Increased proportion of active soil N in Breton loam under cropping systems with forages and green manures

abonos verdes absorption de substances nutritives alberta analytical methods azote cultivo protegido cultivos de grano culture sous abri disponibilidad de nutrientes dosage biologique efectos residuales engrais vert feed crops fodder crops grain crops green manures greenhouses hordeum vulgare invernaderos laboratory experimentation luvisol luvisoles luvisols methode methods mineralisation mineralization nitrogen nitrogen content nutrient availability nutrient uptake organic matter plantas forrajeras protected cultivation residual effects rotation culturale rotational cropping serre soil sol suelo technique analytique teneur en azote