In order to investigate the changes in weed flora in the irrigated wheat fields of Isfahan county over a 15-year period (from 2019 to 2004), a systematic sampling of weeds was conducted in 100 farms with W pattern during wheat tillering to stem elongation stages. In 2004, the dominant weed species was winter wild oat (Avena ludoviciana) with a abundance index of 76.1; however, in 2019 three weed species, including winter wild oat, wild barley (Hordeum spontaneum), and littleseed canarygrass (Phalaris minor) were recognized as the dominant species with abundance indices of 70.1, 42.3, and 28.6, respectively. In 2004, the dominant broadleaf weed species were lambsquarters (Chenopodium album) with a dominance index of 67.9 and prostrate knotweed (Polygonum aviculare) with a dominance index of 31.96. However, in 2019, the highest dominance indices were observed in lambsquarters, prostrate knotweed, and Flixweed (Descurainia Sophia) with abundance indices of 78.4, 38.5, and 39.04, respectively. The correlation between weed distribution and soil factors (nitrogen, phosphorus, potassium, soil texture, and electrical conductivity), crop rotation, and herbicides was examined using canonical correspondence analysis (CCA). Littleseed canarygrass, wild barley, field brome (Bromus commutatus), licorice (Glycyrrhiza glabra), hoary cress (Cardaria draba), and yellow sweet clover (Melilotus officinalis) showed the highest correlation with soil nitrogen levels.

In conditions where don't have enough water for irrigation, intercropping of forage plants is one of the ways to achieve sustainable agriculture. Biochemical and physical properties of soil tillage system can affect the yield of plants in intercropping. Therefore, with the aim of investigating the forage yield and competitive indices of intercropping, this experiment was performed in the cropping seasons of 2020-2021. Treatments included conventional, minimum, and no tillage system. Intercropping patterns also included monoculture of forage sorghum and maize, alternate row cultivation maize and forage sorghum and alternate cultivation on planting rows. The results showed that the highest plant height (295 cm) and leaf area (6.88) was obtained in intercropping and conventional tillage. The highest forage yield was also observed in sorghum monoculture. However, the land equivalent ratio of mix intercropping with 1.17 showed the superiority of intercropping over monoculture. Evaluation of competitive indicators such as dominance index, relative crowding coefficient, and competitive ratio showed that forage maize is the predominant plant in intercropping conditions. The system productivity index with 8.11 showed that intermediate cultivation on planting rows was superior to other treatments in conventional tillage conditions. The results showed that in conventional tillage and intercropping conditions, acceptable yield was obtained; this advantage can increase water efficiency and use of sorghum in intercropping.

Adding organic amendments to the soil increases permeability, water-holding capacity, biological activity, and nutrient content, and consequently increases the soil fertility and the yield of plants. In order to evaluate the effects of municipal waste compost and sheep manure on yield and yield components of wheat, a three-year field experiment was conducted as a randomized complete block design with three treatments, including the application of sheep manure (17.3 kg m-2), compost (15.6 kg m-2), and control (no organic amendment) in three replications in Agricultural Research Station of Zarghan, Fars province, during 2015-2018. The results showed that organic amendments had a significant effect on the number of fertile tillers per area, plant height, ear length, grain number per ear, thousand-grain weight, grain yield, biological yield, and harvest index; however, straw weight was not significantly affected by organic amendments. In all three years of the experiment, sheep manure and compost significantly increased wheat grain yield compared to the control treatment. On average, compost and sheep manure increased wheat grain yield by 63.9% and 46.1% in the first year, 29.3 and 53.7% in the second year, and 37.4 and 26.9% in the third year, respectively, compared to the no-amendment treatment. However, in the most cases, no significant difference was observed between sheep manure and compost. Therefore, farmers can use any of the sheep manure or solid-waste compost to increase wheat yield, the amount of which should be determined based on the amount of organic carbon in the farm soil.

Improving the nutritional status of plants is an effective method for enhancing their ability to withstand drought stress. To evaluate the quantitative, qualitative, and antioxidant properties of castor plant under water deficit conditions stress and foliar application of chemical fertilizers, an experiment was conducted as a split-plot design in a completely randomized block design with three replications. The first factor was irrigation levels including control (normal irrigation), irrigation after 80 mm and 140 mm evaporation from the pan evaporation in the main plots, and eight spraying chemical fertilizers (sulfur, potassium, nitrogen, sulfur+potassium, sulfur+nitrogen, potassium+nitrogen, sulfur+potassium+ nitrogen and control (no spraying)) were included in subplots. The highest proline content, catalase, peroxidase, superoxide dismutase, and total phenol were obtained under irrigation after 140 mm of evaporation conditions and foliar application of nitrogen+potassium+sulfur. Also, the highest grain yield, oil yield, and the lowest oil percentage were observed in the nitrogen+potassium foliar treatment under irrigation conditions after 20 mm of evaporation. Although the content of malondialdehyde increased in water deficit stress treatments, nitrogen+potassium+sulfur and nitrogen+potassium foliar application significantly reduced the peroxidation of membrane lipids (malondialdehyde) under irrigation conditions after 80 and 140 mm of evaporation compared to the control treatment. In conclusion, foliar application of chemical fertilizers in castor can improve the resistance to water stress by strengthening the antioxidant system and then increase its grain and oil yield.

Water deficit stress is considered as one of the most important factors affecting soil microbial activities in dry and semi-dry ecosystems, which reduces microbial activity by limiting access to nutrients. To evaluate the effect of water stress (30%, 50%, 70%, and 100% of field capacity), urea chemical fertilizer (100, 200, and 300 kg/ha), and the impact of biological fertilizers (inoculation with mycorrhiza alone, co-inoculation with mycorrhiza and nitrogen-fixing bacteria, co-inoculation with mycorrhiza and azospirillum, and control) on the yield characteristics of Zea mays hybrid Sc706, a field experiment was conducted as a split-split plot in a randomized complete block design with three replications in two cropping seasons (2018-2019 and 2019-2020) on a farm in Firoozabad, Fars province, Iran. Dual and triple interactions of water stress, urea chemical fertilizer, and biological fertilizer showed significant differences in all yield characteristics. In most traits, the application of urea chemical fertilizer (200 and 300 kg/ha) along with biological fertilizers (mycorrhiza-azospirillum and mycorrhiza-nitrogen-fixing bacteria treatments) produced the best results. Overall, it can be concluded that the use of 200 and 300 kg/ha of urea fertilizer along with a combination of biological fertilizers, mycorrhiza-azospirillum and mycorrhiza-nitrogen-fixing bacteria, can be suitable options for improving the yield and morpho-physiological characteristics of corn under regional conditions.

Pearl Millet (Pennisetum glaucum L.) is one of the most important crops in arid and semi-arid regions that are cultivated for grain and forage. Due to cross pollination and high heterosis, the development of hybrid varieties is the most important breeding method of pearl millet. In order to study the preliminary yield comparison of hybrid cultivars and investigate the possibility of replacing open-pollinated cultivars with hybrid cultivars, 11 promising pearl millet hybrid cultivars with a check variety (Mehran cultivar) were planted in the randomized complete block design with three replications in Karaj, Isfahan and Zabul. The days to 50% flowering, plant height, stem diameter, leaves number, panicle length, panicle thickness, tiller number, fresh fodder yield, dry matter yield, 1000 seed weight, and seed yield were evaluated. The results of combined variance analysis and mean comparisons showed that there is considerable genetic diversity for the studied traits. The results showed that the cultivars H294, H444, H504, H604, H824, and H794 had the highest grain yield compared to the total mean of the experiment. In addition, five cultivars H543, H333, H353, H563, and H604 were above of total average in terms of fodder production and had good potential to be used in the field as commercial cultivars with the aim of fodder and seed production.

The development of herbicide-resistant weed species is a threat to the agricultural industry in Iran and the world. The first step in managing this issue is the identification of herbicide-resistant populations. In this study, 124 and 45 grass weed accessions, including winter wild oat, annual ryegrass, and littleseed canarygrass, were collected from wheat and canola fields, respectively, in different provinces of Iran. The accessions were screened using commonly used herbicides at the three- to four-leaf stage. The weed accessions collected from wheat fields were exposed to the recommended field dose of clodinafop-propargyl, pinoxaden, mesosulfuron-methyl+iodosulfuron-methyl-Na, and mesosulfuron-methyl+iodosulfuron-methyl-Na+diflufenican. Similarly, the canola grass weeds were treated with haloxyfop-R-methyl, sethoxydim, cycloxydim, and clethodim. The experiment was carried out based on a completely randomized design with four replications under controlled greenhouse conditions. Four weeks after spraying, the fresh weight of the populations was measured. The results showed that 52, 9, 19, and 17% of grass weeds in wheat fields were resistant to clodinafop-propargyl, pinoxaden, mesosulfuron-methyl+iodosulfuron-methyl-Na, and mesosulfuron-methyl+iodosulfuron-methyl-Na+diflufenican, respectively. Morover, 47, 47, and 22% of the canola grass weeds showed resistance to haloxyfop-R-methyl, sethoxydim, and clethodim, respectively; while they were susceptible to cycloxydim. Cross-resistance to selective herbicides in canola was observed in 36% of the tested grass weed species. Additionally, multiple resistance to both ACCase and ALS inhibitors in wheat fields was identified in 13% of winter wild oat and 82% of annual ryegrass populations, respectively. It is recommended to avoid the use of herbicides with the same mechanism of action for controlling grass weeds in areas where the wheat and canola rotation system is prevalent

In order to evaluate yield and yield components in intercropping barley with vetch, a two-year field experiment was conducted at the Agricultural and Natural Resources Research Station of Miandoab. The arrangement consisted of 9 mixing treatments with densities of 200 Vetch plant + 300 Barley plant, 200 Vetch plant + 500 Barley plant, 200 Vetch plant + 700 Barley plant, 400 Vetch plant + 300 Barley plant, 400 Vetch plant + 500 Barley plant, 400 Vetch plant + 700 Barley plant, 600 Vetch plant + 300 Barley plant, 600 Vetch plant + 500 Barley and 600 Vetch plant + 700 Barley plant per square meter and sole culture of both crops. The experimental design was a randomized complete block design with four replications. The result showed The highest spikes per square meter, thousand kernel weight, biological yield, and grain yield in barley were observed in the sole culture of barley. Also, the highest plant height, number of seeds per plant, thousand kernel weight, biological yield, and grain yield in vetch belonged to the sole culture of vetch. However, the highest Land equivalent ratio (LER) belonged to treatments of 200 Vetch plants + 500 Barley plants by 1.49,

In order to investigate effects of deficit irrigation and sowing date on qualitative characteristics of oil and fatty acids in Safflower cultivars, a split factorial experiment was conducted based on a randomized complete blocks design with four replications at the research farm of Faculty of Agriculture, University of Zanjan, during the 2015-2016 growing season. In this experiment, irrigation levels included optimal irrigation and deficit irrigation (50% of water requirement) as main plots and combined two sowing dates including (20 March and 20 April) and three spring safflower cultivars (i.e. Gholdasht, Soffeh, and Sina) were allocated to subplots in a factorial arrangement. Drought stress and late sowing date decreased chlorophyll content, seed yield, and oil content. The results showed that deficit irrigation caused decrease in seed yield and oil content. Late sowing date caused a decrease in seed yield. The highest seed yield was obtained on optimal irrigation and on the sowing date 20 March (2036 kg/h) and the lowest seed yield was obtained on 50% of water requirement and the sowing date 20 April (1675.4 kg/h). Among the studied cultivars, the highest seed yield (1986.91 kg/ha) was obtained from Soffeh cultivar. With the sowing date and deficit irrigation, iodine number decreased and acid value increased. Among fatty acids, the content of linoleic and linolenic acids decreased due to deficit irrigation and late sowing date and the amount of oleic and stearic acids was the highest in the second sowing date, while palmitic acid had the highest amount in the first sowing date. Therefore, to obtain the highest yield and the highest oil quality Soffeh cultivar, optimal irrigation and early sowing date are recommended.

To investigate the effect of organic fertilizers on the quantitative and qualitative characteristics of sugar beet under different moisture conditions, a study was conducted as a split plot experiment based on a randomized complete block design with three replications in Mahabad city in 2021. Irrigation treatments, including irrigation after 60 (normal), 90 (mild stress), and 120 (severe stress) mm evaporation from the class A evaporation pan, and organic fertilizer treatments (control, vermicompost, manure, and humic acid) were placed in main plots and sub-plots, respectively. Severe water stress conditions reduced the content of chlorophyll a (22.82 %) and relative water content (RWC) (24.35 %) and increased the content of proline (47.43%), beta glycine (17.89%), catalase (21.30 %), malondialdehyde (47.95 %) and water use efficiency (WUE) (23.83%) compared to normal irrigation conditions. Also, the application of vermicompost increased the amount of chlorophyll a, RWC, proline, glycine beta, catalase content, and WUE by 29.11, 20.15, 34.83, 14.98, 13.70, and 21.56 percent, respectively, and decreased the content of malondialdehyde about 18.53% in comparison to control. In this study, the highest stomatal conductivity (51.01 mol.m-2s-1), chlorophyll b content (16.3 mg.g-1FW), carotenoid (4.27 mg.g-1 FW), roots yield (78.33 t.ha-1) and the lowest content of hydrogen peroxide (0.96 μmol.g-1FW) allocated to the vermicompost treatment under normal irrigation conditions. Root yield showed a positive and significant correlation with stomatal conductance, chlorophyll b, carotenoid, RWC, and WUE, but a negative and significant correlation with catalase enzyme activity, hydrogen peroxide content, malondialdehyde, and sugar content.