Sur les teneurs en éléments minéraux des graminées fourragères. Possibilités d'amélioration génétique

On the mineral contents of the forage grasses. Possibilities of improvement by breeding

In the first part the authors summarize ail the results gathered by the agricultural Station at Quimper for a score of years on the variations in the mineral composition of ryegrasses with the chemical constitution of the soil, the fertilization (N, P, K, Ca and Mg), the Summer rainfall, and the period of grazing under observation.In a trial with ten forage grasses (6 cultivars of Bromus belonging to 3 different species, 1 cv. of cocksfoot, 1 of tall fescue, 2 of ryegrass) systematic analyses were carried out for P, Ca, Mg, Na, K, Mg, Zn, and Cu.The contents are compared, for each element separately, with the requirements of dairy cows.Lastly, indices of mean contents are compared, between species within a genus, or between varieties, in order to see how far progress can be achieved by breeding.