HERE’S THE SHORT VERSION FOR PEOPLE LIKE US
To the Editor
April 12, 2007
Overall a good overview of the growing organic turf and grounds maintenance movement, but I must take issue with two statements by Dr. Rossi of Cornell.
First, the compost teas of the 1990’s were nothing like the compost extracts of today. Those early concoctions were made by simply soaking a mish-mash of raw materials in water for some unspecified time and then applied willy-nilly to lawns and gardens. Today’s professional compost extracts, by contrast, are produced with very specific ingredients under controlled conditions, and batch tested to assure consistent nutrient levels and microbial populations tailored to specific sites and conditions.
Second, the available phosphorus in compost (including that made with animal manures) is on average only a tenth to a sixtieth that of soluble consumer fertilizers, and considerably less prone to leaching into our surface waters and aquifers, even at higher application rates, and there is plenty of peer reviewed research showing its advantage over both soluble fertilizers and manure in this respect.
Shepherd Ogden, Executive Director, SafeLawns Foundation
1. I have observed the process of making extracts first hand and questioned the technicians in detail on the procedure. Most use no avian or mammal manure.
2. The phosphorus content comparison was taken from the Lowe’s website this morning comparing Scotts starter fertilizer versus a composted cow manure product.
3. I previously worked at The Rodale Institute where some of this research was done. You may contact Dr, Paul Hepperly the Research Director for confirmation of this assertion.
AND HERE’S THE LONGER VERSION FOR YOU SOIL SCIENCE GEEKS
To the Editor:
While an excellent overview of the growing market for organic lawn care, I must point out a few misperceptions that the article leaves undisturbed, especially in relation to the comments of Dr Frank Rossi of Cornell.
First, concerning efficacy, is the necessary distinction between compost tea, and compost extract, a distinction that highlights the differences between the organic technology of the 1990s – when the first wave of today’s organic boom crested according to PLN’s Mr. Delaney – and today, when the demand for organic treatments has spurred private sector research and development of new methods and equipment. Compost teas of the 1990 could be haphazardly concocted brews, where a mish-mosh of nutrient sources like compost and manure were soaked in water and the water used for soil treatment. Not only was the nutrient composition rarely assayed, but the microbial populations that are so important to the efficacy of extracts were not monitored or maintained.
No more. Today professional compost extracts are rigorously controlled at every step of the production process. Very specific feedstocks, in combinations tailored for specific properties and conditions, are combined to create consistent nutrient and microbial contents, and batch tested to assure consistency from application to application. Further, the batches are time dated, as the microbial populations rise and fall based on the nutrient content of the extract, giving them a set shelf life. (Work is going on to produce dried extracts with a long shelf life but results so far results have been mixed.)
That there has been insufficient peer reviewed work with these technologies is a shame, the same shame that applies in the farm sector, where all things “organic” were widely ignored until consumer demand drew private sector players. The sad truth is that over the past 30-40 years less than one tenth of one percent of the USDA research budget was applied to exploring and improving organic technologies. Had those monies been more evenly distributed we would be much farther along the path to a sustainable food system than we are. At the SafeLawns Foundation we hope to help avoid repeating this oversight, and find efficacious methods of grounds maintenance that improve on the environmental performance of current, conventional methods.
A similar problem arises in the discussion of compost as a soil amendment applied directly to lawns. There is no question that animal manures contain phosphorus and that phosphorus is damaging aquatic systems nationwide due to overuse. However the content of most composted manures is in the range of 0.5-0.5-0.5 NPK (the analysis on every bag of fertilizer, while synthetic blends range all the way from, say, 29-2-5 NPK to a whopping 20-27-5 NPK for a turf “starter fertilizer.” And not all composts are animal composts, nor are all composted materials applied as compost; many are further processed and formulated into slow release, organic granular fertilizers.
Reading Mr. Rossi’s comment, one would get the impression phosphorus runoff is the fault of backyard composters, and not the millions of bags of these synthetic fertlizers applied annually to our lawns and parks, which is hardly a defensible position. He would rightly note that to match the NPK application of a synthetic fertilizer, the compost would have to be applied at a rate that might lead to runoff and other problems. But this ignores one key point, and lets another slip by un-noticed.
Composted materials do not need to be applied at the same rate as synthetic fertilizers. The NPK rating on a bag of fertilizer is a measure of readily available nutrients, and since the organic materials break down more slowly they must, by law, show a lower NPK rating that is not truly indicative of their fertilizer value over the longer term. Second, the solubility of the quick release fertilizers is precisely the problem, and it is a problem that composting largely avoids. Most farmers are now environmentally aware enough not to stack manure in locations where the pile will seep nutrients into waterways, and that is all to the good. But research at The Rodale Institute has shown conclusively that composting will reduce the leaching potential of manure by 75% due to a firmer binding of nutrients to the humus created by the composting process. So even if one were to over apply compost, the rate at which any phosphorus in the material would affect water quality is hardly on the scale of the synthetic fertilizers whose very design emphasizes the solubility necessary for the quick green up their manufacturers have convinced consumers is the ultimate goal of lawn care.
Shepherd Ogden, Executive Director, SafeLawns Foundation, www.safelawns.org
on April 22, 2007 at 6:07 pm, in the category What's Happening.