Optimizing evapotranspiration and crop irrigation requirements of tropical forages cropping systems in Southern Brazil.

Crop irrigation requirements are usually estimated based on crop evapotranspiration (ET) as determined by the reference evapotranspiration (ETo) and crop coefficient (K). There is a lack of knowledge on the irrigation requirements of tropical forage crops in Brazil, contrasting with the increasing use of irrigation in pastures. The effort of this study was to investigate what would be the water needs of tropical forages in Southern Brazil, based on a robust experimental database.

Evapotranspiration adjustment for irrigated maize-soybean rotation systems in Nebraska, USA.

Irrigation water requirements are commonly estimated based on the estimated crop evapotranspiration (ET) as determined by the reference evapotranspiration (ETr) and crop coefficient (K). Recent studies show that, at high evaporative demand (high ETr), K tends to decrease, creating an inverse ETr-K relationship. The focus of this long-term study is to, if at high atmosphere demand, there is the same inverse ETr-K relationship in Nebraska, USA, one of the most intensely irrigated regions in the world, and as a result, propose an adjustment to the Kc-ETr approach.