March 7th, 2013
There’s a recent state by state trend to ban phosphorous in turf fertilizers. As is often the case with complicated legislative action, a combination of scientific misinformation, corporate gamesmanship and careless bureaucratic immediacy resulted in phosphorous becoming fertilizer nutrient enemy #1. Legislators were led to believe that phosphorous is bad for the environment and therefore voted in zero phosphorous policies because if a lot is bad, then none must be great…….. Next item on the agenda!
Unfortunately, banning phosphorous, which is one of the most abundant minerals on Earth, puts an impossible burden on the producers of natural and organically certified turf fertilizers. This is because all living things contain phosphorous. Plants are full of phosphorous. Flesh and bones are loaded with phosphorous. Manures contain phosphorous. So, how can a company make organic fertilizers with zero phosphorous? The answer is they can’t with the naturally occurring inputs available.
Although organic fertilizers cannot be made with zero phosphorous, chemical fertilizers can easily be concocted without it. Not only that, but the World-wide supply of rock phosphate is expected to run out within the next 100 years and the price has gone up rapidly with mining and shipping costs and the decreased availability. The whole phosphorous debate gave the chemical fertilizer folks a terrific opportunity to join in the slandering of phosphorous’ good name. Vilifying phosphorous was going to save the chemical blenders a fortune!
You might ask, “How are lawns surviving without the heavy doses of phosphorous?” There is usually enough phosphorous in the soil to support growth. The issue is whether or not it is available to plants. Its availability is dependent on many factors including, pH, temperature, organic matter content and biological activity. Many lawns are managed like intense agricultural fields where the crops are constantly removed (bagging the clippings) and high nitrogen chemical fertilizers damage the soil biology. Phosphorous is not going to be as available in this kind of situation, but whose fault is that?
Organic lawn fertilizers, which typically contain .5 – 2% phosphorous, are actually food for the soil biology. This means that most of the phosphorous becomes part of the living system as the fertilizer is “digested.” Studies have shown that the more organic matter, and associated biology, a soil has the less phosphorous leaches out. More phosphorous problems arise from lifeless bare soil and sand than from proper organic fertilizer applications on healthy soil. Again, the damage caused by modern chemically managed agricultural and turf maintenance practices is the biggest problem.
When you look at a fertilizer label, the middle number is the phosphorous percentage. If you choose to fertilize your lawn with a gentle acting organic 4-2-2 or 4-1-3, you are improving your soil with a full course meal compared to a salty quick fix of something with 22% nitrogen like a 22-0-10. Nitrogen is a REAL man-made problem in the environment, but there doesn’t seem to be any urgency to ban it. Look for fertilizers made with ingredients you can pronounce: Chicken manure, alfalfa, soy, corn gluten, bone meal, feather meal, lobster, kelp and fish.