuming would ... Read More

Research Paper

Identification of the Factors Affecting Iron Release Kinetics in Some Calcareous Soils of Orange (Citrus sinensis L.) Orchards at Darab Region, Southern Iran

Hamid Reza Boostani; Mahdi Najafi-Ghiri; Abbas Mirsoleimani

Articles in Press, Accepted Manuscript, Available Online from 23 March 2025

https://doi.org/10.22055/agen.2025.48876.1764

Abstract

Introduction: Darab region is one of the most important citrus production hubs, especially oranges, in Fars province. Given the frequent reports of iron deficiency chlorosis in citrus grown in calcareous soils of Iran, which reduces fruit production and quality, a better understanding of the mechanisms ... Read More Introduction: Darab region is one of the most important citrus production hubs, especially oranges, in Fars province. Given the frequent reports of iron deficiency chlorosis in citrus grown in calcareous soils of Iran, which reduces fruit production and quality, a better understanding of the mechanisms and kinetics of iron release from soil can provide useful information about its bioavailability and the factors affecting it and help us take the necessary measures to optimize soil conditions to prevent iron deficiency in plants and increase its availability in the soil. The aim of the present study is to investigate the kinetics of iron release in some calcareous soils of orange orchards (Citrus sinensis L.) in the Darab region, southern Iran, using six mathematical kinetic models and to find the effective soil characteristics in the release of iron from the solid phase to the soil solution. Materials and Methods: 21 Washington Novel orange orchards (Citrus sinensis L. Osbeck) grafted onto orange (Citrus aurantium) rootstock were selected from different locations in Darab region in southeastern Fars Province through field observations and aerial photo analysis. Soil sampling was carried out from the selected tree bases and their shaded areas in four different directions (from 0 to 30 cm depth) in the vicinity of the drippers. Thus, a total of 10 soil samples were selected with different physical and chemical properties. The kinetics of iron release study was carried out using DTPA solution at pH 7.3 as the extractant, which was as follows: 10 g of each of the three soil sample replicates were placed in a 50 ml centrifuge tube and extracted with 20 ml of DTPA solution on a shaker (120 rpm) for 0.083, 0.25, 0.5, 1, 2, 6, 12, 24 and 48 hours at 25 ± 2°C. After shaking, the samples were immediately centrifuged for 10 minutes at 4000 rpm and the supernatant was passed through Whatman filter paper No. 42. The iron concentration in the resulting solution was measured by atomic absorption spectrometry (PG 990, PG Instruments Ltd. UK). The cumulative concentration of released iron (q) was evaluated as a function of time (t) using six different kinetic models. Relatively high values of the coefficient of determination (R2) and low values of the standard error of estimate (SEE) were used as criteria for selecting the best models. Data analysis was performed using SPSS 17.0 software.Results and Discussion: The pattern of iron release in all soil samples was similar and consisted of a short-term rapid phase (fast phase) and a long-term slow phase (slow phase), so that about 44% (on average) of the total iron released during 48 hours was desorbed in the first two hours. Therefore, this result can confirm the two-stage iron release process from the soil samples. The highest iron release content within 48 hours was observed in soil "A" (17.3 mg kg-1), which could be due to the fact that among the studied soils, the highest organic matter content (7%), cation exchange capacity (2.15 meq 100 g-1 soil) and total iron (7560 mg kg-1) were found in soil A. The power function, parabolic diffusion, and simple Elovich kinetic models had the highest R2 values and the lowest SEE values among the kinetic models, respectively. In the power function kinetic model, the value of the constant “a” ranged from 0.829 to 1.260 with a mean of 1.02, while these values for the constant “b” ranged from 0.23 to 0.30 with a mean of 0.25. The KP constant in the parabolic diffusion kinetic model represents the rate coefficient of iron diffusion (mg Fe kg-1h-0.5) from the solid phase to the soil solution. Among the studied soils, the highest and lowest KP values were for soil A (0.399) and soil B (0.198), respectively.Conclusion: The soil properties such as organic matter, cation exchange capacity, pH, salinity, percentage of sand, silt and clay (soil texture) were effective on the rate of iron release from calcareous soils, while the total soil iron and equivalent calcium carbonate had no effect on iron release. Soil organic matter and percentage of sand had a positive and significant correlation with the rate of iron release in the soil from the solid phase to the soil solution, while there was a significant negative correlation between the rate of iron release and soil salinity, pH, percentage of silt and clay. Finally, it is suggested that management methods, including creating lighter soil texture by adding sand and reducing salinity (leaching) of calcareous soils under orange cultivation in the Darab region, can significantly contribute to the release of native soil iron from the solid phase to the soil solution, and consequently improve iron nutrition.

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Applicable

The application of Material Flow Cost Accounting in optimizing energy consumption and reducing olive production costs

Behnam Mohammadi; Majid Namdari; Alireza Yousefi; Moslem Heydari

Articles in Press, Accepted Manuscript, Available Online from 23 March 2025

https://doi.org/10.22055/agen.2025.49048.1768

Abstract

Introduction: The generation of waste and the emission of pollutants are significant challenges in production processes, leading to increased economic costs and environmental degradation. Addressing these challenges has become a priority, as unsustainable production practices not only harm the environment ... Read More Introduction: The generation of waste and the emission of pollutants are significant challenges in production processes, leading to increased economic costs and environmental degradation. Addressing these challenges has become a priority, as unsustainable production practices not only harm the environment but also hinder long-term economic development. Sustainable production and environmental efficiency are critical goals for manufacturing units aiming to achieve sustainable development. Achieving these goals requires innovative tools and methodologies that can assess and optimize resource use across various production systems. Cleaner production approaches, which focus on optimizing production processes and reducing negative environmental impacts, have emerged as key strategies in this context. One such tool is Material Flow Cost Accounting (MFCA), developed under ISO 14051:2011. MFCA has proven to be a powerful tool for simultaneously improving environmental and financial performance by quantifying material flows and associated costs within production systems. This study applies MFCA to analyze the energy and economic performance of olive production in Tarom County, Iran, a region known for its significant olive cultivation. The research seeks to identify inefficiencies, reduce resource waste, and promote sustainable agricultural practices through an integrated assessment of energy and economic parameters. Materials and Methods: This study was conducted in olive orchards in Tarom County during the 2022 agricultural year, using an approach grounded in both scientific rigor and practical applicability. Data were collected through comprehensive questionnaires covering all major agricultural activities such as plowing, pruning, irrigation, fertilization, pest control, labor, and fuel and electricity consumption. A statistically reliable sample of 50 orchards was selected using Cochran's formula to ensure adequate representation of the region’s olive production practices. MFCA was employed to quantify material and energy flows, focusing on input resources (e.g., water, fertilizers, electricity) and output products (e.g., olives, waste, and emissions). The methodology strictly adhered to ISO 14051 guidelines, which define four cost categories for each quantity center (QC): system costs, material costs, energy costs, and waste management costs. Energy equivalents for inputs and outputs were calculated using standard conversion factors. Additionally, energy indices such as energy efficiency, energy productivity, and net energy were evaluated to provide a comprehensive understanding of the system’s energy dynamics. The economic analysis encompassed parameters such as gross production value, net income, benefit-to-cost ratio, and economic productivity, offering insights into the financial implications of production practices. Results and Discussion: The total energy input for olive production was calculated at 77,417.56 MJ/ha, with electricity (59%), urea fertilizer (15%), and fossil fuels (14%) identified as the primary contributors. Positive energy outputs totaled 40,221.48 MJ/ha, while negative energy outputs, which included product loss and fertilizer waste, amounted to 6,853.04 MJ/ha. Among negative outputs, product loss (71%) and nitrate leaching (21%) represented the largest shares. The energy efficiency ratio was 0.52 using conventional methods but dropped to 0.43 when analyzed with MFCA, underscoring the hidden costs of waste and inefficiencies that traditional accounting methods fail to capture. These findings highlight the need for improved management practices to enhance both energy efficiency and economic viability. Economic analysis revealed that labor costs constituted 67% of variable production costs, whereas electricity, despite its high contribution to energy inputs, accounted for a mere 0.28% of financial costs. This discrepancy points to the critical need for better energy management strategies, including the adoption of renewable energy sources to reduce dependency on fossil fuels. Several inefficiencies were identified, particularly excessive water use during irrigation and significant product loss during harvesting, which adversely affect both energy and economic performance. To address these issues, implementing precision irrigation systems, mechanizing harvesting processes, and integrating renewable energy sources for pumping were proposed as effective strategies to reduce resource waste and improve sustainability. These findings align with those of previous studies on other crops, underscoring the universal applicability of MFCA in identifying inefficiencies and fostering sustainable agricultural practices. Furthermore, the study emphasizes that adopting cleaner production methods not only enhances resource efficiency but also supports broader sustainable development goals. This dual benefit makes MFCA a valuable tool for promoting both environmental stewardship and economic competitiveness in agriculture. Conclusion: This study demonstrates the effectiveness of MFCA in providing a comprehensive analysis of energy and economic performance in olive production systems. By quantifying material and energy flows, MFCA revealed significant inefficiencies in critical areas such as water use and product loss, which are often overlooked in conventional accounting methods. The results emphasize the importance of adopting cleaner production practices, including precision irrigation, mechanized harvesting, and renewable energy integration, to improve both sustainability and economic viability. The application of MFCA not only enhances resource efficiency but also contributes to achieving sustainable development goals by reducing environmental impacts and lowering production costs. Future research should focus on the practical implementation of the proposed strategies and assess their long-term effects on carbon footprint reduction, resource optimization, and market competitiveness. This study underscores the transformative potential of MFCA as a tool for advancing sustainable agriculture, offering valuable insights for policymakers, farmers, and researchers aiming to optimize resource use and promote environmental stewardship in olive production and beyond.

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Applicable

Digital mapping of soil physical and chemical properties using some machine learning algorithms and environmental variables in the Fereydan region, Isfahan Province

Nazanin Sadat Emami; Elham Chavoshi; Shamsollah Ayoubi; Naser Honarjoo; Mojtaba Zeraatpisheh

Articles in Press, Accepted Manuscript, Available Online from 02 April 2025

https://doi.org/10.22055/agen.2025.48843.1761

Abstract

Introduction Soil physical and chemical properties play critical roles in soil health, agricultural productivity, and natural resource management. These properties are key indicators for assessing soil sustainability and carbon storage. Understanding their spatial distribution is essential for effective ... Read More Introduction Soil physical and chemical properties play critical roles in soil health, agricultural productivity, and natural resource management. These properties are key indicators for assessing soil sustainability and carbon storage. Understanding their spatial distribution is essential for effective land management and resource modeling, particularly within the context of sustainable agriculture. The mean weight diameter of soil aggregates (MWD) is a crucial functional parameter that significantly influences the carbon cycle, soil structural stability, and agricultural productivity. Similarly, soil organic carbon (SOC) plays a vital role in environmental sustainability. Digital soil mapping (DSM), which integrates data from environmental covariates and machine learning (ML) algorithms, is a powerful tool for predicting soil properties and enhancing sustainable land management practices. The DSM techniques have proven highly effective in estimating soil parameters across diverse landscapes, minimizing the need for extensive field surveys and enabling data-driven decision-making in precision agriculture. The primary objective of this study was to predict the spatial distribution of MWD and SOC using DSM. Additionally, this study aimed to rank the most influential environmental variables affecting these properties through ML-based modeling and compare the performance of various ML methods.Materials and Methods This study was conducted in the Fereydan region (50º 6' E, 32º 56' N), Isfahan Province, Iran. A total of 100 surface soil samples (0 to 20 cm depth) were collected from various land uses, including irrigated croplands, dryland farms, and pastures, using a systematic sampling network. The collected samples were air-dried, sieved through a 2 mm mesh, and then subjected to laboratory analyses. Six ML algorithms—artificial neural network (ANN), random forest (RF), cubist model, support vector machines (SVM), k-nearest neighbors (KNN), and boosted regression trees (BRT)—were employed to relate environmental variables to the soil properties under investigation. For the modeling process, four datasets were used as predictor environmental covariates: remote sensing data, topography derived from a digital elevation model (DEM), soil properties, and classified land data. The models' accuracy was evaluated across four different scenarios, each using one or more of these datasets. The most suitable environmental variables were selected through a multicollinearity test using the variance inflation factor (VIF). Finally, to model the two soil properties, the dataset was divided into calibration (70%) and validation (30%) subsets. The models' performance was evaluated using various statistical metrics, including the coefficient of determination (R²), root mean square error (RMSE), and mean absolute error (MAE). Results and Discussion The results of model validation revealed that the highest prediction accuracy for MWD was achieved using the KNN model in the fourth scenario (R²=0.59, RMSE=0.19, MAE=0.16). These values indicate a moderate yet significant ability of the KNN model to predict MWD. In contrast, for SOC, the cubist model in the fourth scenario yielded the highest accuracy (R²=0.78, RMSE=4.12, MAE=3.53). These results suggest that the cubist model was particularly effective in capturing the complex relationships between environmental variables and SOC, providing a robust framework for predicting soil carbon content. These findings highlight the strong potential of ML models to capture the intricate interactions between soil properties and environmental factors, allowing for precise spatial predictions of soil characteristics. The ability of these models to process large volumes of data and uncover hidden patterns is particularly useful in soil science, where the relationship between soil properties and environmental variables can be complex and nonlinear. The results also revealed that different environmental variables played varying roles in explaining the spatial variability of MWD and SOC. For MWD prediction, silt content was found to be the most influential variable, followed by VV and CHND, both of which were also significant factors affecting the spatial distribution of MWD. In contrast, for SOC prediction, the most important variables were the multi-resolution valley bottom flatness index (MRVBF) and clay content. These factors are critical for understanding the storage and cycling of organic carbon in soil, as both moisture retention and clay particles are known to influence the stabilization of soil organic matter. The relationship between these variables and SOC highlights the importance of considering soil texture and moisture dynamics when predicting soil carbon stocks.Conclusion The results of this study demonstrated that ML models, such as cubist and KNN can effectively predict soil quality properties across different regions, particularly when combined with topographic and climatic data. These approaches offer an efficient and rapid method for generating digital soil maps and supporting sustainable land management. By leveraging multiple environmental datasets, ML-based DSM enhances soil modeling accuracy while reducing reliance on extensive soil sampling. These models are especially useful in areas with similar climates where full-scale soil sampling may not be feasible, providing a valuable tool for estimating soil quality attributes and enhancing agricultural productivity. Ultimately, the findings of this research can help policymakers and farmers identify critical areas and adopt optimal strategies to improve soil quality and mitigate adverse environmental impacts. To further improve the accuracy and stability of predictions, future studies should incorporate high-resolution spatiotemporal data, advanced algorithms such as cubist and KNN, and dynamic models for analyzing temporal variations. Additionally, investigating soil–water–plant interactions and assessing the impacts of climate change could play a crucial role in enhancing agricultural productivity and promoting the sustainable management of soil resources.

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Research Paper

Application of natural and enriched zeolite on yield, yield components and the concentration of potassium in soil and rapeseed.

Maeda Agooshi; Mohammad Ali Bahmanyar; Mehdi Ghajar Sepanlu; Seyed Mostafa Emadi

Articles in Press, Accepted Manuscript, Available Online from 07 April 2025

https://doi.org/10.22055/agen.2025.48642.1759

Abstract

Introduction: In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Potassium is one of the major nutrients that its deficiency decreased ... Read More Introduction: In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Potassium is one of the major nutrients that its deficiency decreased the growth and yield of rapeseed. After soybean, rapeseed is the world's second produced oilseed. soil inorganic amendments such as zeolite are good strategies to improve soil quality and increase soil potassium content. The addition of zeolite plays an important role in reducing the nutrients loss and increasing fertilizer use efficiency. Considering unique characteristics of zeolites, such as the low-cost and abundance of its mines in Iran, having a special physical and chemical structure and it plays an important role in enhancing the water and nutrients uptake by plant. This research was conducted with the aim of determining the effects of natural and enriched zeolite with potassium on rapeseed yield, component yields and concentration of potassium in soil and rapeseed in two soils with different texture (sandy loam and silty clay loam). Materials and Methods: This experiment was conducted as a split plot in pots conditions for three replicates in the research greenhouse of Sari Agricultural Sciences and Natural Resources University. In this experiment, the main factors include two types of soil (silty clay loam and sandy loam) and the secondary factors in twelve levels include the control (without zeolite and potassium sulphate) (T0), 32 mg. kg-1 potassium sulphate fertilizer (T1), 46 mg. kg-1 potassium sulphate fertilizer (T2), 2 gr zeolite with 32 mg. kg-1 potassium sulphate(T3), 4 gr zeolite with 32 mg. kg-1 potassium sulphate(T4), 6 gr zeolite with 32 mg. kg-1 potassium sulphate (T5), 2 gr zeolite with 46 mg. kg-1 potassium sulphate (T6), 4 gr zeolite with 46 mg. kg-1 potassium sulphate (T7), 6 gr zeolite with 46 mg. kg-1 potassium sulphate (T8), 2 gr enriched zeolite (T9), 4 gr enriched zeolite (T10) and 6 gr enriched zeolite (T11) were considered. Zeolite was enriched by ion saturation method. Rapeseed cultivation was done in 2021. At the end of cultivation season, harvest was done from each plot, grain yield, some yield components (pod number, thousand grain weight, grain oil), leaf potassium and grain potassium were measured. In addition, soil samples were collected from plots after harvest, and soil potassium was measured. Data analysis was done in the Statistic software and the mean comparisons were made by using LSD test.Results and discussion: The results showed that the effects of the soil type treatments were significant on all studied traits except seed potassium. The effects of amendment treatment were significant on all studied and the interaction effect of soil type and amendment treatment was only significant on grain yield. The highest amount of grain yield (6.46 gr) was observed in silty clay loam soil and 4 gr zeolite with 46 mg. kg-1 potassium sulphate (T7) with increasing about 49% compared the lowest amount (4.33 gr per pod) was obtained in sandy clay loam soil and control (T0). The use of 4 gr zeolite with 46 mg. kg potassium sulphate (T7) compared with the control (T0), was increased by 22% of thousand grain weight. Also the highest amount of grain oil (36.36 %) and grain potassium (2.75 %) was obtained in the treatment of 4 gr zeolite with 46 mg. kg potassium sulphate (T7). The results also revealed that the number of pod (85.16 %), leaf potassium (2.28%) and soil potassium (155.83 mg. kg-1) with increasing about 40%, 19% and 21 % respectively, compared with the control were significantly affected by 6 gr zeolite with 46 mg. kg potassium sulphate (T8). Between the enriched zeolite with potassium treatments, 4 gr enriched zeolite (T11) had the greatest effect on the studied traits.Conclusion: overall, it can be concluded that, all studied traits except grain potassium in soil with silty clay loam texture are more than soil with sandy loam texture. The best results were obtained in 4 gr zeolite with 46 mg. kg-1 potassium sulphate (T7). Between the enriched zeolite with potassium treatments, application of 4 gr enriched zeolite with potassium was the most effective treatment on the studied traits. It can be concluded that the combined use of zeolite and potassium sulphate can be a suitable solution for improving rapeseed yield

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Research Paper

Estimation of Zn available contents in surface soils of selected area in northern Khuzestan Province employing artificial neural network

Mohammad Torfi Mohisenpour; ُSaeid Hojati; Ahmad Landi; Hadi Amerikhah

Articles in Press, Accepted Manuscript, Available Online from 14 April 2025

https://doi.org/10.22055/agen.2025.48977.1767

Abstract

Introduction: Previous studies indicate that many soils worldwide lack zinc or contain it in a form that is unavailable to plants. In Iran, over 56% of agricultural soils have DTPA-extractable zinc levels below 0.75 mg/kg, while only 31% exceed 1 mg/kg. Therefore, it is crucial to understand the factors ... Read More Introduction: Previous studies indicate that many soils worldwide lack zinc or contain it in a form that is unavailable to plants. In Iran, over 56% of agricultural soils have DTPA-extractable zinc levels below 0.75 mg/kg, while only 31% exceed 1 mg/kg. Therefore, it is crucial to understand the factors influencing zinc concentration and prioritize their significance in the distribution of this essential element in soil. Employing an effective model to comprehend the logical connections within the results is essential. Artificial neural networks, known for their ability to model complex and non-linear relationships between soil variables, have been widely used in numerous studies over the past few decades. Khuzestan province, located in the southwest of Iran, possesses high potential for producing a variety of agricultural and horticultural products due to its water resources and fertile soils. With an output of 17.5 million tons of agricultural and horticultural products, Khuzestan plays a crucial role in ensuring the country's food security. Considering the diverse topography and land uses, this study aims to estimate the available zinc content in the surface soils of a selected area in northern Khuzestan province using artificial neural networks and to identify the key factors controlling its distribution across the study area.Materials and Methods: Most of the study area is within the catchment area of the Karun River, which forms the backbone of the hydrographic network in Khuzestan province. The eastern sectors are located in the catchment area of the Zohre-Jarhari Rivers. The region has a hot and dry climate, with average rainfall ranging from 240 mm in the center to 590 mm in the eastern parts. Various geological formations, such as Asmari, Gachsaran, and Mishan, are present in this area. The soil moisture regimes include aridic, ustic, and xeric (in the eastern parts), while the temperature regimes are classified as thermic and hyperthermic. The soils in the study area are primarily classified as Aridisol, Inceptisol, and Entisol. Two hundred and three (203) surface (0-10 cm) composite samples were randomly collected from an area of 27,452 square kilometers in northern Khuzestan province. Sampling took place under sunny conditions during winter. The soil samples were air-dried and then passed through a 2 mm sieve. The pH and electrical conductivity of the soil were measured in pastes and saturated extracts, respectively. Soil texture was determined using the pipette method; organic matter was assessed by the wet oxidation method with potassium dichromate; and calcium carbonate equivalent was measured through back titration. To measure the available zinc content in the soils, 10 grams of each soil sample were weighed, and 20 ml of a 0.005 M DTPA solution was added. The suspension was shaken for 2 hours at 120 rpm. Subsequently, the solid and solution phases were separated using Whatman 42 filter paper. Finally, the zinc content of the extracts was measured using a GBS Variant AA atomic absorption device. In the dataset, zinc concentrations of less than 3 mg/kg, between 3 and 6 mg/kg, and greater than 6 mg/kg were categorized as low, medium, and high classes of available zinc content, respectively. A Multilayer Perceptron (MLP) neural network was employed to model available zinc content alongside other soil variables in the SPSS v26 environment, with the optimal structure of the neural network determined through a trial-and-error approach. The normality of the data was assessed using the Kolmogorov-Smirnov test within SPSS v26 software.Results and Discussion: The results indicated that the average content of available soil zinc in the study area is 2.76 mg/kg. The average calcium carbonate equivalent of the soils is 42.25%, suggesting that the soils can be classified as calcareous. Additionally, with an average pH of 7.65, the soils in the region exhibit alkaline reactions. The average soil organic carbon content is 12.6 g/kg. The findings also suggest that the studied soils primarily belong to the loam family. Among the examined soil properties, the highest coefficient of variation is associated with soil salinity (131.9%), while the lowest is related to soil pH (4.2%). The results of the Kolmogorov-Smirnov test revealed that only the silt content of the soils exhibited a normal distribution pattern; the other variables did not pass the test of normality. When various configurations of multilayer perceptron artificial neural networks were evaluated, it was found that the MLPSO7 model, with a stable arrangement of 3 output classes, 5 hidden layer neurons, and 7 input layers, using the sigmoid function for both input and output activation, performed best in predicting available zinc values in soil samples. The results also indicate that organic carbon, calcium carbonate equivalent, and electrical conductivity were the most influential factors in developing the model. The analysis of the estimation matrix for available zinc classes shows that the MLPSO7 model accurately estimated the class with low concentrations of available Zn more effectively than the other two classes. Furthermore, the soil variables used to model the available zinc contents in the study area were able to accurately estimate these contents (97.4% for the training dataset, 97.1% for the test dataset, and an overall accuracy of 90.8%). In contrast, the class with high concentrations of Zn (>6 mg/kg) produced weaker estimates, which can be attributed to the small number of samples examined in this category.Conclusion: It can be concluded that the estimates derived from the optimal neural network model demonstrate good flexibility and efficiency in justifying the available Zn contents in the study area. For future large-scale studies, greater attention must be given to the significant roles of organic matter, the abundance of calcareous compounds, and the salt content of the soils in determining available Zn levels.

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Isolation of Salt-Tolerant Bacteria from The Rhizosphere of Desert Plants and Their Effects on Maize (Zea mays L.) Growth in a Saline Soil

Yasamin Zahra Mazidi Moradi; Mahboobeh Abolhasani Zeraatkar; Mehdi Sarcheshmeh pour

Articles in Press, Accepted Manuscript, Available Online from 01 May 2025

https://doi.org/10.22055/agen.2025.48847.1763

Abstract

Introduction: Abiotic stresses are the most important limiting factors affecting agricultural productivity. Soil salinity is considered one of the most severe abiotic stresses in plants. Crop plants must use biological mechanisms to cope with unfavorable environmental conditions. Their growth, development, ... Read More Introduction: Abiotic stresses are the most important limiting factors affecting agricultural productivity. Soil salinity is considered one of the most severe abiotic stresses in plants. Crop plants must use biological mechanisms to cope with unfavorable environmental conditions. Their growth, development, and yield will be reduced if they fail in coping with such conditions. The plant microbiome provides plants with the main basic support they need to obtain nutrients, resist diseases, and tolerate abiotic stresses. The metabolic and genetic potential of the plant microbiome transforms plants into appropriate organisms for fighting unfavorable environmental conditions. Hence, the use of salt-tolerant halophyte rhizosphere bacteria is an effective strategy for improving plant growth in saline soils. Materials and methods: Consequently, this research intended to isolate indigenous resistant bacteria adapted to salinity stress conditions from the rhizosphere of desert plants in Kerman Province and determine their effects on some physiological and biochemical characteristics of maize plants in soil under salt stress. First, the rhizosphere bacteria of desert trees were isolated and purified. Next, their growth was studied at various sodium chloride concentrations (0, 100, 200, 300, 400, 500, 600, and 650 mM) in solid microbial culture media and then in quantitative testing at various sodium chloride concentrations (0, 320, 650, and 850 mM) in liquid microbial culture media. Four bacterial strains (BZ79, BR90, BG59 and BG71) were selected for the greenhouse stage. The greenhouse experiment was performed on maize plants with three replications using a completely randomized design arranged as a factorial consisting of four salt-tolerant strains and a control at two soil salinity levels: non-saline soil (1.32 dS/m) and saline soil (12 dS/m). The experiment was completed in 90 days. Finally, dry weight of the aerial organs, fresh weight of the aerial organs and of the roots, length of the aerial organs and of the roots, concentrations of chlorophyll a, b, total chlorophyll, and carotenoid content of maize plants in saline and non-saline soils were measured. Results and discussion: The results of the statistical analysis showed that the bacterial strains differed significantly in salt tolerance, and some of them were even able to tolerate high sodium chloride concentrations (up to 850 mM) and grow well. Salt stress causes osmotic stress, ionic imbalance, and oxidative damage in maize plants thereby decreasing growth and photosynthetic efficiency. The results indicated that increases in salinity level reduced dry matter of the aerial organs (51.4%), fresh weight of the aerial organs (24.4%), fresh weight of the roots (15.9%), length of the aerial organs (7.8%), chlorophyll a content (64.2%), chlorophyll b content (115%), and carotenoid content (3%). However, inoculation of the maize plants with salt-tolerant bacteria significantly increased dry weight of the maize plants, fresh weight of the aerial organs and of the roots, length of the aerial organs and of the roots, concentrations of chlorophyll a, chlorophyll b, and total chlorophyll, and carotenoid content in non-saline and saline soils. Of course, the increases in these plant parameters caused by inoculation with salt-tolerant bacteria were more pronounced in saline soil compared to non-saline soil. The results demonstrated that, compared to the uninoculated control (B0), inoculation of the plants with the bacterial strains BZ79, BR90, BG59, and BG71 increased dry weight of the aerial organs in the non-saline soil by 20%, 12.3%, 13%, and 3%, respectively, and by 62.2%, 39.5%, 59%, and 41.4%, respectively, in the saline soil. The largest dry weight of the aerial organs (25.95 g) was recorded in the maize plants inoculated with BZ79 and the smallest (1 g) in those uninoculated with the control (B0). Compared to the uninoculated control (B0), inoculation of the maize plants with BZ79, BG59, and BG71 in the saline soil improved chlorophyll a concentration by 1.7%, 1.9%, and 2.4%, respectively, and increased chlorophyll b concentration by 2.6%, 1.7%, and 1.8%, respectively. However, inoculation with BR90 did not increase chlorophyll a content. In the saline soil, inoculation with both BR90 and BG59 led to a three-fold increase in carotenoid content compared to the uninoculated control. conclusion: Among the indigenous rhizosphere bacteria, BZ79 was the most effective in improving maize plant tolerance to salt stress. These findings indicated the potential of these indigenous salt-tolerant bacteria as an effective factor for reducing the damage caused by salt stress by increasing the physiological performance of the maize plants and the photosynthetic pigments in them. Given the beneficial effect of the indigenous salt-tolerant bacteria under saline soil conditions, these microorganisms have the potential to be candidate as biofertilizer in the future.

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