Research Paper
gholamreza Adim; Elham Malekzadeh; Esmael Dordipour; Farshad Kiani; Hassan Mokhtarpour; seraj Moazzemi
Abstract
Introduction In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Although the use of chemical fertilizers has a high yield of plants, ...
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Introduction In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Although the use of chemical fertilizers has a high yield of plants, its destructive effects in the long-term are known on the soil biological, physical and chemical properties and environmental pollution. Therefore, a strategy must be considered that can improve soil health and quality as well as produce a high plant yield. Organic manures increase the growth, yield and quality of plants by improving soil conditions and the balance of essential elements. An integrated plant nutrition management system by reducing the use of chemical fertilizers is known as one of the ways to achieve the expected yield and meanwhile, minimize the adverse environmental effects of chemical fertilizers in the world.Materials and Methods The objective of this study was to evaluate the effect of single and combined use of chemical fertilizer (urea, triple superphosphate, potassium sulfate as NPK) with organic and biological fertilizers on the yield and yield components of transplanted canola (Brassica napus L.). Experiment was conducted in a randomized complete block design with six treatments and three replications (18 experimental units) in the 2019-2020 crop year at the Iraqi Agricultural Research Station in Gorgan, Iran. Treatments included: 1) Control (without fertilizer, T1), 2) Chemical fertilizer (T2), 3) Poultry manure (T3), 4) Compost (T4), 5) 50% Chemical fertilizer+ 50% Poultry manure+ 50% Compost (T5), 6) 50% Chemical fertilizer+ 50% Poultry manure+ 50% Compost+ Biofarm-1 biofertilizer (T6). Chemical fertilizer was applied based on soil test including nitrogen equivalent to 250 kg/ha urea was added in three stages during planting, stem elongation, before flowering; phosphorus equivalent to 150 kg/ha of triple super phosphate; potassium equivalent to 50 kg/ha of potassium sulfate, respectively. Organic fertilizers were calculated based on their total nitrogen contents and the equivalent of pure nitrogen recommended based on the soil test for chemical fertilizer and by assuming 50% mineralization rate of organic fertilizers in the soil. Biofertilizer was applied as seed inoculation plus spraying on the plant base in two stages of 4 to 8 leaves and stem elongation. Chlorophyll index was measured in the middle of the flowering stage by using SPAD. After physiological maturity, yield and yield components including pods per plant, numbers of seeds per pod, pod length, 1000-seed weight, seed yield, protein and oil contents of grain were recorded. Results and Discussion The results showed that the effect of fertilizer treatments was significant on yield and yield components (p <0.01). The highest 1000-seed weight, grain yield, protein content of the seed, number of seeds per pod, pod length and pods per plant were recorded in the treatment of 50% chemical fertilizer+ 50% Poultry manure+ 50% Compost+ Biofertilizer (T6) which increased by 21.9%, 43.7%, 33.8%, 29.2%, 37.2% and 37.6%, respectively, in compared to the control treatment (with the lowest values). The pods per plant, 1000-seed weight and grain yield were not significantly different between the combined treatments of chemical fertilizer+bio-organic fertilizers (T6) and integrated use of chemical and organic (T5) fertilizers (p <0.05). The control treatment (T1) by 2248.37 Kg/ha of grain yield (the minimum amount) decreased by 43.7% and 38.3% compared to T6 and T5 treatments, respectively. The chemical treatment (T2) and integrated application of chemical fertilizer+ bio-organic fertilizers (T6) showed the most positive effect on the chlorophyll index compared to other fertilizer and control treatments (with the lowest index, 43.66). Chlorophyll index in the T2 and T6 treatments increased by 35.6% and 33.7% compared to the control treatment (T1), respectively. The treated plants by alone use of organic fertilizers (T3 and T4) without notable difference produced the highest grain oil (by an average of 45.73%) which increased by 6.6% compared to the chemical fertilizer (T2) and control (T1) treatments by an average of 42.7%.Conclusion Combined use of chemical fertilizer with bio-organic fertilizers had the most positive effect on yield and yield components, and often showed significant difference with the single application of chemical and organic fertilizer treatments (T2, T3 and T4). Therefore, the combination use of chemical and bio-organic fertilizers is a better option to increase the yield and yield components of transplanted canola than the single use of chemical fertilizers. The highest pods per plant, pod length, number of seeds per pod, chlorophyll index, protein content, chlorophyll, 1000-seed weight, and grain yield were related to the integrated application of chemical fertilizer with bio-organic fertilizers (T6 and T5), so it can be inferred that the use of a mixture of organic, biological and chemical fertilizers is an effective approach to reduce the using of chemical fertilizers and their destructive environmental effects, as well as increase the yield of transplanted rapeseed
Research Paper
Mehdi Naderi Khorasgani; Ghasem Haj Hassani; Jahangard Mohammadi; Ahmad Karimi
Abstract
The Effect of Different Tillage Instruments on Some Soil Physical Characteristics and Soil TranslocationIntroductionTillage is defined as disturbing the soil and changing soil physical condition of seedbed and root zone and making it suitable for cultivation. Soil physical characteristics like soil moisture ...
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The Effect of Different Tillage Instruments on Some Soil Physical Characteristics and Soil TranslocationIntroductionTillage is defined as disturbing the soil and changing soil physical condition of seedbed and root zone and making it suitable for cultivation. Soil physical characteristics like soil moisture and temperature conduction, bulk density, porosity and particle size are changed in the following of soil tillage. Tillage also increases water infiltration rate and plays an important role in soil moisture protection and decreasing flood hazards in arid and semi-arid regions. Molboard plough is currently implemented for tillage in different parts of Iran including Chaharmahal va Bakhtiari province. There are evidences which show Moldboard plough triggers physical soil characteristics deterioration and soil tillage erosion. Tillage translocation coefficient, as a component of tillage erosion, is defined as the amount of soil transition for 1 m width of tillage instrument. Comparing the impacts of available tillage instruments on physical soil characteristics, soil transition and their efficiency with of Moldboard plough may encourage field managers to substitute other instruments with Moldboard plough. This research aimed to: 1) study the impacts of the currently available tillage instruments (Moldboard, Disk and Chisel plough) on some prominent physical soil characteristics and 2) compare soil translocation coefficients of the mentioned tillage instruments. Materials and Methods This research was executed in Research-Training Field of Shahrekord University, Shahrekord county, Chaharmahal va Bakhtiari Province, Iran. A split plot experimental design with complete randomize block was considered with 3 major treatments of tillage instruments (Molboard, Disk and Chisel plough), minor treatments of slope (0, 3, 6 and 8%) and tillage speeds (2, 5, and 8 km h-1) and 3 replications. The conventional tillage depth of 25 cm was adjusted for all three tillage instruments. Standard protocols were applied and soil electrical conductivity (EC), pH, calcium carbonate equivalent (CCE), organic matter and soil texture components were measured before tillage application and soil field capacity (FC), mean weight diameter (MWD) of aggregates, geometric mean diameter (GMD) of aggregates, aeration porosity (Fa), bulk density (ρb) and water stable aggregates (WSA) were measured using standard protocols after tillage implementations. Colored gypsum cylinders were used as indicators for detecting soil translocation. The transition distance of the colored gypsum cylinders of each layer of tillage depth (0-9, 9-18 and 18-25 cm) was measured using tape meter or ruler and mean transition for each layer were calculated. In the next step the depth weight soil translocation was calculated for each tillage instrument. Results and Discussions Chemical analysis of soil samples showed that soils were non-saline, soil OM content was less than 1% and CCE of soil samples was relatively high. Physical soil analysis of soil samples before tillage implementation indicated that there was not any restriction for plant root development and aeration as ρb was relatively low and aeration porosity was 10% <, respectively. Analysis of variance (ANOVA) indicated that the effects of tillage type on MWD and ρb were significant (P < 0.05). Comparing the means of MWD and ρb induced by tillage instruments (Duncan method) revealed significantly higher values of MWD and lower values of ρb for soils which were treated by MB plough, the results were corresponded to the finding of other researchers. There were not significant differences between MWD and ρb of soils which were treated by disk and chisel plough. The results also showed that tillage instruments did not impact on physical characteristics like FC, WSA, GMD and FA. Non-significant impact of MB plough on soil moisture condition also was reported by other researchers in the northwest of Iran. The ANOVA was calculated for soil translocation and showed that the effects of tillage instruments were significant (P < 0.05) for all three layers of soil depth. Mean soil translocation of surficial layer of tillage depth (0-9 cm) was significantly higher than of other layers of tillage depth. Despite other researchers' findings, our research indicated that the slope levels were not significant for soil translocation. This research also revealed that tillage speed significantly (P < 0.05) impacted on soil translocation which was corresponded to findings of other researches in different parts of the world. Interaction of slope-speed and tillage type-speed were significant (P < 0.05) which could be due to accelerated impacts of speed on soil translocation in steep areas. Amount of coefficient of translocation for MB plough was 141 kg m-1 per application. This value was about one third of soil translocation which was reported by others from Belgium (545 kg m-1 y-1) or Denmark (456 kg m-1 y-1) and very closed to the finding of Spanish researchers (164 kg m-1 per application). The coefficient of translocation for disk and chisel plough were 114 and 93 kg m-1 per application, respectively. According to researchers from Portugal, the coefficients of translocation for disk and chisel plough were in ranges of 0-333 kg m-1 and 18-770 kg m-1 per application, respectively. The magnitude of soil translocation coefficients for tillage instruments were in order of MB plough > disk plough > chisel plough. Keywords: Aggregate mean weight diameter, Bulk density, Soil coefficient of translocation
Research Paper
N moallemi; Esmaeil Khaleghi; Abas Danaeifar
Abstract
Acacia with the scientific name Acacia salicina is a tree or shrub from the leguminous family and a nitrogen fixer. This species is native to dry areas in southern Australia. In some areas, this species is used as a source of fodder for livestock, for ornamental purposes, and for revival areas without ...
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Acacia with the scientific name Acacia salicina is a tree or shrub from the leguminous family and a nitrogen fixer. This species is native to dry areas in southern Australia. In some areas, this species is used as a source of fodder for livestock, for ornamental purposes, and for revival areas without vegetation. Climate change is one of the most important concerns of the world's growing population. Drought is one of the most important abiotic stresses that affects the nutritional status of plants. Stresses constantly affect the growth and development of plants, which are considered the most important factors of yield reduction in the world. Stresses are the result of abnormal physiological processes that are caused by one or a combination of biological and environmental factors, and drought is one of the most important abiotic stresses that affect growth and performance, as well as this Stress can cause plant death and limits approximately 25% of agricultural production. One of the most common ways to withstand drought stress is the use of super absorbent polymers. Commercial superabsorbent polymers are hygroscopic materials similar to sugar, and the shape of these polymers must be maintained after absorbing water and swelling. They don't have harm for soil, plants and environment. Considering the increase in temperature and pollution the purpose of this research is the effect of using three types of super absorbent polymers to increase N.P.K. absorption, water retention, reduce irrigation, reduce costs and improve the growth of acacia plants under drought stress conditions for cultivation in areas free of vegetation in Khuzestan to contrast with fine dust. In order to improve the nutritional status of acacia, a research was conducted using three types of superabsorbent polymers in three concentrations at three levels of drought stress in a factorial format in a completely randomized block design with three replications in the agricultural faculty of Shahid Chamran University of Ahvaz. The results showed that the use of superabsorbent polymers significantly increases the amount of nitrogen, potassium and phosphorus absorption by leaves, stems and roots. The concentration of 2 g/kg of A200 hydrogel in the first week increased leaf nitrogen by 12.85%, leaf phosphorus by 17.64%, stem nitrogen by 50.29% and root nitrogen by 4.96%. In the first week, SNF superabsorbent had the highest amount of potassium in stem and phosphorus in the root. Among the hydrogels, SNF superabsorbent polymer had the highest amount of phosphorus in the stem in the second week and a concentration of 1 g/kg, and this increase was significant compared to some treatments, and the lowest amount of phosphorus in the stem were obtained s in the treatment of the first week and a concentration of 0 g/kg Super absorbent polymer A200 and SNF. Increasing the concentration of super absorbent polymers increased the amount of phosphorus in the stem in most cases. increase in the intensity of drought stress caused a decrease in the amount of leaf nitrogen compared to non-stressed conditions, so that the lowest amount of nitrogen was obtained in the third week of treatment with SNF superabsorbent polymer at a concentration of 0 g/kg, which caused a decrease of 29.04% compared to the control. The increase in the severity of drought stress caused a decrease in the amount of phosphorus in leaves compared to the first week, so that the lowest amount of phosphorus was obtained in the second week in the concentration of 2 g/kg of SNF,which had a decrease of 52.94% compared to the control. intensity of drought stress and increasing the frequency of irrigation caused a decrease in the amount of nitrogen in the stem, so that the lowest amount of nitrogen was obtained in the third week and the concentration of 0 g/kg of Barbari hydrogel, which was a 32.16% decrease compared to the control. The lowest amount of root phosphorus was obtained in the third week of treatment with a concentration of 2 grams per kilogram of Barbarii superabsorbent polymer, which caused a decrease of 54.54% compared to the control. Based on the results of this research, the use of A200 superabsorbent polymer compared to other hydrogels had the greatest effect on the nutritional status of the plant and the absorption of N.P.K elements.
Research Paper
Roghayeh Shahriaripour
Abstract
Introduction Phosphorus (P) is the second nutrient and plays a key role in plant growth. The availability of P in the soil depends on the P fractions, which influence the primary productivity of agricultural ecosystems. Having sufficient and accurate information about soil mineral phosphorus is very ...
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Introduction Phosphorus (P) is the second nutrient and plays a key role in plant growth. The availability of P in the soil depends on the P fractions, which influence the primary productivity of agricultural ecosystems. Having sufficient and accurate information about soil mineral phosphorus is very important for the development of sustainable agriculture in arid regions. Awareness of phosphorus deformation in different soils is also very important for phosphorus fertilizer recommendation. When phosphorus is used in its soluble forms, it is rapidly converted into unusable forms for the plant. Native soil phosphorus is often in unusable form for the plant. Therefore, having enough information about phosphorus deformation in different soils is very important to recommend phosphorus fertilizer. The objective of this study was to find out the effects of long-term use of different sources of phosphorus on available P for pistachio plants in southeast Iran.Materials and Methods The aim of this study was to find the effects of long-term use of different sources of phosphorus fertilizers that can be used for pistachio plants. For that, 168 different soil samples from 63000 ha of Sirjan pistachio orchards of Kerman province. Jiang and Gu method was used to isolate and determine the mineral forms of phosphorus in the soil. Each P fraction was extracted as follows: 1g (oven-dry weight) of sample soil weighed out into a 50 mL polyethylene centrifuge tube. A volume of 40 mL of the first extractant, NaHCO3 (Table 1) was added and placed in an automated mechanical shaker at 25° C with 110 rpm for 1 h to allow time for the solution top equilibrate. The tubes were then centrifuged at 6000 × g for 15 min and the supernatant was carefully filtered through Whatman No. 42 with minimum loss of soil. Reactive P in the supernatant was determined using the ascorbic acid method at 882 nm. This method separates phosphorus in the forms of di calcium phosphate, octa calcium phosphate, aluminum phosphates, iron phosphates, occluded phosphates and apatite. The data showed that Ca10-P was the most abundant P forms in the soils tested. Results and Discussion Results showed that the total P was high in these soil samples and the abundance of P fractions was in order to Ca10-P type≥ Al-P >Ca2-P type> Occluded P ≥ Fe-P > Ca8-P type in two depths. These results suggested that continuous P application leads to plant available P convert into unavailable P forms such as Ca10-P. results indicate that NaOH-extractable P has resulted from active Fe oxides. Also, by comparing two depths of soil in the study area, it can be concluded that the occupied phosphorus in the surface layer is more than the deep layer. Finally, it can be concluded that by increasing the stability of various forms of phosphorus, their contribution to other forms of phosphorus increases, so that the concentration of apatite is much higher than phosphate-calcium phosphate. Results showed the amount of available phosphorus (Ca2-P) in the surface layer is more than the deep layer, which can be attributed to surface application of Phosphorus fertilizers. However, there are sections where phosphorus in the surface layer and the bottom is almost equal. Amount of this form of P is less than Al-P and Fe-P. It may be due to increase in Al and Fe contents in in calcareous soils.Conclusion High amounts of total P clarifies that by optimally managing the use of phosphorus fertilizers and soil conditions, the required P of the plant can be provided without additional use. From the results reported in this study, it appears that in the calcareous soils tested, the abundance of different forms of P was in order Ca10-P type≥ Al-P >Ca2-P type> Occluded P ≥ Fe-P > Ca8-P. furthermore, it observed that Fe-P, Al-P and Oc-P are important forms of P and on average constitute 30% of the sum of inorganic P forms. These findings demonstrate that the ability of NaOH to extract Al-P will be reduced with an increase in Al-P content and that NaOH is unable to remove Al-P completely. Therefore, it seems that more research is needed to find some light on whether NH4F can be omitted from the regular P fractionation schemes in the highly calcareous soils of Iran.
Research Paper
Ali Monsefi; Mojtaba Norouzi Masir; Yazdan Izadi
Abstract
Introduction: Despite the many benefits of tillage to crop establishment and production in the past, new herbicide and minimum-tillage management systems have drastically changed today's methods of crop production. Although tillage systems are used to increase soil porosity, they are a short-term solution ...
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Introduction: Despite the many benefits of tillage to crop establishment and production in the past, new herbicide and minimum-tillage management systems have drastically changed today's methods of crop production. Although tillage systems are used to increase soil porosity, they are a short-term solution that has negative consequences on surface soil structural stability, surface crop residue, and surface soil organic carbon, which are critical features that control water infiltration and subsequent water transmission and storage in soil. Physical and chemical properties of soil such as organic matter of soil is a key attribute of quality that affects water infiltration and soil aggregation. The use of conservation tillage along with the application of appropriate management methods such as conservation of residues, the use of proper rotation and weed control caused to stabilize the particles of soil, prevent the destruction of soil structure and increase soil organic matter. Therefore, changing the method of tillage systems from conventional to conservation, especially in crop rotation cycles, is inevitable. Our objectives were to summarize these findings and present additional information with particular emphasis on changes physical and chemical characteristics in different soil depths due to adoption of conservation tillage in corn-wheat crop rotation.Materials and Methods: The present study was performed to investigate tillage systems (4 levels including ZT-ZT: Zero Tillage-Zero Tillage; ZT-CT: : Zero tillage-Conventional Tillage; CT-CT: Conventional Tillage-Conventional Tillage and CT-ZT: Conventional Tillage-Zero Tillage) and 4 levels of weed management (including W1: Control; W2: Post-emergence Nicosulfuron herbicide + hand weeded in cultivation of corn and post-emergence Metribuzin herbicide + hand weeded in cultivation of wheat; W3: Pre-emergence Atrazine + post-emergence Nicosulfuron herbicides in cultivation of corn and post-emergence Clodinafop + post-emergence Bromoxynil+MCPA herbicides in cultivation of wheat; W4: Wheat residues as a mulch + post-emergence Nicosulfuron herbicide in cultivation of corn and corn residues as a mulch + Metribuzin herbicide) on some physical and chemical properties of soil depths (D1: 0 -15 and D2: 15-30 cm) in corn-wheat rotation during the 2021-22 croping year in the farms of Shavur Agricultural Service Center of Shush city was implemented as a split-factorial in the form of a randomized complete block design with three replications and 96 samples. Results and Discussion: The results showed that interaction of the studied treatments significant effects of the all studied traits except for soil pH. The minimum of soil bulk density was observed in conventional tillage-zero tillage × Wheat residues as a mulch + post-emergence Nicosulfuron herbicide in cultivation of corn and corn residues as a mulch + Metribuzin herbicide as weed management treatment × 0-10 cm soil depths treatment with an average of 1.390 g/cm3, also, the highest hydraulic conductivity of the soil was obtained in conventional tillage-conventional tillage × pre-emergence Atrazine + post-emergence Nicosulfuron herbicides in cultivation of corn and post-emergence Clodinafop + post-emergence Bromoxynil+MCPA herbicides in cultivation of wheat × 0-15 cm soil depths treatment (with an average of 0.994 cm/h). The highest amount of organic matter (with an average 0.771 percent) and phosphorus and potassium elements was achieved in zero tillage-zero tillage × wheat residues as a mulch + post-emergence Nicosulfuron herbicide in cultivation of corn and corn residues as a mulch + Metribuzin herbicide × 0-15 cm soil depths treatment (with averages of 13.96 and 234.7 mg/kg, respectively). Interaction effects results (tillage system × sampling depth) indicated that highest amount of total nitrogen was achieved in the zero tillage-zero tillage (ZT-ZT) on soil surface layer (0-15 cm sampling depth) with an average 122.0 kg / ha with an increase of 40.1% compared to the other treatment such as zero tillage-conventional tillage (ZT-CT), conventional tillage-conventional tillage (CT-CT) and conventional tillage-zero tillage (CT-ZT) and soil substrate (15-30 cm sampling depth, with an average of 0.87 kg/ha). In addition, the preservation of residues in the form of mulch and the use of post-emergence Nicosulfuron and Metribuzin herbicides led to maintaining the balance of soil pH in the corn-wheat rotation.Conclusion: Steady-state soil chemical and physical properties was greater under zero tillage than under conventional tillage as a result of soil structural improvements associated with surface residue accumulation and lack of soil disturbance. In addition, our data indicate that conservation tillage along with the application of crops residues in corn-wheat crop rotation is a viable management strategy to improve soil quality in the warm, semiarid region of Khuzestan Province. This strategy could lead to high production, minimal negative environmental impacts, and a socially acceptable farming system. Therefore, the use of previous crop residues in tillage systems will have a positive effect on improving the physical and chemical properties of the soil.
Research Paper
mona daghlavi; Mahmoud Ghasemi Nejad Raeini; Naim Loveimi; amin lotfi jalal-abadi
Abstract
Introduction Achieve more production, efforts should be made to increase yield per hectare. One of the things that play an important role in increasing crop production, disease control, chastity control, improving soil fertility and structure is the implementation of proper crop rotation. Crop rotation ...
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Introduction Achieve more production, efforts should be made to increase yield per hectare. One of the things that play an important role in increasing crop production, disease control, chastity control, improving soil fertility and structure is the implementation of proper crop rotation. Crop rotation increases the efficiency of production and yield through the continuity of soil vegetation, more efficient water use, preservation of soil nutrients, increase of soil organic matter and stability of soil grains, reduction of pests and diseases, and better control of weeds. Also, data collection in the conducted research is done in a traditional way, which is usually difficult, limited and very time-consuming due to the dispersion of farms and their size. Materials and Methods His study was conducted to investigate the effect of crop rotations on wheat yield using satellite images in three crop years 2017-2018, 2019-2028, 2019-2020 in the fields of Shavor region of Khuzestan province. In this research, all the evaluated images are related to the Sentinel-2 satellite and all these images were obtained from the US Geological Survey website. The satellite images were taken at the flowering stage of wheat, and images without clouds and fog were used on February 25, 2019 (for the year before rotation) and February 19, 2021 (for the year after rotation). Also, for pre-processing and processing and extracting information, SNAP software, Sen2Cor and ENVI plugin were used, respectively. The steps of this research were done in three steps. In the first stage, five plant spectral indices EVI, GNDVI, GARI, NDVI and RVI were evaluated to identify the best index to estimate wheat yield. The spectral index, which has a higher correlation with the yield of wheat, was chosen as the base index and was used to continue the research. In the second stage, three farms were randomly selected from each rotation to evaluate wheat yield after their application. In this section, variance analysis was performed in the form of a completely random design in three replications (one replication for each farm). The treatments include four alternations of wheat-wheat-wheat, wheat-canola-wheat, wheat-rice-wheat and wheat-clover-wheat. At this stage, the comparison of means was done by Duncan's multi-range test and in the MSTATC software environment. The third stage is the changes in wheat yield in each rotation in two times before and after applying that rotation. For this purpose, the changes of the base spectral index before and after the application of periodicity were set as criteria. Results The results of variance analysis of five spectral indices studied in this research showed that the coefficient of explanation of each of these indices with wheat yield at the time of flowering is NDVI with 76, RVI with 73, GARI with 71, EVI with 60 and GNDVI with 57 respectively. In this research, the NDVI spectral index has the highest correlation, R2 of 76%, and the minimum error, RMSE of 0.547 earned the results showed that the average and the dispersion coefficient of the NDVI spectral index of intervals have a significant difference at the probability level of 1%. So that in terms of the average, the lowest average of the NDVI spectral index is in wheat-rice-wheat rotation with a rate of 0.2650 and the highest average is in the wheat-clover-wheat rotation with a rate of 0.5603. According to the distribution coefficient, the minimum and maximum values belonged to the rotation of wheat-canola-wheat with the rate of 0.0505 and wheat-rice-wheat with the rate of 0.1970. The results of the corresponding comparison before and after the application of each rotation showed that not observing the rotation and wheat cultivation after two crop years led to a 10% decrease and the use of rice in the crop rotation led to a 50% decrease in the NDVI spectral index. Also, the use of rapeseed and clover in crop rotations has led to an increase of 2 and 30% in NDVI spectral index compared to before rotation. The results of the dispersion coefficient of the NDVI spectral index in the time before and after the application of rotation showed that in the continuous cultivation of wheat, the dispersion coefficient due to the decrease in yield uniformity in different parts of the field led to an increase of 27% and in the rotation of wheat-rice-wheat it led to an increase of 152 became a percentage However, the distribution coefficient of wheat-canola-wheat rotation and wheat-clover-wheat rotation resulted in a decrease of 57 and 32%, respectively, due to the increase in yield uniformity in different parts of the field.Conclusion Heat is one of the strategic products, and the evaluation of different rotations is of particular importance in increasing its yield. In this research, five plant spectral indices EVI, GNDVI, GARI, NDVI and RVI were investigated in order to identify the base index for wheat yield estimation. The results of the analysis of these indices showed that the NDVI spectral index with an explanation coefficient of 76% has the highest correlation with wheat yield. The comparison results of the NDVI spectral index correspondingly in each rotation in two states before and after the rotation showed that the continuous cultivation of wheat in an agricultural land after two crop years led to a 10% decrease in the NDVI spectral index and the use of rice in the wheat-rice rotation. - Wheat leads to a 50% decrease in the NDVI spectral index of wheat; But the use of canola and clover in the rotation of wheat-canola-wheat and wheat-clover-wheat led to an increase of 2% and 30% of NDVI spectral index, respectively. Also, the results of the comparison of the dispersion coefficient of the NDVI spectral index before and after the application of rotation showed that in the continuous cultivation of wheat, the dispersion coefficient increased by 27% due to the decrease in yield uniformity in different parts of the field, and in the wheat-rice-wheat rotation, the dispersion coefficient also as a result of the reduction of yield uniformity in different parts of the farm, it led to an increase of 152%.
