Response of soil microbial biomass, urease and xylanase within particle size fractions to long-term soil management

abonos npk application rates azote biomasa biomass biomasse carbon carbone carbono dose d'application engrais npk enzymic activity farmyard manure fracciones del suelo fraction du sol fumier gestion du sol grosseur des particules manejo del suelo microorganisme microorganismos microorganisms nitrogen npk fertilizers organic carbon particle size phaeozem phaeozems rotation culturale rotational cropping soil soil management soil organic matter soil separates sol suelo ureasa urease