Effects of irrigation frequency and retrieve consumptive use on growth and production of sorghum under semiarid condition

الملخص EN

The aim of this study to evaluate the effect of drip irrigation frequency and retrieve consumptive use rate on growth parameters of Sorghum crop speed feed variety.

the study was carried out at the field of College of Agricultural Engineering Sciences, Duhok University, were studied for growing season (2019-2020) under conditions of Duhok semi-arid region, using drip irrigation system.

the irrigation frequency (IF1, IF2, IF3 and IF4) arranged in main plots under three levels of retrieve consumptive use which were (1.00 CU, 0.70 CU and 0.40 CU) in the sub plots and using 2880 plants density ha-1.

the data were recorded on leaf area index, net assimilation rate, growth rate, leaf area, specific leaf area, plant height and crop response factor (KY) were determined.

the results showed that the actual evapotranspiration (ETa) was linearly related with water applied and retrieve consumptive use Under the three levels of retrieve consumptive use (1.00 CU, 0.70 CU, 0.40 CU) the cumulative actual evapotranspiration (ETa) were 565.40, 395.78 and 226.16 mm, irrigation water 589.05 , 419.55 and 250.13 mm and water use were 595.68, 425.80 and 256.12 mm.

these parameters were measured from the beginning of emergency stage until cutting green forage yield of sorghum crop.

the values of Sorghum growth parameters of leaf area index, net assimilation rate, relative growth rate, leaf area, specific leaf area, stem radius and total leaves number increased with increasing irrigation frequency, IF and retrieve consumptive use.

the highest values of the parameters were obtained for IF1 (once in 1 day) under level (1.00) retrieve consumptive use.

Crop response factor (KY) decreased with increasing irrigation frequency (IF) while it increased with increasing retrieve consumptive use (CU).