Eficiency in nutrient absorption by winter forage crops

Abstract

The knowledge of the factors that determine differences among plant species in the efficiency of nutrient absorption is important to select plants to be grown in specific soil fertility conditions. Four winter forage crops: oat, ryegrass, subterraneum clover and vetch were characterized in relation to the efficiency of nutrient uptake. Plant kinetic parameters (Vmax, Km and Cmin) for nitrogen, phosphorus and potassium absorption, and root morphological characteristics (length, volume, radius and surface) were determined in a nutrient solution experiment. Differences among forage crops were due to the ability of plants to absorb and due to root morphology. Higher rate of nitrogen uptake (per unit of root surface) for vetch and for subterraneum clover were mainly related to high Vmax values, and of phosphorus and potassium, for ryegrass, to high Vmax and low Km and Cmin values.