جستجوی مقالات مرتبط با کلیدواژه "irrigation cycle" در نشریات گروه "زراعت"

Drought is one of the major factors limiting productivity in agriculture and nutrition management, including the use of potash fertilizers, plays an important role in plant resistance to drought. In order to evaluate the quantitative and qualitative characteristics of forage amaranth in comparison with forage millet, a split factorial experiment was designed and conducted in a randomized complete block design with three replications in 2016 and 2017 in Saadatshahr region of Fars province. In this experiment, three irrigation intervals (5, 10 and 15 days) were used as the main factor, potassium fertilizer (50, 100 and 150 kg.ha-1) and forage plants (amaranth and millet) as sub-plots. The results of mean comparison of two-year combined analysis showed that amaranth had significantly more height, stem diameter, inflorescence length, number of leaves per plant, dry forage yield, ash percentage, crude protein and carbohydrate content than millet. Increasing the irrigation interval reduced the height, stem diameter, inflorescence length, number of leaves per plant, 1000-seed weight, percentage of crude fiber, dry matter yield, ash percentage, and soluble carbohydrates. By increasing potassium fertilizer level, plant height, stem diameter, inflorescence length, number of leaves per plant, percentage of crude fiber, dry forage yield, ash percentage, crude protein percentage, ADF percentage and NDF percentage in the plant decreased. In general, it can be concluded that amaranth plant has higher yield and drought tolerance than millet and the application of 150 kg.ha-1 of potassium fertilizer can be recommended to achieve higher yield.

The use of biological fertilizers can be effective and beneficial in abiotic environmental stresses specially in drought stress, arid and semi-arid regions of the world.

An experiment was conducted to investigate the effect of deficit irrigation stress and Pseudomonas bacteria on some morpho-physiological traits of two potato cultivars at the research farm of Shahroud University of Technology located in Bastam region in 2010. Treatments included irrigation cycles as the main factor at three levels (7, 10, and 14-days), Pseudomonas bacteria (inoculation and non-inoculation) and cultivar at two levels (Savalan and Agria) as the sub-factor with three replications.

The results showed that the highest dry matter accumulation in the aerial part was observed in the 7-day irrigation cycle and inoculation with Pseudomonas bacteria. The number of tubers was increased about 12.66% because of inoculation with Pseudomonas fluorescens per square meter. Savalan cultivar interaction and 7-day irrigation cycle also obtained the highest number of tubers with an average of 166.39 per square meter. The application of inoculation with Pseudomonas fluorescens increased chlorophyll A by 9.3%. It compared with non-bacterial inoculation. Chlorophyll B had the highest chlorophyll content in the main treatments of the 7-day irrigation cycle and Agria cultivar. The highest amount of potassium content was obtained at the rate of 2.06% at the highest irrigation cycle (14-day). The application of inoculation and non-inoculation with Pseudomonas caused the highest amount of proline at 14-day irrigation cycle. Inoculation with Pseudomonas bacteria increased the final tuber yield about 22.85%. Furthermore, Savalan cultivar increased the final tuber yield about 110.09% in the 7-day irrigation cycle compared to the 14-day. Finally, the 7-day irrigation cycle was the best irrigation cycle to increase the morpho-physiological traits, chlorophyll, number of tubers, and the final tuber yield. Inoculation with Pseudomonas bacteria increased the effectiveness of these traits. Also, the production of compatible osmolytes (proline and potassium) improved drought stress tolerance in 14-day irrigation cycle. Growth-promoting bacteria improves seed germination, root propagation, shoot and root weight, leaf area, chlorophyll content, hydraulic conductivity, protein, nutrient absorption and plant yield (Batool et al., 2020). Growth-promoting bacteria of polysaccharides increases biomass production under drought stress conditions (Daffonchio et al., 2015). Potassium is one of the most important osmolytes under drought stress conditions and adverse conditions (Anschütz et al. 2014). Cellular and physiological responses are carried out through organic salts as proline to reduce cellular damage during drought stress. It is an osmotic regulator (Merwad et al., 2018)

The 7-day irrigation cycle was the best irrigation cycle to increase the morpho-physiological traits, chlorophyll, number of tubers, and the final tuber yield. Inoculation with Pseudomonas bacteria increased the effectiveness of these traits. Also, the production of compatible osmolytes (proline and potassium) improved drought stress tolerance in 14-day irrigation cycle.

Grass is considered as one of the most important covering plants in designing green spaces. We aimed to assess the growth retarding effects of Paclobutrazol on several physiological characteristics of Bermuda grass under dry stress in the form of a randomized factorial design study with three repetitions. The treatments in this study were paclobutrazol at concentrations of 0, 25, 50, and 75 mg/l and drought stress at four levels (irrigation based on 100, 80, 60, and 40% of the field’s capacity). We found that grass under severe drought stress conditions (40% FC) and were treated with concentrations of 50 and 75 mg/l Paclobutrazol had the highest amount of proline. Grass under moderate drought stress (60% FC) and was treated with Paclobutrazol 50 mg/l had the highest amount of soluble carbohydrates. When using 75 mg/l Paclobutrazol resulted in increased chlorophyll in Bermuda grass. Grass that was irrigated under normal conditions (100% FC) and was treated with different concentrations of paclobutrazol had the highest relative water content. The highest ion leakage was seen in grass under severe drought stress (40% FC) and 0 mg Paclobutrazol. In conclusion, we suggest the use of 50 mg/l Paclobutrazol in order to reduced water consumption or enhancing the growth of grass under drought stress.