Modelling maize yield response to plant density and water and nitrogen supply in a semi-arid region

Fertiliser and supplemental irrigation increased yield for all scenarios except those with low plant density. The optimal N fertiliser rate was identified as 33-102 kg ha−1 in the rainfed system and 38-86 kg ha−1 in the supplemental irrigation system, compared with the national blanket recommendation of 120 kg N ha−1. The simulation results suggested that the national recommended rate is only appropriate for years and regions with adequate rainfall distribution (>300 mm per cropping season).