Abstract
Field experiments were conducted in 2009/10 and 2010/11 irrigation seasons at the Institute for Agricultural Research, Samaru Zaria, to assess the impact of two methods of administering Growth-stage deficit irrigation scheduling (GSDIS) on yield and soil water balance of an early maturing maize variety. The two methods include reducing water application depth at selected crop growth stages and skipping regular irrigation interval at selected crop growth stages. The test crop was SAMAS TZEE early maturing maize variety. Grain yield, biomass yield, harvest index, seasonal water applied, evapotranspiration and deep percolation and crop water productivity were determined. Grain and biomass yields ranged from 2.12 to 3.01 t/ha and 7.57 to 10.0t/ha, respectively, while seasonal evapotranspiration varied from 366 to 486.8 mm across the seasons. This study reveal that at vegetative growth stage of the maize crop, it is better to skip weekly irrigation (to irrigation every other week) and apply water to meet full water requirement than to maintain regular weekly irrigation but apply water at half water requirement. A grain filling to maturity stage, it is more advantageous to reduce irrigation water application by half water requirement than to skip weekly irrigation. Grain yield, biomass yield and seasonal evapotranspiration from such scheduling were not significantly different from that which received weekly irrigation throughout the crop growing season. Moreover, the productivity of water applied was higher while water loss to deep percolation was drastically reduced.

Key words: Deficit irrigation scheduling, Economic net return, Maize crop, Irrigation water management