Abstract
A 50 ha field was delineated into two management zones. Variable Rate Irrigation (VRI) system of Valley Irrigation, USA, was used to impose the treatments. Fertilizer levels formed main treatments, and the irrigation levels formed sub treatments in both management zones. The fertilizer treatments included: Low (126:92:300), Medium (234:138:400) and High (342:184:500) (kg N, P2O5 and K2O/ha/year). The irrigation treatments included: irrigation at 100% (I1 approximate to 3,130.54 mm/annum), 90% (I2 approximate to 2,817.49 mm/annum), 80% (I3 approximate to 2,504.41 mm/annum) and 70% (I4 approximate to 2,191.38 mm/annum) evapotranspiration (ET,). For two cuts, the treatments influenced the hay yield. VRI showed benefits in the first cut. For both cuts and zones, medium fertilizer level proved superior. The highest yield of 3.63 t/ha in September and 2.15 t/ha in October, was obtained with irrigation at 80% ET, and medium fertilizer level. Saving of 626.13 mm/annum (approximate to.20%) of water can be achieved using precision fertigation.