decomposition is when a decomposer recycles / returns nutrients / nitrogen from dead organisms to the soil by eating those dead organisms & if something is returned to a thing then that something is added to that thing ->  decomposers add nitrogen to soil using decomposition  low good / poor / trouble sand has a low alphabet of seeds / return of antinitrogen & fertile soil is high in quality -> fertile soil is high in amount of nitrogen fertile soil is high in amount of nitrogen  decomposers add nitrogen to soil using decomposition & fertile sand is low in mechanism of antinitrogen -> decomposers make fertile soil by adding nitrogen to soil