The effect of moisture depletion on soil water evaporation and barley water consumptive use

الملخص EN

Three soil moisture depletion treatments of 10 % (M1), 25 % (M2) and 50 % (M3) of field capacity were used in a loamy sand soil.

Moisture loss from bare soil by evaporation, transpiration and water consumptive use by barley grown in plastic pots was calculated using the soil moisture depletion method.

There was a remarkable increase in water consumptive use with time, the highest values were recorded at the productivity stage for all moisture treatments.

The M1 treatment gave significantly higher total water consumptive use value (423) mm than the values 298 and 183 mm for the M2 and M3 moisture treatments, respectively.

Moisture loss values from bare soil by evaporation from sowing to maturity stages were 266, 156 and 109 mm for M1, M2 and M3, respectively.

The low values of the top and grain yield dry weights were related with the small amount of water available for plant use in the soil.

The highest reduction in water consumptive use by plant and yield dry weight were recorded in M3 moisture depletion treatment, which was attributed to the adverse effect of water stress during the growing season and seed formation.

The highest water use efficiency was calculated for the M2 moisture treatment.

The amount of water lost by evaporation from bare soil was higher than the amount used by the plant.

This can be related with the availability of pore spaces in the loamy sand soil for air and water movement, which eventually reduce the amount of water available for plant use in the soil.

The M2 moisture depletion treatment gave highest water use efficiency values.

The highest monthly and daily water consumptive uses by plant were recorded during the maturity and seed formation stages.

They were respectively, 129 and 5.25 mm for M1, 90 and 3.50 mm for M2 and 77 and 2.48 mm for M3.