فهرست مطالب همت الله پیردشتی

This research was conducted in order to investigate competitive ability of four rice cultivars in competition with in interference with barnyard grass.A field experiment was conducted as a factorial arrangement based on RCBD with three replications in Babolsar. Factors included rice cultivar (Tarom Hashemi, Shiroudi, Deylamani and Hasani) and and barnyard grass density (0, 10, 20, 30, 40 and 50 plants m-2).The highest and lowest amount of barnyard grass biomass was observed in Tarem Hashemi at a density of 50 plants m-2 and Shiroudi at a density of 10 plants m-2 (301.3 and 68.3 g m-2, respectively). The highest and lowest biological and seed yield of rice were observed in Shiroudi at weed-free conditions and Hasni in interference with the density of 50 plants m-2, respectively. The amount of decrease in grain yield in the conditions of interference with the investigated densities of barnyard grass compared to weed-free condition are 2.6-30, 3.2-18.8, 2.8-31.5 and 5.6-30.8%. , it was in Tarem Hashemi, Shiroudi, Deylamani and Hasni cultivars, respectively.The rice yield data cultivars fitting in competition with barnyard grass densities indicated that Shiroudi cultivar had higher competitive ability than other cultivars. So this cultivar can be recommended for cultivation in paddy fields with a history of high sorghum weed infestation. The use of its higher competitive power against the weed of barnyard grass reduced the use of herbicides and minimized the harm caused by their use, and took a step towards achieving sustainable agriculture.

Experiments were conduccted to study the response of cress (Lepidium sativum) sensitive plant to allelochemical compounds to aqueous extract obtained from the different organs of important weeds such as Silybum marianum and Malva sylvestris. Experiment for each plant was performed as factorial based on the completely randomized design with three replications in 2023. The first factor was the different organs in three levels, namely root, stem, and leaf of weeds, and the different concentrations of the extracts obtained from each of the organs were at 5 levels (0 (control), 25, 50, 75 and 100%) as the second factor. To extract the samples, after collecting and drying them, first 5 g of the plant powder of each organ (weight) was extracted separately with 100 ml of distilled water as solvent (volume). Then different concentrations were prepared from the extract obtained from the stock (base solution). The results showed that the percentage and rate of germination, length of radicle and, plumule, length of seedling, ratio of radicle to plumule, seed length vigor index, dry weight of radicle and, plumule, seedling dry weight and seed weight vigor index of cress were influenced by aqueous extract of the Silybum marianum organs, different concentrations and interaction effect of them. Among the different organs, the aqoues extracts of leaf had the highest inhibitory effect on germination characteristics of cress. So that the difference in the effect of different concentrations of organs was dependent on their concentration threshold. As the findings showed that the effect of aqueous

This study was performed to evaluate the effect of Rahnella aquatilis and Burkholderia cepacia bacteria on yield, yield components, and uptake of potassium and zinc elements in rice (Oryza sativa L.).

The experiment was conducted as a split-plot in a randomized complete block design with three replications in 2022. Treatments included two levels of chemical fertilizer (100 and 75% of chemical fertilizer consumption based on the soil test results as optimal and reduced fertilizer levels, respectively) and four inoculation treatments (separate inoculation of R. aquatilis, B. cepacia, a co-inoculation (R.aquatilis+B.cepacia) and control (non-inoculation)).

The results indicated that there was no significant difference between the optimal and reduced fertilizer levels in all the studied traits. The separate inoculation of R. aquatilis, B.cepacia and their co-inoculation increased the panicle length (from 5.88 to 11.3%), the number of total tillers in hill-1 (from 19.4 to 29.1%), the total number of grains in panicle-1 (from 22.8 to 46.5%), paddy yield (from 22.8 to 44.3%), biological yield (from 20.3 to 33.6%), 1000-seed weight (from 2.4 to 8.8%), potassium uptake in grain (from 6.0 to 41.4%) and in above-ground biomass (from 38.4 to 65.4%), zinc uptake in grain (from 6.29 to 40.9%) and in above-ground biomass (29.4 to 54.6%) as compared with the control (non-inoculation).

The application of plant growth-promoting rhizobacteria in combination (as the best inoculation treatment) reduced chemical fertilizers consumption without a significant reduction in the paddy yield, indicating the importance of these rhizobacteria for achieving sustainable agriculture goals.

Salinity stress is one of the most important limitations of rice cultivation worldwide. On the other hand, the use of physical and chemical mutagens can be very important not only to the development and combination of new genes or alleles with agricultural importance but also to introduce genotypes more adaptable and stable to adverse weather and soil conditions. For this reason, with the development and progress of rice varieties that are tolerant and adapted to salinity, it is possible to increase the sustainable production of this stable food. Therefore, the present study was conducted with the aim of investigating the response of the tenth generation (M10) of rice mutants to salinity stress in the reproductive stage using agronomic and biochemical characteristics.

In this research, 13 mutant lines of Seng-e-Tarem, Hashemi and Khazar cultivars using gamma ray irradiation from Cobalt 60 which have been previously identified as tolerant lines in molecular studies were used along with the tolerant cultivars of Nonabukra and Deylamani and sensitive cultivars of IR29 and Sepidrood. The genotypes were exposed to three levels of salinity (0, 4 and 8 dS/m) from the source of sodium chloride. A factorial experiment based a randomized complete block design (RCBD) and a factorial split based a RCBD with three replicates were used to evaluate agronomic traits along with yield and biochemical traits, respectively. The measured parameters were tillers number (TN), the number of filled (NFG) and unfilled grains (NUG), 1000 grains weight (TGW), plant height (PH), Days to 50% of flowering (DTF) and the paddy yield (PY), and for the biochemical traits, the activity of catalase (CAT) and superoxide dismutase (SOD), protein (PN), proline (PR) and malondialdehyde (MDA) contents and electrolyte leakage (EL) percentage.

The results of the variance analysis showed that the effect of salinity and genotype and their interactions were significant for all the measured traits. A wide range of genetic diversity was observed among the genotypes for the agronomic and biochemical traits. Among the traits, PY was identified as the best and the most indicative trait to classify the tolerant genotype under salt stress conditions. Among the investigated mutants at different levels of salinity, the highest PY was recorded in MP6, MP10 and Deylamani genotypes, respectively. PY value in MP10 mutant at the salinity level of 8 dS/m was closed to Deylamani variety (tolerant check). With the increase of salinity from zero to 8 dS/m, the measured traits adversely affected. The cluster analysis diagram of studied genotypes based on agronomic traits and PY at a salinity level of 4 dS/m classified the genotypes into three separate groups. The genotypes MP2, MP3, MP4, MP9, and MP10 were grouped in the second group, in which Deylamani cultivar was also present as a tolerant check. The cluster analysis diagram of agronomic traits and PY at the salinity stress level of 8 dS/m divided the genotypes into four different groups. In the third group, two genotypes of MP9 and MP10 were included with Tarem Deylamani variety (tolerant check). The correlation coefficient between agronomic traits in 8 dS/m of salt conditions showed that PY had a positive and significant correlation with PH (r=0.51), the NFG (r=0.88) and TGW (r=0.63). Also, there is a negative correlation between DTF with PH (r=-0.70) and NFG (r=-0.62) and a positive and significant correlation with TN (r=0.60). Biplot analysis divided the studied lines into four groups based on agronomic traits at a salinity level of 4 dS/m. The first group includes six mutant lines as very sensitive group, the second group includes two mutant lines as sensitive group, the third group with three genotypes including lines MP9, MP10 and Tarem Deylamani variety (tolerant check) as tolerant group and the fourth group with six genotypes included lines MP11, MP12, MP13 and Nonabukra variety (international tolerant check) as well as Sepidrood and IR29 varieties as high salt tolerant group. Also, biplot analysis based on agronomic traits at a salinity level of 8 dS/m divided the studied lines into four groups. The first group consisted three mutant lines as very sensitive group, the second group included six lines as sensitive group, the third group involved five genotypes including MP11 and MP13 lines and Nonabukra varieties (tolerant check), Sepidrood and IR29 as the tolerant group and the fourth group with three genotypes included MP9 and MP10 lines and Tarem Deylamani variety (native tolerant check) as high salt tolerant group. For biochemical traits at 8 dS/m of salt stress, the highest amount of SOD was recorded in Deylamani cultivar (tolerant check), PN for MP2 mutant, PR for MP3 mutant, and the lowest amount of EL and MDA was recorded for MP2 and MP10 mutants, respectively.

In general, PY of MP10 mutant line in salt stress conditions was closed to Deylamani as a native salt tolerant cultivar, therefore could be introduced as a superior line for further research in saline conditions.

Energy is a limiting factor for agricultural sustainability due to costs and supply security. Agriculture section as one of the world's major food suppliers, has faced challenges in recent times due to increased energy consumption trends. This rise in energy consumption has led to increased production costs, negative impacts on food security, and environmental concerns. Therefore, achieving a balance between energy demand and supply in agricultural systems and assessing their economic performance is essential. With the recognition that soybean [Glycine max (L.) Merril] plays a crucial role in ensuring food security; a study was conducted in 2019 to analyze the energy flow and economic costs of soybean production at the provincial level in Mazandaran, Iran.

To assess the economic efficiency and energy consumption pattern in soybean farms, data were collected through direct interviews with 301 soybean farmers. The inputs used for estimating energy efficiency per hectare of soybean cultivation included fossil fuels, machinery, human labor, seeds, irrigation water, electricity, fertilizers, and chemical pesticides. The produced soybean grain was also considered as an output energy source. Life Cycle Cost (LCC) methodology was employed to evaluate the economic efficiency of soybean production; for this purpose, the farm gate was defined as the system boundary, and one hectare of soybean farm was taken as the base unit for all analyses. The social costs of emissions, in addition to the fixed and variable production costs that are addressed in most studies, were evaluated and analyzed. In the current study, the social costs of pollutant emissions in soybean production agroecosystems were considered from two aspects: (1) emissions on the farm and (2) pollutants generated from electricity generation. These costs were estimated using the standard coefficients established in previous researches.

Based on the results, diesel fuel, nitrogen chemical fertilizers, and consumed seeds had the highest shares of total input energy in soybean production with 47.90%, 19.61%, and 13.53% respectively. The average energy productivity for soybean production in Mazandaran province was calculated to be 0.16 kg MJ-1. From this point of view, Galugah county was the best with 0.25 kg MJ-1, while Amol was the worst with 0.11 kg MJ-1 compared to other scrutinized counties. In terms of the type of consumed energy, the results indicated that the current soybean production in Mazandaran province is not sustainable due to heavy reliance on non-renewable energy resources such as diesel fuel and nitrogen chemical fertilizers. The LCC of soybean production in Mazandaran province, including variable, fixed, and social costs resulting from emissions, was estimated to be an average of $327.90 per hectare. Among these costs, variable costs accounted for the highest share in soybean production in the region with $299.52 per hectare (approximately 91%).The average wage paid to owners of agricultural machinery and equipment was $141.85 per hectare (equivalent to 47.36%), and the average wage for human labor was $85.77 per hectare (equivalent to 28.64%). These two factors were the first and second most significant contributors to production costs for the soybean crop, respectively. Together, they accounted for approximately 69% of the total production cost (LCC). Carbon dioxide emissions, accounting for 41.16% (mainly due to diesel fuel combustion and urea fertilizer consumption on the farm), constituted a significant portion of the social cost resulting from emissions (at $7.38 per ton).

In general, the results of the survey of 301 farms indicated that soybean production in Mazandaran province, with an average energy efficiency of 2.43, is economically justifiable in terms of energy balance and constitutes a profitable agricultural product in the region, with a profit-to-cost ratio of 1.86.

Since, salinity stress threatens food security and sustainable agriculture production, the response of plants to salinity stress has always been one of the most important subjects of physiological and biochemical studies. In order to evaluate the mutant lines in terms of agronomic, physiological and enzymatic traits under salt stress, a factorial experiment was carried out based of a randomized complete block design in three replications using paddy soil and adjusting its salinity in pots. The treatments included four mutant lines (MLST1, MLTH1, MLTH2 and MLTH3) along with two tolerant controls (Deilamani and Nonabukra) and two sensitive controls (IR29 and Sepidrood) at three salinity levels (zero, 4 and 8 dS/m). Results indicated that the highest amount of proline was obtained at a salinity level of 4 dS/m in the MLTH2 mutant, which showed an increase of more than 1.3 times compared to the conditions of no salinity stress. Obtained. The highest and lowest amounts of malondialdehyde (MDA) were respectively at the salinity level of 4 dS/m and no salinity stress related to the MLTH3 genotype. According to the results, the highest level of superoxide dismutase (SOD) enzyme activity was related to the MLTH2 mutant at 4 dS/m salinity and the lowest was related to the MLST1 mutant at 8 dS/m salinity. In the absence of salinity stress, the highest paddy yield was recorded in the salt sensitive cultivar of Sepidroud. By comparison, after applying salinity stress, the lowest yield reduction was obtained in the MLTH2 mutant. In general, based on the biochemical and yield evaluation, the MLTH2 genotype was identified as the best salt tolerant line, which will be to recommend for further research

Obtaining a high dry matter yield is one of the most important goals of plant physiologists. In this regard, it is necessary to know the effective traits in the production of plant dry matter. Salinity stress is also one of the most important non-biological stresses that limits plant growth and affects the morphological, physiological and biochemical properties of plants. Therefore, in order to understand the relationship between dry matter yield and antioxidant properties, photosynthetic and non-photosynthetic pigments of mint under salinity stress, an experiment was conducted as a factorial split-plot (18 mint ecotypes, including longifolia, pulegium, spicata, rotundifolia, mozafariani and piperita, salinity stress at control, 2.5, 5 and 7.5 dS/m levels and harvest stage at   2 stages), based on a randomized complete block design with four replications. The results showed that salinity stress affected the correlation between dry matter and other studied traits. Also, path analysis at different levels of salinity stress showed that total chlorophyll traits had a very high direct effect on dry matter yield. On the other hand, at a 7.5 dS/m salinity level, the dry matter yield of the plant depended on a greater number of traits compared to lower-salinity stress levels. Also, the correlation between traits in the first and second harvest stages was different. The anthocyanin pigment trait had a positive and significant correlation with dry matter yield at 7.5 dS/m. The indirect role of carotenoid pigment was also evident in severe stress. Based on path analysis, all the studied traits, including non-enzymatic antioxidants and anthocyanin and carotenoid pigments, were strongly dependent on the total chlorophyll trait to affect the dry matter yield.

An intelligent growth chamber was designed in 2021 to model and optimize rice seedlings' growth. According to this, an experiment was implemented at Sari University of Agricultural Sciences and Natural Resources, Iran, in March, April, and May 2021. The model inputs included radiation, temperature, carbon dioxide, and soil acidity. These growth factors were studied at ambient and incremental levels. The model outputs were seedlings' height, root length, chlorophyll content, CGR, RGR, the leaves number, and the shoot's dry weight. Rice seedlings' growth was modeled using LSTM neural networks and optimized by the Bayesian method. It concluded that the best parameter setting was at epoch=100, learning rate=0.001, and iteration number=500. The best performance during training was obtained when the validation RMSE=0.2884.

Seed germination and emergence are the most sensitive stages of growth and development of rice plants. In this regard, the use of growth-promoting fungi in the form of seed biological pretreatment (bio-priming) for germination and optimal growth of seedlings can be feasible. Therefore, this study aimed to investigate the effect of isolated root symbiotic fungi on the improvement of germination and growth components of two traditional and bred rice (Oryza sativa L.) cultivars.

This experiment was done as a factorial-based completely randomized design with three replicates at Sari Agricultural Sciences and Natural Resources University in the summer of 2021. Experimental treatments included 22 isolates of root symbiotic fungi (isolated and identified from previous experiments) and control (without inoculation) and two native (Hashemi) and bred (Roshan) rice cultivars. After the end of the germination period, the number of normal seedlings was counted and five normal seedlings were randomly selected to measure the length of the root, stem, and seedling as well as the fresh and dry weight of the root, stem, and seedling.

Based on the results of cluster analysis the fungi were divided into four and three groups in Roshan and Hashemi cultivars, respectively. In both cultivars, group I was selected as the best group. In this group, the highest positive effect on vegetative traits varied from 5 to 59% compared to the control in fungal treatments was related to Bjerkandera adusta (ST1), Trichoderma atroviride (SF1), Monosporascus cannonballus (B3) and Trichoderma atroviride (SN1) in Roshan cultivar and Bjerkand adusta (ST1) in Hashemi cultivar. The best fungal treatments in germination traits of Roshan and Hashemi cultivars were Chaetomium globosum (SE2) and Bjerkandera adusta (ST1), respectively.

Overall, the results indicated the positive effect of most symbiotic fungi on the growth and germination characteristics of rice in both Roshan and Hashemi cultivars. These results show that symbiotic fungi use different mechanisms to increase growth and improve germination indicators in plants.

Highlights:

1- Growth-promoting fungi in the form of seed biological pretreatment were used (bio-priming) for optimal growth and germination and of rice seedlings.
2- The effect of native fungi isolated was investigated for the first time in two native (Hashemi) and bred (Roshan) rice cultivars.

Most research on intercropping cultivation in the past has focused on seed yield and yield components, and less attention has been paid to below-ground interaction processes. However, the connection of plants in the below-ground sector is a vital issue in identifying the mechanism of competition and productivity in intercropping cultivation. Meanwhile, the selection of a legume plant due to the biological nitrogen fixation (BNF) increases the productivity in intercropping cultivation. However, the BNF by the legume component can be affected by the component crop in intercropping cultivation. Therefore, creating the optimum conditions for the BNF in planting ratios plays an essential role in the dynamics of inter-species interaction. Therefore, this study aimed to evaluate the interactions of the below-ground sector and the percentage of nitrogen derived from the atmosphere in different ratios of intercropping cultivation.

A field experiment was conducted for two years (2018-19) at the research farm of Sari agricultural science and natural resources university, Iran (33º, 36ʹ N, 53º, 03ʹ E with 43 m altitude). The experimental design was a randomized complete block with four replications. The experimental treatment was 75% soybean + 25% niger, 50% soybean + 50% niger, 25% Soybean+75% niger based on the replacement method and monoculture. For example, a 25:75 combination consisted of three rows of planting a soybean and one row of niger and vice versa in the 75:25 combinations. The 50:50 also included planting two rows of each of the studied plants. This study investigated the percentage of nitrogen derived from the atmosphere, nitrogen yield, total enzymatic activity of the soil, and root activity in different planting ratios.

The percentage of nitrogen derived from the atmosphere (Ndfa) in all different planting ratios was higher than a single soybean crop. This trend continued until it reached 90 days after planting. At 75 and 90 days after planting, the highest Ndfa has related to 50:50 and 75:25 planting ratios in both cultivation years. Also, the yield of Ndfa was higher than expected in planting ratios, and its value increased further as it approached the final stages of growth. In addition to the above, the total microbial activity of soil in different ratios of intercropping cultivation was higher than the monoculture of the studied plants. Its amount in 50:50 planting ratio was 16.38 and 31.69% higher than monoculture soybean (0: 100) and niger (0: 100) at 60 days after planting, respectively. The most increased total microbial activity of the ground in niger and soybean plants in the middle and late stages of growth was observed at a depth of 0-20 and 10-30 cm, respectively. Also, niger plant in different ratios of intercropping cultivation, while increasing root activity, have a higher number of secondary compounds in root extract. In general, the increase in root activity in the late stages of growth was accompanied by a decrease in the number of rows of niger plants, especially in the planting ratio of 75:25. Also, the total phenol and flavonoids in the niger root extract increased to 105 days after planting and then decreased. Thus, in general, different ratios of intercropping cultivation were more successful in producing secondary compounds than the monoculture of niger.

Increasing the significance of nitrogen derived from the atmosphere and the other activity of niger root as a complementary plant in intercropping cultivation ratios can play an essential role in the dynamics of underground sector interactions intercropping cultivation patterns. In addition to the above results and based on the total microbial activity of the soil, the complementary structure of niger and soybean root in intercropping cultivation can affect the ability of interspecific competition in intercropping cultivation by distinguishing ecological niche even in a short period.

 Drought is one of the most important environmental stressors that adversely affects agricultural products, especially in arid and semi-arid regions. Using Trichoderma fungus along with biopolymers such as chitosan is one of the ways to reduce drought stress. Trichoderma fungus as plant growth-promoting fungus is the most common fungal and soil-modifying species that are able to directly with plant roots in the rhizosphere and improve growth as well as biological control of living stresses such as pathogenic fungi and non-living stresses such as drought, salinity and heavy metals. On the other hand, one of the effective ways to protect the plant in conditions of low irrigation is the use of anti-transpirants, including the biostimulant of chitosan, which markedly limits transpiration from the plant surface. The anti-transipirants action of chitosan can be attributed to the involvement of chitosan in the abscisic acid pathways, which closes the stomata and thus reduces transpiration. Chitosan is readily soluble in water and organic acids. Therefore, it can be used in various methods such as mixing with soil, foliar spraying and impregnation with seeds in agriculture.

 This research was conducted in a split factorial arrangement based on randomized complete block design. The main plot factor was irrigation interval in three levels (two days as normal irrigation and three and four days as deficit irrigation conditions) and sub-plots were inoculated with T. longibrachiatum at two levels (inoculation and uninoculated control) and chitosan at three levels (0, 0.2 and 0.4 g/L). Each experimental plot consisted of three planting lines two and a half meters long and one meter wide .T. longibrachiatum was obtained from Tabarestan Agricultural Genetics and Biotechnology Research Institute. The first irrigation was done simultaneously with planting basil. Up to one month after sowing the seeds (six to eight leaf stage of plants), the plots were irrigated evenly with tubes and from this stage onwards, irrigation treatments were applied. Pesticides and herbicides were not used during the experiment and weed control was done manually. Chitosan was prepared from Sarina Teb store and prepared in three levels of zero, 0.2 and 0.4 g/l and sprayed in three stages: vegetative, before flowering and 50% flowering.

 The results showed that with increasing the irrigation period from two to four days, the morphological traits of basil, such as root length and stem length, leaf dry weight, root, stem and dry matter yield decreased. Also, physiological traits of basil such as carotenoids and chlorophyll meter increased while chlorophyll a, b and total chlorophyll decreased. Application of 0.2 g/L of chitosan inoculated plants increased chlorophyll b content by 68%. The highest percentage and yield of essential oil in both normal and irrigation deficit conditions were obtained when plants inoculated with Trichoderma and foliary sprayed by chitosan. The highest percentage and yield of essential oil were observed with an average of 0.88 and 42.87% in normal irrigation conditions, application of Trichoderma and zero level of chitosan, respectively. According to the results, increasing the irrigation cycle along with chitosan application and fungal inoculation increased the percentage and yield of essential oil. However, by increasing the irrigation cycle, chitosan alone decreased the percentage and yield of essential oil and only in the three-day irrigation cycle, it increased the percentage of essential oil compared to the control.

 Overall, the findings showed the positive effect of concomitant use of Trichoderma fungus and chitosan on improving the growth of sweet basil and increasing drought resistance.

Rice (Oryza sativa L.) is one of the most important food resources of more than half of the world's population. Rice, as the second most strategic crop, is the most important cereal after wheat. Excessive use of renewable and non-renewable resources in the agricultural sector, chemical control of rice diseases, and irreparable environmental damage of these systems potentially have a variety of environmental impacts on agricultural systems, such effects can be assessed by the life cycle assessment (LCA) approach. The purpose of the present research is to assess of knowing and comparing the trend of environmental pressure of the second and ratoon cropping systems of rice production in the paddy fields.

This research was conducted in 2020 in the paddy fields of Amol city with the focus on recognizing and comparing the trend of environmental pressure in rice production in the second and ratoon cropping systems. Accordingly, all data related to the second and ratoon rice cropping systems in different stages of rice production, from planting to harvesting phases, was collected in Amol region. In this study, to classify and quantify the environmental effects of rice production in two cropping systems using the LCA method are addressed. Furthermore, the environmental impacts of these systems such as global warming potential, eutrophication, and acidification of water and soil were also calculated. In this study, the functional unit of rice production systems were considered equivalent to one ton of paddy. Therefore, in order to evaluate the emission of greenhouse gases and energy in paddy fields, the required information was collected and interviewed by paddy farmers.

The findings of this study indicated that the highest global warming potential of rice was related to the rice second cropping system about 1896.92 kg carbon dioxide per ton of produced rice. Evaluation of the LCA in rice production process showed that in the group of environmental impact of global warming, about 1673.99 kg equivalent of carbon dioxide to the atmosphere has been released per ton of rice in ratoon cropping system. Direct emissions from on-farm activities in all two studied systems have played a major role in increasing global warming. The source of these pollutants is the combustion of diesel used in agricultural implements and machinery, accompanied by the emission of nitrogen dioxide, nitrogen oxides and other nitrogenous compounds resulting from the use of nitrogen fertilizers. Also, rice second cropping systems had a greater impact on the three categories of human health damage, ecosystem quality, and climate change than ratoon cropping systems. Moreover, the values of damages on the quality of the ecosystem in these systems were about 10089.08 and 7146.58 PDF*m2 * yr in the second and ratoon cropping systems, respectively. In addition, both rice production systems have shown the greatest impact on ecosystem quality and then on human health. Direct emissions from on-farm activities in the two studied systems have played a major role in increasing global warming. The source of these pollutants is the combustion of diesel used in agricultural implements and machinery, as well as the emission of nitrogen dioxide, nitrogen oxides and other nitrogenous compounds resulting from the use of nitrogen fertilizer.

The results revealed that the rice second cropping system had the higher amount of total emissions than the ratoon cropping system, therefore, rice ratoon production system is more environmentally friendly than the rice second cropping systems.
Acknowledgements
This research was funded by the Sari Agricultural Sciences and the Natural Resources University (SANRU) under contract No. d-110-99-16690. We would also like to thank the esteemed rice farmers in Amol region, Mazandaran province, Iran for their cooperation.

Intercropping cultivation is an excellent method to increase agricultural productivity per unit area based on environmental mechanisms. In this planting system, it is necessary to select crops with different capabilities in uptake resources and establish a complementary relationship. However, legumes in intercropping cultivation can be used an alternative and sustainable way to increase efficiency. Besides, it is necessary to study the interactions in the above and belowground parts to achieve the mentioned goals. Therefore, this study aimed to investigate inter-specific interactions in millet and soybean intercropping cultures.

A field experiment was conducted for two years (2018-19) at the research farm of Sari agricultural science and natural resources university, Iran (33º, 36ʹ N, 53º, 03ʹ E with 43 m altitude). The experimental design was a randomized complete block with four replications. The experimental treatment was 75% Soybean + 25% Niger, 50% Soybean + 50% Niger, 25% Soybean+75%Niger based on the replacement method and monoculture. This study investigated the agronomic traits, LAI, TDW, nitrogen derived from the atmosphere, and total microbial activity in the soil in different planting ratios.

The results showed that soybean monoculture had the highest plant height during different stages of growth. Furthermore, with the increase in the share of planting soybean in intercropping cultivation, the shoot height of the millet also increased. Also, unlike the millet, the soybean succeeded in producing more leaf area indexes among different mixed cultivation ratios than monoculture. The leaf area index of millet showed a significant decrease as the proportion of soybean plantings increased. However, despite this decrease, the total dry matter of soybean exhibited a higher percentage increase at various growth stages compared to the decrease in millet yield. As a result, after 60 days of planting, the intercropping cultivation of millet and soybean demonstrated positive complementarity in terms of competition impact. Additionally, the intercropping cultivation showed a higher percentage of nitrogen derived from the atmosphere compared to soybean monoculture. During the study period, the planting ratio of 75% millet and 25% soybean exhibited the highest increase in nitrogen fixation (Ndfa), with average values of 93.84% and 83.85% at 90 days after planting, respectively. Increasing the number of millet sowing rows in the intercropping patterns played a crucial role in intensifying competition with soybeans during the early growth stages and had an impact on the biological activity of soybeans. Moreover, the microbial activity in the soil (at a depth of 0-30 cm) was higher in the different intercropping ratios compared to monocultures of soybean and millet. In addition, soybean and millet monoculture had the highest and lowest grain yields. Among the different intercropping ratios, the 75:25 in 1398 with an average of 4639.77 kg. ha-1 had the highest grain yield. Besides, the planting ratio of 25:75 and 50:50, with an average of 1.23 and 1.02, respectively, had an LER higher than one. With increasing the share of soybean planting in intercropping, the competitiveness of the plant increases, and the competition ratio of millet was higher than the unit only in the planting ratio of 25:75 (millet-soybean). Therefore, the competitiveness of millet in mixed cultivation is significantly reduced by reducing the share of planting row. Finally, increasing productivity in the 25:75 combinations reduced soybean's competitive dominance, increasing millet grain yield in comparison to expected values and improving total microbial activity.

Due to limited growth period, millet had competition played an essential role in increasing total microbial activity and the percentage of nitrogen derived from the atmosphere at a 25:75 planting ratio before the initial reproductive growth. In addition, 25:75 and 50:50 planting ratios reduce soybean's competitive dominance, resulting in enhanced productivity. Finally, the selection of complementary plants based on physiological, morphological characteristics, and competitiveness in intercropping cultivation can be effective in the above and belowground interactions.

Today, increasing sustainability in agriculture is essential to meet future food needs. In this regard, the intercropping culture has been considered as viable and environmentally friendly approach to sustainable agriculture. Further, investigation of complementary species relationships in annual cropping systems could be addressed to achieve sustainability and development. In order to fully understand the inter-specific interactions between crops, it is crucial to know how to react to neighboring species. The selection of species with the different spatial structures in the intercropping culture pattern can be helpful in this regard. The differences of crop’ canopy in intercropping cultivation increase the efficiency of using water, light, and nutrients as well as facilitating inter-species competition. Therefore, this study investigated the competition between soybean and Niger seed on yield and yield components, radiation efficiency, and yield advantage in the intercropping cultivation system.

A field experiment was conducted in two years (2018-19) at the Research Farm of Sari Agricultural Science and Natural Resources University, Iran (33º, 36ʹ N, 53º, 03ʹ E with 43 m altitude). The experiment was done based on a randomized complete block with four replications. The experimental treatment was 75% soybean + 25% Niger, 50% soybean + 50% Niger, 25% soybean+75% Niger based on the replacement method and soybean monoculture (100:0) and Niger monoculture (0:100). For example, a 25:75 combination included around three rows consisting of sowing a soybean and one row of Niger, along with vice versa in the 75:25 combinations. The 50:50 combinations also included planting two rows of each studied crops. The seed was sown directly on the 5th of May with a density of 28 plants per square meter. This study was investigated agronomic traits, radiation use efficiency, and the impact of competition on intercropping using Hill and Shimumoto models.

Based on the achieved results, different planting ratios significantly affected plant height, dry weight, radiation use efficiency, yield, and yield components of both crops. The highest shoot heights of soybean and Niger with an average of 76.3 and 189.7 cm were related to planting ratio of 75:25, respectively. Also, the number of pods per plant of soybean and the number of capitule per plant of Niger in intercropping cultivation increased compared to monoculture. The reduction in the share of soybean and Niger sowing rows in different intercropping ratios increased the crop yield components. Also, the shoot’ dry weight of both crops increased in different planting ratios compared to the expected values. The highest percentage of dry shoot weight in soybean and Niger was related to 25:75 and 75:25 planting ratios, respectively. Besides, during different stages of growth, the radiation use efficiency of Niger in planting ratio was 50:50 and 25:75 higher than soybean. Also, the amount of radiation use efficiency in intercropping cultivation was more elevated than in monoculture. Due to the growing trend in its amount compared to the expected values, the effect of competition on radiation use efficiency during different growth stages was the type of mutual co-operation. According to the results, soybean (100:0) and Niger monoculture (0:100) had the highest and lowest grain yield with an average of 4965.7 and 462.4 kg. ha-1, respectively. Among the different intercropping, the combination 75:25 with an average of 4173.73 kg. ha-1 had the highest grain yield. Finally, the average land equivalent ratio in all different intercropping ratios was more than one, and the planting ratio of 50:50 had the highest average yield (LER = 1.28).

Increasing resource utilization efficiency and establishing a mutual co-operation relationship is essential in improving the usefulness of Soybean and Niger intercropping cultivation compared to monoculture. Furthermore, the selection of Niger in intercropping systems can be beneficial due to their morphological features and facilitation of competition.

To evaluate the competition of millet (Panicum miliaceum L.) and soybean (Glycine max (L) Merrill) in the intercropping system, a field experiment in two years (2018-19) was conducted in a randomized complete block design with four replications at the Sari Agricultural Science and Natural Resources university. The planting ratios were 0:100, 25:75, 50:50, 75:25, and 100:0 (Soybean: Millet, respectively). The results showed that the radiation use efficiency (RUE) was higher in different intercropping ratios than the millet monoculture (0:100). In different intercropping ratios, the RUE of millet decreased significantly with increasing the share of soybean. So that in the 105 days after planting, the RUE of millet in 75:25 was 47.74 and 29.41 percent less than the expected values in studied years, respectively. Also, the planting ratio of 25:75 in the 90 days after planting had the highest chlorophyll a/b ratio in soybean and millet. The 25:75 had the most elevated land equivalent ratio index (1.23), and the millet actual yield loss (AYL) was only positive (2.01) in the 25:75. Therefore, increasing the RUE in intercropping culture and improving millet grain yield as the dominant species played an important role in increasing productivity in the planting ratio of 25:75.

This study aimed to investigate the possibility of heavy metals contamination in the soil next to MDF factory located in Sari, Mazandaran province, Iran and their effects on soybean yield.

Accordingly, in an area of 3600 square meters 32 soil samples from 16 points (0-15 and 15-30 cm) and 48 plant samples were collected. After transferring the samples to the laboratory, absorption of heavy metals in the soil was measured. Also, the correlation between the yield and yield components with heavy metals were determined.

Distribution map of heavy metals and stepwise regression results showed that the cadmium significantly affected the number of unfilled pods per plant. When Cd increased, the number of unfilled pod increased as the rate of 0.5 per unit. In addition, a significant interaction existed between cadmium and iron for the 1000 grain weight. Accordingly, the maximum 1000 grain weight (131 g) was observed at the areas with the lowest concentration of cadmium and iron. Also, overlapping of distribution map of Zn and the number of unfilled grain per plant indicated that this parameter mainly controlled by Zn. Hence, the number of unfilled grain per plant increased as the rate of 0.53 per unit of Zn in the soil.

In conclusion, determining distribution map of heavy elements and overlapping with the yield and yield components not only help to identify contaminated areas and effective factors on spread of heavy metals into the soils but also help to evaluate their consequence effects on plant performance.

Nitrogen (N), an essential nutrient for growth and development of plants, is added to agricultural fields to boost crop yields, however, its applications limited in the aquatic ecosystems due to leaching. Accordingly, accelerated surface water eutrophication, and public health issues due to consumption of contaminated groundwater have been linked to enrichment of excess use of N that can be lost to the environment through leaching to the groundwater. These losses can be reduced by adoption of appropriate methods or best management practices, that increase the accessibility of N for plant use, enhance plants’ N uptake ability, and match nutrient applications with agronomic needs. Thus, improving N use efficiency through a combination of agronomic and soil management methods is critical for crop profitability and environmental management.One way to improve the efficiency of nitrogen fertilizer application and reduce its losses is the simultaneous use of organic and biological fertilizers along with chemical fertilizers. There are several ways to increase soil organic matter, but the most of these materials are not resistant to microbial decomposition and decompose quickly and lost from the soil. Biochar is one of the types of organic fertilizers, which is resistant to microbial decomposition.Biochar can affect chemical and biological N reactions in the soils. Biochar increase nitrogen use efficiency (NUE), influence nitrification rates and adsorption of ammonia, and improve NH+ accumulation by enhancing cation exchange capacity in soils.Nitration ofgroundwater due to improper use of chemical fertilizers and high leaching of nitrogen fertilizers and also low efficiency of nitrogen application in flood irrigation of rice, indicates the need for alternate management methods in rice cultivation, including changing irrigation methods and fertilizers types. The use of biochar fertilizer along with nitrogen-fixing bacteria in rice irrigation rotation can be a good solution to reduce the mentioned problems.

Materials and Methods :

This research was conducted at the research fields of the Sari Agricultural Sciences and Natural Resources University (SANRU) in 2017. The experimental site is located at 36º 39ʹ42ʺ N latitude and 53º03´54ʺ E longitude with -11 m above sea level. Soil samples were taken from depths of 0-30 cm before land preparation. The experiment was done in split split plot arrangement based a complete randomized blocks design with three replications. Two irrigation regimes (flooding and irrigation regimes) was the main plot. Nine fertilizers levels (100% of recommended nitrogen or N100, N100+ 10 ton biochar or biochar 10, N100+ biochar 20, N75, N75+ biochar 10, N100+ biochar 20, N50, N50+ biochar 10 and N100+ biochar 20) and seedling inoculation with Azospirillum lipoferum (without inoculation was also included as control) were sub and sub sub plots, respectively.

Results showed that biochar and nitrogen fertilizers, irrigation methods and also seedling inoculation with bacteria had significant effects on NUE, the amount of nitrogen and protein in the rice grains. Mean comparison of combination effects showed that consumption of 20 tons of biochar along with N50 or N75 had the greatest effect on NUE and the amount of nitrogen and protein in the grain, and the lowest amount of these traits was recorded in plots with N100 and no application of biochar. On the other hand, the highest level of nitrogen efficiency indices was obtained when 20 tons of biochar applied with N50 or N75 while the lowest amount of nitrogen use efficiency indices was obtained by using N100 and no biochar consumption.

 It seems that biochar improves nitrogen uptake by the rice plant by maintaining nitrogen in the soil and consequently increases the concentration of nitrogen in the grains and rice plants organs. There was no similar trend for effect of biochar on nitrogen uptake when fertilizer application rates increased.

Due to the negative effects of agricultural production activities on the environment, especially water and soil pollution, one of the most important decisions in the agricultural sector is the optimal allocation of resources. This decision should be in such a way that while maximizing the profit of farmers, it will result in less environmental effects. This action is often done by determining the optimal cropping pattern (CP). In this research, by quantifying the economic, social and environmental effects, a compatible CP with agricultural resources was presented by using a multi-objective planning model.

The social effects of different agricultural crops were calculated using various indicators such as social solidarity, social security, participation and quality of life through interviews with farmers. The environmental effects and economic efficiency of the CP were also considered through the concept of life cycle assessment (LCA) and gross margin per ha, respectively. Further, by calculating socio-economic and environmental indicators, the optimal CP was formulated by developing a multi-objective function based on maximizing profit, reducing water and fertilizer consumption, reducing negative environmental effects of production and improving social indicators. In order to solve the multiple programming model, the method of weighted LP-metric model was used. The information required in this study included information on the production pattern, consumption of inputs, price and yeild of major agricultural crops of Sari County.

The results showed that considering the social indicators, the least attention of the farmers was related to corn and onion, and the five priority crops were identified as wheat, cotton, lentils, rice and canola, respectively. The results of LCA showed that the cultivation of tobacco, canola and corn in this city have the most negative environmental effects. In the optimal CP by combining economic, social and environmental goals, alfalfa, cotton and corn were removed from the stydy area, and the cultivated area of cucumber and clover showed positive changes compared to the current pattern. Also, the cultivated area of the cereal decreaseed in the areaChanges in the cultivated area of barley were predicted more than wheat and rice. The total cultivated area reduced by 15%, resulting in 12.91% and 14.46% reduction in water and fertilizer consumption, respectively. In addition, the efficiency of the program in the studied area decreased by 12.97%.

The development of environmental goals in the implementation of CP programs requires that policymakers consider appropriate economic incentives for farmers. Therefore, policy makers should find suitable solutions to make the farmers to follow the proposed CP.

Water deficit is one of the most important factors limiting the crops performance like basil. Using growth-promoting bacteria along with silica could improve them. Accordingly, the present research was conducted to investigate the effect of Enterobacter sp. and foliar application of silica on vegetative and physiological characteristics of basil under water deficit irrigation.

Methods & Materials:

 This research was conducted in a split factorial arrangement based on randomized complete block design. The main plot was irrigation levels (two, three and four days) and sub-plots were Enterobacter (inoculation and control) and silica concentrations (0, 6C, 6X and 12X).

Results showed that irrigation with three- and four-days intervals reduced vegetative and some physiological traits alone. However, SPAD in irrigation with three and four days intervals and essential oil percentage (EOP) and yield in four days intervals showed an increase at the range of 11 and 29%. 12X silica was very useful in some of these traits with increasing irrigation intervals. Although using bacteria inoculation with 12X silica was able to produce the highest amount of chlorophyll a and a+b in complete irrigation and dry matter yield in water deficit irrigation. However, when plants grown under water deficit irrigation, using 12X silica was maximally improved the EOP and yield.

In conclusion, the positive effect of silica was more pronounced than Enterobacter on improving the vegetative and physiological traits of basil. In addition, silica with high concentration (X) showed better results than low (C) concentration.

In order to evaluate the ability of forage sorghum (Sorghum bicolor L.) to remediate the heavy metal cadmium with biochar and Pseudomonas putida, a factorial experiment has been conducted based on completely randomized design accomplished in greenhouse conditions with four replications at Sari Agricultural Sciences and Natural Resources University, in the summer of 2019. Results show that the presence of cadmium in the medium of sorghum reduce the dry weight of root and shoot. However, adding biochar and bacterial inoculation significantly increase the mentioned traits. Bioconcentration factor and bioaccumulation factor have increased from 25 to 100 mg of cadmium, when the highest shoot bioaccumulation factor (2.31) is observed at a concentration of 100 mg Cd per kg soil and in the simultaneous application of Biochar and Pseudomonas putida, which is a significant increase of 28.33% compared to the control. The lowest translocation factor of sorghum (1.000) is related to non-application of biochar, non-inoculation of Pseudomonas putida and without cadmium contamination, itslef reduced by 20% compared to the control, while the highest translocation factor (1.94) is observed at a concentration of 25 mg of cadmium per kg of soil and treatment of non-application of biochar and non-inoculation of Pseudomonas putida. Plant tolerance index has decreased by increasing cadmium concentration, while the use of biochar and inoculation of Pseudomonas putida has increased this index when the highest tolerance index (1.22) is related to the treatment of combined use of biochar and bacteria with no cadmium, increased by 22% compared to non-application of biochar and non-inoculation bacteria. As the tolerance index of forage sorghum in all concentrations of cadmium is more than 0.60, this plant can be classified in the highly-tolerant group to the heavy metal cadmium stress and sorghum could be used for cadmium phytoremediation.

Soil pollution with heavy metals and its transfer to agricultural products is expanding as a global problem. Cadmium is one of the heavy metals that increase its concentration in the root environment of the plant causes metabolic disorders in the plant. Studies have shown that the use of intercropping systems while increasing diversity, increasing yield, improving resource efficiency, reducing weed damage, pests and diseases(such as Uromyces and Botrytis Vicia-Faba), increasing the stability of the system follows.This study investigates the effect of different levels of cadmium on plant pigments as one of the effective factors in the process of photosynthesis, as well as the amounts of phenol and flavonoid compounds and antioxidant activity in legumes (faba beans, peas) and potatoes in monoculture and intercropping culture.

The pot experiment was carried out as a factorial based on a completely randomized design with 4 replications at Gaemshar Agricultural Research Station, Mazandaran province during two agronomic seasons 2018-2019 examined in pot conditions. Treatments were included planting pattern at five levels of monoculture potato, faba bean, pea and Intercropping (potato+fabaBean), (potato+ pea) and five cadmium concentrations of 0 (control), 5, 10, 20 and 30 milligrams of cadmium per kilogram of soil as cadmium nitrate was added to the soil. For this purpose, methanolic extract was prepared from the dried leaves of the studied plants. Total phenols and flavonoids were assayed by spectrophotometry and the antioxidant activity of the extracts was evaluated by free radical scavenging methods (DPPH).Statistical analysis was performed using SAS software and comparison of means was performed by Duncan's multiple range test at the level of one and five percent probability and graphs were drawn using SigmaPlot and Excel software.

The results showed that different cadmium concentrations had a significant effect on the amount of photosynthetic pigments (P≤0.01). The reduction trend of chlorophyll a, chlorophyll b and carotenoids was plinomial. With the application of the highest level of cadmium (30 mg of cadmium in the soil), carotenoids, chlorophyll a and chlorophyll b were significantly reduced.In concentration of 30 mg of cadmium in soil, the amount of chlorophyll a in the faba bean reached 3.84 mg/kg soil. In other words, with increasing the concentration of cadmium in the soil, the amount of chlorophyll a decreased by 83.07%. The decrease in total chlorophyll due to cadmium may be due to the inhibitory effect on the activity of its molecules. Total chlorophyll of faba bean with increasing concentrations of cadmium (from 5 to 30 mg soil) was a significant decrease. The sensitive treatments to increasing cadmium concentration were faba beans (7.66 mg/kg soil), potatoes (9.19 mg/kg soil) and chickpeas (9.28 mg/kg soil), respectively. In this study, faba bean plant had the highest mean of phenol (0.1643 mg que/g DW) and intercropping culture (potato+bean) had the highest flavonoids (0.00814 mg que/g DW) and antioxidant (56.03 %) obtained in the treatment of 30 mg of cadmium per kg of soil.

The results of the present study indicate a significant difference between the different treatments in terms of the total amount of phenolic and flavonoid compounds that the existence of such diversity can indicate the role of plants and genetics in the production of these compounds. with increasing the concentration of cadmium, the amount of chlorophyll a and chlorophyll b pigments was significantly reduced. In general, from the findings of this study, it can be concluded that these plants, cadmium toxicity in all three plants led to the induction of phenolic compounds.

In order to investigate the effect of biopriming of wheat seeds with Trichoderma and Aspergillusalong with ZnSo4 on improving germination indices and the tolerance threshold of wheat to zinc a factorial experiment was done based on a completely randomized design with three replications. Experimental treatments included six levels of zinc (0, 0.6, 6, 60, 300 and 600 mg/L) and four fungal treatments (no inoculation, inoculation with Trichoderma harzianum, Trichoderma longibrachiatum and Aspergillus niger). Nonetheless, based on the results, the coexistence of wheat seedlings with Trichoderma fungi especially Aspergillus fungi reduced the lipid peroxidation of the membrane in all application levels of zinc. Also, based on the results, the highest proline content was observed in the highest level of zinc in inoculated wheat seedlings by T. harzianum (fourfold increase as compared to the uninoculated control) and in other levels of zinc in seedlings inoculated with A. niger. However, the results showed a negative relationship between malondialdehyde (MDA) content and superoxide dismutase (SOD) activity and growth indices of wheat seedlings. There was also a negative relationship between MDAecontent with both SOD activity and growth indices of wheat seedlings. Inoculation of wheat seedlings with fungal treatments with higher production of SOD may led to higher resistance and avoidance to higher concentrations of Zn. Overall, the results showed an increase in the tolerance threshold of wheat seedlings to a concentration of 60 mg/L and therefore, more effectiveness of this micronutrient in seeds inoculated with Trichoderma and Aspergillus especially inoculated with Trichoderma longibrachiatum.

The field experiment has been conducted as a split split plot based on a randomized complete block design with three replicaitons at Rice Research Institute of Mazandaran Province, Amol, in 2017. In this experiment, the seeds are sown in seedling box with different six bed treatments. These beds include S1: sulfur bed with 50% rice bran, S2: sulfur-free soil with 25% rice bran, S3: sulfur bed with 25% rice bran, S4: sulfur bed with Thiobacillus and 50% rice bran, S5: sulfur-free bed with wood compost and 25% rice bran, and S6: sulfur bed with Thiobacillus with 25% bran rice. After some measurements, the seedling is transplanted in the main field. In the field, different beds in box, seedling number per hill (3 and 5) and planting space (20×20 cm, 30×14cm) are assigned to the main plot, sub plot, and sub sub plot, respectively. The results of main cultivation show that the highest grain yield (5043 kg.ha-1) and biological yield (12319 kg.ha-1) are obtained from the treatment of bed soil with sulfur with 50% bran. Planting arrangement treatment in ratoon cultivation on number of hollow seeds (4.1), grain yield (1617 kg.ha-1), number of plants per hill treatment on number of tillers (10.3), leaf area (10.6 cm2), panicle length (20.4 cm) and grain yield (1613 kg.ha-1), and seedling type treatment on tiller number (10.4) show a statistically significant difference. Seedling grown in sulfur with 50% rice brain display the best performance in terms of yield and yield components in both main and ratoon cropping.

Closing the gap between actual yields which are currently obtained from the fields (actual field yields) and the maximum yields that can be achieved under favorable management conditions (attainable yield) is one of the most critical problems in crop production in Iran and the world. Quantifying the yield gap and identifying its primary causes for this purpose can be a key and promising strategy to increase production per unit area and to achieve food security. Meanwhile, considering the importance of oilseeds like soybean [Glycine max (L.) Merril] in the global economy and the need for edible oils and vegetable proteins, estimating and identifying the causes of the yield gap, while increasing production, it can improve land use and labor efficiency, and leads to costs saving and sustainable production. In this way, a survey study was conducted in 2019 to identify and determine the share of each of the managerial factors affecting the soybean yield gap in 301 farms in Mazandaran province.

In the present survey, CPA method was used to investigate the decision-making factors which limit soybean yield and to estimate its yield gap in 13 soybean cultivated cities of Mazandaran province. For this purpose, all information relevant to crop management, from seedbed preparation to harvesting, was gathered through interviews with 301 soybean producers. These management factors included items such as use or non-use of a plow, number of secondary tillage, planting method, field area, previous crop, the used cultivar, seed rate and its preparation site, inoculation/non-inoculation of seeds with N-fixing bacteria, type and the amount of fertilizers, type, amount, and number of herbicides, fungicides, and insecticides usages, number of irrigations and the amount of used water, irrigation type and harvesting methods. Field monitoring data included 81 quantitative and qualitative crop management variables that the relationship between all these variables and actual field yields was analyzed using stepwise regression in SAS (v9.1) software. In the end, the contribution of each limiting factor to the creation of a yield gap was determined using the resulting production function and management parameters values.

The findings of this study revealed that of the 81 studied management variables, the final production function with 10 independent variables was selected. These variables included the sari variety (J.K-695), previous crop (faba bean), use the row planter, number of secondary tillage, sulfur rate, application of herbicide, KCl, and (NH4)2HPO4 fertilizers, sprinkler irrigation system, and surface irrigation, which were identified as the main limiting factors for soybean yield in Mazandaran province. Based on the difference between the average actual yield recorded on farms (2464.97 kg ha-1) and the maximum attainable yield (6028.66 kg ha-1) predicted by the production function, the yield gap was 3563.70 kg ha-1, which is three factors including sulfur rate, previous crop (faba bean) and sprinkler irrigation system with the values of 873.87, 620.49 and 546.33 kg ha-1, respectively, had the highest share (24.52, 17.41 and 15.33%, respectively) in of the soybean yield gap.

According to the predicted attainable yield which derived from actual farm data it seems that adoption of proper crop managements such as using sulfur fertilizer resources appropriate to plant needs, an appropriate crop rotation and selection of plants suitable for rotation, providing facilities and modernization of agricultural machinery, and develop and promote new irrigation can reduce this gap (59%) and significantly improve soybean yield in Mazandaran province.

Earth monitoring satellites and vegetation indices are very useful to study the plant greenness at different stages of growth. Widely paddy fields in the north of the Iran has provided the opportunity for research related to rice crops by new technologies, but cloudy sky in plant growth periods leads to remote sensing information in humid areas is less welcomed. The existence of spatial-temporal fusion algorithms has provided the opportunity and rebuilding satellite images in cloudy periods to use remote sensing data in the period of plant growth. In this study, spatial-temporal fusion algorithm were used to rebuilding the images of Landsat 8 and Sentinel 2 satellites during the growing season of rice to estimate the leaf area index as a representative of vegetation health and development at different stages of growth.

To achieve the objectives of this study, images of Landsat 8 and Sentinel 2 satellites were used. In the cloud period, with the help of STARFM algorithm, two satellite images were rebuilt and used to extract Normalized Difference Vegetation Index (NDVI), Rice Growth Vegetation Index (RGVI) and Soil Adjustment Vegetation Index (SAVI).To estimate leaf area index by satellite images, a suitable relationship was obtained between vegetation indices and rice leaf area index at different stages of growth.

Due to the cloudiness in July and the peak of greenery of the rice plant, using the STARFM algorithm to rebuild the images was very efficient. With the help of 15 images in the whole rice growth period (90 days), four linear relationships were established between Normalized Difference Vegetation Index (NDVI), Rice Growth Vegetation Index (RGVI) and Soil Adjustment Vegetation Index (SAVI) for four stages of growth with leaf area index. The highest and lowest correlation coefficients were observed between vegetation indices and leaf area index of 0.96 for NDVI index in transplanting and maturing stage and 0.75 for RGVI index in transplanting stage, respectively. Also, the map of changes in leaf area index for both satellites during the crop growth period showed well the changes in the greenness of rice cover.

In general, it seems that by using satellite data and image rebuilding on cloudy days, it is possible to achieve the leaf area index with high accuracy and extract various information such as age and growth stage for the rice plant