EFFETS DE LA FERTILISATION ET DES REGIMES HYDRIQUES SUR LE RENDEMENT, L’UTILISATION D’EAU ET LA COMPOSITION CHIMIQUE DE LA LUZERNE ET DU TREFLE LADINO

Abstract

Four fertility levels and four different soil moisture regimes were combined factorially to evaluate, in a greenhouse study, the yield, the consumptive use of water and the quality of alfalfa and ladino clover grown on St-Jude sand and on Ste-Rosalie clay. Usually, alfalfa yielded twice the amount of dry matter and had more difficulty in tolerating frequent irrigations. Ladino clover transpired less and, consequently, the number of irrigations was reduced. With the increase of yield and the decrease in water consumption, fertilization increased water use efficiency (WUE). The WUE for alfalfa (0.326 g of DM/cm of water) was greater than for clover (0.271 g/cm). In general, the crude protein and the digestibility were higher for clover than for alfalfa. Crude protein level and digestibility increased with soil moisture stress and decreased with the increase in soil fertility. The soil type influenced protein content but not digestibility. Finally, alfalfa absorbed a higher level of phosphorus than clover and mobilized this element at greater tensions. Phosphorus content of the legumes was decreased proportionally with dry water regimes, while potassium content was increased.