EVALUATING DIFFERENT IRRIGATION SCHEDULING CRITERIA FOR AUTUMN-SOWN MAIZE UNDER SEMI-ARID ENVIRONMENT

Abstract

Drought is a foundation reason of low grain yield in many field crops including maize (Zea mays L.). Identifying growth stages of any promising cultivar under local climate and soil fertility permits irrigation scheduling to maximize yield. Potential soil moisture deficit (PSMD) approach (a difference between potential evapotranspiration and rainfall plus irrigation) describes the response of canopy growth to water shortage. To examine the productivity of different autumnsown maize hybrids under irrigation scheduling at different growth stages and PSMD levels, a field study was conducted with a split plot arrangement at the Agronomic Research Area, University of Agriculture, Faisalabad (Pakistan) during 2009. The treatments consisted of two maize hybrids (Monsanto-919 and Pioneer-30Y87) and seven irrigation levels: I1 = no irrigation (control), I2 = 4 irrigations, I3 = 6 irrigations, I4 = 8 irrigations, I5 = 10 irrigations (1st irrigation starting at 6 leaf stage, followed by subsequent irrigations at an interval of 4 leaf stages in all irrigation treatments and addition of two reproductive stages in I3, I4 and I5 successively), I6 = irrigation at 25mm PSMD and I7 = irrigation at 50mm PSMD. The results showed that Pioneer-30Y87 produced more plant height but the two hybrids did not differ significantly in other growth and yield parameters. Among all irrigation treatments, 6 and 8 irrigation treatments were statistically at par with treatments of 10 irrigations and irrigation at 25 mm PSMD in radiation use efficiency, water use efficiency, 500-grain weight, grain yield and TDM production. More number of irrigations is not a standard for getting maximum yield in all maize hybrids. PSMD can be used as a useful measure for scheduling irrigation in irrigated conditions of Pakistan.