جستجوی مقالات مرتبط با کلیدواژه « دور آبیاری » در نشریات گروه « زراعت »

It is predicted that at least 10 million people will be hungry and malnourished in the world by the end of this century. To reduce the food insecurity, crop production will have to be doubled, and produced in more environmentally sustainable ways. This can be achieved by expanding the area of crop production, increasing per hectare yield and improving crop quality. Furthermore, during the second half of the past century, rise in per hectare crop productivity was due to improved or high yield potential. The productivity of plants are strongly influenced by environmental stresses. In the water scarcity condition, using deficit irrigation and appropriate cultivar are the most strategies to improve water productivity. A new generation of dry-tolerant forage varieties would allow for landscape development in stresses environments and where fresh water is limited or not available for irrigation. Hence, the present study was to design with the following

To determine yield and morphogical parameters of quinoa (Chenopodium quinoa Willd.) and forage sorghum) sorghum bicolor), verities at different levels of irrigation and plant densities.

A field experiment was conducted during 2015 and 2016 at Aghghala salinity station. The experiment was laid out in a randomized complete block design in form of factorial split plot factorial experiment and replicated four times. At this research effects of irrigation frequency at four levels (irrigation after 5, 10, 15 and 20 days), and plant density at three levels (11.1, 16.7 and 33.3 plants per m2) on quinoa (Santa Maria and Sajama Iranshahr) and verities of KFS3 and Speed feed sorghums were investigated. Sowing date was the time of soil temperature reaching to 12 °C and the harvesting date was the time of 5% flowering of each plot. For yield estimation, after removing borders, 6 m2 harvested. Data were analyzed using SAS. Treatment means were compared using LSD at the 95%probability level.

Results showed that, the difference in most treats between treatments was significant. Investigation of dry forage yield at irrigation treatment showed, irrigation every 5 days interval with dry yield of 6.01 ton ha-1 had the highest yield and yield components of dry forage. With increasing plant density and dicrasing irrigation frequency dry matter dicreased but this dicreasing mostly accurse at interaction affect of irrigation every 20 days interval and plant density of 333000 plant ha-1. Plant density of 11.12 plants per m2 with yield of 4.98 ton ha-1 had the highest yield. The suitable treatment was variety of Santa Maria at 11.1 plants per m2 with dry yield of 4.77 ton ha-1 had the highest dry yield and variety of Speedfeed sorghum at plant density of 33.3 plants per m2 with yield of 2.53 ton ha-1 had the less ranking.

In all, in order to high quantitative yield irrespective of variety, most frequently irrigation had higher yield than less and intermediate irrigation regime. Though, when comparing the four varieties, quinoa (Santa Maria variety (significantly with dry yield of 4.42 ton ha-1 produced higher dry forage yield. The present findings suggest that in semiarid environments (where saving water is important) it seems that incrasing irrigation frequency is effective for good stand establishment in the saline soils could be insured if proper management is applied in the farms.

In order to investigate the effect of irrigation intervals, 15 selected Okra genotypes from the National Gene Bank of Iran were cultivated and evaluated in a randomized complete block design with three replications in the 2020-2021 crop year in the experimental research farm of the Seedling and Seed Breeding Research Institute in Karaj (Seed and Plant Improvement Institute).

After the plants entered the three-leaf stage, irrigation was done once every 5 and 10 days.

The results of the analysis of variance showed that the effect of drought stress on all measured traits, including plant height, fruit yield, biological yield, number of ripe fruits, weight of ripe fruit, diameter of ripe fruit, number of seeds per ripe fruit, 1000-seed weight, sugar, and protein content, was statistically significant. Under drought-stress conditions, the mean of all evaluated traits (except soluble sugars) was reduced. The highest fruit yield (12.06 tons per hectare) belonged to genotype 10, which decreased by 37.5% compared to the non-stress conditions of this genotype. Genotypes 1 and 12 had the least change in protein content, genotypes 4 and 6 had the least change in sugar content, and genotypes 9 and 11 had the least change in biological function.

Based on the results obtained from this experiment, the best genotype in terms of fruit yield was genotype 10, and in terms of biological function, genotypes 9 and 11 were recommended for use in areas with water shortages.

In order to study the effects of nitrogen and irrigation interval on Broomrape (Orbanche aegyptiaca) damage reduction in cucumber (Cucumis sativa L.), an experiment with two factors, nitrogen (urea in three levels 100,200 and 300 Kg/ha) and irrigation interval (with three levels 3,6 and 9 day) in three replications was performed in the greenhouse of Northern Khorasan Agricultural and Natural Resource Research Center. The results showed that the growing velocity was maximum in the treatment of 200 Kg N/ha. However, height and the number of cucumbers were lower. The effect of irrigation interval on the number of flowering days was significant, whereas nitrogen fertilizer did not have a significant influence on this parameter. Hence, irrigation level rising caused reduction in the number of flowering days. Maximum length and diameter of cucumber was observed in the treatment of highest nitrogen level and minimum irrigation interval or the treatment of lowest nitrogen level and medium irrigation interval. The maximum number of cucumbers and weight was obtained in maximum nitrogen and irrigation interval. In addition, rising irrigation interval caused the number of cucumber increase and decrease in cucumber weight. The maximum wet weight of shoot and root was observed in the highest nitrogen treatment. On the other hand, the maximum wet weight of shoot and root was derived from the highest nitrogen and medium irrigation treatment and the highest nitrogen and minimum irrigation interval treatment, respectively. The comparison of water percent in wet and dry weight of shoot showed that the highest value was observed in 300 and 100 Kg N/ha treatments respectively. Maximum shoot/root ratio was observed in the treatment of 100 Kg N/ha and a six-day irrigation interval.

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 effectiveness of productivity and sustainable agricultural development depends on the availability of natural resources as well as the efficiency of management measures in agricultural lands. Increasing water use efficiency is a promising way to manage agricultural production in arid and semi-arid regions where there is little or no prospect of expanding water resources (Boutraa, 2010). According to Malik et al. (1993) bean yield may be reduced up to 70% when faced in competition with weeds. Extending the irrigation cycle (limited irrigation) in beans is expected to diminish not only the water consumption but also to influence the weed density along with dry matter too.

This project was conducted at Khair-abad research station in Zanjan, Iran, over a period of two years starting from the 2017 growing season. The experimental design utilized a randomized complete block design (RCBD) with 24 treatments and three replications. The treatments were arranged in a strip plot layout. The vertical factor of the experiment consisted of three levels of irrigation intervals: efficient irrigation (every 4 days), limited irrigation (every 9 days), and more limited irrigation (every 12 days). The horizontal factor involved eight sub-factors of herbicides: Trifloraline, Imazethapyr, Trifloraline + Bentazone, Imazethapyr + Bentazone, Imazethapyr + Sitogate, Bentazon + Gallant Super, traditional hand mowing, and a test sub-factor with no control. Several traits were evaluated in this study, including the number of pods, number of seeds per pod, 100-seed weight, bean grain yield, biological yield, harvest index, and productivity index. Data analysis and mean comparisons were performed using the SAS statistical software, employing Duncan's multiple range tests.

The Results indicated that both the herbicides and irrigation periods were effective on density and dry matter of weeds. Reducing irrigation intervals will allow for greater control of weed density and dry matter. Imazethapyr and Trifloraline herbicides as pre-emergence and pre-plant followed by post emergence application of Bentazone leads to about 85 and 82 % reduction at in weeds density at bean 3rd three leaflet appearance stage, 85 and 82 % reduction at 50% flowering stage bean in tow year of the study recorded the most reduction on weeds density. Moreover, these herbicides inducing about 88 and 81% decrease at bean 3rd three leaflets and 91 and 87% decrease at bean 50% flowering stage. These treatments after weeding had the highest control on weed density and dry matter. Trifloraline, when applied as a pre-plant treatment, showed the lowest effectiveness in controlling weeds among all the treatments. It resulted in an average reduction of 49% at the appearance of the bean's third three leaflets and approximately 70% reduction at the 50% flowering stage of the bean plant. This treatment consistently ranked the lowest in terms of weed control throughout the study period. The treatments of Imazethapyr, whether applied solely as a pre-emergence treatment or in combination with Situgate as a post-emergence treatment, were found to be ineffective in controlling weeds. Therefore, these treatments are not recommended for weed management in beans, particularly under limited irrigation regimes. The maximum number of sheaths, grains per sheath, and weight of 100 grains were observed in the irrigation regime of every 4 days when integrated with the application of Trifloraline, traditional hand mowing, Imazethapyr + Situgate, and Imazethapyr alone. In terms of bean harvest, the highest yields of 5175 kg/ha, 4707 kg/ha, and 4624 kg/ha were obtained from the irrigation regime of every 4 days when integrated with traditional hand mowing, the application of Imazethapyr + Bentazone, and Imazethapyr + Situgate, respectively. On the other hand the best biological performance as 9950, 9783, and 9733 kg/ha were related to 4 days interval when integrated with application of Imazethapyr + Bentazone, hand mowing, and Imazethapyr + Situgate. The maximum bean harvest index at 52.82 and 50.80 percent were related to 4 and 9 days intervals integrated with hand mowing, followed by 50.54 percent related to 4 days round integrated with Imazethapyr and 9 days round integrated with Trifloraline+ Bentazone. The highest water efficiency as 0.83 was related to 9 days interval whereas the lowest one as 0.48 was related to 4 days round. Regarding the horizontal factors, during the two years study the maximum water efficiency as 0.86, 0.77, and 0.76 were registered at treatments of hand mowing, application of combined Imazethapyr + Bentazone, and combined Imazethapyr + Situgate, respectively.

Based on the overall results and considering water shortage as well as water usage efficiency and decreasing the amount of both performance and traits of performance reduction in Chiti bean "Kosha" leading to desirable weeds control and bean yield, nine days round irrigation could be recommended provided with application of Imazethapyr or trifloraline herbicides with Bentazone.

In order to evaluate different irrigation regimes and planting date on yield, water use efficiency, and harvest index of Roselle (Hibiscus sabdarjffa L.), an experiment was conducted in form of split plot in randomized complete blocks with three replications in Karaj in 2017. Experimental treatments included irrigation round (Irrigation intervals of 8, 10, and 12 days) as a main plot, andplanting date treatments at three levels of 4th June, 18th June, and 2th July as a sub-plot. Results showed that the main effect of irrigation treatments was significant on all traits except harvest index. Planting date had a significant effect only on plant height, stem diameter, biological yield, flower water use efficiency, and sepal water use efficiency. The interaction of irrigation treatment levels and planting date only made a significant difference in biomass water use efficiency. Also, the flower harvest index was not affected by any of the applied treatments.The greatest plant height (181.2 cm), stem diameter (2.91 cm) and biological yield (14.6 t.ha-1) were obtained in the irrigation interval of 8 days. The highest sepal water use efficiency of (0.18 g.L-1), flower water use efficiency (0.034 g.L-1) and sepal harvest index (11.12 %) were observed in the irrigation interval of 12 days. The irrigation interval of 10 days had the highest sepal yield (1.59 t.ha-1) and flower yield (307.7 kg.ha-1).Delay in planting caused a decrease of 12, 16, and 7% in plant height, stem diameter, and biological yield, respectively and increase in the sepal water use efficiency and biological yield water use efficiency by 22 and 20%, respectively compared to optimum planting time. The highest biological yield water use efficiency (2.41 g.L-1) was obtained in irrigation interval of 12 days and one month delay in planting. Based on the obtained results, irrigation interval of 10 days is recommended to achieve maximum flower yield and sepal yield, increase the flower water use efficiency and sepal harvest index. Also, in order to shorten the cultivation period and save water consumption, the date of 18th June is recommended for plant cultivation in Karaj.

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.

Most bean cultivated lands are in areas that facing water deficit during the growing season. In order to investigate the effect of irrigation period and nitrogen fertilizer on yield, yield components and water use efficiency of red bean (cv. D-81083), an experiment was conducted as a split-plot based on a randomized complete block design with four replications at Boroujerd Agricultural Research Station (Lorestan) during two crop years. The main-plots were included four irrigation times after 36 (I1), 54 (I2), 72 (I3) and 90 (I4) mm of cumulative evaporation from class A evaporation pan and sub-plots were included the amounts and method of nitrogen fertilizer consumption including N1: without the use of nitrogen fertilizer (urea) or control, N2: consumption of 50 kg/ha of urea fertilizer at planting, and N3: consumption of 50 kg/ha of urea fertilizer at planting + 50 kg/ha of urea fertilizer at the beginning of the flowering stage. The results showed that, the highest number of pods per plant (18.3 pods), number of grains per pod (6.13 grains), grain yield (2538.8 kg/ha), biomass (5330.8 kg/ha) and water use efficiency (0.376 kg/m3) were achieved from I2N2 treatment. In the treatment of I4 application of nitrogen fertilizer didn’t have much effect on the traits. In general, the irrigation period can be planted from the beginning of sowing to before flowering stage every 7 to 8 days and after this period arranged for 5-6 days. Also, it is recommended to consumption of 50 kg/ha of nitrogen fertilizer at planting to stimulate early root growth until they sufficiently infected with rhizobium bacteria.

Drip irrigation delivers moisture to the soil surrounding the plant root, leaving the uncultivated ridges mostly dry. The dynamics of dryness and moisture can help adjust the soil salinity and redistribute moisture and salinity (Li et al., 2013; Wang et al., 2011). Further, the distribution of soil salinity in arid regions is affected by a multitude of factors, including the water table (Ming et al., 2016), groundwater salinity, (Abliz et al., 2016), irrigation system (Lie et al.,2013;Zhang et al.,2017), and soil texture (Hu et al., 2011; Zhang et al., 2014). Given the complexity of investigating moisture and salinity distribution in the soil and their uptake by plant roots, the subject has been addressed by several studies around the world. The present study attempts to investigate and evaluate the effects of different irrigation regimes (two-, three-, and four-day) using a tape drip irrigation system on the diffusion and distribution of salinity and moisture around the root of summer maize over two crop years (2018–19) in the South Khuzestan region, where a heavy soil texture is predominant.

Located between the 29°57’ N and 33°0’ N relative to the equator, and between 47°40’ E and 50°33’ E relative to the prime meridian, Khuzestan Province occupies 64,057 square kilometers in Southwest Iran. The present study was carried out in a research farm at the Center for Agriculture and Natural Resources Research and Training, Ahwaz, Khuzestan Province, in summers 2018 and 2019. With clay and silty clay soil textures, shallow and saline groundwater (1.5 m depth), and its particular climate, this research farm can be representative of the farmlands of Central and Southern Khuzestan. The required volume of water during each irrigation by the drip tape irrigation system under different irrigation regimes (two-, three-, and four-day) was calculated for different plant development stages and treatments, thus enabling control over the different irrigation hours in different regimes. the farm soil was sampled at four stages, namely before planting, upon germination, during the middle development stage, and after planting), for physical and chemical characterization and monitoring salt levels from three depths (0–25, 25–50, and 50–75 cm) at a 20 cm distance from the tape by manual excavation using an auger (10 cm in diameter and 20 cm in length). Soil salinity and other quality criteria were measured in the lab. Further, the SMC was measured by the weight percent method, which involves weighing and drying the samples.

The present study addressed moisture and salinity distribution in the soil profile around the plant root under different irrigation regimes. The moisture distribution results showed that all irrigation regimes (two-, three-, and four-day) could maintain the moisture around the FC, slowing down the vertical flow and minimizing penetration into depths. The soil salinity results showed that, considering the soil salinity conditions at the start of the growing season, using the drip tape irrigation first reduced and then increased salinity in the first year of cropping. In contrast, in the second growing season, soil salinity at the end of the growing season using two-, three-, and four-day irrigation regimes was cut to a fourth and a third of its initial level. This shift in the behavior was, however, due to the differences in the quality of irrigation water. This outcome shows the susceptibility of using the drip tape irrigation system in soils that are prone to sodicization and salinity, which requires preparing the conditions to ensure the sustainable function of the irrigation system. The final set of samples showed that, under all irrigation regimes, the emitter output effectively reduced soil salinity, and that this reduction is more effective with frequent irrigations, washing the salts further away from the source. Further, the 0–25 cm deep layer was found to have the least salinity among the studied layers. All irrigation regimes (two-, three-, and four-day) were successful in controlling salinity in the root zone, but the two-day treatment, with a shallower irrigation depth and shorter irrigation intervals, offered the best leaching. The results of performance analysis in two years showed that the year did not have a significant effect on grain and dry matter yield. The results also showed that irrigation regimes did not have a significant effect on dry matter yield but significant on grain yield at 5%.

To evaluate different irrigation regimes and planting dates on plant height, stem diameter, yield, and yield components of okra (Abelmoschus esculentus L.) a split plot experiment based on randomized complete blocks with three replications was conducted in Karaj during 2017 growing season. Experimental treatments were irrigation intervals (8, 10 and 12 days) as a main plot, and planting dates with three levels (4th, 18th of June and 2th July) as a sub-plot. The results of analysis of variance showed that the main effect of irrigation interval was significant on all traits under study. Planting date treatment had a significant effect only on plant height, stem diameter, number of plant branches, number of plant leaves, number of fruits, fresh fruit yield and dry fruit yield. The interaction of irrigation interval treatment and planting date had no significant effect on the trails under study. The highest chlorophyll concentration (3.68 mg.g-1 FW), plant height (100.4 cm), number of branches (3.1), number of leaves per plant (24.8), number of fruits per plant (10.5) and fresh fruit yield (4023 kg.ha-1) were belonged to the irrigation interval of 8 days. Irrigation interval of 12 days decreased by 30.4, 21.7, 21.3 and 28.4 % in stem diameter, fruit length, fruit diameter and dry fruit yield, compared to irrigation interval of 8 days interval, respectively. The highest plant height (99.2 cm), number of branches (2.5), number of leaves per plant (23.3) and number of fruits (9.77) were observed of June 4th planting date. The highest fruit yield was obtained in June 18th planting. Based on the results obtained it can be concluded that irrigation interval of 8 days is recommended to achieve maximum fruit yield and to shorten the length of growing period, saving in water consumption and maximum yield performance in the Karaj region, the date of 18th June is recommended.

Borage officinalis L. is an annual herbaceous plant that is distributed in temperate and subtropical regions, especially in the Mediterranean. Nowadays, foliar application of salicylic acid (SA) as one of the growth regulator for improving plant stresses tolerance such as drought stresses. Biochar is a carbon-rich product in the stable form that benefits from organic fertilizers and is used soil fertility. Considering the importance of medical plant cultivation especially in the drought region, investigation the effects of water deficit on Borage officinalis L has particular importance and according to previous studies on the positive effect of salicylic acid and biochar on mitigation of adverse effects of drought as well as improving water relations in soil, therefore this study aimed to investigate the effects of biochar and salicylic acid (SA) on some characteristics of Borage officinalis L under different irrigation intervals

These experiments were performed in a four replicated-split plot factorial arranged in CRBD with three factors irrigation intervals (5, 10, and 15 day) in the main plots and biochar application (0, 5 and 10 tons per hector) and foliar application of salicylic acid (0,0.5Mm) in sub plots. This study was carried out in research field of Shahrood university of technology, Shahrood, Iran during 2017-2018.

the results indicate that with increasing irrigation intervals in all biochar levels, leaf relative water content (RWC) significantly decreased and biochar application had no significant effect on drought stress. Salicylic acid increased leaf relative water content (RWC) in both irrigation intervals of 10 and 15 days compared to non-treated treatments but it had no positive effect on stress reduction due to increases irrigation intervals. As the irrigation intervals increased, flavonoid levels also declined significantly, salicylic acid partially moderating its use, but biochar application had different effects on flavonoid depending on irrigation intervals. Increasing irrigation intervals up to 10 days increased the level of anthocyanin, but with increasing irrigation intervals to 15 days, it decreased significantly. Biochare application had no significant effect on anthocyanin content (both under and without salicylic acid application) but with increasing irrigation intervals to 10 days, biochar application alone without salicylic acid caused anthocyanin content increased. Nitrogen percentage of borago officinalis.L leaf increased significantly with 5 tons/ha biochar for 5 days irrigation intervals and 10 tons/ha biochar for 15 days irrigation intervals, compared to control (non-biochar). The results also show that the application of biochar 10 tons/ha at 10 and 15 days' irrigation interval moderated the stress caused by increased irrigation interval for leaf nitrogen. Increasing irrigation intervals also reduced the number of flowering shoots, which improved by biochar and salicylic acid application.

biochar had a positive effect on the improvement of some physiological and qualitative indices of borago officinalis. L under drought stress condition, but there were no significant differences between different levels of biochar in terms of positive effects in reducing the effects of irrigation intervals on some traits, Besides, the simultaneous application of biochar and salicylic acid in most traits increased their efficiency in reducing drought stress effects.

To evaluate drought tolerance of three cultivares of forage millet and one variety of sorghum, this experiment was conducted as split split plot based on a randomized complete block design with three replications. Irrigation frequencies consisted of irrigation after 80 (control), 120 and 160 mm evaporation from class A pan as main plots and sub-plots was consisted of sorghum cultivar (Sorghum bicolor cv. Speedfeed) and three cultivares of millet (Setaria italica cv. Bastan, Panicum miliaceum cv. Pishahang and Pennisetum americanum cv. Nutrifeed). Flage leaf sampling was done at three stages, before, one and three days after irrigation. According to the results, delaying in irrigation caused a reduction in leaf pigments and yield of forage, and it also increased proline, sucrose and soluble sugars of leaf.  Continuation of drought stress effects was observed in the days after irrigation. According to the results for the studied cultivars, 120 and 160 mm evaporations were the moderate and sever irrigation frequencies respectively. It needed at least three days to recover the effects of moderate stress. Speedfeed sorghum produced maximum yield, in each irrigation frequencies. The highest forage dry yield (9376 Kg/ha) belonged to speedfeed sorghum under normal irrigation for. There were positive correlations between yield and proline and sucrose as osmotic regulators, but leaf pigments had no significant correlation. Speedfeed sorghum had also high ability to adapt, and it repaired damages faster than millet cultivares after irrigation.

IntroudationSalvia sahendica is a perennial native odorant plant of Iran with a right stem, crustal and about 90-40 cm height. Due to the importance of the use of Salvia sahendica in various pharmaceutical, food and sanitary industries, and because of its potential for cultivation in stressful climates, this plant has attentions to cultivate in low-yielding lands. Until now, there is not a comprehensive study on the response of Salvia sahendica to drought stress. Therefore, in order to evaluate the possibility of production and development of its cultivation under drought stress conditions, this research was carried to investigate the effects of drought stress on some physiological parameters, percentage and yield of essential oil of Salvia sahendica and determining the tolerance threshold of this plant to stress in 1395 in field conditions. Material and MethodsThis experiment was conducted at the research farm of Mobarakeh steel complex which located at 40th kilometers of southwest of Isfahan, at latitude of 32˚ 21′ northern and longitude of 51˚ 27′ eastern. After field preparation, the plants were cultivated in plots with size of 1.5 × 1.5m by 50 × 50 cm spacing in a randomized complete block design with three replicates and 9 plants per replicate. At the beginning of planting, all plots were irrigated three times a week for two weeks until the plants were established. Then, the effect of various irrigation intervals including 4 (as control, which is traditionally the optimum irrigation rate of plant in studied area), 8, 12 and 16 days intervals were applied. At the end of the summer, a sample was taken from the cultivated plant. The plants were fractioned to roots and shoots and some physiological and biochemical indices including, relative water content of leaves (RWC), water potential of leaves, total chlorophyll and chlorophyll a and b, proline and soluble sugars contents, electrolyte leakage, the essential oil percentage and yield were determined. Statistical analysis was performed on the data using MSTAT-C software at 5% level and the correlation between traits was determined by SPSS software. Results The results of analysis of variance showed that the effects of different levels of irrigation intervals on water potential of leaves, relative water content of leaves, soluble sugars, electrolyte leakage, percentage and essential oil yield were discriminated at 1% statistical level while on proline and total chlorophyll, chlorophyll a and b contents at 5%. Based on the results of the comparison of the mean, by increasing irrigation interval from 4 to 8 and 12 days, the differences in the means of all investigated parameters were not significant and only in 16 days irrigation interval the noted parameters differed significantly(pr<0.05). The highest amount of RWC (95%), chlorophyll a, b and total chlorophyll were 2.47, 1.32, and 0.98 mg.g-1 respectively in control treatment. The highest water potential of leaves (-1.78 MPa), proline accumulation (3.1 mg.g-1) and electrolyte leakage (57.7%) were observed in16- day irrigation interval. Maximum amount of soluble sugar, percentage and essential oil yield by the mean of 2.55 mg.g-1, 0.3% and 14.3 kg.ha-1 respectively were obtained in the 12-day irrigation interval. The correlation of traits showed a negative relationship between chlorophyll a, chlorophyll b with proline, soluble sugars, percentage and essential oil yield. Conclusion By considering that non-significant differences were observed in stress resistance indices of this plant up to 12-days interval in comparison with control, it can be concluded with 95% confidence that an optimal irrigation interval for using of this plant in areas arid and semi-arid regions is 12 days irrigation interval, which saves irrigation water. Also, the results of this study showed that Salvia sahendica resisted to water stress by increasing accumulation of proline and soluble sugars (osmotic regulation). Therefore, the accumulation of proline and soluble sugars can be considered as a sensitive indicator for determining the degree of leaf turgidity. Also, in order to produce the highest amount of essential oil from Salvia sahendica, the mild stress (12-day irrigation) can be used.

In order to protect environment and improve plant growth under drought stress conditions, an experiment was conducted as factorial in a completely randomized design with three replications on Niger )Guizotia abyssinica (L.F) Cass( seed at the research greenhouse of Shahrekord University in 2015. Physically pre-treatment as a seed placement in different magnetic field intensities including 0, 50, 100, 150 and 200mT (at 5 minutes time) as the first factor and  irrigation intervals at three levels of 2, 4 and 6 days as the second factor were considered. The effect of magnetic field, drought stress and their interaction were significant on all of the evaluated characteristics. The maximum root dry weight in 150mT field intensity under 2 days irrigation intervals, the maximum leaf dry weight, root length and number of flower in 100mT field intensity under 2 and 6 days irrigation intervals, respectively, the maximum content of chlorophyll a and (a+b) and carotenoids in 50mT field intensity under 6 days irrigation intervals, the maximum content of chlorophyll b in 150mT field intensity under 4 days irrigation intervals and minimum malondialdehyde content in 200mT field intensity under 2 days irrigation intervals were obtained. The maximum number of flowers (as the most important index on increasing yield) were obtaind at 200mT fields intensity for 2 and 4 days and at 50 and 100mT fields intensity for 6 days irrigation intervals. In general, it can be said application of magnetic field with moderate intensities can alleviate stress conditions.

Flowers number and quality of olive tree is the main factor which influence on fruit and oil yield. On this case, water limitation during flowers differentiation and development in winter can reduce productivity by increasing incomplete flowers. Therefore, one of the most important times for irrigation where there is not enough rainfall in the late winter is one month before flowering, which unfortunately usually does not pay attention enough. Therefore, in this study, effect of winter irrigation with three (WI3), six (WI6) and nine days (W19) on flowering, fruit set and fruit and oil yield of two olive cultivars, Zard and Manzanilla was investigated. Rain fed irrigation (Rain fed) and common irrigation schedules in the orchard with, seven days (Control) were as a control. Irrigation of trees in treatments was performed from January to mid-April for three and a half months. The characteristics such as inflorescence number and length were measured from four main branches in each tree. Thereafter, total flowers number, complete flowers and final fruit set after natural flowers abscission was determined form six secondary shoots in each main branch. Fruit yield per tree in each treatment was calculated after fruit maturation. Furthermore, oil yield was measured after oil extraction. The Results showed there was a significant difference between different irrigation treatments for number of inflorescences, number of flowers, complete flowers, final fruit set percent, fruit yield and oil yield and fruit weight was not influence by irrigation. The best winter irrigation interval was dependent to olive cultivars so that The lowest inflorescence number, total flowers numbers, complete flowers and final fruits was found in rain fed olive tree and the highest values inflorescence number, total flowers numbers, complete flowers was found after six days interval for cv Zard and after nine days interval for cv Manzanilla. There was no significant difference between winter irrigation treatments for fruit yield, but there was a significant with rain fed tree. The highest values fruit yield was found after six days interval. Winter irrigation increased fruit yield by about 35 percent and increased oil yield by about 50 percent compared to rain fed treatment, the highest fruit yield was found after six days winter irrigation interval and highest oil yield was found nine days winter irrigation interval. Overall, winter irrigation in olive orchards could increase fruit and oil yield by increasing complete flowers number, final fruit set percentage, oil yield, and fruit weight.

  Rice is the main source of calories in more than one-third of the world's population, increasing by 30 to 35 percent by 2050, according to demand, Iran supplies 50 percent of imports of rice, the import figure in 1993 was about 185 million tons worth one billion and four hundred and ten million dollars (Jedari, 2017). Drought is the most important limiting factor in rice production in 40 million hectares of rice cultivated land in Asia (Ghiasi et al., 2014). Water stress during the vegetative stage reduces the buds; if the stress at the reproductive stage and grain filling causes a decrease in the number of seeds and weight (Rahman et al., 2002). Water stress in the vegetative stage affects the overall biomass reduction, which results from reduced photosynthetic rates and dry matter weights (Tahmasebi et al., 2008). Due to lack of water resources, low irrigation efficiency in rice field, the necessity of increasing water productivity and sensitivity of rice plant to drought stress. In this research, the effect of low irrigation management on morphological traits and yield of rice varieties, as well as determining the best level of irrigation for production Desirable performance in rice varieties has been evaluated. In order to investigate the effect of irrigation management on morphological traits and yield of rice cultivars, four separate experiments were carried out in a randomized complete block design in a research farm of GonbadKavus University in 1395. Four experiments were carried out separately in 5, 10 and 15 days irrigation and irrigation periods. The irrigation treatments were applied for 40 days after planting in the field at maximum tillering stage. The second factor also includes six rice cultivars (An Iranian cultivar Domsiah and three cultivar IR66424–1-2–1-5، IR70360–38–1-B-1, IR 55411-50 and the two lines are being introduced 87.110 and 87.5.103). Morphological traits included : 1- Main cluster length, 2- Plant weight, 3- Leaves number, 4- Plant Height As well as yield and yield components including number of tillers per plant, number of pods in the main cluster, number of filled seeds in the main cluster, Fertility percentage, full grain weight in main cluster, grain weight per plant, grain yield and harvest index As well as the number of days to be considered. Analysis of variance showed that there is a significant difference between all experimental treatment levels. Exerting stress reduces grain yield. The mean comparison results in terms of flood waters showed a cultivar of 87.110, Minimum time to treat and grain yield, which had no significant difference in grain yield in comparison with native damsayah cultivar. In drought stress, 5 days the highest grain yield and the lowest number of days till the cultivar was 87.5.103 was observed. Grain yield in 10-day irrigation stress was significant in IR 55411-50 cultivar compared to other cultivars. Also, the results showed that the figure 87.5.103 was early childhood. In the irrigation round 15 days, while the figure is 87. 110 did not have the highest grain yield, However, there was no significant difference between Damsayeh variety, Also, the Cultivar 87.110 is the earliest and best cultivar in the region.

In order to investigate the effects of irrigation and nitrogen application on some morphological traits and grain yield of corn (SC704) an experiment was conducted in agricultural research farm of Lahijan during 2010. Experimental design was split plot based on Randomized Complete Blocks Design in three replications. Main plots were three irrigation regimes including (rainfed, irrigation interval after 6 and 12 days). Sub plots were five nitrogen rates (0, 60, 120, 180 and 240 kg N ha-1). The results indicated no irrigation and nitrogen application caused significant reduction in leaf area index, total dry matter and grain yield. Non significant differences exist between 180 and 240 kg N ha-1 treatments and also 6 and 12 days irrigation interval in above traits. With reduction of irrigation water and nitrogen rates, silking and ear formation delayed and flowering duration decreased. In general, the most appropriate management of irrigation and nitrogen obtain in irrigation interval after 12 days and 180 kg N-1 treatments.

Drought stress is a major cause of damage to crops throughout the world by reducing the yield by 50 percent. Drought stress when increases that the high evaporation capacity of leaves be higher than the ability of roots to absorb water from the soil. Considering that Iran is in the arid and semi-arid of world, at this areas there is a lot of rain fluctuations and there may be some important stages of plant growth due to water shortage be confronted by reduce soil water potential. Beans (Phaseolus Vulgaris L.) are an important source of food around the world that has a high nutritional value because of protein, fiber and vitamins in grains. This plant is considered a major source of vegetable protein in many developing countries. Reduce the effect of environmental stresses using methods such as irrigation, fertilizer and appropriate methods of planting in these areas is limited. Therefore, genetically breeding plants to minimize environmental stress is worth the effort. Considering the importance of legumes and drought stress, the aim of this study was to identify the tolerant and susceptible bean cultivars using morphological and agronomic traits under drought stress condition and also identify desirable traits be to select tolerance cultivars.
For evaluation the reaction of twenty Red beans ecotypes to drought stress an experiment was conducted in split plot of Randomized Complete Block Design with 3 replications cropping years (2016-2017) at research field of Graduate University of Advanced Technology, Kerman, Iran. In this study, the main plots were three irrigation levels and sub-plot were twenty Red beans ecotypes. After applying the treatments and harvesting time morphological and agronomic traits such as stem height, number of lateral branches, number of pods per plant, seeds per pod, pod infertile, pod length were measured and economic performance. In addition, the weight of the bushes after harvesting and drying, the scales were identified. Analysis of variance and mean comparison of traits was done by SAS software.
The results of variance analysis of traits were showed significant difference between stress levels and between cultivars for all studied traits. In studied red beans ecotypes, the Dhzarchy and Hassan Abad ecotypes had the largest stem height, while Baft ecotype was lower stem height. Most and lowest plant dry weight Obtained from ecotype Mahan (28.27 g) and DashtAb ecotype (15.51 g), respectively. Also, the maximum length pods related to DashtAb ecotype and the lowest be related to the ecotype Bardsir. Economic yeild is affected by water stress applied in the experiment were significantly lower. Studied ecotypes showed significant differences in terms of yield, this may be the result of the effects of water shortages on their yield components.
Conclusions ;According to archived results of mean comparisons, Ghazvin, Mahan, Hasan Abad and Dehzarchi were the most tolerant cultivars and Baft was the most sensitive cultivar. So, it seems that these tolerant cultivars are suitable for direct culture in farm that has limitation for irrigation. Also ecotype Baft in most traits had lower values than other ecotypes which can be considered this ecotype as the most sensitive ecotypes. Totally recommended tolerant ecotypes directly planted or that these ecotypes were crossed to susceptible ecotypes to create a new variety.

In order to select drought resistant or tolerant local olive genotypes an experiment were conducted in field conditions. Seven olive genotypes (D1, Dd1, GW, Ps1, Bn3, Bn6 and Ds17) used as plant materials. A split plot experiment in time was used based on a completely randomized block design with three replications and three irrigation regimes for field experiment. Irrigation treatments period for field experiment were 6, 9 and 12 days interval and 6 days period was as control. Some vegetative characteristics such as plant height, trunk diameter, leaf number, leaf, shoot, and root fresh and dry weight were recorded. Result in field experiments show that Ds17 genotype had the highest trunk diameter and Dd1 genotype had the lowest trunk diameter. Bn3 genotype had the highest number of leaf and D1 had the lowest but D1, Dd1 and GW were in a statistic class. Genotypes show significant differences in leaf fresh and dry weight so that Bn3 genotype had the highest leaf fresh and dry weight and D1 had the lowest. Genotypes show significant differences in shoot and root fresh and dry weight so that Ds17 genotype had the lowest shoot fresh and dry weight and GW had the lowest root fresh and dry weight. The results indicated that olive genotypes had different resistance to drought and vegetative growth status of Bn3 and Ds17 genotypes were better in drought stress conditions.