نشریه تحقیقات علوم زراعی در مناطق خشک
سال دوم شماره 2 (پیاپی 4، پاییز و زمستان 1399)

In order to investigate the effect of selenium foliar application on the physiological and biochemical characteristics of rosemary under irrigation treatments, a factorial experiment was conducted in a completely randomized design in the greenhouse of University of Zabol, Agricultural Research Institute in 2018. The first factor was two levels of irrigation (80% and 30% of field capacity) and the second factor was four levels of selenium foliar application (0, 50, 75 and 100 mg/l). The results showed that foliar application of selenium increased the RWC, carotenoid, protein and ascorbate peroxidase under stress conditions, and the highest amount of these traits were obtained at 75 and 100 mg/l selenium. Foliar application of selenium especially at 75 mg/l under stress conditions increased the soluble carbohydrate, total phenol, guaiacol peroxidase enzyme, polyphenol oxidase enzyme and essential oil percent. The content of ion leakage, proline and catalase increased with stress and the contents of chlorophyll a, b and total decreased. The content of chlorophyll a, b and total, proline and catalase enzymes were increased by foliar application of selenium, especially at 75 mg/l and ion leakage was reduced by selenium foliar application, especially at 75 and 100 mg/l. In general, selenium application by increasing antioxidant compounds (phenol, flavonoid and antioxidant enzymes), osmotic regulators (proline and soluble carbohydrates) and photosynthetic pigments, and reducing ion leakage, alleviation drought stress in rosemary.

The present study was aimed to elucidate the effects of nitrogen and phosphorous fertilizers on A. Canescens as a forge halophyte plant. The treatments; three rates of nitrogen fertilizer (0, 25 and 50 kg N ha-1 in the form of ammonium nitrate) and phosphorous fertilizer (0, 25 and 50 kg ha-1 in the form of triple superphosphate), arranged in a split plot design with three repelication. Each experimental unit consisted a pot with 1 m height and 45 cm diameter. Plants were irrigated with irrigation water salinity of 14 dS m-1 using bubler irrigation system. The results showed the negative effect of age on forage production. At first year, 19.2 ton ha-1 of shoot fresh weight was produced but it was decreased to 14.8 and 11.49 ton ha-1 at second and third years, respectively. In addition, the results showed the positive effect of nitrogen fertilizer on forage production. Application of nitrogen at a rate of 25 and 50 kg ha-1 increased shoot fresh weight from 7.91 to 15.13 (91%) and 21.85 (176%) ton ha-1. While the same trend was found for total dry weight, leaf and stem dry weight, nitrogen application had not significant effect on leaf to stem ratio. It should be noted that phosphorous application had not significant effect on A. Canescens performance. Overall, application of nitrogen fertilizer at a rate of 50 kg ha-1 is recommended for improving A. Canescens performance irrigated with saline waters with electrical conductivity of 14 dS m-1. The results showed that forage production significantly decreased with increasing plant age. While fresh forage equaled to 19.21 ton/ha at first year, it decreased to 14.18 and 11.49 ton/ha at second and third year of experiment. While application of nitrogen was essential for halphyte production, application of phosphorous fertilizer did not affect plant performance. Applicaton of nitrogen at a rate of 25 and 50 kg/ha urea increased forage productin at a rate of 91 and 176 percent respectively. Overall, it was concluded that productin of halophytes such as Atriplex canescens under saline calcareous soils of Yazd province for forage productin is possible and urea fertilizer improves plant performance.

The application of superabsorbent polymeric materials may prevent yield reduction of some crops under drought stress conditions. To investigate the effect of adsorbent polymer consumption on yield and yield components of sunflower under drought stress conditions, an experiment was conducted as a split plot in a randomized complete block design with 3 replications in a farm located 20 km away from Sabzevar during 2013-2014. Factors were irrigation regimes (12-day and 24-day intervals) as main plot and different amount of super absorbent polymer (0, 30, 60, 90 and 120 kg ha-1) as subplot. The results showed that plant height, number of seeds per head, percentage of empty seeds, 100-seed weight, economic yield and biological yield were significantly affected by irrigation intervals. Increasing the irrigation interval reduced plant height by 26.3%, number of seeds per head by 39.5%, 100-seed weight by 17.9%, economic yield by 31.2% and biological yield by 17.9%. The highest yield and yield components were obtained at application of 120 kg ha-1 superabsorbent polymer and the lowest at control treatment. Although the yield response to the use of superabsorbent polymer was higher in the 12-day irrigation interval, use of superabsorbent polymer reduced the negative effects of drought stress. In 12-day irrigation interval, consumption of 120 kg ha-1 absorbent polymer and in the 24-day irrigation interval, consumption of 30 kg ha-1 absorbent polymer produced the maximum net income. In total, the highest grain yield and economic income were obtained at application of 120 kg ha-1 superabsorbent and 12-day irrigation interval.

In order to evaluate the effect of water stress on grain yield and its components and parameters of dry matter remobilization in sorghum genotypes (Sorghum bicolor L.), a field experiment as a split plot design was carried out with three replications in 2014 at the research farm of the southern Khorasan Agriculture and natural resources research and education center. Main factors including normal irrigation (control), irrigation cut off in vegetative growth stage (emergence of terminal leaf as rolled) and irrigation cut off in generative growth stage (50% of plants in start of flowering) and genotypes including KGS29, MGS2, Sepideh, KGFS27, MGS5, KGFS5, KGFS17, KGFS13 and KGFS30 were as sub factors. Results showed that water stress had significantly effect on grain yield, biological yield, harvest index, 1000 seed weight, seed number per panicle and caused to decrement of them. The grain yield reduction was about 42% at the highest level of water stress (irrigation cut off in vegetative growth stage) in comparison with the control. The genotype KGFS13 had the highest grain yield, biological yield and harvest index. The effect of water stress was significant on ARDM (Amount of Remobilized Dry Matter) and %REP (Remobilization Percentage) at %5 probability level and this effect was not significant on %REE but each of those parameters were highly increased with water stress inducing and stress severity increasing. Generally, remobilization process can be considered as one of the optimal and selective mechanisms in sorghum cultivars and genotypes, especially in terms of drought stress condition.

Application and nutrition of the maternal plant have a great role in germination and vigor of the produced seeds. In order to study the germination characteristics of barley native seeds obtained by application of different foliar application under saline irrigation (12 dS/m electrical conductivity), a factorial experiment with completely randomized design with three replications, was carried out at Isfahan Kaboutarabad Agricultural Research Station, in 2018-19. The first factor (foliar application) was in five levels: no foliar application, Zinc sulfate, Potassium sulfate, Salicylic acid and Superoxide dismutase at the beginning of tillering at 7 days interval and on three occasions. The second factor (barley cultivars) was Gohran, Mehr and Armaghan. Attributes such as germination percentage and rate, root length, shoot length, seedling vigor index, root dry weight, shoot dry weight, seedling vigor index, germination uniformity, and allometric coefficient was measured. Under saline water and different foliar application conditions, Mehr cultivar produced more radicle length, shoot length and seedling vigor index (except zinc sulfate). Seed longevity (root length, shoot length, seedling vigor index) appeared to be effective in selecting salinity tolerant cultivars. In foliar application of potassium sulfate, germination uniformity and germination rate of Mehr (salt tolerant) cultivar were higher than Armaghan (salt sensitive). The highest allometric coefficients of seed belonged to foliar application of potassium sulfate (0.85) and zinc sulfate (0.84) in Mehr (0.81) and Armaghane (0.83) cultivars.

In order to investigate the effect of mixing nicosulfuron herbicide with salicylic acid and cocowet adjuvant on growth, yield and weeds control in corn, a field experiment was conducted as factorial based on randomized complete block design with three replications at the research field of Shahrood University of Technology. Factors were including weed control method (A) at four levels, control (a1), weeding (a2), consuming 1 liter of herbicide (nicosulfuron) (a3) and consuming 2 liters of herbicide (a4) and salicylic acid (B) in two levels, 0.7 mM salicylic acid (b1) and the absence of salicylic acid (b2) and cocowet (C) in two levels, consumption of 2 liters per hectare cocowet (c1) and absence of cocowet (c2). The results showed that the maximum plant height (143.2 cm) and leaf area index (7.76) was obtained with combined use of salicylic acid and cocowet. Also the highest grain (7528 kg.ha-1) and biological (20490 kg.ha-1) yield was observed in weeding × salicylic acid consumption treatment. The results indicated that no significant difference was observed in grain yield and total weed density between the cocowet + reduced herbicide dose (1 L.ha-1) with recommended herbicide dose (2 L.ha-1). Based on the results of present study, application of cocowet in combination with reduced dose of herbicide can be an effective method of weeds control and increase growth and yield of crop and also reduce herbicide consumption.

The aim of this study was to examine the effect of different sources of potassium in soils contaminated with lead and cadmium and their effect on photosynthesis by investigating changes in chlorophyll content in lavender (Lavandula officinalis L.). This study consisted of two independent factorial experiments in a completely randomized design with three replications. In the first experiment, two factors of potassium fertilizers (potassium chloride, potassium sulfate and potassium nitrate were applied at two levels of 55 and 110 mg kg-1 soil along with control) and cadmium chloride (0 and 15 mg kg-1 soil). In the second experiment, the factors included potassium fertilizers, similar to the first experiment, and lead nitrate (0 and 100 mg kg-1 soil). Analysis of variance of data showed that potassium fertilizers have a significant effect on the amount of chlorophyll a, b and total chlorophyll. The results showed that in soil contaminated with cadmium and lead, the chlorophyll content decreases significantly compared to uncontaminated soil. The results also indicated that in soils contaminated with cadmium, the greatest amount of total chlorophyll was obtained at the level of 110 mg kg-1 of potassium chloride, which showed a significant increase of 70% over the control level. The results of laboratory analyzes confirm that in lead contaminated soils, the greatest amount of chlorophyll a was obtained at the level of 110 mg kg-1 of potassium chloride, which showed a significant increase of 71% over control; Therefore, it seems that the use of potassium fertilizers may be effective in increasing the amount of chlorophyll, in which the effect of potassium chloride fertilizer is greater than that of the other two fertilizers.

Lemon balm (Melissa officinalis), which belongs to the Lamiaceae family is one of the most important medicinal plants which is characterized by the smell of lemon. In order to study the symbiotic effects of Piriformospora indica (an endophytic fungus) on morpho-physiologic characteristics of lemon balm under salt stress, an experiment was conducted in the research greenhouse of Malayer University in 2017 as a factorial based on the completely randomized design (CRD) with three replications. Experimental treatments were included various forms of P. indica (mycelium, spores application once, spores applications twice, and control) as the first factor and different levels of salinity (0 and 4 dS/m) as the second factor. Based on the results, the interaction of experimental treatments on plant height, root length, leaf dry weight, chlorophyll a, relative water content, membrane stability, and soluble protein content was significant. The highest amount of plant height, root length, and leaf dry weight was related to the treatment of spores applications twice without salinity stress. The highest amount of chlorophyll a and membrane stability observed in the mycelium treatment under control conditions. In general, according to the results of this experiment, it seems that the use of this fungus is recommendable to moderate the negative effects of salinity stress, and among the various treatments, spores applications twice has more ability to reduce the negative effects of salinity stress.

Drought is one of the most important environmental stresses in agroecosystems. In order to determine the optimum level of water-superabsorbent that can reduce drought effect on growth traits in foxtail millet, an experiment was conducted as a factorial based on completely randomized design at Research Greenhouse, College of Agricultural Science and Engineering, Razi University. Different levels of drought included non-drought (short-term irrigation interval) and drought (long-term irrigation interval). Different rates of superabsorbent included 0, 0.2, 0.4 and 0.8 g per kg of soil. Results showed that non-drought with water-superabsorbent rate of 0.8 g per kg of soil produced the highest leaf dry weight, stem dry weight and seedling dry weight. Drought with non-application of water-superabsorbent produced the lowest leaf dry weight, stem dry weight and seedling dry weight. Application of water-superabsorbent increased leaf relative water content in foxtail millet. Drought increased chlorophyll index in foxtail millet, but application of water-superabsorbent decreased this index. In conclusion, the results show positive effect of water-superabsorbent on growth and dry matter production in foxtail millet under drought condition.

In order to investigate the inoculation of chickpea seeds with rhizobium, arbuscular mycorrhiza and pseudo-endomycorrhiza, an experiment was conducted, in factorial by arrangement of three factors with a completely randomized design and three replications in research greenhouse, Faculty of Agriculture, Ferdowsi University of Mashhad. First factor was consisted of two sterilized levels (put the soil at 121°C for 15min in autoclave) and non-sterile soil and second factor was consisted of three levels mycorrhiza (arbuscular mycorrhizaof Glomus mosseae, pseudo-endomycorrhiza of Piriformospora indica and non-used mycorrhiza) and third factor was consisted of two rhizobium levels (using rhizobium strain of Mesorhizobium ciceri and non-used rhizobium). The results indicated that mycorrhiza significantly increased weight, area and root colonization. But effect of mycorrhiza wasn’t significant on number of rhizobium nodules. Application of rhizobium significantly increased weight, area and number of rhizobium nodules. But effect of rhizobium wasn’t significant on root colonization. In conditions of non-sterile soil, number of rhizobium nodules and root colonization were significantly increased. In study of interactions was found that in condition of using mycorrhiza in sterile soil in traits of area and root colonization, were assigned the highest rate compared to other treatments. The combined application of mycorrhiza and rhizobium was caused significant superiority in length and area of roots. Using rhizobium in non-sterile soil conditions than non-using rhizobium and sterile soil, increased number of rhizobium nodules significantly at the rate of 90.5%. It seems that the use of mycorrhiza in chickpea cultivation can be effective to improve root characteristics

To examine the intercropping system of roselle with mung bean, a field experiment was carried out at the research farm of the University of Zabol. Split plot experiment performed on the basis of an RCBD with three replications. The main plot consisted of three tillage systems (no-till, minimum and conventional tillage) and the subplot was 5 planting ratios (sole culture of roselle and mung bean, 50% roselle + 50% mung bean, 25% roselle + 75% mung bean, 75% roselle + 25% mung bean). The parameters studied in this experiment included land equivalent ratio (LER), relative crowding coefficient (RCC), completive index and dominance index. The highest RCC was obtained at no-till (3.02) and the lowest RCC was obtained in conventional tillage (2.51). The highest RCC was obtained at 25% roselle + 75% mung bean (4.63). Among different tillage systems, the greatest dominance index of roselle was obtained from the no-till system (0.79). The interaction of tillage systems and different ratios of intercropping showed that the highest dominance index for roselle was obtained from no-till and intercropping of 75% mung bean + 25% roselle (1.69). The highest LER was obtained in plants grown at 75% mung bean + 25% roselle. Comparison of competitive indices of intercropping of roselle and mung bean showed that roselle with higher economic yield is more competitive than mung bean.

Considering Iran’s climatic conditions, which is located in an arid and semi-arid climatic region, investigating the methods of water-saving and more efficient use of water resources, is one of the most important research priorities. For this reason, in this research, the effects of organic and inorganic mulches on the performance of the flowering plant of Gaillardia aristata were investigated. The experiment was conducted as a randomized complete block design with three replications. The experiment included four mulch treatments of wood chips, scoria, polyethylene, pine leaves and no mulch as the control. The results showed that mulches had significant effects on the number of the days to flowering, flowering period, flower diameter, plant height, dry and fresh weight of roots and shoots, visual quality, percentage of weeds, water use efficiency, chlorophyll index, chlorophyll a and b but relative water content and stem diameter were not significantly affected by the mulch treatments. The results showed polyethylene and pine leaf mulches had the best effects on most of the traits compared to the other mulch types. Based on these results we can recommend using polyethylene and pine leaves as mulches for planting Gaillardia aristata in arid and semi-arid climate regions.

In order to study the effects of marjoram extract on soybean (Glycine max), an experiment was conducted in research field of Shahroud University as factorial based on completely randomized blocks in 3 replications. Experimental treatments included marjoram extract in 5 levels (no pretreatment, pretreatment with extract of 40 and 60 percent each for 6 and 9 hours) as the first factor and foliar application of extract in 3 levels (distilled water spraying, extract spraying of 40 and 60 percent) as the second factor. The highest dry weight of leaf (253.3 g.m-2) and stem (279.0 g.m-2) was obtained in pre-treatment with concentration of 40% for 6 hours with foliar application of 40% extract. The maximum leaf area index and number of secondary lateral branches, was obtained with foliar application of 40% marjoram extract that caused a significant increase by 8.8 and 18.3 percent compared with control respectively. The maximum carotenoid (0.029 mg.g-1 dry weight) and total chlorophyll (1.12 mg.g-1 dry weight) was observed in pre-treatment with concentration of 60% for 9 hours in combination with foliar application of 60% extract. In general, it can be said that the use of marjoram extract, while increasing the growth characteristics and yield of crops, can also reduce the environmental pollution.