The aim of this study was to assess the crop water stress index (CWSI), derived from leaf temperature using infrared thermometer measurements, to investigate the water stress status and irrigation timing of olive trees. Fpr this purpose a regression function was determined between crop water stress index and relative water content of leaf (RWC) and soil water content (SWC). The experimental treatments involved two olive cultivars (Koroneiki and T2) and four water regimes (irrigation of 100, 85, 70 and 55% of crop water requirement). The results showed that the non-water stressed baseline is varied throughout the study period as well as during the day. The daily variations of non-water stressed baseline were mainly due to variations in the intercept of the non-water stressed baseline that can be explained by variations in zenith solar angle. After investigating the relationship between vapor pressure deficit (VPD) and the difference between crop and air temperature (𝑇 𝑐 − 𝑇 𝑎 ), the equation of Tc-Ta =-0. 45 VPD+1. 06, r2 = 0. 99 was determined for the non-water stressed baseline of the olive trees at 12: 30 pm. Crop water stress index of olive trees increased significantly in deficit irrigation regims compared with control trees. crop water stress index was significantly correlated with relative water content (Kroneiki: r2=0. 82**, T2: r2=0. 80**) and soil water content (Kroneiki: r2=0. 66**, 𝑇 2: r2=0. 69**). Therefore, the crop water stress index is a good indicator of the water stress status of the Koroneiki and T2 olive trees.

An infrared thermometer can become a readily usable tool for crop agricultural water management since it allows a quick determination of canopy surface temperature that, as linked to transpiration, can give an idea of crop water status. This study aimed to calculate the crop water stress index (CWSI) of Quinoa. This study was conducted in a completely randomized design with four irrigation levels of 100 (T1), 75 (T2), 50 (T3), and 25 (T4) % of crop water requirements in three replications, and experimental treatments and measurements were mainly carried out during Quinoa growing season at 2017-2018 years. The results revealed that the highest of leaf, stem, root, inflorescence dry weights, and biomass by 11. 3, 8. 8, 2. 8, 16. 8, and 39. 7 g were in the T1 treatment. Using the T2, T3, and T4 compared with T1 were decreased grain yield (by 37. 6, 52. 5, and 64. 8%), harvest index (by 30. 4, 34. 5, and 30. 7%), and Biomass (by 16. 4, 29. 7, and 51. 1%). But, these treatments caused to WUE increase (by 19. 4, 36. 6, and 77. 4%) compared with T1. CWSI correlated significantly (P < 0. 01) and negatively with grain yield and biomass. Also, the results showed that the highest and lowest quinoa grain yield at average CWSI values of almost 0. 05 and 0. 61. Therefore, to achieve the highest grain yield in irrigation, the quinoa crop should be irrigated at 0. 05 of the CWSI. The lowest CWSI values were observed in T1(by 0. 04) and the highest in T4 (by 0. 72). In this study, the average CWSI was calculated in the days before irrigation in T1, T2, T3, and T4 treatments, and its values were 0. 05, 0. 19, 0. 48, and 0. 72, respectively. The results also revealed that with crop water requirement change from 100 to 75 percent, the CWSI was about 3. 8 times higher. Accordingly, the CWSI can be used to plan irrigation. The best irrigation time is based on T1 treatment when (Tc-Ta)a=2. 41-0. 21 VPD (5≤, VPD≤, 20).

Irrigation scheduling in agricultural lands needs to know time and amounts of irrigation. In agricultural lands at the Khoozestan, sugarcane is planted and time of irrigation was scheduled using a conventional method namely crop-logging method. This method is time consuming and expensive. In this study, feasibility of application of crop canopy - air temperature difference method for irrigation scheduling was investigated. This research was accomplished in sugarcane lands in Imam Khomainy cultivation and industry company, Shooshtar, Iran. Two treatments including "Plant" and "Ratoon 3" in six replication were selected. Crop water stress index and leaf sheath moisture before the irrigation was measured simultaneously. Lower base line equation was estimated using the measured crop canopy-air temperature difference and vapour pressure as: Tc - Ta=0.522-0.115 (VPD), in which Tc, Ta, and VPD are crop canopy temperature, air temperature, and vapor pressure deficit respectively. Upper base line was determined as 1oC. For the sugarcane lands which the time of irrigation was reached, leaf sheath moisture and crop water stress indexes (CWSIs) were measured simultaneously. The results showed crop water stress indexes varied between 0.1 to 0.3. Based on the average value of CWSI in the irrigation time, an equation was proposed using Idso method to determine the time of irrigation. The results showed this method can be replaced the crop-logging method.

این آزمایش با هدف بررسی تاثیر هیومی پتاس در افزایش سطح تحمل به شوری گیاه پوششی فیلا (Phyla nodiflora L.) بر اساس ویژگی های مورفوفیزیولوژیک انجام شد. طرح کرت های خردشده در یک آزمایش گلخانه ای با دو عامل به صورت بلوک های کامل تصادفی در سه تکرار اجرا شد. کرت اصلی شامل شوری کلرید سدیم در 5 سطح مختلف (صفر، 4، 8، 12 و 16 دسی­زیمنس بر متر) بود؛ در حالی که، کرت فرعی شامل سه سطح هیومی پتاس (صفر، 500 و 1000 میلی­گرم) بود. نتایج نشان داد، بدون در نظر گرفتن تیمار کودی، وزن تر شاخساره و کیفیت ظاهری در تیمار شوری 16 دسی زیمنس بر متر در مقایسه با گیاهان شاهد به ترتیب کاهش معنی دار 02/19 و 34/24% نشان دادند. دیگر ویژگی مثبت گیاه فیلا در تنش شوری 16 دسی زیمنس بر متر، وضعیت به نسبت مطلوب رنگدانه های گیاهی بود. افزون بر این، کیفیت ظاهری همبستگی قوی و مثبتی با طول شاخساره، وزن تر و خشک شاخساره و وزن تر ریشه نشان داد. به طور کلی نتایج بیانگر آن بود که فیلا در زمان تنش شوری از ویژگی های رشدی خود کاسته است. بدین ترتیب از کیفیت ظاهری در شوری بالا تا حدودی کاسته شد؛ اما در عوض سبزینگی فیلا در شرایط تنش حفظ شد. بر اساس نتایج وزن تر و خشک شاخساره و ریشه، محتوای نسبی آب (RWC) برگ و کیفیت ظاهری گیاه فیلا تا سطح شوری 8 دسی زیمنس بر متر از وضعیت مطلوبی برخودار بود و نیازی به استفاده از تیمار هیومی­پتاس تا این سطح از تنش وجود ندارد. در سطوح شوری بالا (12 و 16 دسی زیمنس بر متر)، ویژگی های مورفوفیزیولوژیک فیلا کاهش یافت. در نتیجه در سطح شوری بالا برای بهبود وضعیت کلی گیاه، کاربرد هیومی پتاس پیشنهاد می شود. به طوری که، هیومی پتاس 500 میلی گرم بر لیتر سبب افزایش طول شاخساره، تعداد شاخساره جانبی و RWC در سطح شوری 16 دسی زیمنس بر متر شد. افزون بر آن، 1000 میلی گرم بر لیتر هیومی پتاس، سبب بهبود رنگدانه های گیاهی در تیمار شوری 12 دسی زیمنس بر متر گردید.

In order to determination of water stress threshold and dryland wheat genotypes water status in different nitrogen managements, this experiment was carried out in split split plot RCBD design in three replications in 2010-2011 cropping year. Treatments included: N application time (whole fertilization of N at planting time, and its split fertilization as 2.3 at planting time and 1.3 in early spring), N rates (0, 30, 60 and 90 kg ha-1) and 7wheat genotypes. Also these genotypes were grown in supplemental irrigation condition for calculation of crop water stress index (CWSI) parameters. Canopy temperature (Tc) was measured in flowering and early milk ingstages. Crop water stress index (CWSI) was calculated. A non-water stressed baseline (lower baseline) werefitted as Tc-Ta=4.523-3.761×VPD; R2=0.92 and non-transpiring baseline (upper baseline) determined 6oC for rainfed wheat genotypes. Water stress threshold was 0.4 and crossing of that occurred 8 days before heading stage. In water stress threshold boundary, was depleted 60 mm available water from 0 to 50 cm soil depth. There was negative significant relationship (p<0.01) between CWSI and grain yield in all treatments and different nitrogen rates. Nitrogen application reduced water stress and increased grain yield of rainfed wheat genotypes. Ohadi and Rasad genotypes showed highest resistance to water stress and high grain yield production for N30 insplit and planting time application, respectively. Cereal4 and Rasad genotypes were suitable for N60 applicationin split and planting time application, respectively.

Considering the great value of water, irrigation scheduling, and cultivation of medicinal plants, this research was conducted at the Faculty of Agriculture, Lorestan University, with the aim of scheduling irrigation of summer savory using CWSI and applying different levels of water stress under the condition of pot planting. In this research, seeds of summer savory were cultivated with three replications under four irrigation treatments of 100%, 80%, 60%, and 40% of readily available water (RAW) (IR100, IR80, IR60 and IR40). Irrigation of the control treatment (IR100) was carried out when all the soil RAW was depleted. Irrigation of the other three treatments was carried out at the same time but with, respectively, 80%, 60%, and 40 percent of the volume applied to IR100. The canopy cover temperature in IR100 and air temperature (dry and wet) were measured on the day after (8-14 o’ clock) and before irrigation (12-15 o’ clock) in order to construct the lower and upper limits base lines required to calculate CWSI. According to the result, the upper base line equation is (𝑇 𝑐-𝑇 𝑎 ) UL = 0. 69, and the lower base line is (𝑇 𝑐-𝑇 𝑎 ) LL = 0. 2787-0. 1134 (VPD). Result showed that the effect of water stress on yield was significant. The highest yield was observed in IR100 (1. 756 g / plant) and the lowest yield was observed in IR40 (1. 421 g / plant). The crop water stress index (CWSI) of the four treatments in the day before irrigation was 0. 19, 0. 21, 0. 28, and 0. 46, respectively. According to this information, the permissible CWSI index for irrigation scheduling of summer savory growing in pots was 0. 19. The result of means comparison indicated that differences between IR100 and IR80 in values of CWSI and canopy cover temperature were not significant, but they were significant between IR100, IR60 and IR40. The increment of CWSI in IR80, IR60and IR40 were 10%, 47%, and 142 percent relative to the IR100. In this research, a strong correlation (r=-0. 978*) was obtained between CWSI and stomatal conductance.

Water scarcity is considered as one of the important factors affecting the production of agricultural products. Using crop management models such as the AquaCrop model can be a useful tool for reviewing the options and the ability to examine them in different situations. This study was conducted to evaluate the AquaCrop model's ability to determine the irrigation time of sugarcane plant and it’ s monitoring with water stress index in 2017 in cultivars and cultivars of sugarcane arranger cultivars in a R7-11 field with a total area of 25 hectares and a plant (new crop) Variety CP69-1062 was performed in south Ahwaz. The calibration was done to determine the accuracy of the model at the time of irrigation of the sugarcane plant, including an examination of the water stress index (CWSI) with a reddened thermometer. This calibration showed that the AquaCrop model has a relatively high simulation ability in determining the cannabis irrigation time. The statistical analysis of the accuracy of the model in predicting the irrigation time of the field with the actual field conditions was RMSE = 2. 0-day, d = 1. 0 and CRM= 0. 006. The irrigation scheduling of R7-11 farm with AquaCrop model was carried out with a total irrigation interval of 16. 6 rounds (from April to October 2017), the number of irrigation intervals with the number of irrigation intervals in plantations of CP69-1062 plant cultivars and dental industry Compared with the total irrigation intervals in the farms of 20. 8 rounds, the Khazaee was compared, it is observed that a R7-11 farm saved a quarter of the irrigation round in that year. The yield of this field yielded 128 tons per hectare and the average yield of planted plots of CP69-1062 varieties and cultivars were about 106. 63 tons per hectare. The quality of the R7-11 sugarcane syrup contains purity (PTY %) and the percentage of white sugar (RS %) of PTY = 90. 0 % RS = 11. 1 % and the average plant plantation varieties of CP69-1062 cultivars and cultivars, PTY = 88. 6 % and RS = 10. 8 % were obtained. The results of this study showed that considering the AquaCrop model has high accuracy, the use of this method to determine the irrigation time compared to the current method (crop log) that is common in sugar cane companies in Khuzestan, both in terms of cost and in terms of its use in research projects.

The ability of remote sensing (RS) in irrigation scheduling has been accepted in the world due to the collection of data on a large scale and the determination of water stress indicators with greater speed and less cost. Crop Water Stress Index (CWSI) and Water Deficit Index (WDI) are components of the most recognized water stress indices. Despite the accuracy and precision of the CWSI index that has been proven in plant irrigation scheduling, the lack of complete density of vegetation, especially in the early stages of growth, is one of the most important defects of using this method in crop irrigation scheduling. While estimating the water deficit index using remote sensing technology does not have these limitations. An experiment was performed in the crop year 98-99 in the city of Karaj to check the accuracy of this index. The amount of WDI and CWSI in a wheat field with optimized irrigation management was determined and compared and evaluated using statistical parameters. The results showed that the coefficient of explanation between these two indicators in the months of April, May, and June is 0.77, 0.85, and 0.71, respectively.

The Crop Water Stress Index (CWSI) is a practical method for monitoring plant water status, detecting the onset of moisture stress, predicting crop yield, and irrigation schedule for variouscrops. The CWSI values range from zero to one, where zero indicatesthat the plant is not uunderwater stress and has the most ideal conditions for transpiration, while a value of one signifies maximum water stress and complete cessation of transpiration. The present research was conducted to calculate the CWSI,determine the moisture stress threshold for safflower and identify optimal irrigation management practices by analyzing the relationship between the CWSI and various deficit irrigation managements  approaches.The research was carried out over two agricultural seasons, 2020-2021 and 2021-2022at Khuzestan University of Agriculture and Natural Resources. The experiment used a randomized complete blocks design with a conventional irrigation treatment (CI) and four deficit irrigation treatments including (RDI80, RDI60: deficit irrigation adjusted by supplying 80% and 60% of soil moisture deficit, respectively) and (PRD80, PRD60: deficit irrigation in the form of partial root zone drying methods with 80% and 60% of soil moisture deficit, respectively) and with four repetitions. Results showed that the CI treatment had the lowest value of 0.17 and the RDI60 treatment had the highest CWSI at0.67. Irrigation planning was done with the aim of achieving the maximum efficiency of water productivity, and based on this, the relationship between the permissible limit of the temperature difference of the Canopy cover of the plant and the air for the months of March ((Tc-Ta)a = 1.618 - 0.215 VPD), April ((Tc-Ta)a = 2.46-0.220 VPD) and May ((Tc-Ta)a = 4.636-0.164 VPD) were obtained. The moisture stress threshold for safflower was obtained from the regression relationship between the CWSI and the temperature difference of the Canopy cover of the plant and the temperature of the surrounding air (Tc-Ta) equal to 0.61, which was introduced for the study area and with the research conditions

This research was carried out to investigate changes in crop water stress index (CWSI) of bean and its relationship with soil moisture under different regimes of drip irrigation at Lorestan University College of Agriculture. For this purpose, three varieties of Pinto bean Contains sadri (S), COS16 (C) and Kusha (K) in main plots and irrigation regimes in four levels including T120 (120% crop water requirement), T100 (100% crop water requirement) T80 (80% crop water requirement) and T60 (60% crop water requirement) were subplots. The results showed that in all three cultivars of the beans, the highest values of CWSI during the season were related to severe tension (T60) which was equal to 0. 3 and in contrast to (T120), the lowest values of water stress index and Equal to 0. 14. The correlation coefficient between of soil moisture content and CWSI was found to be 0. 91 which was significant at 1% probability level, and therefore a relation was used to estimate the soil moisture content using the CWSI. Finally, using the proposed relationship and the allowable drainage coefficient, the threshold value of CWSI was 0. 21.