Nitrogen and phosphorus limited production of cereals and semi-natural annual-type pastures in South-Western Spain

azote biomasa biomass biomasse carence du sol cereal crops composition globale crecimiento croissance cultivos de cereales deficiencia de minerales deficiencias del suelo disponibilidad de nutrientes espagne fosforo growth mediterranean zone mineral deficiencies nitrogen nutrient availability nutrientes nutrients nutrition des plantes pastizales pastures phosphore phosphorus plant nutrition proximate composition soil deficiencies spain substance nutritive zona mediterranea