Abstract:
The response of second crop corn (Zea mays L.) to different irrigation treatments in a semi arid climate was
carried out in the field during the 2003 and 2004 growing season. Water stress was created at different
development stages: early vegetative, vegetative, before tasseling, after tasseling, milk stage and after milk in
order to determine the effect of irrigation treatments on vegetative growth, grain yield and yield components of
corn. The effect of water stress at any stage of development on plant height, dry matter accumulation, kernel
weight, kernel number per ear, ear length and ear diameter were studied. A rainfed (non-irrigated) treatment
and 9 deficit irrigation treatments were applied to the Pioneer 3394 corn hybrid on a loam soil with 3
replications. Water stress significantly affected the corn grain yield. and yield components. The grain yield
increased with irrigation water amount, and the highest average grain yield (11160 kg ha-1) were obtained from
the well irrigated treatment (K1). Seasonal evapotranspiration increased with increased amounts of irrigation
water applied. The highest seasonal ET (average of 650 mm) was determined at the (K1) treatment. Water stress
occurring during vegetative and tasselling stages reduced plant height. Total dry matter (DM) accumulation was
accelerated after each irrigation application. Yield response factor (ky) value of 1.02 were determined based on
averages of two years. Significant linear relations were found for grain yield and seasonal evapotranspiration
(ET). It is concluded that well irrigated treatment (K1) could be used for the semiarid climatic conditions under
no water shortage. In the case of more restricted irrigation, the limitation of irrigation water at the vegetative and
tasselling stages should be avoided to maintain satisfactory growth.
