Cereal yield in Mediterranean-type environments: challenging the paradigms on terminal drought, the adaptability of barley vs wheat and the role of nitrogen fertilization

Abstract

Under Mediterranean environments most of the cereals are produced under rainfed conditions, exposing crops to different severity of water stress due to scarce and variable rainfall. In this chapter, we revise three elements that are commonly accepted in cereal production in Mediterranean type-environments: First, the notion that annual crops in these environments are exposed to terminal drought. Using physiological and environmental analysis, we showed that this label over-emphasises grain filling, and neglects the most critical pre-flowering period; this has implications for both crop management and breeding. Second, the notion that barley performs better than wheat at the lowest end of the rainfall range. We emphasise the lack of solid scientific evidence supporting this view, and briefly consider the implications for patterns of land cover. Third, the notion that nitrogen fertilisation may reduce yield in low rainfall sites and seasons. We argued that, again in this case, the scientific evidence does not fully support this viewpoint, and discuss the opportunities to improve yield and water use efficiency by better management of nitrogen fertilisation.