Organic matter in soil will improve water quality in streams.
Organic matter (OM) is fertilizer and is composed of the sameelements that make up commercial fertilizers. If it is applied in excess, it will cause pollutionproblems just as surely as commercial fertilizers can. It is true that organic matter provides aslow release of nutrients if used in moderation, but applying organic matter at unnaturally high rates means the nutrient release is likewise increased. A heavily amended landscape soil (33 percent OM) releases much greater amounts of nitrogen, phosphorus, and other nutrients than an ideal soil (5 percent OM). Loading up your soil with high levels of nutrients flies against the natural order of terrestrial systems; any soluble nutrients not immediately utilized by microbes or plants will contribute to nonpoint source pollution; i.e., they will run off or leach away quickly and contaminate streams and other watersourses. The best way to steer clear of any problems associated with excessive fertilization is to start with a soil test to identify nutrient deficiencies, then amend your soil to correct only those deficiencies.