ROOTS DISTRIBUTION UNDER DEFICIT IRRIGATION FOR MAIZE PRODUCTION

Root growth and its distribution is fundamental in explaining crop responses to irrigation systems and determining its appropriate management. An experiment was conducted to study the effect of drip emitters (Em) under full and deficit irrigation on root distribution, yield and water use efficiency (WUE) of maize crop in sandy soil. Four emitter types were used to irrigate the crop by three percentages 100, 80 and 60% of evapotranspiration (ETc). The emitters discharge and emission uniformity (EU) were evaluated. Under operating pressure of 100 kPa, the emitters Em₁, Em₂, Em₃ were classified as excellent EU, while the Em₄ was poor EU. The root distribution increased by increasing emitter EU with low discharge. Also, the distribution root decreased by reducing ETc% and increasing the distance from emitter. 60% ETc concentrated the roots near the emitters, while, 80% ETc has enough distribution to increase the plant ability to withstand winds. The highest yield was achieved with 100% ETc and Em₁, while WUE of both 60% and 80% was approximately the same and greater than WUE of 100% ETc. It could be recommended that to have the highest yield of maize in sandy soil, a low discharge and excellent EU emitters should be used with adding 100% ETc. While, adding 80% ETc is preferred when the priority to water saving.