The practice of fertilizing soils based on hoped-for crop yields while ignoring nutrients already present in the soil or about to be released by biological processes may be directly contributing to a potentially explosive situation of algal blooms on the Great Lakes – and other places. Images that NOAA has released over a 10-year period for Lake Erie show that in 2011 the algal bloom was the most extensive – worse yet – in the lakes history. National Geographic (May issue) also covered the Lake situation. Will Brinton traveled to Guatemala in 2011 and observed the massive algal bloom on Lake Atitlán – visible in outer-space to NASA imaging: “The only distinguishing feature in these crises is the source of the nutrients: in Guatemala it’s septage; in the USA its agricultural nutrients.” What makes the USA situation possibly worse than Guatemala is that we are doing it in plain day with an arsenal of tools, technology, soil testing and agricultural machinery that is supposed to be the most advanced in the world. “But in fact, the inefficieny of it is about as primitive as raw septage leaking in the waterways”. Since 2002, 15,930 metric tons of nitrate and a lesser but significant amount of phosphorus has entered Lake Erie. No one is anxious to assume any blame.
A recent Crops&Soils magazine article on the topic quotes agronomist Robert Mullen of the USA Potash Corp: “If no action is taken, there’s a greater likelihood of regulation from the state and federal level” – regulation that many do not want. Some experts are questioning if we have enough information to stop the problem. Woods End’s efforts to get a new soil test off the ground that measures the biological ability of soil to release bound nitrogen (and P), is meeting with slow, steady acceptance “but too slow to stem the problem”. says Brinton, developer of the Solvita Soil test. Presently 32 labs across America and a dozen internationally are offering the test. However, according to Woods End lab, what the soil labs are saying is that farmers are not requesting the new tests – in other words, there is a lack of understanding about the usefulness of the test and why they should do it. This possibly makes soil labs become part of the problem by recommending more-than-enough fertilizer to make for high yields, without accounting for natural sources. Organic-bound N and P is like capital in the bank, and the release each year is the interest coming out. Modern fertilizing practices appear to be the spend-happy consumer, ignoring existing capital and the interest it generates.
Failing to measure nutrient potential of soils is not the only source of the problem; the other half is the manner in which soils are prepared and tilled or not-tilled, according to most reports. Excessive tillage may increase soil washing into waterways from erosion, carrying nutrients with it, but no-tilling is also in the cross-hairs by contributing to surface washing of surface-applied chemicals. The big perspective must be soil-health starting at home and the soil lab – start appreciating the soil’s intrinsic ability to provide nutrients and stop over-using and over recommending fertilizers based on incomplete soil testing.