The influence of earthworms and Vesicular-Arbuscular Mycorrhiza on the availability of phosphate in ecological arable farming

agriculture biologique cultivated land disponibilidad de nutrientes fauna del suelo faune du sol flora del suelo flore du sol fosfatos fosforo hordeum vulgare lumbricidae micorrizas arbusculares vesiculares nutrient availability organic agriculture phosphate phosphates phosphore phosphorus soil fauna soil flora tierras cultivadas vesicular arbuscular mycorrhizae