Abstract

Aim: The presented work aims to analyze the potential impacts of the temperature and precipitation changes as two main characteristics of climate change in addition to water salinity on the agricultural water demand. Changes in humidity concentration were not evaluated, nor were the changes in wind velocity and solar radiation. The study was carried out on 5 representative crops (Olive, Palm, Grape, Citrus and Guava) that cover around 83% of the orchard farms in Gaza Strip, considering eight simulated climate change conditions.

Methodology: To achieve this goal, CropWat modeling software version 8.0, is used to calculate the reference evapotranspiration rate and crop water requirement under different temperature and precipitation scenarios. Furthermore, a survey was conducted to evaluate the farmer’s current irrigation practices and the impact of water salinity on leaching requirements and production yield.

Result: The study results showed that the increased temperatures by +1°C or +2°C caused an increase of the annual average evapotranspiration by 45mm and 91mm relative to the current climate condition and leading to increase of irrigation requirements by 3.28% and 6.68%, respectively. Considering the increase of temperature +2°C, and decrease of precipitation by 10%, the irrigation requirements will be increased by 8.69% relative to the current scenario. In order to devoid the salinity effect on yield, leaching requirements do not exceed 15% in case of EC value less than 2 dS/m, while it begin to increase rabidly for the EC value over 3 dS/m for grape, citrus and guava and accounted for 250%. Generally, the impact of salinity increase on the irrigation requirements is much higher than the impact of evapotranspiration increase due to the temperature increase by 2°C and 10% precipitation reduction.

Conclusion: Currently, the farmers use excessive amount of irrigation water; higher than the required increase due to the proposed climate change effect. The impact of salinity increase on the irrigation requirements is much higher than the impact of climate change.

Keywords: Gaza strip; Climate change; Irrigation requirements; Salinity and leaching fraction