Relations of shoot C, root C and root length with root-released C of two barley cultivars and the decomposition of root-released C in soil

agroecosystems biological activity in soil biologie du sol carbon carbone carbono chemical composition composition chimique cycling degradation ecosistema ecosystems exsudation exudation flora del suelo flore du sol hordeum vulgare kinetics largura length longueur organic matter racine roots soil soil biology soil flora sol stems suelo tallo tige transformation variedades varieties