Potential productivity and water requirements of maize-peanut rotations in Australian semi-arid tropical environments-A crop simulation study

The growing demand for maize (Zea mays L.) in intensive livestock and other industries has opened up fresh opportunities for further expansion of the maize industry in Australia, which could be targeted in relatively water rich semi-arid tropical (SAT) regions of the country. This crop simulation study assessed the potential productivity and water requirements of maize peanut (Arachis hypogaea L.) rotations for the SAT climatic zone of Australia using the Agricultural Production Systems Simulator (APSIM) model. APSIM was configured to simulate maize (Pioneer hybrid 3153) either in the dry (May-October) or wet season (November-April) and peanut (cv. Conder) in the following season for three soils found at Katherine (14.48 degrees S, 132.25 degrees E) from 1957 to 2008. The simulated mean total yield potential of the dry season maize and wet season peanut (DMWP) rotation (15-19.2 t/ha) was about 28% greater than the wet season maize-dry season peanut (WMDP) rotation because of the higher yield potential of maize in the dry season compared to in the wet season. These high yields in the DMWP rotation have been achieved commercially. The overall simulated irrigation water requirement for both rotations, which varied from 11.5 to 13.8 ML/ha on different soils, was similar. The DMWP rotation had 21% higher water use efficiency. Similar yield and water use efficiency advantages of the DMWP rotation were apparent for eight other agriculturally important locations in the Northern Territory, Western Australia and Queensland. The simulations for Katherine also suggested that the irrigation requirement of the two rotations could increase by 17.5% in El-Nino years compared to La-Nina years for only a small gain in yield, which has implications for climate change scenarios. (C) 2009 Published by Elsevier B.V.