To investigate the effects of fertilizer regimes on quantitative and qualitative traits of Dracocephalum kotschyi Boiss, a field experiment at three replications with the Split Plate arrangement in a completely randomized block design was conducted in the Research Field of Tarbiat Modares University during the 2017-18 growing season.Water deficit stress (irrigation after discharging 20 (optimal irrigation), 40 (mild water deficit stress), 60 (moderate water deficit stress) and 80% (severe water deficit stress) of water used (available water)) in the main plot and fertilizer regime (urea, nitroxin, vermicompost, azocompost and no fertilizer) in the subplot were studied. The results showed that the highest leaf fresh weight (1797 kg ha-1) and total biomass (2957 kg ha-1) were obtained by application of urea in mild water deficit stress condition and the highest dry matter digestibility percentage was observed in azocompost treatment in moderate water deficit stress condition (57.8%). The highest crude protein was produced in severe water deficit stress condition (19.72%) and moderate water deficit stress (18.4%), respectively.. The highest percentage of water soluble carbohydrate and neutral detergent fiber were obtained from no fertilizer in moderate water deficit stress (22.06%) and application of urea in severe water deficit stress conditions, respectively. Mild water deficit stress application to produce high biomass is recommended for Dracocephalum kotschyi Boiss. According to the results, application of urea in mild water deficit stress was selected as the best treatment to produce forage 32% more than control.

To evaluate the effect of nitrogen and water withholding in vegetative growth stage of corn on efficacy of nicosulfuron and 2,4-D+ MCPA an experiment was conducted as a factorial arrangement in a randomized complete block design with three replications at Tarbiat Modares University in 2017. The first factor contained four treatments including application of nicosulfuron, 2,4-D+ MCPA, weed free and weed infested as control. The second factor consisted of normal irrigation and water withholding from 4 to 8 leaf stage. Third factor contained either urea application or no fertilizer application. Normal irrigation and nitrogen fertilizer application significantly increased nicosulfuron and 2,4-D+ MCPA efficacy in weed control and total weed dry weight decreased to 341 and 361 g.m-2 respectively compared 1370 g.m-2 as weed infested. Nicosulfuron and 2,4-D+ MCPA reduced weed total dry weight significantly under irrigation withholding. Grain yield increased with application of nitrogen and nicosulfuron. Grain yield was higher with application of 2,4-D+ MCPA than nicosulfuron without nitrogen application under irrigation withholding. Application of nicosulfuron with nitrogen application provided satisfactory weed control and increased grain yield.

Using saline water for irrigation of crops is a strategy for irrigation water management. In this study, the cyclic application of saline and non-saline water was investigated. Field experiments were carried out during a growing season in 2012 under drip irrigation for maize crop with nine treatments in randomized complete block design in Karaj. The treatments were based on alternative irrigation management of saline and non-saline water on three salinity levels of 0.4, 3.5 and 5.7 dS/m and freshwater application in every one, three and five saline water application (1: 1, 3: 1 and 5: 1, respectively). The 1: 1 management was better than the other managements in terms of crop yield. The results showed that while the highest wet weight yield (56.2 t ha-1) was obtained in the F treatment (irrigation with non-saline water constantly), but the highest irrigation water use efficiency based on wet weight (14.9 kg m-3) was acquired in the 3S1: 1F treatment (thrice saline water (3.5 dS m-1) andonce non-saline water, alternatively). Thus irrigation water use efficiency was increased in cyclic using of saline and non-saline water because of less water use in saline irrigations, despite the relative reduction of crop yield. The results indicated that the percentage of crop yield decreased by 10.3 for every 1 dS m-1 increase in salinity level of irrigation water in fixed management. In this study, the crop yield in alternative management was higher than mixing management.

To investigate the effects of water deficit stress and bio and non-bio fertilizers on Thymus Vulgaris, a split plot experiment was conducted based on randomized complete block design with three replications in 2017 in Asgarya agricultural field in Yazd. The treatments included water tension: W1=7 (Control), W2=12 and W3=17 days irrigation intervals as the main factor and bio and non - bio fertilizers at five levels including B1= control (without fertilizer), B2= endo mycorrhiza (Glomus), B3= Azospirillum bacteria, B4= Pseudomonas bacteria and B5= chemical fertilizer (NPK) a sub – factors. Results showed that the highest flowering branches yield, a, b, and total chlorophylls and nitrogen and phosphorus elements were observed in 17 days of irrigation (W3). 12 days of irrigation treatment (W2) showed the highest potassium element rate. The highest a, b and chlorophylls and nitrogen were observed in Azospirillum treatment (B3). The highest total chlorophyll, phosphorus element, carotenoids and flavonoids were observed in Pseudomonas treatment (B4); the highest potassium element rate were obtained in mycorrhiza treatment (B2); the highest flowering branches yield were observed in NPK treatment (B5) and control (B1) treatment resulted in the highest anthocyanin

Increasing scarcity of water resources and its influence on quality and quantity of crop yield motivates farmers to apply deficit irrigation as an approach to overcome the lack of water. On the other hand, the importance of water as an intermediate good in agriculture has increased competition to access water as an economic good. Consequently, determining the irrigation water price under deficit irrigation is necessary to improve water productivity. In order to assess the impact of water price on water productivity, in this study green pepper was cultivated under four different water levels including 50, 70, 100 and 120% of crop water requirement. The crop yield was then harvested and its dry matter measured at the end of growth period. Results indicated that after applying deficit irrigation and optimizing irrigation water depth, water price was reached to its maximum which was 183. 4 × 10 4 Rials per cubic meter. In addition, irrigation efficiency, physical productivity, physical-economical productivity and economical productivity under deficit irrigation were 5. 67(kg/m³ ), 5. 1(kg/m³ ), 191. 4 × 10 4 (Rls/m³ /ha) and 1. 04, respectively, which were all higher than those of other water treatments results. Furthermore, the deficit irrigation before water depth optimization did not considerably affect irrigation efficiency, while after water depth optimization, deficit irrigation resulted better irrigation efficiency than full irrigation scheme.

Water is one of the most important resources needed by human society and the first and most important factor for the production of agricultural products, more than 90% of this vital liquid is consumed in this sector. One of the most important factors that affect the performance of a water conveyance and distribution network is the water distribution and delivery program. In order to obtain turnouts’ discharges, the water requirement of the eastern Aghili area was estimated using the Global Land Data Assimilation System (GLDAS) and controlled using the results of the NETWAT model. For this purpose, three-hour evapotranspiration was estimated with GLDAS, and the six-hour discharges of turnouts were calculated according to the cultivated area of each turnout and irrigation efficiency. The hydraulics of the eastern Aghili canal were simulated using the above-mentioned data for six hours. The results showed the appropriate accuracy of GLDAS so that at a maximum of 12.7%, GLDAS underestimated the evapotranspiration values compared to NETWAT. The minimum values of efficiency and adequacy indicators of 0.95 and 0.94, respectively, were obtained, which are in the "good" performance class.

Increasing irrigation efficiency and reducing water losses in gardens is necessary due to the severe shortage of water resources in the country. In order to increase the irrigation systems efficiency it is necessary to evaluate them. For this purpose, 6 gardens with basin irrigation system were selected. The amount of irrigation water volume, depth of root development, yield, application efficiency (early, mid and late of the growing season) and water productivity were determined. Also, the water requirement was calculated by the Penman Monteith method using meteorological data (recent ten years) and compared with the values provided in the National Water Document. In apricot orchards, the average application efficiency varied from 43.3 to 58.4 percent (average of 49.7 percent) and in vineyards from 41.7 to 61.9 percent (51.4 percent on average). Deep percolation was the major portion of irrigation water losses in apricot and grape gardens by 49.7 and 51.4%, respectively. The average water productivity of these products was 0.78 and 5.2 kg.m3 respectively. The results showed that in gardens where land leveling and water supply of the trees were well done, irrigation efficiency and water productivity were significantly increased. Comparing the computational water requirement with the volume of irrigation water shows the imposition of deficit irrigation in these gardens. The results also showed that the computational water requirement was much higher than the values mentioned in the National Water Document, which highlights the need to update the National Water Document.

Increasing irrigation efficiency and reducing water losses in gardens is necessary due to the severe shortage of water resources in the country. In order to increase the irrigation systems efficiency it is necessary to evaluate them. For this purpose, 6 gardens with basin irrigation system were selected. The amount of irrigation water volume, depth of root development, yield, application efficiency (early, mid and late of the growing season) and water productivity were determined. Also, the water requirement was calculated by the Penman Monteith method using meteorological data (recent ten years) and compared with the values provided in the National Water Document. In apricot orchards, the average application efficiency varied from 43.3 to 58.4 percent (average of 49.7 percent) and in vineyards from 41.7 to 61.9 percent (51.4 percent on average). Deep percolation was the major portion of irrigation water losses in apricot and grape gardens by 49.7 and 51.4%, respectively. The average water productivity of these products was 0.78 and 5.2 kg.m3 respectively. The results showed that in gardens where land leveling and water supply of the trees were well done, irrigation efficiency and water productivity were significantly increased. Comparing the computational water requirement with the volume of irrigation water shows the imposition of deficit irrigation in these gardens. The results also showed that the computational water requirement was much higher than the values mentioned in the National Water Document, which highlights the need to update the National Water Document.

This research was conducted at Torogh Agricultural Research Station in Khorasan-e Razavi province to determine the impact of irrigation cutoff at different growth stages and percentage of water use on the yield and water use efficiency (WUE) of wheat cultivars using sprinkler irrigation. The study was done from 2006-2008. The experimental design was a randomized complete block design with a strip split plot layout and three replications. The three vertical plots were for irrigation (70%, 85%, 100% of plant requirement), the three horizontal plots were for irrigation cutoff point (full irrigation, irrigation cutoff at stem elongation, cutoff at pollination) Three wheat cultivars (Alvand, Toos, Gaskozhen) were the subplots. The yield means at 70%, 85% and 100% water consumption were, respectively, 3182, 4639, and 4748 kg/ha. Water consumption of 85% and 100% fell into statistical group A. The highest value for WUE was 1.849 kg/m3 at 85%, followed 1/389 kg/m3 for 70%, and 1.618 kg/m3 for 100%. The irrigation cutoff treatment showed significant differences (P£ 0.05) for grain yield and WUE. Full irrigation showed the highest grain yield (4557 kg/ha) and irrigation cutoff at stem elongation and cutoff at pollination actually decreased yield to 4195 and 3817 kg/ha, respectively. Full irrigation and irrigation cutoff at stem elongation fell into statistical group A. Cutoff at stem elongation had the highest WUE (1.778 kg/m3). Combined analysis showed that wheat cultivar had a significant effect on grain yield and WUE. Alvand cultivar had the highest yield (4447 kg/ha) and WUE (1.718 kg/m3). The results showed that, where water shortage was not an issue, full irrigation produced the best results. In areas of water shortage, 85% irrigation using the cutoff at stem elongation method is recommended for the best results in yield, water consumption and WUE.