Applicable
Plant Nutrition, Soil Fertility and Fertilizers
Ali Reza Jafarnejadi; Farhad Moshiri; Fatemeh Meskini-Vishkaee
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 ...
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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.
Applicable
Soil Physics, Erosion and Conservation
Bahareh Kiani; Farshad Kiani; Azam Rezaee; Pouneh Ebrahimi; Samaneh Mahzari
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 ...
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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.
Applicable
Land Evaluation and Suitability
Sina Bigdeli; Heidar Ghafari; Mojtaba Norouzi Masir; Abdolamir Moezzi
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 ...
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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.
Applicable
Plant Nutrition, Soil Fertility and Fertilizers
Sepideh Raeisi; Nafiseh Rangzan; Naeimeh Enayatizamir
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 ...
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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.
Applicable
Soil Physics, Erosion and Conservation
Mitra Yarahmadi; Ataallah Khademalrasoul; hadi Amerikhah
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 ...
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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.
