عنوان مقاله [English]
Determining the precise water use efficiency is a critical issue in crop production temperature, precipitation, and evapotranspiration play an essential role in the hydrological cycle and crop production and as well as in assessing hydro climatological studies, plants water balance, water use efficiency, and water requirements measurements (Alizadeh, 2015). The purpose of this study was to evaluate the water requirement of tomato (Solanum lycopersicum L.) plants in Hormozgan province and compare it with other southern regions that are adjacent to this province, including Ahvaz, Dezful, Fasa, Isfahan, Kerman, Shiraz, and Yazd, in a 47-year long period from 1967 to 2013, using time series analysis.
Material and Methods
In order to compare the water requirement of tomatoes in Hormozgan Province and other southern regions adjacent to the province, crop water requirement (CWR) and irrigation requirement (Irr.Reg) of Tomato was estimated in Bandar Abbas, Ahvaz, Dezful, Fasa, Isfahan, Shahrekord, Kerman, Shiraz, and Yazd. The CWR was acquired by estimating two components: reference evapotranspiration (ETo) and crop coefficient (Kc). ETo was calculated via the Penman-Monteith method (Allen, 2003). Time series analysis of total precipitation, average maximum temperature (Tmax) and minimum (Tmin) and diurnal temperature range (DTR) during the growing season of Tomato was calculated by using the non-parametric Mann-Kendall test (Mann, 1945; Kendall, 1975) in the studied areas during a 47-year long period from 1346 to 1392. The Pettitt test's presence of change-point in the series was also studied (Pettitt, 1979). It should be noted that ETo and CWR were calculated using the Ref ET and CROPWAT 8 software and the Man-Kendall and Petti test with r software.
Results and Discussion
The results showed no significant trend observed in crop water requirement (CWR) and irrigation requirement (Irr.Reg) of Tomato in Bandar Abbas, similar to Ahvaz, Fasa, Kerman, and Yazd. In comparison, the highest and lowest decreasing trend of crop water requirement was recorded in Dezful (with slope -5.42 mm) and Isfahan (with slope -1.56 mm), respectively. Also, the highest average tomato water requirement was observed in Yazd and Dezful (1135 and 1131 mm, respectively), while the lowest average tomato water requirement was observed in Shahrekord and Ahvaz (602 and 702 mm, respectively). On the other hand, high water requirement and irrigation of tomatoes in Dezful and Yazd can be attributed to an increase in the evaporation rate from the soil surface and transpiration from the plant surface due to the higher mean of the maximum (39 and 36.7 °C, respectively) and the minimum temperature (20.8 and 21.3 °C, respectively) and the sunshine hours of these two areas during the growing season compared with other areas. Bandar Abbas has the lowest water requirement and irrigation requirement of Tomato with the length of a growing season and growing season, similar to Ahwaz. In general, it can be stated that planting fall tomatoes in Ahwaz and Bandar Abbas is more cost-effective than summer planting due to reduced evapotranspiration. The t-student test results for comparing water requirement with irrigation requirement of Tomato showed that there was no significant difference between the amount of water requirement of tomatoes for all stations compared to the amount of irrigation requirement of Tomato due to the average low rainfall in these areas.
By analyzing the time series of evapotranspiration and climate variables and plant sensitivities to the minimum and maximum temperature for germination and growing, it is possible to decide about crop planting in a particular region, so the highest crop yield was achieved by maintaining more water resources in the region. In addition, due to climate change and the importance of Iran's food security in a warm and dry climate, acceptance and spending on appropriate strategies to adapt crop planting systems to warmer and more humid climates and new irrigation systems are essential.
Funding for this research was supported by Hormozgan University (Research Grant 96/6976).