Hazem H. Al-Ashwal (1)* and Mohamed M. Alsanabani (2)
(1). Northern Highland Agricultural Research Station, Agricultural Research and Extension Authority (AREA), Sana’a, Yemen.
(2). Soil and Water Department, Faculty of Agriculture, Sana’a University, Sana’a, Yemen.
(*Corresponding author: Hazem H. Al-Ashwal.E-Mail: hazemalasshwal@yahoo.com).
Received: 01/05/2020 Accepted: 12/06/2020
Abstract
An experiment was conducted at Northern Highlands Agricultural Research Regional Station in Sana’a, Yemen, to simulate distribution of soil moisture under alternative furrow irrigation, and soil water balance. Six treatments applied, namely: EFI1, EFI2, EFI3, AFI1, AFI2 and AFI3; which EFI means conventional (or full) furrow irrigation, and AFI alternative furrow irrigation, and the numbers 1,2,3 related to levels of irrigation water 100%, 75% and 50% respectively, which the treatment EFI1 was the farmer practice. VS2DI model was used to simulate water movement in soil for all treatments. EFI1 treatment used for calibration process to calibrate some parameters related to soil and transpiration, and the rest 5 treatments for verification. Results showed that there was satisfactory agreement between measured and estimated soil water content, and there was goodness of fit in the statistical values of (R2), (RMSE), and (D) in all cases. The results also showed that the pattern of soil moisture distribution plays an important role in benefit of alternative furrow irrigation over conventional irrigation, which has been found that the soil moisture in parts of soil profile (under irrigated furrow) maintain high, and suitable for plant in AFI treatments compared with EFI at the same level of irrigation water, generally compared with AFI, the deep percolation was higher in EFI, the cumulative evaporation and transpiration didn’t affected by irrigation method, but the evaporation and transpiration rates are affected; In the first stages after irrigation the evaporation and transpiration rates was higher in EFI than AFI, and vice versa in the late stages after irrigation, then at a certain time after irrigation, the transpiration rate dramatically decreased in EFI, but that wasn’t noticeable effect in AFI; this explain the slightly effects on yield in AFI with decrease in irrigation water compared with EFI. The study concluded that another studies concerned in the physiological response of plant in transpiration to partial root zone drying and soil moisture distribution must be conducted, and the root activity function must be improved in VS2D model. Also concluded that the AFI technique is practicable and useful in arid areas where the water is cost.
Key words: Alternate furrow irrigation, Soil moisture distribution, Simulation, VS2DI module.