Research Article
Irrigation
F. Borzoo; H. Ramezani Etedali; A. Kaviani
Abstract
IntroductionClimate change is one of the most important issues in the world in the 21st century which affects various sectors of agriculture, forestry, water and financial markets, and has serious economic consequences (Reidsma et al., 2009). In recent years, the management of agricultural water consumption ...
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IntroductionClimate change is one of the most important issues in the world in the 21st century which affects various sectors of agriculture, forestry, water and financial markets, and has serious economic consequences (Reidsma et al., 2009). In recent years, the management of agricultural water consumption has always been considered as one of the important issues in water resources management. Koochaki and colleagues (Koochaki and Kamali, 2006) by evaluating the climatic indicators of Iran's agriculture showed that during the next 20 years, the average monthly temperature will increase in almost all regions of the country, and the increase in evaporation and transpiration is one of the most important consequences of this warming. Simulated climate parameters can be obtained through different general GCM atmospheric models. Due to the low spatial resolution of these models, its output should be downscaled using dynamic or statistical methods. Materials and MethodsThe LARS-WG model predicts meteorological variables for a period of time in the future by using a series of basic and fine-scale meteorological data, output of one of the GCM models. Research has shown that the LARS-WG model has the necessary accuracy for this task. Calculating the amount of evapotranspiration and yield of very complex plants are time-consuming and dependent on spending a lot of money and limited to the tests performed, the shortness of the test time and also the limitation in the number of scenarios that are checked by the test. Therefore, plant models are considered and evaluated by researchers. The AquaCrop model has demonstrated commendable accuracy in various regions of Iran and globally for forecasting plant growth, water consumption efficiency, and evapotranspiration requirements. These predictions hold significant potential for optimizing irrigation strategies across different agricultural settings. AquaCrop is one of the applied agricultural models that was obtained from the modification and revision of FAO publication No. 33 by prominent experts from all over the world. In this study, the values of green water footprint of winter wheat plant (Pishgam) were estimated in climatic conditions obtained from LARS-WG model and DKRZ database under scenarios 4.5 and 8.5 and at different planting dates (15 October, 1 November, 15 November, 30 November and 15 December), in the next 4 periods (2021-2040, 2041-2060, 2061-2080 and 2081-2100) and by Aquacrop model. Results and DiscussionThe results showed that if planting date is on October 15, in the climatic conditions obtained from the LARS-WG model and under scenarios 4.5 and 8.5, in all future periods, the footprint of green water will increase compared to its value in the base period, and if planting is the rest of the dates, in each of the next 4 periods, the average green water footprint will decrease compared to its value in the base period. The results obtained for the DKRZ database show that the green water footprint attained for the dates of cultivation and periods investigated in scenarios 4.5 and 8.5 does not have a particular trend. On the planting dates of October 15 and November 1 for the periods of 2061-2080 and 2081-2100, the green water footprint will decrease and on the other three dates (15 November, 30 November, and 1 November) for these periods, there will be an increasing trend. On 15 December, for the DKRZ database, in both scenarios defined for all periods, an increase in green water footprint compared to the base period is reported. However, in the period of 2081-2100 in scenario 8.5, a decrease compared to the base period will be observed. The highest amount of green water footprint in all these periods and models for the period 2041-2060 under the climatic conditions of the DKRZ database in scenario 4.5, if the planting date is 15 October, it is estimated that the amount of water consumed is equal to 4272 cubic meters per ton with a standard deviation of 5018 cubic meters per ton is predicted. The lowest footprint of green water for the period 2081-2100 under the climatic conditions obtained from the LARS-WG model in scenario 8.5, if the planting date is on 15 December, is reported to be 232 tons per hectare with a standard deviation of 52.3 tons per hectare.
Research Article
Irrigation
S. Habibi; M. Khoshravesh; R. Nouri Khajebelagh
Abstract
IntroductionIn today's world, challenges related to agriculture, food security, water and energy resources, productivity, and greenhouse gas emissions have emerged as significant issues for global societies. Through their international impacts, these challenges have led to economic, social, and environmental ...
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IntroductionIn today's world, challenges related to agriculture, food security, water and energy resources, productivity, and greenhouse gas emissions have emerged as significant issues for global societies. Through their international impacts, these challenges have led to economic, social, and environmental changes on a global scale. One of the most crucial issues that should be highlighted is the shortage of water resources. Water, as a vital factor in agriculture and food production, holds special importance. Therefore, in order to achieve sustainable agriculture, it is necessary to pay attention to the energy indicators, the efficiency of water consumption in the production of agricultural products and the amount of greenhouse gas emissions. In general, a combination of energy indicators, water efficiency and reduction of greenhouse gas emissions in agriculture can help to develop sustainable agriculture and preserve the environment and help to provide safe and accessible food for the society. The aim of the present study was to investigate the indicators of physical water, energy efficiency, and greenhouse gas emissions on alfalfa and barley crops in two different climates: a warm and arid climate (Shahr-e-Qom Plain, Qom) and a temperate and humid climate (Sari Plain, Mazandaran). This was done to assess the impact of climate on the outcomes of these indicators. Materials and MethodsTo investigate the physical water efficiency and evaluate energy indicators in this study, major agricultural products in Sari and Sharifabad Plains, including barley and alfalfa, were analyzed using cross-sectional data from the agricultural year 2021-2022. Initially, the sample size was determined based on the Cochran formula and the Bartlett method (2001). Subsequently, sampling was carried out using a questionnaire designed by the researchers themselves. The questionnaires totaled 250 (Sari Plain: 150, Sharifabad Plain: 100), and the collected information included the amount of input consumption and production quantity. The questionnaire, designed by the researcher, was validated for validity and reliability by experts and specialists. The inputs used in the study of water efficiency and energy indicators for the mentioned products in Sari and Sharifabad Plains included person-days of human labor, machine working hours, fuel consumption of machines, the quantity of nitrogen, phosphorus, potassium fertilizers per hectare, the quantity of various chemical pesticides (herbicides, fungicides, and insecticides) per liter per hectare, the amount of water consumption in cubic meters per hectare, and the amount of seed consumption in kilograms per hectare.Results and DiscussionThe results of the descriptive statistics of input consumption in Sari and Sharifabad Plains in barley and alfalfa crops showed that the highest input consumption of manpower in the cultivation of alfalfa crops in Sharifabad Plains with an average of 225 hours per hectare, the highest amount of fertilizer consumption related to the alfalfa crop in Sharifabad Plain is related to nitrogen fertilizer with an average of 130 kg per hectare, the highest amount of fuel consumption of machinery related to alfalfa crop in Sari Plain with an average of 405 liters per hectare, the highest amount of water consumption related to alfalfa crop in Sharifabad Plains with an average of 17500 cubic meters per hectare and the highest yield of alfalfa was obtained in Sharifabad Plains with an average of 11550 kg per hectare. The obtained results indicated that the highest input energy level in Sharifabad Plain for alfalfa was 5,674.50 MJ per hectare. The results of energy efficiency indicated that alfalfa production in Shahrifabad Plain had the highest value with 0.19 kilograms per MJ, while this index for alfalfa in Sari Plain was 0.13 kilograms per MJ. Additionally, the energy efficiency for barley in Shahrifabad Plain was 0.13 kilograms per MJ, and for Sari Plain, it was 0.12 kilograms per MJ, showing a somewhat similar level. The physical water use efficiency results revealed that the highest and lowest efficiency levels were observed for barley in Sari Plain, amounting to 0.96 kilograms per cubic meter, and for alfalfa in Shahrifabad Plain, amounting to 0.57 kilograms per cubic meter, respectively. Furthermore, this index for alfalfa in Sari Plain was 0.67 kilograms per cubic meter, and for barley in Shahrifabad Plain, was 0.8 kilograms per cubic meter. The results for greenhouse gas emissions demonstrated that the level of emissions in Sari Plain was higher than Sharifabad Plain, attributed to excessive fertilizer and pesticide use in Sari Plain. The highest greenhouse gas emissions in Sari Plain for alfalfa were 2681.65 kilograms of CO2 per hectare, while in Sharifabad Plain, was 2351.85 kilograms of CO2 per hectare. ConclusionThe overall results indicated that crop performance in humid regions was not higher than in dry and semi-arid regions, and this index depends on various parameters, including water consumption and managerial considerations. However, water consumption in temperate and humid regions is significantly lower than in dry and semi-arid areas due to higher precipitation. This result is increased efficiency in temperate and humid regions.
Research Article
Irrigation
M. Zokaee Khosroshahi; K. Parvizi
Abstract
IntroductionWater is a critical factor for the growth and fruiting of the grapevines. Considering the water scarcity crisis in Iran and most parts of the world in recent years, it is necessary to apply methods such as deficit irrigation for the optimal management of water use in agriculture. It has been ...
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IntroductionWater is a critical factor for the growth and fruiting of the grapevines. Considering the water scarcity crisis in Iran and most parts of the world in recent years, it is necessary to apply methods such as deficit irrigation for the optimal management of water use in agriculture. It has been determined that by deliberately reducing water consumption in vineyards, it is possible to preserve the existing water resources and improve the water use efficiency. Materials and MethodsA research was carried out in summer 2023 in a randomized complete block design with three replications on 8-year-old vines of the Turkmen-4 variety, to investigate the effect of deficit irrigation levels on the quantitative and qualitative traits and water use efficiency of grapevines. The vines were planted with 2 x 4 meter intervals, were trained as a vertical trellis on a bilateral cordon system, and the vineyard was irrigated by drip irrigation. The experimental treatments included full irrigation (providing 100% of vine water requirement; as control), 25% deficit irrigation (providing 75% of vine water requirement) and 50% deficit irrigation (providing 50% of vine water requirement). Irrigation of the vineyard started from May 22 and continued until November 6 at 7-day intervals, according to the conventional procedure. The water requirement of each vine in non-stressed condition was calculated by a class A evaporation pan based on reference crop evapotranspiration (ETo) and crop coefficient (Kc) throughout the season. Then, the amount of water for each treatment was determined according to the irrigation levels in the treatments and applied in volume form. Results and DiscussionThe amounts of water consumption of control, 25% and 50% deficit irrigation treatments were 5140, 3855 and 2570 m3 per hectare, respectively. The results showed that irrigation levels had a significant effect on the berries length, berries diameter, cluster length, cluster width, berries weight, cluster weight, sugar percentage, chlorophyll index, relative water content, midday leaf water potential, vegetative growth, vine yield, yield index and water use efficiency. The 25% and 50% deficit irrigation treatments caused a decrease of 7.2% and 14.2% of the berry length compared to full irrigation, respectively. Also, these treatments caused a reduction of 8.3% and 13.9% of the berry diameter, respectively. While the 25% deficit irrigation treatment had no significant effect on the berries sugar content (°Brix), the 50% deficit irrigation treatment caused a significant decrease (5%) in sugar content compared to the control. Both relative water content and midday water potential of the leaves decreased significantly with the reduction of irrigation levels. Reducing the level of irrigation led to a significant decrease in the SPAD index and vine vegetative growth. Increasing the intensity of deficit irrigation had a significant negative effect on yield components including berry weight, cluster weight, vine yield and yield index. The highest and lowest yields were obtained from full irrigation and 50% deficit irrigation, respectively but the effect of 25% deficit irrigation on yield reduction was not significant. Although the 25% and 50% deficit irrigation treatments caused a 5.8% and 27.5% decrease in vine yield, respectively but these treatments increased water use efficiency by 34% and 44.5%, respectively compared to the control. The lowest water use efficiency was related to the control (3.53 kg of fresh fruit per cubic meter of water used), while the water use efficiency of vines under 25% and 50% deficit irrigation was 4.73 and 5.10 kg of fruit per cubic meter of water, respectively. The 25% and 50% deficit irrigation treatments had a statistically significant difference with the control in terms of water use efficiency, but the difference between the two was not significant. ConclusionIn the present study, reducing the volume of irrigation water led to a decrease in vine yield, but what is important is the low yield reduction rate compared to the amount of water consumption. The decrease in vine yield was 5.8% and 27.5%, respectively with a 25% and 50% decrease in water consumption. Also, with 25% and 50% reduction in water consumption, the yield index decreased by 6.1% and 27.3%, respectively. Meanwhile, the water use efficiency of vines increased by 34% and 44.5% in response to 25% and 50% deficit irrigation treatments, respectively. It is recommended to apply 25% deficit irrigation to increase the water use efficiency of Turkmen-4 grapes in climatic conditions of Malayer, but 50% deficit irrigation leads to a decrease in quality of grapes.
Research Article
Soil science
Kh. Salarinik; M. Nael; M. Sayyari; S.S. Moosavi
Abstract
IntroductionApplication of agricultural waste composts, in addition to improving soil fertility, has positive effects on the quality of agricultural products and the environment by reducing the use of chemical fertilizers and recycling agricultural waste. Spinach (Spinacea oleracea L.) is a suitable ...
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IntroductionApplication of agricultural waste composts, in addition to improving soil fertility, has positive effects on the quality of agricultural products and the environment by reducing the use of chemical fertilizers and recycling agricultural waste. Spinach (Spinacea oleracea L.) is a suitable plant for studying the effects of composts and chemical fertilizers due to some physiological characteristics such as high antioxidant activity and oxalic acid, significant amount of mineral compounds and vitamin C, and nitrate accumulation. Despite relatively extensive studies on the effect of different composts on plants, no study has been conducted so far to investigate the effect of grape pomace (GP) composts on plants in Iran. Therefore, the objectives of the present study were: 1- to investigate the effect of different GP composts on yield, nutrient elements, and some physiological parameters of spinach in comparison with two levels of urea fertilization in a pot experiment in two consecutive growing seasons, and 2- to investigate the relationship between nutrient elements and physiological indicators of spinach based on principal component analysis. Materials and MethodsTo investigate the effects of GP composts on yield, nutrient elements, and physiological parameters of spinach (Persius hybrid), an outdoor pot experiment was conducted in a randomized complete block design with eight compost treatments, two levels of urea fertilizer (46%), and a control treatment (C0) in three replications and two consecutive growing seasons (spring and fall). Compost treatments included: High grape pomace (HG) (60-63%) with chickpea straw and alfalfa (HG-Ch-A), high GP with chickpea straw and sugar beet pulp (HG-Ch-B), high GP with alfalfa and sugar beet pulp (HG-A-B), high GP combined with chickpea straw, alfalfa, and sugar beet pulp (HG-All); four other compost treatments included low level of grape pomace (LG) (37-42%) combined with other residues/wastes similar to the first four treatments (LG-Ch-A, LG-Ch-B, LG-A-B, and LG-All). Urea fertilizer treatments included: 150 kg per hectare (C150) (two-stage top dressing) and 500 kg per hectare (C500) (three-stage top dressing). Prior to planting, the composts were separately mixed into the soil (sandy loam) at a rate of 2% by weight(. The first crop was grown for 50 days in May 2018 and the second crop was grown for 45 days in September 2018. In both seasons, plant samples were taken in the early morning at the end of the growing season to determine the fresh and oven-dried weight of shoot and root samples, leaf area, nutrient elements, and some physiological indicators. Some of the shoot samples were wrapped in aluminum foil and stored in a freezer (-20 °C) to determine the amount of chlorophyll (type a, type b, and total), carotenoids, total phenol, vitamin C, and antioxidant activity. Oxalic acid, zinc, iron, copper, sodium, potassium, phosphorus, calcium, magnesium, and nitrate were determined in oven-dried samples. One-way ANOVA was applied separately to spring and fall data, and mean comparisons were made using Duncan's test at the 0.05% level. Principal component analysis was used to determine the relationships between nutrient elements and physiological indicators of spinach. Results and DiscussionThe LG-Ch-A and C500 treatments (in spring cultivation), and the LG-A-B, LG-All, and HG-All treatments (in fall cultivation) had the highest leaf number, leaf area, and yield and were significantly difference from the C0 treatment. The high yield in C500, LG-Ch-A, LG-All, and HG-All treatments was associated with nitrate accumulation in spinach. In both cultivations, there was a significant positive correlation between the amount of P, K, Mg and Zn in spinach and the amount of these elements in the corresponding composts. A synergistic relationship was also observed between P and Mg; P and Zn; and Mg and Zn in spinach. On the other hand, an antagonistic relationship was observed between Ca and Mg in spinach because a high concentration of calcium inhibits magnesium uptake by reducing cell permeability. In both seasons, the chemical fertilizer treatments showed the highest amount of chlorophyll and carotenoids because these compounds increase with increasing nitrogen availability. On the contrary, the amount of antioxidant activity was significantly higher in compost treatments than in chemical treatments. In the spring cultivation, the highest and lowest amount of oxalic acid and oxalic acid/Ca ratio were observed in the LG-Ch-B and HG-All treatments, respectively. Interactions between nutrients and physiological indicators were observed. The uptake of all micronutrients, P, and Mg (in both cultivations) and K (in the fall cultivation) was inhibited by high Ca concentration. With the decrease of micronutrients uptake, an increase in nitrate accumulation may occur because micronutrients are present in the structure of nitrate reducing enzymes. The interdependence between Mg and oxalic acid/Ca (in spring), K and oxalic acid (in fall), and Na and oxalic acid/Ca (in fall) may be related to the role of oxalates in the uptake of mineral ions by plants, since oxalates are usually combined with Na, Mg, Ca, and K in the form of soluble and insoluble salts. ConclusionThe use of urea chemical fertilizer (at two levels) and agricultural waste composts had different effects on the physiological indicators, growth and nutrients in spinach. Spinach grown in soils treated with composts rich in P, K, Mg, and Zn had higher nutritional value. The grouping of treatments by principal component analysis showed that chemical and control treatments were clearly separated from compost treatments with high amount of chlorophyll, carotenoid, nitrate, K, and Zn and low amount of oxalic acid, oxalic acid/Ca ratio, antioxidant activity, phenol, and Na. In general, the use of C500, LG-Ch-A, LG-All and HG-All treatments is not recommended due to nitrate accumulation in spinach.
Research Article
Soil science
O. Toorajzadeh; H. Piri; A. Naserin; M.M. Chari
Abstract
IntroductionAppropriate and practical use of agricultural waste reduce the pressure on the environment. Recently, there has been significant promotion of biochar utilization in agricultural lands. It serves as a valuable source of organic material for enhancing plant growth and as an effective soil amendment ...
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IntroductionAppropriate and practical use of agricultural waste reduce the pressure on the environment. Recently, there has been significant promotion of biochar utilization in agricultural lands. It serves as a valuable source of organic material for enhancing plant growth and as an effective soil amendment to improve soil properties. Due to its unique chemical and physical properties, biochar can be used as a soil conditioner and has many benefits for optimal agricultural and environmental management. Studies have shown that biochar is a useful amendment for improving the physical and chemical properties of soil and effective in maintaining organic matter and soil moisture. Materials and Methods This research was conducted with the aim of investigating the effects of biochar on the physical and chemical properties of soil under conditions of water stress and irrigation using saline water. The experiment was carried out in a factorial based on a completely randomized design with three replications in greenhouse conditions. The treatments include three irrigation water treatments (60, 80, and 100 percent water requirement of the plant, respectively, I1, I2, and I3), three treatments of biochar prepared from northern forest trees at a temperature of 300 degrees Celsius (0, 2, and 4 percent by weight of potting soil, respectively, B1, B2, and B3) and three water quality treatments (with electrical conductivity 1, 4 and 7 dS/m, respectively, S1, S2 and S3). The pots were weighed every other day and at each level of biochar and salinity, the water deficit up to the agricultural moisture level was calculated based on the changes in the pot's weight. After harvesting (in the first half of April 2022), in order to investigate the effect of biochar on the amount of soil nutrients and some physical and chemical parameters of the soil under the conditions of water stress and irrigation water salinity, sampling was done from the soil of each pot. The samples were taken to the laboratory and parameters of apparent and actual specific gravity, acidity and salinity of the soil, percentage of nitrogen, phosphorus and potassium absorbable of the soil were measured in the laboratory. Referring to the yield to irrigation water ratio, water productivity is obtained by the following relation (Payero et al., 2009): WP=Y/IR, where, WP represents water productivity (kg/m3), Y denotes the yield (kg/ha), and IR shows the amount of irrigation water (m3/ha). Analysis of variance for the results obtained from different treatments was conducted using SAS software (SAS 9.1, SAS Institute, Cary, NC, USA). The mean values of the main factors and interactive effects were compared using the Duncan method at the 1% and 5% levels of significance. Results and DiscussionThe results showed that the amount of biochar, irrigation water and water salinity and their mutual effects had a significant effect on the measured parameters at the probability level of one and five percent. Adding 2 and 4 mass percent biochar to the soil increased the amount of phosphorus (35 and 60%, respectively), potassium (57% and 61%), nitrogen (83% and 91%), pH (13% and 13%) and electrical conductivity (EC) (13% and 57%) of the soil. By adding 2% and 4% of biochar to the soil, the actual specific gravity of the soil decreased by 13% and 21%, respectively, and the apparent specific gravity decreased by 11% and 22%, respectively. The actual and apparent specific gravity of the soil decreased by adding biochar to the soil. Decreasing the depth of irrigation water and increasing water salinity increased the amount of phosphorus, potassium, nitrogen, pH and EC of the soil. The amount of irrigation water had no significant effect on the apparent and actual specific gravity, however, the salinity of the irrigation water caused a significant increase in the apparent and actual specific gravity of the soil. Although the addition of biochar to the soil increased the nutrients required by plants in the soil, high amounts of biochar in the soil should be used careful, because the addition of this organic matter to the soil at high levels increased soil EC significantly. Based on the findings derived from the research, the utilization of biochar is recommended as a viable approach for enhancing both the chemical quality and productivity of nutrient-poor and sandy soils.
Research Article
Soil science
J. Al-Jomah; A. Halajnia; A. Lakzian; A.R. Astaraei
Abstract
Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing ...
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Introduction
Saline soils resulting from natural and/or anthropogenic processes are very diverse and widely distributed under all climates. Soil salinity as a serious environmental problem has negative effects on plant growth and development in arid and semi-arid as well as humid regions. Since increasing global food security is a fundamental goal to feed the growing world population, it is necessary to develop suitable and efficient techniques for the rehabilitation of salt-affected soils and their exploitation. Chemical fertilizers are usually used to provide nutrients required for plant growth in order to increase crop yield, but application of these chemical components has negative environmental effects and reduces the quality of soils and agricultural products. The use of beneficial microorganisms (bacteria and fungi) as fertilizers and biological amendments has a high potential to improve productivity in saline soils. The aim of this study was to investigate the effect of using Acidithiobacillus bacteria along with mycorrhiza on the production of some photosynthetic and biochemical metabolites in maize under salt stress and comparing it with control conditions.
Materials and Methods
To perform this experiment, a surface soil sample was collected from a depth of 30 cm from the campus of Ferdowsi University of Mashhad, and some physical and chemical properties of the soil were measured by usual laboratory methods. To prepare saline soil a mixture of four compounds MgSO4.7H2O, Na2SO4, NaCl, and CaCl2. 2H2O were used. The mycorrhizal fungus (Funneliformis mosseae) and mesophilic Acidithiobacillus bacteria species two types of bacteria, Acidithiobacillus thiooxidans PTCC No: 1692 (DSM 504) and Acidithiobacillus ferrooxidans PTCC No: 1646 (DSM 583), were purchased from Turan Biotechnology Company (Semnan Science and Technology Park) and Iran Microbial Scientific and Industrial Research Center (PTCC), respectively. In this research, the effect of biological treatments including: two levels of mycorrhiza (inoculation and non-inoculation), two levels of salinity (0.96 and 6 d/m) and four levels of Acidithiobacillus control (C), Acidithiobacillus thiooxidans (T), Acidithiobacillus Ferrooxidans (F), Acidithiobacillus thiooxidans and Ferrooxidans (T+F) were compared with each other on some photosynthetic and biochemical characteristics of Zea mays under greenhouse conditions in the form of a completely randomized design with factorial arrangement with three replications. 10 gr of salt mixture (this amount of salt was obtained to reach electrical conductivity of 6 in the pre-experiment) was added to 5 kg of soil and the soil moisture of the pots was kept for one month in the field capacity. Bacterial treatments were inoculated with 30 mL of cell suspension per pot (approximately 107 CFU mL-1). In the simultaneous use of two bacteria, 15 ml of each bacterial cell suspension (15+15) was added to each pot. Single-cross 704 variety of maize was grown in pots and soil moisture was maintained during the growth period in the field capacity by weighing. Chlorophyll a, b and carotenoid, concentrations of flavonoids, anthocyanins and proline and electrical leakage were measured in fresh leaf samples (third leaf on the stem).
Results and Discussion
The results showed that salinity decreased the percentage of root colonization and chlorophyll a and b content in leaves. Salinity decreased chlorophyll a, b and carotenoid in leaves by 27.9, 68.42% and 50%, respectively. Salinity increased proline concentration (42.62%), electrolyte leakage (33.30%), anthocyanins concentration (96.36%) and leaf flavonoids (84.73%) compared to control soil. Inoculation with mycorrhiza compared to no inoculation had a remarkable and significant effect on all investigated parameters in both saline and control soils. In saline soil, mycorrhizal inoculation reduces electrolyte leakage (56.75%) and increases chlorophyll a (2.3 times), chlorophyll b (6.6 times), carotenoid (1.3 times), proline concentration (24.39%), anthocyanins amount (24.07) and flavonoids (20.4%) in the plant. The effect of bacterial treatments on the investigated parameters in plants inoculated with mycorrhiza was greater than non-inoculated treatments. The effectiveness of the simultaneous application of both bacteria was greater than the effect of each of them alone. In saline soil, simultaneous inoculation of mycorrhizae with both bacteria species reduces electrolyte leakage (14.72%) and increases chlorophyll a (39.80%), chlorophyll b (106%), carotenoid (50%), proline concentration (10.12%), the amount of anthocyanins (14.17%) and flavonoids (4.06%) compared to mycorrhiza treatment alone. The results showed that these bacteria can probably be considered as helping mycorrhizal bacteria.
Conclusion
The objective of this study was to examine the impact of simultaneous inoculation of mycorrhizae and Acidithiobacillus bacteria on select photosynthetic and biochemical metabolites of maize subjected to salinity stress conditions. Confirming the results of other studies, the results of this research also showed the clear and distinct effect of mycorrhiza on increasing chlorophyll and producing metabolites effective in increasing plant resistance to salt stress. In addition, the results showed that although the use of each species of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans alone was effective on the measured parameters in both saline and control soils, the simultaneous inoculation of both Acidithiobacillus bacteria species and mycorrhiza had the greatest effect on increasing chlorophyll, production of proline, anthocyanins and flavinoids and reducing electrolyte leakage and as a result, increasing tolerance to salt stress. In other words, these bacteria can be considered as mycorrhiza helper bacteria, whose activity can improve the function of mycorrhiza. On the other hand, mycorrhiza symbiosis may have increased the efficiency of these bacteria by changing the soil conditions and the environment around the roots. However, further greenhouse and field experiments with other plant species are necessary to confirm these findings.
Research Article
Soil science
Y. Kooch; A. Shahpiri; K. Haghverdi
Abstract
Introduction
Forests, encompassing approximately 30% of the Earth's land area, hold significant ecological importance due to their rich biodiversity and the multitude of environmental services they provide. These ecosystems outperform other terrestrial habitats, making them invaluable to all life forms ...
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Introduction
Forests, encompassing approximately 30% of the Earth's land area, hold significant ecological importance due to their rich biodiversity and the multitude of environmental services they provide. These ecosystems outperform other terrestrial habitats, making them invaluable to all life forms on our planet. The destruction of forest habitats and changes in land use patterns exert significant impacts on the variability of soil quality indicators. The consequence of forest degradation encompass various adverse consequences, including the destruction of wildlife habitats, climate change, global warming, diminishing plant and animal biodiversity, and reduced water conservation capacity. Extensive research has been conducted to investigate soil quality in diverse land uses within temperate regions. However, there is a noticeable scarcity of studies focusing on semi-arid regions. It is imperative to note that a comprehensive and practical assessment of soil condition necessitates the simultaneous measurement of physical, chemical, and biological indicators. Such an integrated approach ensures a thorough and effective evaluation of soil quality. The primary objective of this study was to assess the impact of various land uses, namely natural forest (C. betulus - P. persica), plantation (Q. castaneifolia), garden, rangeland, and agricultural lands (rice), on the physical, chemical, and biological properties of the organic and mineral soil layers. Specifically, the investigation focused on the evaluation of fauna and flora, microbial communities, and enzyme activities. The study was conducted in the semi-arid region of Kajur Nowshahrmourd.
Materials and Methods
To achieve this objective, contiguous sections of the study area were carefully chosen, ensuring minimal variations in height above sea level, percentage and direction of slope. Subsequently, three slice of one-hectare dimension plots (100 × 100) were selected within each study habitat, with a minimum distance of 600 meters between them. From each one-hectare plot, four leaf litter samples and four soil samples (30 cm × 30 cm, 10 cm depth) were collected and transported to the laboratory for analysis. In total, 12 litter samples and 12 soil samples were collected from each of the habitats. The soil samples were divided into two parts: one part was air-dried and then passed through a 2 mm sieve for subsequent physical and chemical testing, while the other part was stored at 4 degrees Celsius for biological assessments. One-way analysis of variance tests were employed to compare the characteristics of the organic layer and soil among the studied habitats. Furthermore, Duncan's test (P>0.05) was utilized to compare the average parameters that exhibited significant differences among the different habitats.
Results and Discussion
The findings derived from this investigation underscore the substantial variability in organic layer characteristics across different vegetation types. Natural forests emerged as the most prominent in terms of thickness, nitrogen content, and calcium concentration, whereas agricultural areas exhibited the lowest values. Grassland areas displayed the highest carbon content and carbon-to-nitrogen ratio, while agricultural and natural forest areas demonstrated comparatively lower values. Agricultural lands demonstrated elevated bulk density and sand content, whereas natural forests exhibited the lowest values. Notably, natural forests showcased the highest porosity, aggregate stability, silt percentage, and macro- and micro-aggregate quantities, while agricultural areas presented the lowest values. Chemical analysis of the soil indicated that natural forests recorded the highest values for most chemical characteristics, while agricultural lands displayed the lowest values. Biological attributes generally exhibited the highest levels in natural forests and the lowest levels in agricultural areas. Specifically, the abundance and biomass of epigeic and endogeic fauna did not exhibit significant differences among different land uses during the summer season. Managed forests demonstrated the highest values for moisture content, basal respiration, substrate-induced respiration, and microbial biomass carbon. Conversely, agriculture exhibited the lowest values in these regards. The microbial biomass carbon-to-nitrogen ratio was highest in agricultural areas, while natural forests displayed the lowest value. Natural forests displayed the highest values for most nitrogen transformation characteristics, whereas agricultural areas exhibited the lowest values. Nitrogen nitrification and mineralization showed a decreasing trend across different land uses during the summer and autumn seasons. The type of vegetation cover also significantly influenced the variability of soil ammonium and nitrate levels.
Conclusion
Based on the results obtained from this study, it can be inferred that the preservation and conservation of natural forest cover should be given utmost importance. Additionally, in degraded areas, the establishment of woody vegetation can serve as a viable approach for the restoration of ecosystems with similar ecological conditions. Furthermore, the presence of tree covers, specifically C. betulus and P. persica, is of greater significance compared to rangeland and agricultural land uses in enhancing soil fertility and creating favorable biological conditions. As a result, this research provides valuable insights into the impact of different land uses on the characteristics of the organic and mineral soil layers in mountainous habitats. The information obtained can be instrumental in guiding natural resource managers and offering practical assistance in decision-making processes.
Research Article
Soil science
T. Nazari; M. Barani Motlagh; S.O. Rastegar; M.H. Sedri
Abstract
IntroductionPhosphorus is an essential element for all living organisms, and it cannot be replaced by any other element. Phosphorus has however a limited resource, and it is estimated that the extracted phosphorus resources (Apatite) will last for another 50 to 100 years. One of the most widely used ...
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IntroductionPhosphorus is an essential element for all living organisms, and it cannot be replaced by any other element. Phosphorus has however a limited resource, and it is estimated that the extracted phosphorus resources (Apatite) will last for another 50 to 100 years. One of the most widely used technologies for recycling phosphorus is the precipitation of phosphorus from sewage sludge and leachate. Phosphorus Recovery as struvite (NH4MgPO4.6H2O) from sewage sludge has attracted special attention due to its potential for use as an ecological and slow release fertilizer. Struvite is a white, grain-like solid, odor-free and sludge–free ingredient, composed of magnesium, ammonium and phosphate at equal molar concentrations. Therefore, this study is designed to examine the effect of struvite replacement with triple superphosphate fertilizer on some physiological parameters and phosphorus availability in wheat plants in calcareous soils deficient in phosphorus. Methods and MaterialsSoil with phosphorus deficiency was collected from 0-30 cm depth under arable lands of Hajjiabad-e Seyyedeh located in Ghorveh township, Kurdistan Province, Iran. The soil was air-dried and ground to pass through a 2-mm sieve, followed by laboratory analysis to determine its physico-chemical properties. The struvite used in the research was obtained by optimizing the three main factors of sulfuric acid concentration, solid-to-liquid ratio, and time for the leaching process, and the three key factors of Mg:P ratio, N:P ratio and pH for the precipitation process by Response Surface Methodology. To achieve the aim of this study a factorial experiment was carried based on completely randomized design with 4 replications. The factors included the application of different proportions of struvite replaced with triple superphosphate (S0:P100, S25:P75, S50:P50, S75:P25 and S100:P0) and 4 levels of phosphorus (0, 50, 100 and 150 kg TSP ha-1) and a total of 54 pots. The application rate for struvite was calculated based on total phosphorus (P2O5). Then 10 wheat seeds were planted in each pot at 2-cm depth which after plant emerging and greening, declined to 4 plants in each pot. The pots were randomly moved twice a week during the growth period to eliminate environmental effects. Irrigation and weeding operations were applied by hand. Plants were harvested 60 days after planting (beginning of flowering), washed with distilled water and dried with tissue paper. The samples were air-dried and then oven dried at 70˚C to a constant weight in a forced air-driven oven. Phosphorus concentrations in plant extracts were measured by the molybdenum vanadate or yellow method and chlorophyll content (a, b and ab) and carotenoids using the Arnon method. The statistical results of the data were analyzed using SAS software and LSD test (at 5% level) was used for comparing the mean values. Results and DiscussionBased on the obtained results, all the investigated treatments and their interactions were significant at p<0.01. However, the interaction effect of fresh weight shoots and height was significant at p<0.05. The comparison of the average data showed that the highest amount of fresh weight shoots (7.79 g pot-1), dry weight shoots (1.130 g pot-1) and height (29.66 cm) was obtained from the application of S75:P25 150 kgTSP ha-1. By use of struvite instead of triple superphosphate fertilizer, the phosphorus concentration and uptake of wheat increased at all three fertilizer levels, so that the highest phosphorus concentration (0.174%) was obtained from S75:P25 150 kg TSP ha-1. However, there was no statistically significant difference for S100:P0 (0.169%) treatment. The highest amount of phosphorus uptake in wheat with an average of 0.197 g pot-1 was obtained from the S75:P25 treatment (150 kg TSP ha-1), compared to the treatment of 100% struvite (S100:P0) and 100% triple superphosphate fertilizer (S0:P100) with the averages of 0.158 and 0.109 g pot-1, respectively, showing 19.79 and 44.67 percent increase. Also, the results showed that the treatment of 150 kg TSP ha-1 100% struvite (S100:P0) compared to 100% triple superphosphate fertilizer (S0:P100) increased the amounts of chlorophyll a, b, ab and carotenoids by 7.78, 3.82, 6.44 and 6.84 percent, respectively. ConclusionDespite struvite's low solubility, it is a highly soluble phosphorus fertilizer for plants . However, the reasons for this apparent contradiction and also the specific mechanisms of struvite dissolution are still unclear. Hence, further accurate measurements at different pH and EC conditions with different physical and chemical properties of soil studying phosphorus fractionation in soil will help to better understand the use of struvite. Therefore, it is recommended to optimize the timing and application rate of struvite in relation to the demand for different agricultural and garden crops.
Research Article
Soil science
B. Abolfazli Behrooz; S. Oustan; H. Mirseyed Hosseini; H. Etesami
Abstract
IntroductionCadmium (Cd) contamination has been a widespread concern in paddy soils because of its subsequent transfer to the food chain. Biochar amendment is proposed to stabilize Cd in the contaminated soils. However, the pristine biochar shows limited functionality towards Cd sorption in practice. ...
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IntroductionCadmium (Cd) contamination has been a widespread concern in paddy soils because of its subsequent transfer to the food chain. Biochar amendment is proposed to stabilize Cd in the contaminated soils. However, the pristine biochar shows limited functionality towards Cd sorption in practice. Recently, Mg-modified biochars have attracted much attention for their low toxicity. These biochars are coated by MgO or Mg(OH)2 precipitates during the pyrolysis process. Magnesium chloride (MgCl2)-modified biochars have been used widely in the removal of heavy metals from the aqueous solutions. However, there is little literature about their performance in soils. The present study therefore was conducted to investigate the effects of application of unmodified and MgCl2-modified rice husk biochars on the kinetics and isotherms of Cd sorption in a calyey paddy soil. Materials and MethodsThe unmodified and MgCl2-modified biochars were produced from rice husk at 600°C. Some relevant characteristics of the produced biochars (including elemental composition, pzc, pH1:10, ash content and BET surface area) were determined. Moreover, the studied soil was taken from a paddy field (0-20 cm) in the Qaemshahr region of Mazandaran province. The biochars (< 0.5 mm) were added to the soil samples at three levels (0, 3, and 5% w/w) and the amended soils were incubated at 25°C for 45 days. Then, the kinetic experiments of Cd sorption at a concentration of 375 mg Cd/L at times of 0.25, 0.5, 1, 2, 4, 8, 16, 24 and 48 hours and the isothermal experiments of Cd sorption at concentrations of 50, 100, 150, 200, 300, 350, 400, 600 and 800 mg Cd/L were performed. In both kinetic and isotherm experiments, a 0.01 M KCl solution was used as the background electrolyte. Finally, the relevant kinetic and isotherm models were fitted to the sorption data and their parameters were calculated. Results and DiscussionBiochar characterization indicated that modification with MgCl2 resulted in an increase of the O/C ratio (from 0.27 to 0.48) and pH (from 7.67 to 8.60). This modification also increased the H/C ratio (from 0.032 to 0.071) and the specific surface area (from 195.6 to 231.2 m2/g). As a result, the MgCl2-modified biochar was more hydrophilic and less carbonized than the unmodified one. Moreover, the characteristic peaks of the MgCl2-modified biochar (3700, 1428 and 500 cm-1) were present in its FTIR spectrum. The results revealed that about 74 to 89% of the Cd sorption by the soils occurred in times less than 2 hours. With MgCl2-modification, the sorption equilibration time was reduced from 48 hours to 24 hours. In contrast, the unmodified biochar had no considerable effect on the Cd sorption kinetics. Among the kinetic models, the Elovich model with lower SEE was the best to fit the Cd sorption kinetic data. The intra-particle diffusion model was not satisfactory for Cd sorption on the biochars. Freundlich model with lower SEE well described the Cd sorption isotherms. Application of 3% and 5% MgCl2-modified biochar increased the Freundlich KF parameter by 2.4 and 2.8 times as compared to the control. Moreover, the aforementioned treatments increased the heterogeneity parameter of the Freundlich model (n) from 3.48 to 6.08. The Temkin model could not reasonable fit the sorption data. In contrast, the unmodified biochar did not show any considerable effect on the Cd sorption capacity of the clayey soil used in this research. This finding means that the unmodified biochar could not improve the sorption performance of negatively charged soil clay particles. ConclusionAccording to the results obtained, it could be concluded that the Cd sorption behavior of the soil treated with unmodified rice husk biochar was similar to that of the untreated soil. Whereas, the MgCl2-modification improved both sorption rate and sorption capacity of the soil for Cd. Application of MgCl2-modified biochar improved the Cd sorption properties of a clayey soil with high intrinsic sorption ability. Thus, this may be a promising approach in remediation of Cd-contaminated paddy soils with the aim of reducing Cd mobility and availability. However, there is need to do more research to create awareness about the importance of biomass nature as well as pyrolysis temperature, the ratio of MgCl2 to biomass, the mechanism of Cd stabilization and the desorption of Cd from soils treated with MgCl2-modified biochars.
Research Article
Agricultural Meteorology
A. Faraji; M. Kamangar; S. Ashrafi
Abstract
IntroductionSnow is a prevalent form of precipitation, particularly in mountainous and high latitude regions, characterized by ice crystals in various microscopic structures. It naturally accumulates in cold and elevated areas through the freezing of air and the unsuccessful melting of water into crystalline ...
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IntroductionSnow is a prevalent form of precipitation, particularly in mountainous and high latitude regions, characterized by ice crystals in various microscopic structures. It naturally accumulates in cold and elevated areas through the freezing of air and the unsuccessful melting of water into crystalline form (WMO, 2022). Snow cover plays a crucial role in determining water reserves, especially during warmer seasons. Monitoring snow cover is a specialized field within weather and climatology. Snow cover plays a key role in the balance of energy due to its high albedo. Climatologists and meteorologists, who analyze global climate changes, emphasize the significance of snow monitoring due to its impact on both daily weather patterns and long-term climate shifts (Bashir et al., 2010). Spatial studies of snow cover by using satellite data have become one of the high priority topics in geomatics research due to their applicability and high accuracy. Considering that the snow cover area in many regions of the world, including mountainous regions, affects water resources and meteorology, accurate spatial analysis and investigation of changes in the area of snow cover is very important. In this regard, use of satellite data and new tools in the spatial analysis of the snow cover area, as an efficient method in geomatics research, has received much attention (Cheng et al., 2019).Data and MethodThis research examines the changes in snow cover in the western part of Iran from 2001 to 2021. The study area includes the provinces of Kurdistan, Kermanshah, Ilam, Hamadan, and Lorestan, covering a total area of 466,121 square kilometers. The region is located between latitudes 31°51'36" to 36°49'45" N and longitudes 45°27'18" to 50°04'26" E. It encompasses the northern part of the Zagros Mountain range, which serves as the entry point for western weather systems into the country. Snow cover was assessed using Modis satellite images, with the NDSI index used to identify snow. The analysis revealed a trend in snow cover, which was further examined using the Mann-Kendall method. The spatial distribution and changes in spatial components (length, width, and height) were assessed using the G* Index. Results and Discussion To analyze snow cover in the western region, the snow cover index was calculated by averaging the images for each period. The area of snow cover was then determined for each period. Analysis of the winter snow cover area revealed a decreasing trend. The application of the Mann-Kendall method confirmed this decreasing trend, which is statistically significant at the 95% confidence level. Additionally, considering the annual sinusoidal behavior of snow, it can be concluded that the seasonal component is the dominant factor in the region, with temperature changes primarily driven by seasonal variation due to its relative distance from the equator. Spatial analysis indicated that the distribution of snow cover follows a northwest-southeast direction, as evidenced by the standard deviation ellipse. More than 99% of snowfall is concentrated in high-altitude areas with a specific spatial arrangement. The hotspot map shows that surface snow cover is clustered in the west and southeast directions, predominantly at altitudes above 2200 meters. The clustering pattern of snow cover is more pronounced at higher latitudes and towards the western borders. These findings have important implications for water resource management, drought prediction, and the development of strategies to mitigate droughts. Conclusion This research demonstrates a decreasing trend in the area of snow cover during the winter season in the western part of Iran. Spatial analysis reveals that the major axis of snow distribution follows a northwest-southeast orientation, aligned with the mountainous terrain in that direction. The hotspot map highlights that surface snow cover is concentrated in the west and southeast directions, particularly at altitudes above 2200 meters. Hotspot analysis indicates that snow cover is clustered towards higher latitudes and more pronounced towards the western borders.
