IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
capítulos de libros
Título:
A modeling approach to explore water management strategies for late-sown maize and double-cropped wheat-maize in the rain-fed Pampas region of Argentina
Autor/es:
MERCAU, J.L.; OTEGUI, M.E.
Libro:
Advances in Agricultural Systems Modeling
Editorial:
American Society of Agronomy
Referencias:
Lugar: Baltimore; Año: 2014; p. 351 - 374
Resumen:
Most of Argentine maize (Zea mays L.) production takes place under rain-fed farming in the Pampas region, where water availability is the main limiting resource. Most crops are still sown early in spring, in order to have the critical period of silking before the frequent mid-summer water deficit. Early sowing date (September) has been also linked to the need of escaping the increased incidence of insect pests associated with late sowings, a restriction that has been drastically reduced with the introduction of Bt hybrids. Therefore, very late sowing dates (December) became an actual alternative that must be evaluated. We estimated the combined effect of late sowings, variable levels of plant available soil water (PASW) at sowing in single and double-cropped crops, and variable levels of soil N supply on the interannual variation of maize yield in four sites of the region. For this purpose we used 41 years of daily, measured weather data and the CERES-Maize simulation model. Rain-fed yield was very stable along December sowings (> 7.5 Mg ha-1) for latitudes < 36º S, provided PASW (1.8 m) at sowing were 100% and initial N availability reached ca. 130 kg N ha-1. This strategy had almost no yield penalty as compared to potential yield. The response rate to mentioned N availability turned negative for PASW at sowing ≤ 35%. Due to the apparent yield stability across December sowings, farmers should be recommended to survey PASW rather than to tie late sowing of maize to scattered rainfall events.