Editorial
Volume 11, Issue 2 , January 2024
ترویجی
Saeed Saadat; Leila Esmaeelnejad; Hamed Rezaei; Rasoul Mirkhani
Abstract
About 80 percent of the world's agricultural lands, supplying nearly 60 percent of all human food, is under rain-fed cultivation. Considering the uneven distribution of global rainfall, arid and semi-arid areas call for measures to prevent soil and water salinization. Being one of the most important ...
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About 80 percent of the world's agricultural lands, supplying nearly 60 percent of all human food, is under rain-fed cultivation. Considering the uneven distribution of global rainfall, arid and semi-arid areas call for measures to prevent soil and water salinization. Being one of the most important resources for agricultural production, especially in the face of the current restrictions on the development of irrigated lands, drylands are especially stressed by soil salinity as an important limitation on dry farming, which causes decreased production especially when combined with other limitations such as lack of moisture. In order to gain an enlightened knowledge of the salinity status of rain-fed lands in Iran, a research project of national-scale including 849 study sites was performed and soil samples were collected from different depths across the study sites to determine their Electrical Conductivity (EC) as well as soil physical and chemical characteristics. The results showed that the highest and lowest salinity levels of the surface soil (depths of 0-30 cm) in rain-fed lands under cultivation were 97.5 and 0.19 dS/m, respectively, with an average value of 2.28 dS/m while more than 50% of the soils collected exhibited salinity levels greater than 0.6 dS/m. The results of principal component analysis showed that the variability of soil salinity in rain-fed lands were affected by climatic parameters (such as temperature and precipitation as well as indices resulting from their interactions including standardized precipitation indices and effective drought). Moreover, soil characteristics such as organic carbon, clay, and soluble salt (especially sodium) contents were found to have due effects on salinity level.
ترویجی
Abdoulrasool Shirvanian; behrooz hassanpour
Abstract
Chemical fertilizers are nowadays one of the basic production inputs toward enhanced yields of agricultural products. The private businesses stepping into the chemical fertilizer market increasingly encourage farmers to consume more fertilizers, which, in turn, ushers in doubts about their optimal application ...
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Chemical fertilizers are nowadays one of the basic production inputs toward enhanced yields of agricultural products. The private businesses stepping into the chemical fertilizer market increasingly encourage farmers to consume more fertilizers, which, in turn, ushers in doubts about their optimal application at the farm level. To address this issue, the present study was designed and implemented to determine the factors involved in the optimal application of nitrogen fertilizers on wheat fields in Fars Province. For this purpose, data were collected through the multi-stage cluster sampling method and the survey method using a questionnaire admninistered to 457 wheat farmers in Fars Province. The data thus collected were analyzed through descriptive statistics and the Tobit model. Results showed that 78.56 percent of wheat farmers had failed to observe optimal fertilizer consumption levels. It may, therefore, be recommended that the policies pertinent to optimal use of nitrogen fertilizers as tailored to soil and plant requirements should still be enforced as the pivotal approach. For this purpose, informal education on the whole crop rotation may be suggested as the main agenda with due heed paid to farmers’ socio-economic characteristics that affect their learning while farm water management as realized by the fertilizer-irrigation approach management of soil resources as implemented through soil tests prior to field operations and disseminated as a social culture among farmers, and the main focus placed on planting dicotyledonous plants in alternation with wheat.
ترویجی
Somayeh Fazelikia; Seyed Ali Abtahi; Mohamad Kargar; Mojtaba Jafarinia
Abstract
Microbial urease has specific applications in biotechnology, agriculture, medicine, construction and geotechnical engineering. MICP technology is an ecological process based on microbial urease activity that has recently been used for soil stabilization. Due to its catabolic ability and high ...
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Microbial urease has specific applications in biotechnology, agriculture, medicine, construction and geotechnical engineering. MICP technology is an ecological process based on microbial urease activity that has recently been used for soil stabilization. Due to its catabolic ability and high survival, Bacillus is considered as a suitable candidate for use in the biocementation process. The aim of this study was isolating and identifying Bacillus with MICP potential from various ecosystems of Iran.200 environmental samples were collected from the ecosystems of Iran and were analyzed by microbiological and molecular methods including PCR amplification and sequence analysis of gyrA and 16S rRNA genes in order to isolate and identify bacilli. Growth in presence of urea, salinity, pH and different temperatures, SEM, XRD and wind tunnel analysis were used to determine the ability of isolates to produce biocement. A total of 12 isolates(6%) were identified as urease-positive bacilli belonging to 4 different species, including 4 isolates of Bacillus paramycoides(33.33%), 3 isolates of Bacillus paralicheniformis(25%), and 3 isolates of Bacillus velezensis. isolate(25%) and Bacillus Pasteuri 2 were isolated(16.66%). The optimal conditions for MICP by isolates are 30°C, pH 9 and salinity 6%. After MICP, the ratio of soil loss in the flow rate of 95 km/h showed a 100-fold decrease. In conclusion, the results showed that bacilli have the potential ability to adapt to harsh environmental conditions. Also, by using MICP-producing bacilli on the soil surface, we can have a significant effect in reducing soil losses due to erosion.
ترویجی
sayyad Asghari Saraskanrood; Hosein Sharifi Tolaroud
Abstract
Given the significance of the Hyrcanian Forests, inscribed by the UNESCO as a world heritage site, it is essential to monitor the changes in and the devastation of the forest cover in this ecoregion for the planning and management of national lands. It is the objective of the present study to monitor ...
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Given the significance of the Hyrcanian Forests, inscribed by the UNESCO as a world heritage site, it is essential to monitor the changes in and the devastation of the forest cover in this ecoregion for the planning and management of national lands. It is the objective of the present study to monitor changes in both land use and forest cover in Astara region using Landsat TM, OLI 1 & 2 sensors for the years 1995 and 2022. For this purpose, images captured on days with cloud covers of less than 10% were selected over three time intervals and the relevant enhanced Vegetation Index (EVI) values were determined based on Landsat inter-band relations. In the next stage, the index values were combined to derive the land use map using the support vector machine (SVM) algorithm. The results of accuracy evaluation showed that the overall accuracy and Kappa coefficients of the land use map for the year 1995 were equal to 89 and 92% and those for 2022 were 0.86 and 0.75%, respectively, indicating acceptable results. The results of land use changes in Astara city during the period from 1995 to 2022 showed that residential land use had increased by 7% equal to 2954 ha while rangeland and agricultural uses had decreased by 1 to 2% equal to 258 and 997 ha, respectively. However, an important land use along the Caspian coast line – that is, forest cover - stretched over an area of 34283 ha equal to 80% of the study area, which declined in 2022 to 32522 ha equal to 76%, showing a decrease of 4% equal to 1761 ha. It is clear that, owing to its rich archive of satellite images, the GEE system can be used as a strong and useful tool for monitoring and managing forest lands.
مروری
Ali Asadi kangarshahi; Negin Akhlaghi Amiri
Abstract
Management of nitrogen fertilizer application for citrus trees was evaluated to obtain an enlightened understanding of plant nitrogen requirements, amount of fertilization needed, appropriate fertilization timing, and nitrogen uptake and storage in these plants. The knowledge thus obtained could be effectively ...
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Management of nitrogen fertilizer application for citrus trees was evaluated to obtain an enlightened understanding of plant nitrogen requirements, amount of fertilization needed, appropriate fertilization timing, and nitrogen uptake and storage in these plants. The knowledge thus obtained could be effectively exploited toward formulating recommendations that ensure optimized nitrogen fertilization. Mature citrus trees reportedly contain 500 to 1000 kg N/ha, 40 to 50 percent of which belongs in the leaves and fruits while only 15 to 20 kg N is deposited in their skeletal structure. These findings and the long-term survey of citrus fertilization experiments in Iran and elsewhere indicate that annual application of 200 kg N/ha seems sufficient for stable fruit production, improved fruit yield and quality, and proper tree growth and health. Moreover, it is found that 30-50% of this amount of N application will be incorporated into the fruits while about one tenth will be deposited and stored in the tree, with the balance between nitrogen uptake and consumption by the tree being secured by N leaching from the soil profile and lost as gas into the air. The results of an experiment with labeled fertilizers (15N) showed that the highest N-uptake rate in citrus trees occurred during the period from fruit set to fruit maturity and, further, that N uptake was very low during the post-harvest period, especially during minimum tree activity (winter) and the beginning of the growing season. This indicates that nitrogen storage in older tissues plays the greatest role in the growth and development of leaves, branches, flowers, and fruits at the beginning of the growing season when N uptake from the soil is still very low (i.e., when branches and flowers begin to sprout and fruits are in the form). It has also been reported that the nitrogen present in soil organic matter ranges from 1000 to 2000 kg/ha in orchard soils containing 1 to 2% O.M. and that both the soil nitrogen content and that stored in the tree bodies play important roles in regulating the supply of nitrogen to new organs (i.e., leaves, blooms, and fruitlets), especially in the beginning of the growing season. It follows that the purpose behind N fertilization should be to ensure stable production, proper tree growth, and improved fruit yield and quality such that soil application of fertilizers before the flowering and fruit set stages have no effects on the growth of spring buds or flowering and fruit setting in the current year. Producers are, therefore, recommended to start fertilizer application with a maximum of 10-15% of the annual plant requirement during the period prior to flowering and fruit setting, gradually increase application rate (by some percentage of the annual requirement) as determined by the phenology of fruit growth, and increase it to its maximum rate by the middle of the first stage up to the early second stage of fruit growth. Then, in the middle of the second stage of fruit growth, nitrogen rate should be reduced to its minimum or stopped altogether (depending on plant variety).
مروری
Mirnaser Navidi; Hadi Asadi Rahmani; Mansour Chatrenour; Rasoul Kharazmi; Mohammad Jamshidi; Alireza Ziaee Javid; Zahra MohamadEsmaeil; fatemeh ebrahimi meymand
Abstract
Al land use changes pose a most serious challenge to agricultural production, resulting in the loss of fertile soil and food security. The present study was conducted to investigate the challenges associated with fertile agricultural lands in Iran as an attempt to examine and identify the different aspects ...
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Al land use changes pose a most serious challenge to agricultural production, resulting in the loss of fertile soil and food security. The present study was conducted to investigate the challenges associated with fertile agricultural lands in Iran as an attempt to examine and identify the different aspects of the threats agricultural lands are faced with. As a second step, the laws and regulations governing land use change in different countries and in Iran were reviewed and the general policies related to the protection of agricultural lands were examined. The review of land use laws in Iran showed that, despite their abundance, they have suffered from poor law enforcement as a result of both social and historical reasons as well as a public negligence of and non-adherence to the laws. Evaluations of temporal changes in the growth and development of metropolises as provincial centers revealed that they had greatly expanded beyond their original limits to annex fertile agricultural lands in the suburbs to these large cities. The five-year statistics of the requests submitted for land use change in each province also revealed landlords’ increasing demands submitted for land use change motivated by more profits out of their property, which result in loss of fertile soil, decreased agricultural production, and endangered food security.
مروری
Shno Karimi; Zahra Kolahchi
Abstract
Although plastic products nowadays widely mass-produced bring convenience to people, they definitely cause plastic pollutants to accumulate in the environment. Microplastics are generally defined as plastic particles less than 5 mm in size. Large amounts of such wastes are annually released and dumped ...
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Although plastic products nowadays widely mass-produced bring convenience to people, they definitely cause plastic pollutants to accumulate in the environment. Microplastics are generally defined as plastic particles less than 5 mm in size. Large amounts of such wastes are annually released and dumped into the environment so that they are now widely detected in open oceans, freshwater, marine organisms, soil, and sewage sludge, among others. Pollution with microplastics and the associated environmental hazards are nowadays a major global concern, with soil pollution with microplastics being of special importance because soils provide a wide range of ecosystem services essential for life while they house most of the microplastic waste released into the environment. A wide array of sources has been identified for soil pollution with these materials including composts, sewage sludge, irrigation, plastic mulch, littering, and atmospheric deposits. The transport and persistence of microplastics in soil are governed by the interaction effects of microplastic properties (namely, the extent of their swarm into the environment, particle size, and type of their constituent compounds) and environmental factors. Moreover, plastic materials present in soil can change the interactions among soil particles, water, chemical compounds, and living organisms to alter the different characteristics of agro-ecosystems. To shed more light on these issues, the present article provides a review of the research projects performed, both at the national and international levels, on the sources of microplastics in soil and their detrimental impacts on soil and human beings.
Research Paper
Yaser Azimzadeh
Abstract
Biochar is a black solid containing stable carbon with many positive effects on the physical, chemical, and biological properties of soil. One important positive effect of biochar on soil is its contribution to nutrient (e.g., nitrogen) mobility and dynamics in soil. Negatively charged on the surface, ...
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Biochar is a black solid containing stable carbon with many positive effects on the physical, chemical, and biological properties of soil. One important positive effect of biochar on soil is its contribution to nutrient (e.g., nitrogen) mobility and dynamics in soil. Negatively charged on the surface, biochar is capable of adsorbing and storing ammonium ions (NH4+) and small nitrogen-containing organic molecules. It also releases nitrogen into the soil to change the carbon to nitrogen ratio (C/N), whereby the mineralization-immobilization balance of nitrogen is affected. Moreover, biochar indirectly affects soil nitrogen cycle and dynamics by changing such soil properties as pH, cation exchange capacity, electrical conductivity, organic carbon, biological activity, nutrient availability, porosity, ventilation, and water relations, among others. It is through these changes that water, air, and nutrients are provided to make soil a suitable habitat favorable to soil microorganisms that help improve biological fixation of nitrogen. Biochar also reduces N2O emission, as a greenhouse gas, from the soil by reducing soil nitrogen sublimation. In general, biochar has a synergistic interaction with nitrogen and can enhance nitrogen use efficiency to reduce nitrogen fertilizer consumption. However, only scant knowledge is presently available on soil nitrogen changes induced by biochar, especially in calcareous soils. Further research is needed to investigate the effects of biochars produced from different types of biomass under different temperatures on the mobility and availability of nutrients, especially nitrogen, in calcareous soils.
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