In this study, WATER USE EFFICIENCY index ((WUE)) was USEd to assessing the effect of drought on the carbon and WATER cycle. To calculate this index, we USEd the gross primary product (GPP) and evapotranspiration (ET) products obtained from the MODIS sensor, and the trend of their changes and reaction of this index to drought were calculated for the period 2017-2001 in Fars province. Finally, we assessed the land degradation and desertification in different land USEs for study area. The results showed that the indices of evapotranspiration, GPP, WATER USE EFFICIENCY, and drought increased by 75. 25%, 29. 9%, 78. 51%, and 67. 23%, respectively. The effects of drought on evapotranspiration in agricultural lands and grasslands showed more than 67% positive relationship and also, in these land USEs, we observed a significant positive relationship (33. 4% and 12. 5% for the agricultural lands and grassland, respectively). However, in shrubs lands, and savannas, it is more than 66. 6% and 87. 5%. The effect of drought on WATER USE EFFICIENCY in grassland showed that more than 87% of these areas have a positive relationship. The effectiveness of WATER USE EFFICIENCY in plants shows a positive relationship in 40. 9% in this area, of which only 0. 9% has a significant positive relationship. The negative relationship of this land USE is about 59. 1% of it. Of this negative amount, only 1. 6% of the area had a significant negative relationship. The study of this relationship in the USE of savannas shows 75% of this area, which includes 1. 5 square kilometers.

For investigate the WATER USE EFFICIENCY ((WUE)) in haloxylon (Haloxylon aphylum), design was carry out in four successive years (1999-2005) in Yazd shahidsadoge control desert research station and at near of manual plants. After establishment of plantlets moisture treatments including: 1- replenishment of total soil moisture depletion (SMD) up to FC point; 2- rechargement of 1/3 SMD and 3- without any irrigation of terward were applied in a CRD design with 3 replication. A control lysimeter was USEd for checking the SMD measurement. Requirement WATER for reach to enough moisture provide weekly and via weigh of lysimeters was accessible for plants. Imply at dry treatment next of plant complete establishment, irrigation was avoidance. For evaporation amount minimum of lysimeters surface, they were cover with fiberglass thin foil and one of lysimeters was USE for counted of evaporation amount without plant. Sum of output WATER (Drain + Evaporation) was deducted from input WATER (Rainfall + Irrigation) and equipollent transpiration. Moisture treatment in during two of growth season and the end of experiment with remove and drying of shoot and root dry weights as well as shoot/root ratios of plants, and also WATER USE EFFICIENCY ((WUE)) were measured. The results of this research suggest that among of root and shoot dry weight at 1% level of probability were affected of moisture treatment.

This experiment was conducted to study the effect of different Irrigation levels on yield and WATER USE EFFICIENCY ((WUE)) of four varieties of rapeseed in Karaj during 2003-2004. The experiment was a randomized split-plots as complete block design with three replications. Irrigation levels including, 50, 75, 100 and 125 percentage of WATER requirement were considered as a main plots and four varieties: Licord, SLM046, Okapi and Reg Cobra as sub plots. The WATER requirement calculated on the basis of meteorolgicale data using Penman-Monteith method. ANOVA and averages comparison indicated as blow: Irrigation levels, varieties and interaction effects were not significant at 5% on plant height. Irrigation levels effect was significant at 5% level on branches numbers per plant. The interaction effects were significant in 5% level on seeds number per pod. The irrigation levels and varieties effects were not significant at 5% level on 1000 seed weight. The effect of irrigation levels and varieties on gratin yield were significant at 1% level. The irrigation with 75% WATER reopurement 2727 kg/ha yield was maximum and the level of 50% with 1912 kg/ha was minimum respectively. Although, Reg Cobra variety with 2783 kg/ha and Licord variety with 2132 kg/ha were maximum and minimum respectively. The interaction effects were significant at 5% on seed yield. The 75% Irrigation level in variety Reg Cobra with 3229 kg/ha and the 50% level in variety Licord was minimum of yield. The irrigation Levels and variety effects on (WUE) was significant at 1% level. The 75% level with 1.114 and the 50% level with 0.684 kg/m3 were maximum and minimum respectively.WATER USE EFFICIENCY of level 75% was 62.86% more than level 125% with 99% probability. Reg Cobra variety with 1.064 kg/m3 and Licord variety with 0.826 kg/m3 were maximum and minimum respectively. WATER USE EFFICIENCY of Reg Cobra variety was 28.8% more than of Licord variety.

This research was designed to evaluate and compare the applicability of two different types of irrigation including traditionally (surface irrigation) and simple sub-surface drip irrigation (using pricked-pipe covered with plastic cloth). Two plots containing 39 pistachio trees with 720 m2 area were selected in Rafsanjan, Iran. Both plots were irrigated using exactly the same quantity and quality of WATER for 2 years. At the end of the second year the yield was harvested separately and compared. The weight of fresh and dried crops in sub-surface irrigation plot to those of surface irrigation plot were 1.895 and 2 respectively. Annual shoot growth of tree was measured in two plats. The value of Plot Growth Index (PGI) in surface irrigation plot and sub-surface irrigation plot calculated 2237.5cm and 4580.5cm respectively. In addition, the dried weight of weeds in surface irrigation plot was 82kg while it was only 21 kg in subsurface irrigation plot. Results show the considerable difference in two irrigation systems efficiences and relatively higher preference of sub-surface system than traditionally surface method. Finally, due to sever shortage of agricultural WATER in the studied area, it has been advised to optimize traditionally USEd irrigation systems toward new methods with minimum WATER loss such as evaluated subsurface method.

Biomass production, shoot, root, leaf, root to shoot ratio (R/S), specific leaf area (SLA) and WATER USE EFFICIENCY ((WUE)) of eucalyptus (Eucalyptus camaldulensis Dehnh) were investigated under three different soil WATER regimes, 100%, 70% and 40% of field capacity (FC). The research was conducted based on a complete randomized design with 3 replications under lysimetery and natural conditions in an arid region. The experiment was carried out during 2006-2008 at Shahid Sadouqi Desert Research station of Yazd. Results showed that biomass production, shoot, root, leaf, root to shoot ratio and shoot to life ratio decreased significantly with reduction in soil WATER content. Specific leaf area increased significantly with reduction of soil WATER content. WATER USE EFFICIENCY increased significantly with reduction of soil WATER content but was not significant between 70% and 40% field capacity treatments. Regarding wood production, WATER USE EFFICIENCY increased significantly for 70% field capacity treatment, compared to other treatment.

Factor analysis is one of the multivariate statistical techniques that considers the interrelationships between apparently irrelevant variables and helps researchers to find the hidden reasons for the occurrence of an event. In order to evaluate the effects of different irrigation levels and humic acid foliar application and identify the factors affecting WATER USE efficiencies of sesame (Sesamum indicum L. ), maize (Zea mays L. ) and common bean (Phaseolus vulgaris L. ), a split plots experiment based on RCBD design with three replications was conducted during the 2014-15 growing season, at the Research Farm of Ferdowsi University of Mashhad, Iran. Irrigation levels (50 and 100% of WATER requirement) and foliar application and non-application of humic acid were assigned to main and sub plots, respectively. The results showed that in sesame, the highest seed yield and biological yield were obtained from 100% of WATER requirement and humic acid spraying treatment. In maize, humic acid spraying under condition of supplying 50% of WATER requirement increased seed weight per plant, plant height, and leaf area index and soil pH In bean, the highest seed weight per plant, plant height, leaf area index, crop growth rate and soil phosphorous content were observed in the treatment of 100% of WATER requirement and humic acid spraying. Factor analysis results also showed that in sesame, the variables of seed yield, biological yield, seed weight per plant, plant height, leaf area index, crop growth rate, soil phosphorous and WATER USE EFFICIENCY were assigned to the first factor and the variables of soil nitrogen, soil pH and EC were assigned to the second one. In maize, seed yield was assigned in the same group with the variables of biological yield, leaf area index, crop growth rate, soil phosphorous, EC and pH and WATER USE EFFICIENCY; in bean, this was with the variables of seed yield and WATER USE EFFICIENCY. In general, the research results revealed that identifying the effective variables in each factor and those logical nominations according to Eco physiological knowledge can lead to the direct management of effective variables with regard to associated factor, thereby leading to WATER EFFICIENCY improvement.

In this research, the effect of biochar on the EFFICIENCY of irrigation WATER consumption and the EFFICIENCY of nitrogen consumption at different levels of WATER and nitrogen fertilizer for karla plant was investigated in Zahedan. The experiment was carried out in the greenhoUSE conditions in a factorial manner and in the form of a completely random design with three replications (planted in February 2018 and harvested in April 2019). The treatments include three irrigation WATER treatments (I1) 50, (I2) 75 and 100 (I3) percent of irrigation WATER, four biochar treatments (zero (B1), 1.25 (B2), 2.5 (B3) and 5 (B4) weight percentage of pot soil) and three nitrogen fertilizer treatments (50 (N1), 75 (N2) and 100 (N3) percent of plant fertilizer requirement). WATER stress levels during the growing season were measured by weighing the pots daily. Harvesting was done once a week. A total of five harvests were done. The yield and EFFICIENCY of irrigation WATER consumption and the EFFICIENCY of nitrogen consumption and soil salinity were calculated at the end of the growing season in each treatment. Also, soil nitrogen and fruit sugar were measured in each harvest. The results showed that the effects of irrigation WATER and biochar levels on the measured parameters were significant at the probability level of one and five percent. The highest amount of yield (15.5 tons per hectare) was obtained from the treatment of 100% of the amount of irrigation WATER, which was not significant with the treatment of 75% of irrigation WATER. The USE of biochar up to 2.5 percent by weight of the soil increased the yield. More USE of biochar (5% by weight of soil) decreased plant yield. The highest WATER consumption EFFICIENCY (3.14 kg/m3) and nitrogen consumption EFFICIENCY (94.55 kg/kg) were obtained with the USE of 75% nitrogen fertilizer (150 kg/ha) and 2.5% by weight of biochar. The USE of the appropriate amount of biochar reduced the negative effects of moisture stress in comparison with the control. Therefore, it is recommended to USE it for the plant and especially in the conditions where the plant is under drought stress or in greenhoUSEs and storages in order to reduce the amount of WATER consumed and improve the performance of the plant, although it is suggested to test in The farm should also be completed.

One of the main objectives of promoting the development of greenhoUSEs in Iran is increasing production productivity and WATER USE EFFICIENCY. Accordingly, in this study the EFFICIENCY of WATER USE in Sistan greenhoUSEs was investigated for 2008 using Data Envelopment Analysis (DEA). In addition, determinants of WATER USE EFFICIENCY were investigated using Tobit Regression Model (TRM). The results showed that the mean efficiencies of greenhoUSE units under study in the constant and variable return to scale conditions were 63 and 87 percent, respectively. Also, the mean efficiencies of irrigation WATER in the constant and variable return to scale conditions were 49 and 71 percent, respectively. Based on the results, in the variable return to scale condition, age, education, experience and WATER resource had positive and size of land had negative effect on WATER USE EFFICIENCY. According to the findings, a suitable irrigation WATER price policy and extension classes seem to be effective on improvement the operation of units under study.

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.