Guar is an annual plant that tolerates salinity and drought from the legume family, which can be used as an alternative product in low water plains. Considering the characteristics of the guar, such as having the ability to biologically nitrogen fixation and a relatively deep root system, high adaptability to drought and poor soils, high competitive power and favorable morphology, it seems that placing it in intercropping cultivation, it can increase the efficiency of final yield of intercropping crops. Utilizing the intercropping system for plants, is an effective measure to improve soil fertility, increase the absorption of nutrients and improve the efficiency of water consumption, and it is considered one of the most important scientific methods to help maintain the stability and balance of the living system of the soil. Therefore, this research was carried out with the aim of comparing different patterns of intercropping cultivation of guar next to the roselle with its pure cultivation at different levels of nitrogen fertilizer in field of Toos Planting Manager Company in Taybad city, located in Polband plain. The experiment was performed as a split plot in the form of a randomized complete block design with two factors and in three replications. The first factor included eight ratios of mixed crops, which were implemented as follows: sole cultivation of guar, one row of guar + one row of roselle, two row of guar + one row of roselle, three row of guar + one row of roselle, one row of guar + two row of roselle, one row of guar + three row of roselle, two row of guar + three row of roselle and Three row of guar + two row of roselle. The second factor included nitrogen fertilizer, based on recommendation of the soil laboratory, at three levels: without giving nitrogen fertilizer (zero kg per hectare) and 50 and 100 percent of guar's requirement for nitrogen, one half at the time of planting and the other at the time of pod formation. The results indicated a significant superiority of sole cultivation of guar treatment in 100 percent of guar's requirement for nitrogen fertilizer in terms of the number of pods per plant and the number of seeds per pod. Nevertheless, in attributes of pod length and weight of 100 seeds, significant superiority changed in favor of treatment of three row of guar + one row of roselle under conditions of 100 percent of guar's requirement for nitrogen fertilizer. In attributes of shoot dry weight and seed yield, the two treatments of sole cultivation of guar and three row of guar + one row of roselle in condition of providing 100 percent of nitrogen fertilizer requirement have a significant advantage and were placed in a statistical group. Based on the results of this research, in terms of shoot dry weight, yield components and seed yield, the only treatment that was in the same statistical group with sole cultivation of guar or had a small statistical difference with it, is the treatment of three row of guar + one row of roselle in the condition of supplying 100 percent of nitrogen fertilizer requirement. Therefore, it seems that this intercropping combination is recommendable for farmers who like this type of planting system. Because doing intercropping for species with different phenology can increase the productivity of agricultural lands while creating biodiversity and guaranteeing production. Also, according to the findings of present research, the reduction of nitrogen fertilizer consumption to less than requirement of guar was effective in reducing the yield and its yield components. Therefore, it is recommended to use full nitrogen fertilizer based on recommendations of the soil laboratory.

The aim of this study was to evaluate the tillage and fertilization methods of sesame plants with respect to the impact of water deficit stress conditions in the years (2022-2023). The experiment was performed as a split plot in the form of a randomized complete block design with three replications. The main factors included three tillage methods (no tillage, low tillage and conventional tillage), the sub-factor of two irrigation levels (normal and low irrigation) and the sub-factor of four fertilization methods (no fertiliser, nitrogen fertiliser, vermicompost and combination of nitrogen and vermicompost). The results showed that the reactions of the traits to water deficit stress were different in different combinations of fertilizers and tillage. In 2022 the reduction of grain yield in different treatments ranged from 14.3% (low tillage with combined nitrogen fertilizer and vermicompost) to 23% (conventional tillage without fertilizer). In 2023 the decrease in grain yield was between 9.8% (low tillage with integrated fertilizer) and 20% (conventional tillage without fertilizer). In both years, the least negative effect was observed in the low tillage treatment with combined nitrogen fertilizer and vermicompost and the highest negative effect was observed in the conventional tillage treatment without fertilizer. Treatments without tillage and treatments with separate application of nitrogen fertilizer or vermicompost showed moderate results. Based on the results of this two-year study, the use of low-tillage method along with the combined application of nitrogen fertilizer and vermicompost is recommended for managing sesame fields in water-limited conditions.

The simultaneous application of nitrogen fertilizer and growth regulators in rainfed conditions improves plant growth and development parameters. For this reason, research was conducted in two regions in the crop years of 2022-2023 in Poldokhtar and Khorram Abad cities. The experiment was carried out as a factorial design in the form of a basic randomized complete block design with three replications. The first factor includes four levels of nitrogen chemical fertilizers, including 0, 50, 100 and 150 kg.h-1 urea, and the second factor was foliar application of blank (spraying solution with distilled water), paclobutrazol (120 mg/liter), spermidine (1 mM), and chlormequat chloride (three grams per liter). The highest seed yield was observed in the treatment of 100 kg.h-1nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 2686.4 kg/ha, and the lowest rate was obtained in the absence of nitrogen fertilizer and no foliar spraying at the rate of 1284.8 kg/ha. The highest protein yield was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 313.25 kg.h-1. The highest total chlorophyll was observed in the treatment of 100 kg.h-1 nitrogen fertilizer and paclobutrazol foliar spraying at the rate of 10.38 mg/g of fresh weight. According to the results of this study, the use of nitrogen fertilizer and foliar application of growth regulators can significantly improve the growth, yield and photosynthetic pigments of barley in rainy conditions.

Lemongrass (Cymbopogon citratus (DC.) Stapf), a perennial plant from the Gramineae family, is renowned for its rich polyphenol compounds, having significant medicinal, cosmetic, and culinary applications. Enhancing the quantitative and qualitative yield of lemongrass is of considerable economic importance. Salicylic acid, a key regulator of physiological and biochemical processes, acts as an elicitor to enhance the accumulation of secondary metabolites in plants. Similarly, nitrogen plays a vital role in plant growth, improving yield quantity and quality. This study investigated the effects of nitrogen fertilizer and salicylic acid on various quantitative and qualitative traits of lemongrass. A factorial experiment based on a randomized complete block design was conducted in 2021 at the Agricultural Sciences and Natural Resources research farm of the University of Khuzestan, Ahvaz, Iran. The experiment evaluated the effects of different levels of salicylic acid (0, 10 µM, and 100 µM) and nitrogen fertilizer (0, 50, 100, 150, and 200 kg/ha from a urea source) on lemongrass. Each treatment was replicated three times. In each fertilizer treatment, 20% of the nitrogen was applied after plant establishment, with the remainder applied in four stages alongside irrigation water to minimize leaching losses based on soil nitrogen content. Salicylic acid was applied via foliar spraying using a backpack sprayer when 70% of each plot was covered by lemongrass, with a second application 15 days later. Each plot measured 3 meters in width with six planting lines, each 3 meters long, 60 cm apart, and plants within lines were spaced 40 cm apart. The soil had a silty clay texture, pH of 7.5, and electrical conductivity of 2.6 dS/m. The studied traits included chlorophyll a, b, and total chlorophyll, carotenoid content, total fresh and dry weight, antioxidant activity percentage, total phenol content, and essential oil percentage and yield. The interaction between salicylic acid and nitrogen fertilizer significantly influenced all studied traits except antioxidant activity percentage. Nitrogen fertilizer alone significantly affected antioxidant activity, with the highest percentage (89.8%) observed at 150 kg/ha of nitrogen. The highest levels of chlorophyll a, b, and total chlorophyll were achieved with no salicylic acid and 150 kg/ha of nitrogen, showing increases of 140%, 42%, and 116%, respectively, compared to the control (no salicylic acid or nitrogen). The highest total fresh and dry weight was obtained with 100 µM salicylic acid and 100 kg/ha of nitrogen, representing a 75% increase over the control. The highest essential oil percentage (0.87%) and yield (65.6 g/m²) were observed with 10 µM salicylic acid and 150 kg/ha of nitrogen. In contrast, the lowest essential oil yield (18.29 g/m²) and percentage (0.45%) were recorded in the absence of salicylic acid and nitrogen and with no salicylic acid but 150 kg/ha of nitrogen, respectively. Applying nitrogen fertilizer and salicylic acid enhanced the yield and percentage of essential oil, total dry matter, and total phenol content in lemongrass leaves compared to the control. The highest essential oil yield was achieved with 10 µM salicylic acid and 150 kg/ha of nitrogen fertilizer, demonstrating the synergistic effects of these treatments on lemongrass productivity and quality.

Beans are known as an important plant in agriculture and are cultivated in many tropical and temperate regions. The presence of weeds reduces the performance of this valuable plant, which can be compensated by the use of herbicides, but excessive use of herbicides causes damage to the environment, which shows the need to identify the appropriate dose. Nitrogen fertilizer also increases the yield of beans and weeds. Therefore, the present study examines the mutual effect of herbicide and nitrogen fertilizer on the performance characteristics of broad beans and weeds in heavy and sandy soils of two regions of Dareh Shahr and Malekshahi during the crop year of 2020-2021 in Ilam province (Iran). The experiment was performed as a split plot in the form of a basic design of randomized complete blocks with three replications. The first factor includes 5 levels of Treflan herbicide with EC 48% (no use, 0.5, 1, 1.5 and 1 liter per hectare) and 5 levels of haloxyfop armetyl herbicide with EC 10.8% (no use, 0.3, 0.6, 0.9 and 1.2 l.ha-1). The second factor included nitrogen fertilizer at 3 levels: 0, 50 kg.ha-1 and 100 kg/ha. The results of the average comparison showed that the highest seed yield was obtained in the treatment of 50 kg of nitrogen per hectare and the consumption of 0.9 liters per hectare of haloxyfop in the amount of 2506.3 kg per hectare, which is compared to the lowest amount in the treatment of no nitrogen consumption and no consumption. Herbicide increased by 68%. There was no significant difference between 50 kg of nitrogen per hectare and the use of 0.9 liters per hectare of haloxyfop with the treatment of 50 kg of nitrogen per hectare and the use of 1.5 or 2 liters per hectare of treflan. There was no significant difference between the superior treatment with the treatment of 50 kg of nitrogen per hectare and the consumption of 0.6 liters per hectare of haloxyfop. Also, at all levels of nitrogen fertilizer use, increasing the use of haloxyfop or treflan by 1.2 and 2 liters per hectare, respectively, caused a decrease in this index. Increasing consumption from 50 to 100 kg per hectare caused a decrease in grain yield, which was significant in some treatments. The highest wet weight of weeds was obtained in the treatment of maximum nitrogen fertilizer application and no use of haloxyfop in the amount of 283.7 grams per square meter, which is compared to the lowest value in the treatment of no nitrogen application and the use of 1.5 liters per hectare of Treflan. It increased about 1/4 times. Also, at all levels of nitrogen fertilizer use, increasing the use of haloxyfop or treflan up to 0.9 and 1.5 liters per hectare, respectively, caused a decrease in this index, but in the case of maximum herbicide use; Weed fresh weight decreased. Also, increasing the consumption from 0 to 100 kg per hectare increased the wet weight of weeds. In general, the results of this study showed that with the consumption of 50 kg of nitrogen, the yield can be produced almost equal to the consumption of 100 kg of nitrogen per hectare. Therefore, by reducing the consumption of nitrogen, the harmful environmental effects of this type of fertilizer are also reduced and help to maintain the sustainability of the environment. Also, with regard to the two herbicides, Treflan and Haloxyfop, it is possible to produce a good yield and reduce the weight and density of weeds by consuming 1.5 and 0.9 liters per hectare, respectively. Because there was no significant difference with the treatments of 2 and 1.2 liters per hectare of treflan and haloxyfop. On the other hand, this event also reduces the environmental risks of using herbicides.

In order to investigate the antifungal effects of essential oils of some medicinal plants, including rosemary, which is often consumed as an edible vegetable, a comparative study of the fungicidal effects of rosemary essential oil under the influence of different fertilizers on Fusarium fungus was designed and implemented. In the first part, the experiment was conducted in a randomized complete block design with four treatments and three replications, in which the fertilizer treatments were control, nitrogen fertilizer from urea source, organic animal manure (cow), and vermicompost, after planting and passing the period. At the end of the operation, the plants were harvested and their essential oils were measured using conventional and recommended scientific methods. According to the results obtained, the most essential oil was from the use of chemical nitrogen fertilizer from urea fertilizer source, and the lowest amount of essential oil was from the control treatment (no fertilizer use). In the second stage, the experiment was conducted by planting spores of the Fusarium fungus in the designed culture medium, while confirming the antifungal effects of the essential oil of the medicinal plant rosemary. It led to the conclusion that the essential oils produced from the use of chemical fertilizers and vermicompost showed more and better inhibitory effects than other essential oils.

The present research was performed with the aim of investigating the efficiency and productivity of water and fertilizer in guar cultivation and analyzing the profit obtained from it, under different levels of nitrogen and plant density in Taibad city of Khorasan Razavi Province. The experiment was performed as a split plot in the form of a randomized complete block design with two factors and in three replications. The first factor included nitrogen fertilizer, based on the recommendations of soil laboratory, at three levels without giving nitrogen fertilizer (zero kg per hectare of urea) and 50 and 100% of guar's need for nitrogen (equivalent to 150 and 300 kg per hectare of urea, respectively), that was applied half of it at the time of planting and other half at the time of podding stage of guar. The second factor also included three levels of guar plant density, which was implemented as densities of 20, 33 and 66 plants per square meter. The results indicated that the highest use efficiency and productivity of fertilizer was obtained in condition of no nitrogen consumption and at a density of 66 plants per square meter. However, the highest seed yield and water use efficiency and water productivity, as well as the highest net profit, were obtained in condition of supplying 100% of guar nitrogen fertilizer requirement (300 kg of urea per hectare) and in two densities of 33 and 66 plants per square meter, the increase in plant density from 33 to 66 plants per square meter did not have a significant effect on improving seed yield and increasing the net profit of guar cultivation. Nevertheless, in conditions of not fully supplying the plant's nitrogen needs, increasing plant density was able to neutralize the effect of nitrogen deficiency and increase yield and net profit significantly.

Currently, more than 90% of the edible oil needed in Iran is supplied through imports from other countries. This amount of oil import is not suitable for a country with high potential and capacity to produce agricultural products. Therefore, it is necessary to increase the production of oilseeds in the country. Camelina (Camelina sativa L.) is a new and unique oilseed plant for Iran. This oil plant is part of the Brassicaceae family, and it has been shown in various tests that it has much less water needs and more resistance to spring cold than other oil plants, especially canola. Therefore, considering the importance of self-sufficiency in oil production in the country and the introduction of crops that can have a good yield in the dry climate of most parts of the country, this research aims to evaluate the effect of sowing date and nitrogen fertilizer application on the nitrogen productivity of camelina as a new crop was implemented in the crop rotation with most of the rainfed crops.

This study was conducted in order to investigate the effect of sowing date and nitrogen fertilizer application on the nitrogen capture and use efficiency of camelina under the conditions of rainfed fields in the climatic conditions of Kermanshah city in 2018-2019. A split plots experiment was conducted based on the randomized complete blocks in three replicates at the research farm of the Campus of Agriculture and Natural Resources at Razi University. The main factor was the sowing date (October 25, November 9, and November 21), and the secondary factor was nitrogen fertilizer application (0, 50, 100, 150 kg.ha-1). The implementation of the sowing date treatment was based on the occurrence of effective rainfall, and the source of nitrogen fertilizer application was 46% urea fertilizer. The nitrogen fertilizer was applied at three stages (at the end of the six-leaf stage, at the end of the stem elongation stage, and at the beginning of the grain filling stage). The plant was harvested on each sowing date according to the physiological maturity (browning of 90% of pods). The evaluated traits were grain protein percentage, grain protein yield, nitrogen harvesting index nitrogen capture and use efficiency, and nitrogen productivity.

The results showed that the treatments of sowing date and nitrogen fertilizer application had significant effects on the evaluated traits. In the maximum fertilizer application treatment, compared to the control condition, the grain protein percentage and grain protein yield increased by 39.0% and 128.8%, respectively. The highest nitrogen capture efficiency (0.81 kg of total plant nitrogen.kg-1 of soil nitrogen) and nitrogen use efficiency (11.4 kg of grain.kg-1 of nitrogen) was observed on the November 9 sowing date and the lowest of these belonged to the November 21 sowing date. The increase in the amount of nitrogen fertilizer application decreased the nitrogen capture efficiency (64.8 %), nitrogen use efficiency (63.7 %), and nitrogen productivity (51.3 %) in the treatment of 150 kg of nitrogen application per hectare compared to the treatment of no nitrogen application.

The results showed that most of the investigated traits of camelina were observed in the sowing date of mid-November, and the delay in the sowing date led to a decrease in these traits. The highest nitrogen capture efficiency, nitrogen use efficiency, and nitrogen productivity were observed in the treatments with the lowest amount of nitrogen fertilizer application and the control treatments. In general, the results of this research showed that under the climatic conditions of the Kermanshah region, it is better to sow the camelina in the rain-fed fields in the middle of November, and because of the undeniable effects of using nitrogen fertilizer on improving the grain yield, but if the environmental risks of excessive use of chemical fertilizers are considered, it is better to application nitrogen fertilizer in the minimum amount the plant's needs.

Increasing soil carbon, both globally and on a farm level, has been considered as a fundamental strategy to reduce atmospheric carbon dioxide and increase soil productivity. Because agricultural ecosystems cover 11% of the earth's surface and wheat is one of the three most important grains in the world, any study on increasing soil carbon through land management and organic additive management can lead to a better understanding of our potential for soil improvement, ecosystem services, higher biomass yields, nutrient recycling, potentially increasing agricultural and ecological productivity. Crop rotation significantly affects the sequestration capacity of atmospheric carbon dioxide, and the change of cropping systems from fallowing to continuous cultivation can affect the rate of carbon sequestration in the soil through the introduction of more organic carbon. Also, managing the use of fertilizers, especially nitrogen, will not only increase crop yields, but also increase carbon sequestration as a secondary benefit to the land. Due to the alkalinity of most soils in arid and semi-arid regions, the addition of organic matter reduces soil acidity and improves plant growth conditions, increases the ability to absorb elements such as phosphorus and iron, moreover has a positive effect on increasing biomass production and carbon sequestration.

This study was conducted to take advantage of a set of desirable crop measures in diverse production systems with the aim of improving the chemical properties of soil and carbon sequestration with a focus on wheat during the two cropping years of 2018-19 and 2019-20 in a farm in Taybad plain. In this study, the factor of the cropping system in four levels (wild rocket-wheat, fallow-wheat, mung bean-wheat and corn-wheat) and the factor of nitrogen fertilizer levels (100, 50% and without nitrogen fertilizer application) were implemented in a randomized complete block design as factorial with three replications. Soil chemical properties such as acidity, organic carbon, total nitrogen, available phosphorus and iron were measured.

The highest amount of acidity was observed in corn-wheat treatment with 50% nitrogen fertilizer supply and the lowest amount of acidity was observed in wild rocket-wheat treatment with 100% nitrogen fertilizer supply. The study of treatments shows that wild rocket and mung bean showed the best results in increasing soil organic carbon and carbon sequestration. Corn less than were able to increase soil organic carbon, although with increasing nitrogen fertilizer supply in the corn-wheat cropping system, organic carbon improved compared to the control treatment. The results also showed that wild rocket-wheat treatment with 100% nitrogen fertilizer supply experienced the highest increase (56.7%) and corn-wheat treatment with 50% nitrogen fertilizer supply experienced the lowest (21.4%) increase in soil organic carbon. Soil nitrogen was also significantly affected by the increase of soil organic carbon mainly in two treatments of wild rocket-wheat (25.6%) and mung bean-wheat (17.9%) in conditions of 100% nitrogen fertilizer supply, while fallow-wheat and Wheat maize without nitrogen fertilizer showed the highest reduction in soil nitrogen content of 15.3% and 20.5%, respectively. Phosphorus and iron levels also increased in all treatments. The results of trait correlation also showed that reducing acidity in alkaline soils is the key to success in increasing plant access to phosphorus (r = -0.37 **) and iron (r = -0.33 **). It seems that the most important factor in the improving farming practices, which leads to an increase in organic carbon and consequently soil fertility, is the removal of fallow and continuous cultivation of agricultural lands.

The results showed that soil organic carbon increased in all treatments and led to increased carbon sequestration and improved soil chemical properties. The results regarding nitrogen also showed that non-use of nitrogen fertilizer in all cropping systems reduce or stop the increase of nitrogen and the need for optimal use of nitrogen fertilizer even in the case of using cover crops or legume as a nitrogen stabilizer. Reducing acidity in alkaline soils is the key to success in increasing plant access to phosphorus, although the capacity of soil organic carbon to retain phosphorus and iron in the soil should not be underestimated. Also, cropping systems affected by the type of crop rotation had different effects on soil properties. It seems that in addition to determining the quantity and quality of plant residues, plant rotation will have a different behavior on the concentration of soil elements depending on the amount of harvest of each nutrient.

This study was conducted to examine the interaction between cultivars and the nitrogen fertilizer applied to spring safflower growth and yield. It was performed as a factorial experiment within a randomized complete block design with three repetitions at the experimental field of the Faculty of Agriculture at Tarbiat Modares University during the 2021 crop season. The treatments included two safflower cultivars, Parnian and Goldasht, and six levels of pure nitrogen (0, 45, 90, 135, 180, and 225 kg/ha). The cultivar influenced the leaf area index and the number of capitula per unit area, while nitrogen fertilizer affected all traits significantly. The leaf area index was approximately 25% higher in the Parnian than the Goldasht cultivar. However, there was no significant difference in dry matter production between the cultivars. The highest leaf area index and dry matter were observed under 135 and 180 kilograms of nitrogen per hectare, respectively, and higher nitrogen did not result in significant increases. The highest number of capitula and seeds per capitula were obtained with 180 and 135 kg/ha, respectively, and further nitrogen did not significantly increase these traits. The increasing nitrogen enhanced seed and oil yield in safflower, with the highest significant yields obtained at the 180 kilograms per hectare of nitrogen. The number of capitula and seeds per capitula had a higher correlation with seed yield. Based on the results of this study, an increase in safflower yield can be expected with an increase in nitrogen fertilizer up to 180 kilograms per hectare.