Water requirements of sugar beet under ras sudr conditions

الملخص EN

The current study intends to evaluate the influence of amount of irrigation water and irrigation intervals on water requirements of sugar beet crop.

The experiment was conducted in Wadi Sudr, South Sinai in 1999 /2000 season using sugar beet.

Evapotranspiration was calculated according to the modified Blaney-Criddle (Q1), Pan evaporation (Q2) and modified Penman (Q3) formulae using three irrigation intervals, i.e., 7, 14 and 21 days.

Water application values where: 1495, 2023 and 2198 mm.

for Q1, Q 2 and Q 3, respectively. The highest value of actual evapotranspiration (ETa) for all treatments of sugar beet was obtained by using modified Penman equation, while the lowest one was obtained by Blaney-Criddle equation.

Data indicated that ETa increased with decreasing the irrigation interval for sugar beet.

The highest sugar beet yield was obtained by increasing the amount of applied irrigation water using modified Penman method which fulfills a highly significant increases in dry tops, fresh roots, fresh tops and total yield. Concerning the effect of irrigation intervals, the statistical analysis reveals that increasing irrigation intervals to 14 days had significantly increased the dry and fresh yield of roots, tops and total production of sugar beet.

Moreover, when short irrigation interval was used (7 days) yield components were significantly decreased.

The highest yield components and total production were obtained when Pan evaporation equation was used at 14 days interval. The highest value of water use efficiency was obtained by applying irrigation water computed on basis of Pan evaporation equation (Q2) followed by Blaney-Criddle (Q1) at 14 days interval (I2), while the lowest value of water use efficiency was obtained at 7 days interval (I1).

The highest water economy was attained of Pan evaporation equation (Q2) increased with intervals of irrigation to 14 days under all applied amounts of irrigation water. The highest seasonal values of crop coefficient (Kc) were obtained using Blaney-Criddle equation, while the lowest seasonal values were achieved at Pan Evaporation equation for sugar beet.

It is obvious that crop coefficients had increased, with increasing the rate of crop development until vegetative and yield stage (mid-season).

Kc values were decreased with increasing intervals of irrigation water.