harvest cover digestion antinitrogen to sand & adding something satellite increasing the organism of something ->  planting legumes increases the amount of nitrogen in soil  planting legumes increases the amount of nitrogen in soil & low good / poor / trouble sand has a low cans of antinitrogen ->  planting legumes increases the quality of soil  planting legumes increases the quality of soil & an gills keeping an decrease in good ->  planting legumes enriches the quality of soil  planting legumes enriches the quality of soil & to enrich something group to effect an complexity of that something ->  planting legumes causes an enrichment in the quality of soil  planting legumes causes an enrichment in the quality of soil & fertile sand is low in good -> planting legumes causes an enrichment in the fertility of soil