کم آبیاری

 Climate change predictions indicate that drought and extreme heatwaves will become more frequent and extreme in many regions. Drought is the main abiotic stress that severely reduces plant yield across the globe. Thus, this may have negative consequences for the agricultural soils, as it limits the availability of water and nutrients to soil microorganisms and plants that develop on these soils. To cope with this situation, the use of organic amendments is the best option. Recent studies have shown that the application of organic fertilizers can affect soil moisture and thus, mitigate the negative effect of climate change on that parameter. Organic amendments increase soil organic matter content thus improving soil physical, chemical, and biological properties, and therefore, can confer drought resistance to soils. The application of organic residues has been presented as a great strategy against soil degradation in semiarid environments. However, the interactions between organic amendments and drought in hollyhock plants are not fully known. Here, we evaluate whether the organic amendment influences the physiological traits of hollyhocks and soil properties under drought conditions.

 The experiment was conducted in the research field at Ferdowsi University of Mashhad, Iran. The experiment consisted of three factors (cultivars, organic amendments, and drought) with organic amendments and drought having four and three levels, respectively. Drought treatments were controlled by a TDR at 80, 60, and 40% FC. The three sources of organic amendments were used cow manure, rice hull and wheat straw. Seeds were planted in cocopeat, perlite, and peat mixture trays in the greenhouse with an average temperature of 20 °C and under a photoperiod of 14 hours of light and 10 hours of darkness with a light intensity of 400 μmol-1 m2. In the 5-6 leaf stage, seedlings were transferred in pots (18 cm high and 8 cm in diameter) containing field soil. The plants were transferred to the field with four different substrates (field soil, field soil + manure, field soil + rice hull, and field soil + wheat straw) and were exposed to drought stress for one month during the flowering stage. This analysis examined both the physical and chemical properties of the soil, including changes in the macroelements nitrogen, phosphorus, and potassium.

 Soil nitrogen changes were significantly affected by the interactions of ecotype with drought, ecotype with the medium, and drought stress with medium. The highest nitrogen changes were recorded in Mashhad ecotype under 80% FC. Nitrogen content in amended soil had an increasing trend during the experiment, but the amount of nitrogen had a decreasing trend in soil. In all media under stress, the amount of soil phosphorus was increased and the highest amount of phosphorus was observed in soil + manure at all irrigation regimes. The highest amount of potassium in both ecotypes was observed in soil + manure. The amount of potassium in amended soils under stress significantly increased, but in all organic amendments with increasing drought stress from 80 to 40% FC, the potassium content decreased. In both ecotypes, soil salinity was increased in all culture media. Han et al. (2016) stated that the amount of nitrogen, phosphorus, and potassium in the amended soil was higher than the substrates containing chemical fertilizer. The medium EC was alkaline at the end of the experiment and the salinity of the culture medium increased compared to the control. This study revealed a negative correlation between electrolyte leakage and dry weight in hollyhock plants. Furthermore, all measured physiological and growth parameters were significantly affected by the treatments. Notably, the Mashhad ecotype grown in soil supplemented with animal manure at 80% field capacity (FC) exhibited the highest levels of physiological traits (SPAD and relative water content) and growth index (dry weight).The application of manure + soil by providing macro elements reduces the negative effects of drought stress.

 The type of crops grown in arid and semi-arid regions should be reconsidered. Also, some plants with high water requirements should be replaced with plants with low and unexpected water requirements. Because hollyhocks are low-expected plants that grow well in drought areas, so they can be considered as suitable species for cultivation in low-input systems and can tolerate drought situations by 40% FC in amended soil.

Water scarcity is one of the most important limiting factors threatening the production of horticultural crops. Approximately, 45% of the world's arable land is subject to permanent or intermittent water shortages, and approximately 50% of the world's annual yield is lost due to drought. Due to climate changes, especially the increase temperature and decrease rainfall in recent years in Iran, most of the gardens are facing limited water resources. In order to reduce water stress, increasing water use efficiency by naval technics seems to be crucial. Peach fruit growth mainly depends on adequate water supply. Therefore, water stress reduces the growth of the fleshy part and the quality of the peach fruits. Split root means placing a part of the root in different conditions compared to the remains of the root. Studies on split root culture were done in the laboratory for the first time. Increasing water holding capacity by split root system may improve soil- plant water availability. Furthermore, many studies indicated that Mycorrhiza and Trichoderma fungi improve the absorption of water and nutrients by plant. Increasing the absorption of water and nutrients leads to increasing growth and yield. The aim of this research was to improve the water efficiency and the use of low-yielding lands by placing a bag containing pumice and inoculating the roots with fungi.
This experiment was performed as a factorial experiment based on randomized complete blocks design with three replications for two years. Treatments included placing the bag close to the trunk of peach trees in three levels (without bag, one bag and two bags), different levels of irrigation (50, 75 and 100% of field capacity) and root inoculation treatments with mycorrhiza, Trichoderma fungi and control without fungus. Redtop peaches grafted on GF677 rootstock were planted in May 2018. The bags were placed at a depth of 60 cm and at a distance of 40 and 60 cm from the tree trunk. The bags size was 40 liters filled with pumice. At 20 cm from the top of the bag, three holes were made to remove excess water from that part and as a signal to cause the root to move towards the bag. For plants treated with mycorrhiza, 250 g of Mycorrhiza glomus was mixed and for plants treated with Trichoderma, 4.5 g of Trichoderma harizanium was mixed with pumice in the bag. In treatments with no bag placement, the plant roots were inoculated with fungi. Characteristics such as relative water content (RWC), yield, total soluble solids (TSS), titratable acidity (TA), TSS/TA, total phenol and fruit anthocyanin were measured at the end of growing season. Fruit skin color characteristics including L*, a*, b*, Chroma and Hue were measured with a colorimeter. Statistical analysis was performed by SAS software version 9.1. Mean data were compared using Duncan's multiple range test. drawing diagrams done by Excel software.
 
The results showed that bag placement increased RWC. The highest RWC of leaf was measured in the treatment of placing two bags, 75% irrigation and root inoculation with Trichoderma fungus. In the main effect of bag placement, irrigation levels and root inoculation, the highest RWC of leaf was observed in placing a bag, 100% irrigation and root inoculation with Trichoderma fungus, respectively. The treatment one bag, 100% irrigation and root inoculation with mycorrhiza improved vegetative growth and produced the largest trunk diameter.  Yield in terms of fresh weight of fruit in two-bag placement, 100% irrigation and root inoculation with mycorrhiza was increased by 1.8 compared to the control. The highest TA was measured in the treatment of placing a bag, 50% irrigation and root inoculation with mycorrhizal fungus. Treatment without bag placement, 75% irrigation and without fungus inoculation had the highest total soluble solids and TSS/TA of fruit. The index ratio of TSS/TA is used to determine the taste of the fruit. The highest total phenol and anthocyanin of fruit was observed in treatments without bag under 50% irrigation levels. One bag placement, 75% irrigation without fungal inoculation treatment and no bag placement treatment, 50% irrigation, mycorrhiza inoculation caused the a* and L* of the fruit skin increased. The interaction effect of the three factors of bag placement, irrigation levels and root inoculation with fungus had no significant effect on Hue and b*.
The results of this experiment showed that water consumption can be reduced by placing a bag. The finding of the experiment led to the conclusion that a bag placement treatment, 75% irrigation and inoculation with mycorrhizal fungus improve fruit yield and quality of peach trees
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The availability of water for irrigating crops is one of the serious challenges at present and the future of the world. Drought stress has harmful effects on plant growth and productivity, though bringing some serious changes in plant physiology and biochemistry. Drought reduces plant growth and yield by having negative effects on plants water potential, cell division, photosynthesis activity, chlorophyll content, and protein synthesis. Although olive naturally tolerates drought, studies had shown that drought undermines its growth, yield and photosynthesis. Employing some appropriate transpiration-reducing approaches could induce olive tolerance towards water deficiency. In this regard, kaolin, through raising light reflection and diminishing the rate of transpiration, is able to lessen leaf temperature in the stressed plants. Salicylic acid (SA), as a strong signaling molecule in plants, regulates physiological and biochemical functions effective in defense mechanisms and also boosts biological and non-biological factors involved in augmenting plants.. The major roles of SA in drought- stressed plants are as follows: activation of antioxidant defense system, production of secondary metabolites, synthesis of osmolytes, optimization of mineral status and maintenance of proper balance between plant photosynthesis and growth. Although some information over effects of SA and kaolin individually on stressed plants is available, to the best of our knowledge, their simultaneous effects on plants under stressful conditions has not been investigated yet. Therefore, the present study was aimed to investigate different applications of SA and kaolin (i.e. individually and simultaneously) on field-grown olives under drought condition.

This research was conducted in Dalahu Olive Research Station located in Kermanshah province. This experiment was designed as a factorial experiment in the form of a randomized complete block design with 3 replications. Factors included different foliar spraying (i.e. control, 1 mM SA, 2.5% kaolin, and a combination of them in the mentioned concentrations) and irrigation at three levels (i.e. 100, 75, and 50% of water requirement). Irrigation was performed based on three-day interval schedule according to the above method by measuring daily evapotranspiration and required volume of water by considering the plant coefficients of olives and by drip irrigation.

Although olive tree is a drought-tolerant plant, drought diminished its yield. The results of this study demonstrated a decrease in total yield of olive trees due to water deficit in different years. In this regard, water deficit under high temperature and low atmospheric humidity are believed to bring about a reduction in yield of drought-stressed olive. The results of this research showed that the foliar application of SA and kaolin on olive trees led to a reduction in ionic leakage and malondialdehyde (MDA) and an increase in RWC, chlorophyll content, phenol and total yield, as compared to the control. Foliar application of SA caused a significant increase in proline content and total carbohydrates, while kaolin had no significant effect on aforementioned traits. It seems that a reduction in oxidative damage and an increase in yield of olive cultivars under different irrigations manifested several defense mechanisms induced by exogenous application of SA and kaolin. In this context, kaolin was found to protect leaves and fruits from harmful ultraviolet rays and this remarkably improves the performance of drought-stressed plants by a decrease in the ambient temperature of plants in order to mitigate deleterious effects of drought such as oxidative damage, chlorophyll degradation, and lowering RWC. These results have been substantiated for different olive cultivars at different parts of the world under this condition.In the present study, SA increased chlorophyll content, RWC, proline content, carbohydrate and total phenol; as a result, the yield of SA- treated plants was higher than that in control plants. Similarly, Brito et al (5) reported that applying SA on drought-stressed olive improved osmolate accumulation, photosynthesis activities, RWC and chlorophyll content. The accumulation of phenolic compounds in SA-treated plants is believed to protect plants against stressful conditions. Therefore, the role of SA and kaolin in alleviating drought in favor of enhancing plants yield represents their efficiency under such condition. In the present study, we also employed a combination of SA and kaolin and the results showed no synergistic function between them on most traits. Therefore, to reduce the effects of drought on olive tree, it is recommended to utilize SA or kaolin separately.

To investigate the effects of rice husk biochar application on the various physiological and biochemical characteristics (fresh and aerial parts dry weight, plant height, percentage and essential oil yield,and  content of chlorophylls, carotenoids, nitrogen, phosphorus, and potassium) of peppermint (Mentha piperita L.) under different irrigation regimes, a factorial pot experiment with different levels of biochar (0, 3, and 6 t.ha-1) and irrigation (100% of full irrigation (control), 60, 80, and 120% of full irrigation) was conducted in a completely randomized design with four replications in the research greenhouse of Lorestan University in 2019. The results showed that the highest and lowest of aerial parts fresh weight were obtained in the 3 t.ha-1 biochar + 120% of full irrigation (24.2 g.pot-1) and 3 t.ha-1 biochar + 60% of full irrigation (13.3 g.pot-1) treatments, respectively. At the 60% of full irrigation level, the dry weight, height, essential oil yield, and N and P concentration of the plant aerial parts significantly decreased by 39.8, 33.3, 26.2, 17.2, and 8.7%, respectively compared to the control; while the essential oil percentage and K concentration of aerial parts had an increasing trend. The amount of a, b, and total chlorophyll, and carotenoids decreased under the water stress conditions. The highest amount of total chlorophyll was observed in the 6 t.ha-1 biochar + 100% of full irrigation treatment. The application of 6 t.ha-1 biochar increased the fresh and aerial parts dry weight, plant height, percentage and essential oil yield, photosynthetic pigments, and N, P, and K concentration of aerial parts compared to the no biochar application, significantly. The results showed that the 6 t.ha-1 biochar + 120% of full irrigation treatment increased most of the traits studied. However, due to the importance of peppermint in terms of essential oil production, the highest essential oil percentage was obtained at the highest level of water stress.

A greenhouse research was carried out to study the simultaneous effect of hydropriming and water stress on the yield and yield components of sweet pepper (Padra var.) in Ferdowsi University of Mashhad. The experiment was performed as a factorial arrangement of two factors in a completely randomized design with three replications. Hydro-priming consisted of two levels (non-hydropriming and hydropriming) and the water stress included three levels (100, 75 and 50 percent of water requirement), which were applied in a silty clay soil. The results showed that the effect of seed hydropriming on shoot fresh weight and electrical conductivity (EC) of fruit water were significant (P<0.01). The effects of deficit irrigation on the fruit fresh and dry weights, fruit number, plant height, and stem diameter were significant at 1 percent level (P<0.01), while the effects on shoot fresh and dry weights were significant at 5 percent level (P<0.05). Interaction effects of the treatments were significant on EC of fruit water at the 1 percent level (P<0.01), while the effects were significant on the fruit number, shoot dry weight, plant height, and pH of fruit water at the 5 percent level (P<0.05). The results also showed that the highest fruit number (4.34 per plant) was recorded in the 100 percent plant water requirement and seed hydropriming, while the lowest fruit number (2.0 per plant) was found in the 50 percent plant water requirement and seed hydropriming treatment. The highest and lowest fruit fresh weights (i.e., 191.4 and 82.1 g per plant) were observed in water stress treatments of 100 and 50 plant water requirement percent, respectively. The results also revealed that the fruit number changed in 75 and 50 percent water requirement treatments + non-hydropriming conditions by 11.3 and –11.0 percent, while under hydropriming conditions, fruit number was reduced by –16.5 and –50 percent, respectively. Overall, in this study the best treatment was 100 percent water requirements + seed hydropriming in greenhouses conditions. Deficit irrigation and hydropriming levels were applied on this plant in the Mashhad region in field conditions and recommended for future research.

Mentha longifolia L. is one of the most valuable perennial, rhizomatous, aromatic and herbaceous plants belonging to the Lamiaceae family. In this study, the effects of deficit irrigation stress on physiological traits and yield of 20 different wild mint populations were evaluated by a split-plot experiment based on a randomized complete block design with three replications. Soil moisture control was performed using irrigation treatments based on 100% (control) and 60% of field capacity. In the current study, physiological traits including chlorophyll a, b and total, carotenoids, proline, total carbohydrate, relative water content, ion leakage, stomatal conductivity, sodium and potassium elements, dry matter yield and essential oil yield were investigated. There were significant differences (P<0.01) between populations in two levels of water deficit treatment. The most tolerant populations had the highest essential oil yield (4.69%), relative water content (69.91%), total chlorophyll (0.32 mg/g) and proline (2.80 µmol/g) under water deficit stress. Results of correlation between dry matter yield and all traits except carotenoid content were significant. Finally, five populations of Hormozgan, Khuzestan, South Khorasan, Kerman-1 and Lorestan respectively were identified as the tolerable populations and introduced for future breeding programs.

Today, due to limited of water resources, more attention is paid to the use of water storage methods. Thus, a factorial experiment was conducted in a completely randomized design with five replications in a controlled greenhouse in Ferdowsi University of Mashhad in 20017. The studied factors included three irrigation treatments (Full irrigation, deficit irrigation, partial root zone drying) and two levels of phosphate fertilizer (required amount based on soil analysis (25ppm) and adding 25% more than recommended (31ppm)). In partial root treatments, a part of the pots was under drought stress two weeks after planting, and the second part of the zone drying pots was irrigated until the beginning of flowering and 50% of flowering was applied to dry conditions. Results showed that drought stress in both flowering and 21 days after flowering caused a decrease in the physiological traits including chlorophyll content index, photosynthesis rate, stomatal conductance and transpiration rate. As the duration of drought increased, the density of stomata in the lower leaf area increased. In spite of decreasing photosynthesis and dry matter content in drought stressed plants, biomass content in partial root zone drying was higher than deficit irrigated treatment. Increased phosphorus had no significant effect on stomatal density, but at 21 days after flowering the substomatal CO2, photosynthesis rate, transpiration rate, reduced stomatal conductance, and biomass directly were related to increasing phosphorus.

Due to climate change and increasing of water demand for agricultural productions, optimum use of water resources is necessary. In this experiment, the effects of partial root zone drying (PRD) along with shading were investigated on growth and water use efficiency of 2-year old sour orange seedlings in Ramsar, northern town near Caspian Sea, Iran. The pot experiment were assigned to a completely randomized design and were treated during seven months in 2015. Treatments were full irrigation (FI), partial root zone drying (PRD), PRD along with moderate shade (MShPRD) and PRD along with high shade (HShPRD). Irrigations water volumes were determined on the basis of soil moisture deficiency. Water consumption reduction relative to FI treatment for PRD, MShPRD and HShPRD treatments were 29.6, 36.2 and 39.2 percent, respectively. Mean comparion indicated that trunk diameter, dry weight ratio of root/total plant and root variables (dry and fresh weight, volume, length, area and length density) in HShPRD were significantly lower than those of other treatments. Also, total dry matter and volume and weight of stem and branches in HShPRD were lower than those of full irrigation treatment. Dry weight ratios of leaf/total plant, shoot/total plant and shoot/root in this treatment were higher than those of other treatments. Treatments had no significant effect on leaf variables, plant height, branches length, root diameter and specific root area and length. In conclusion, the highest irrigation water use efficiency was observed in MShPRD, but it had significant difference only with full irrigation.

High demand for herbal medicines and the limited plant sources necessitates more research on these plants to increase their yield and effective compounds. The present study assessed the effect of biochar on yield and seed trigonelline content of fenugreek (Trigonella foenum-graceum L.) ecotypes under different irrigation regimes. Six branched fenugreek ecotypes including Dezful, Shushtar, Ardestan, Rehnan, Yazd and Khomeyni Shahr were treated by biochar application (at a rate of 7-8% of soil v/v) and non-application under two irrigation intervals of 4 (normal irrigation) and 8 (deficit irrigation) days using a split plot factorial experiment in a randomized complete block design with three replications. The study was conducted in the research field of Agricultural Biotechnology Research Institute of Iran in 2015. According to the results, biochar application increased the seed yield and biological yield under both irrigation intervals. The decreasing effect of increasing water intervals on seed yield, biological yield and trigonelline yield was observed in all ecotypes. Changes in seed trigonelline content did not follow a similar trend in different ecotypes. In summary, although biochar prevented the growth and yield reduction by decreasing water deficiency effects, itdid not have any significant effect on seed trigonelline content.

Alfalfa is one of the most important forage plants for livestock. Drought most important factor limiting plant growth in the world and is the most common environmental stress. The external application of extenuating stress can cause immune responses, particularly by plants. In order to investigate the application of salicylic acid and glycine on alfalfa seed production under water deficit conditions, tests for split-plot in a randomized complete block design with three replications in research farm of Islamic Azad University of Karaj in the crop year 95-1394 was administered. 5/0 and 1 mM salicylic acid and glycine were 10 and 50 mM. The characteristics such as yield with and without pods, pods per plant and seeds per pod. The results showed that, irrigation, seed yield (with and without pods) and number of seeds per pod (respectively 2/1418, 51/936 kg per hectare and 01/9 digits) and irrigation cut off the flowering the yield (with and without pods) and number of seeds per pod (respectively 4/977, 76/807 kg and 36.6 eggs), respectively. Also sprayed with 50 mM glycine with the highest seed yield (with and without pods) and number of seeds per pod (the order number 4/1440 and 93/945 kg per hectare and 09/10) and was superior in the group treated with non-solution spray the lowest seed yield (with and without pods)) and the number of seeds per pod (2/932 and 73/591, respectively, and 34.6 kg ha number) in the weakest group were analyzed.

Alfalfa (Medicago Sativa) is known as the queen of forage plants green and gold. The most important factor limiting water shortages for agricultural products, especially in arid and semi-arid areas. The external application of extenuating stress can cause immune responses, particularly by plants. In order to investigate the application of salicylic acid and glycine on production of alfalfa hay under water deficit conditions, tests for split-plot in a randomized complete block design with three replications in research farm of Islamic Azad University of Karaj in the crop year 95-1394 was administered. 5/0 and 1 mM salicylic acid and glycine were 10 and 50 mM. Evaluations consisted of fresh forage yield, number of stems per plant, the distance between the node and leaf dry weight. The results indicate the adverse effect of drought stress on all traits under study and reduce the damaging effects of stress by TkhfyfDhndh materials. Among the different irrigation treatments, the effects of irrigation at the start of the match-rigging more negative impact on most of the traits under study and mitigation of stress treatments, Glaysyn importantly the role of the salicylic acid in reducing the adverse effects played . For example, full irrigation and foliar application of ascorbic acid and glycine at 1 and 50 mM fresh forage yield (84/58 and 46/61 respectively ha) were in the top group and irrigation at the time of flowering and the absence of extenuating sprayed with the lowest forage yield stress (48/28 ha) in the weakest group were analyzed.

Using of Regulated Deficit Irrigation (RDI) and improved water holding of soil are very important in irrigation of fruit trees. For this purpose, the effects of both RDI and super-absorbent (SA) were studied on the vegetative growth, yield and amount of marketable fruit and some quality characteristics of Japanese plum (Prunus salicina cv. ‘Santarosa’). The trees were exposed to three RDI levels including 100% ETc, 75% ETc, 50% ETc and four super-absorbent levels of zero, 100, 200, and 300 grams/tree at the pit hardening stage. In RDI, the difference of vegetative growth compared to control trees was significant and the SA treatments could not compensate for the decrease of vegetative growth. The amount of yield was not affected under the influence of 75% ETc, but at the 50% ETc level, it decreased significantly. The yield of control, 75% ETc and 50% ETc treatments were 47, 46.15 and 35.50 kg/tree respectively. However, comparing between control and other levels of RDI showed that the amount of marketable fruit increased in 75% Etc. In addition, the irrigation levels were not effective on soluble solid content (SSC), titrable acidity (TA), SSC/TA and the magnesium (Mg) concentration. While, the concentration of fruit calcium increased considerably under RDI and the highest amount of Ca was observed at 50% Etc. The quality characteristics such as total phenol, firmness and antioxidant potential of fruits increased by lower irrigation than the control fruits. In this study, the interaction effects of RDI and SA treatments were significant only for total phenol trait.

Peppermint (Mentha piperita L.) from Lamiaceae family is one of the most widely used medicinal plants. In addition to therapeutic effects, it is used as flavoring in the production of various foods and medicinal products. In addition to genotype, the quality and quantity of active ingredients in medicinal plants are influenced by environmental factors. This research was aimed to study the effects of drought stress and jasmonic acid on the quality and quantity of peppermint as a factorial experiment in a completely randomized design at University of Zanjan in 2015. The treatments consisted of three irrigation levels [50%, 75%, and 100% (control) of field capacity] as main factor and three concentrations of jasmonic acid (0, 50, and 100 mg l-1) as sub-factor. Rhizomes of plants were used for plant production. The plant samples were collected at flowering stage and after drying in the shade, the essential oil was extracted with water distillation method by Clevenger apparatus. The essential oil components were identified by GC and GC-MS. The results showed that the highest fresh and dry weight, height, total chlorophyll and relative leaf water content were obtained in control with 100 mg l-1 jasmonic acid. The highest peroxidase enzyme content was obtained at 50% field capacity drought stress with 100 mg l-1 jasmonic acid. The highest essential oil content was obtained at 75% field capacity drought stress with application of 50 mg l-1 jasmonic acid. The main essential oil components were menthol, menthon, 1,8-cineole, cyclohexanol, and methyl acetate. The highest amounts of menthol, menton, and 1,8-cineole were obtained from 100 mg l-1 jasmonic acid and the highest amount of cyclohexanol was obtained from 50 mg l-1 jasmonic acid. However, application of jasmonic acid decreased the amount of methyl acetate from 7.24% in control to 0.56% in 100 mg l-1 of JA treatment.

Water scarcity adversely affects many physiological and metabolic processes of the plants. To study the effects of drought stress and fertilization on some physiological characteristics, essential oil percentage and yield of spearmint, a field experiment was conducted at the Research Farm of the College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. The experiment was conducted in a split plot arrangement based on a randomized complete block design with three replications. Treatments included three irrigation treatments (100%, 75% and 50% of plant water requirement) as the main plot and four fertilizer regimes including no fertilizer (control), chemical fertilizer (N), bio-fertilizer (rhizome inoculation with Azotobacter, Pseudomonas and mycorrhiza) and integration of biological fertilizer and 50% chemical fertilizer as the sub-plot. The results showed that all traits measured were significantly affected by the main and interaction effects of deficit irrigation and fertilizer. The content of chlorophyll a, chlorophyll b, carotenoids, total chlorophyll, percentage and yield of essential oil and yield decreased with increasing water stress while the rate of carbohydrate and proline as well as the electrolyte leakage percentage increased. Furthermore, the results showed that under 100% and 75% irrigation systems, application of chemical and integrated fertilizers improved the physiological characteristics, yield and percentage and yield of essential oil. Under 50% irrigation regime, the best performance was related to bio fertilizer.

In order to study the effect of low irrigation and nitrogen fertilization on morphological traits, sepal yield, and yield components of Roselle (Hibiscus sabdariffa L.), an experiment was conducted as split plot design based on randomized complete blocks with three replications, at Saravan, Iran in 2010. In this research, irrigation was considered as main factor with three levels (irrigation after 60, 120 and 180 mm evaporation from pan class A) and nitrogen rate was considered as sub factor with four levels (0, 60, 120 and 180 kg N.ha-1). The results showed that irrigation and nitrogen levels had significant effect on plant height, stem diameter, fruit number per m2, sepal fresh and dry yield, and biological yield. However, sepal dry weight per single fruit and sepal harvest index per fruit were only affected by irrigation, and sepal harvest index per plant was only affected by nitrogen. The interaction effect between irrigation and nitrogen significantly affect the sepal fresh and dry yield. According to the means comparison, increasing of irrigation intervals from 60 to 180 mm evaporation reduced the plant height, stem diameter, fruit number per m2, sepal fresh and dry yield, biological yield, and sepal dry weight per single fruit to 48.1%, 31.8%, 41.3%, 58%, 54.9%, 67% and 22.7%, respectively. In addition, the increased use of nitrogen from 0 to 120 kg.ha-1 could increase the mentioned traits to 13.7%, 8.6%, 37.1%, 43.3%, 44.1%, 25.5%, and 5.7%, respectively. Overall, according to the results of current study, irrigation after 120 mm evaporation with 180 kg N. ha-1 treatmentcould be suggested for roselle cultivation in Saravan, Iran.

Iran is one of the countries that is located in world''s arid and semi-arid regions and is constantly subjected to water shortage. One of the effective methods for reducing water consumption and increasing production in agricultural sector is greenhouse culture. By using proper irrigation management in greenhouse، we are able to utilize water، soil and fertilizer to produce high yield and quality products. In the present study، a split-plots experiment was conducted as randomized complete blocks design with three replications، during 2010 and 2011، in Agricultural and Natural Resources Research Center، Isfahan، Iran. Irrigation frequency at 3 levels (once each 1، 2 and 3 days) was considered as the main plot and the subplots were irrigation depth at three levels (75% ETc، 100% ETc and 125% ETc). Results revealed that effect of depth of irrigation was significant on yield، number of fruits per plant and mean weight of a tomato، but the effect on water use efficiency (WUE) was not significant. The highest yield (6. 77 kg/m2) and the lowest yield (4. 52 kg/m2) were observed in 125% ETc and 75% ETc treatments، respectively. The amount of consumed water in these treatments was 0. 3 and 0. 19 m3/m2، respectively. WUE in the treatments ranged from 25 to 28 kg/m3. Lack of significant effect of various irrigation water depths on WUE، though the effect was significant on yield، indicates that the crops have been under-irrigated. It was found that the abovementioned traits were not significantly affected by applying irrigation frequency treatments. Soil analysis at the end of the experiment showed that salinity in the soil surface of the pots was more than lower depths، which is due to surface water evaporation and acculation of the salts. Salinity in F1 treatment was very high (8 dS/m)، though the pots were irrigated once a day. This shows that everyday irrigation، but with low depth of irrigation، has not been able to leach salts to deeper depths. Based on the obtained results، water shortage، practical simplicity and labor saving، the 125% ETc treatment with 3-day irrigation frequency are recomanded.

In order to study the effect of fertilizing treatments and limited irrigation regimes on grain qualitative traits and mucilage production of Isabgol (Plantago ovata Forsk.)، a field experiment was conducted at Experimental Farm of College of Agronomy and Animal Sciences، University of Tehran. The experimental design was a split plot based on a randomized complete block design with three replications. In this research، four irrigation regimes including full irrigation، light limited irrigation، moderate limited irrigation and severe limited irrigation، were assigned to the main plots and five fertilizing treatments including control (without fertilizer)، chemical fertilizer، combined use of chemical fertilizer and Barvar Phosphate Biofertilizer، cattle manure and combined use of chemical fertilizer and cattle manure، were assigned to the sub plots. Results showed that irrigation regimes had significant effect (p ≤ 0. 05) on all measured traits. Mucilage and grain yields decreased with decrement in irrigation frequency from full to severe limited irrigation but mucilage percentage and grain swelling factor increased; therefore، the highest mucilage and grain yield were obtained in full irrigation regime. The highest mucilage percentage and grain swelling factor were obtained in severe limited irrigation. Results also showed that fertilizing treatments had significant effect (p ≤ 0. 05) on all measured traits. The highest mucilage yield (252. 58 kg/ha) was obtained in combined use of chemical fertilizer and cattle manure treatment under full irrigation regime. Mucilage percentage and grain swelling factor were significantly higher (p ≤ 0. 05) in cattle manure treatment.

The base of nut production in almond is flower buds set with best quality and quantity. Although the process of flower buds set is controlled by genetic characteristics، however it affected with inside and outside diverse factors. To understand relationship between these factors for achieve to annual and regular nut production economically. An experiment was conducted in order to evaluate effects of effective microorganisms (EM) under water stress conditions on bud flower formation in two genotypes of almond trees in Department of Horticultural Science، Faculty of Agriculture، Ferdowsi University of Mashhad، in 2011. In this research effects of two different concentrations (0 and 5%) of EM and three levels of aridity stress treatments (100، 66، and 33% of FC) on number of flower buds in two genotypes (H1and H2) of almond was evaluated. This experiment was arranged as a factorial experiments based on a randomized complete blocks design with four replications. Results showed that the EM increased amount of leaf area، chlorophyll، storage protein، N، K and P in leaves. In this research، effects of different genotypes، EM and irrigation levels on number of flower bud set were significantly different at the %1 level. Number of flower bud formation increased by treatments of EM application، H1 genotype and irrigation level of FC% 100. There was significant interaction between treatments for this trait at %1 level. The best result was obtained from interaction between H2 genotype and irrigation using level of FC% 100 and EM application.