influence of planting and irrigation management methods on maize water productivity in a semiarid region

in arid, semiarid, and mediterranean climates, particularly in west asia and north africa, farmers face limited water resources and must develop irrigation management methods to increase crop production while reducing water use. this study examined methods to reduce irrigation water loss and increase maize water productivity at safiabad agricultural research center in dezful, iran in 2007 and 2008. the experiment was a randomized complete block design with a strip-split plot arrangement of treatments in three replications. planting and irrigation management methods used were: (t1) planting on 75 cm wide ridges and full irrigation (current method and the control treatment); (t2) planting on 75 cm wide ridges and variable alternate furrow irrigation; (t3) double row planting on 75 cm wide ridges and full irrigation; (t4) single row planting in 75 cm apart furrows and converting furrows to ridges at the 2-4 leaf stage; (t5) single row planting in 75 cm apart furrows keeping fixed furrows and ridges until the end of the growing period and; (t6) planting on 75 cm wide ridges using full drip irrigation. the three maize hybrids studied were ossk-602, bc-666 and sc-704. grain yield, biomass, irrigation water consumption, crop water productivity, and irrigation water productivity were recorded for evaluation of the planting and irrigation management methods. the results indicated that there were no significant differences in yield among the maize hybrids. in the control treatment, water loss occurred mainly as runoff. treatment t5 resulted in a 31% decrease in irrigation water and higher grain yield over the control treatment. mean crop water productivity was 1.45 kg/m3. this study showed that effective surface irrigation management methods and furrow planting increases irrigation water productivity (iwp) 45% over the control treatment.  in addition, drip irrigation increased iwp three fold, approaching cwp for all the studied maize hybrids.