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Elyas Ostadi; abbas Khasheisiuki; amir salari
Abstract
The necessity of increasing economical productivity of agriculture and the increasing global demand for medicinal plants and considering the low water requirement of these plants have shifted the cropping pattern to their benefit. Water needs of Nigella sativa L., an important medicinal plant, was not ...
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The necessity of increasing economical productivity of agriculture and the increasing global demand for medicinal plants and considering the low water requirement of these plants have shifted the cropping pattern to their benefit. Water needs of Nigella sativa L., an important medicinal plant, was not known, therefore, we aimed to determine its water needs. (ETc) and crop coefficients (Kc) for different phenological stages in arid conditions of Birjand, in 2018. In order to conduct the research, three weighing lysimeters (with a diameter of 20 cm and a height of 16 cm) were used in three replications. Actual daily evapotranspiration was estimated by water balance in lysimeters and reference evapotranspiration was calculated based on 12 cm grass. The results showed that, in the initial stage, the rate of evapotranspiration was low, in the developmental stage it had an increasing trend, and after stabilization in the middle stage, with the onset of aging in the maturity stage of growth, the rate of evapotranspiration decreased. Actual and reference crop evapotranspiration was obtained as 670 mm and 1439 mm, respectively. The values of crop coefficients in the initial, development, middle, and final stages were obtained as 0.39, 0.53, 0.59, and 0.28, respectively. The general conclusion of the research is that by using the values of crop coefficients and water requirement, it is possible to cultivate this crop with maximum water productivity in the arid region of Birjand.
Mehri Saeedinia; Seyed Hamzeh Hosseinian; Farhad Beiranvand; Ali Heydar Nasrollahi
Abstract
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 ...
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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 (𝑇𝑐-𝑇𝑎) UL = 0.69, and the lower base line is (𝑇𝑐-𝑇𝑎) 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, IR60 and 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.
Majid Alihouri
Abstract
It is necessary to determinate of crop water requirement for optimum use of agricultural water resources. This research was carried out for determining water requirement and crop coefficient of Barhee date palm in the first to third year of vegetative growth. A drainage lysimeter was used to measure ...
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It is necessary to determinate of crop water requirement for optimum use of agricultural water resources. This research was carried out for determining water requirement and crop coefficient of Barhee date palm in the first to third year of vegetative growth. A drainage lysimeter was used to measure reference evapotranspiration (ETr) and three drainage lysimeters were used to measure evapotranspiration of date palm (ETc). The amounts of reference evapotranspiration and ETc were calculated using soil water balance. The results showed that ETr values in the first to third year were 2105, 1827, and 2021.8 mm, respectively, while seasonal ETc in vegetative growth were 274.3, 402.7, and 597.2 mm, respectively. ETc increased 46.8% and 48.3%, yearly. The crop coefficient of Barhee date palm was 0.08-0.18 in the first year. In this year, the minimum crop coefficient was recorded in May, while the maximum crop coefficient was in October and January. But, the date palm crop coefficient was 0.10-0.30 in the second year and 0.19-0.43 in the third year of vegetative growth. In second and third years of vegetative growth, the minimun crop coefficient was recorded in March. In the second year, the maximum crop coefficient was observed in August and January, while the maximum crop coefficient in the third year was obtained in November. The increasing plant age and vegetative growth could be the main reasons for the difference in the amounts of water requirement and crop coefficient of date palm in the first to third year.