Commentary: No-till being blamed for green slime
More “green slime of cyanobacterial,” which most people call blue-green algae, was in Lake Erie, and some lakes and water reservoirs, during 2011, and it has environmental activists foaming slime at their mouths.
At least one environmental scientist is extremely upset that a lake such as the shallow Lake Erie and others were infected with more blue-green algae than in the past, and he is blaming it on no-till cropping systems combined with global warming.
“The Lake Erie algal bloom of 2011 set records, eventually reaching about 5,000 square kilometers, or about three times larger than the next-biggest bloom. But records show that algal blooms have been increasing since the mid-1990s, after several decades of progress,” wrote Doug Gurian-Sherman, a senior scientist, food and environment, with the Union of Concerned Scientists, on The Equation blog site.
The decades of progress that Gurian-Sherman refers to is reduced phosphorus from sewage treatment plant water put into the lake and reduced laundry detergent phosphorus going into water. Today, he claims high amounts of phosphorus coming off crop ground that is being no tilled is the problem.
He sees increased eutrophication, the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates, as a problem to totally blame on farmers. To scare people as much as possible, he also says the algae problem is more than foul odor and fish kills because cyanobacteria can produce liver or neurotoxins, which were found in the Lake Erie “at alarming levels.”
“The increase in harmful algal blooms coincides with increasing use of no-till in the Corn Belt. It turns out that without tillage, applied phosphorus fertilizer or phosphorous in manure becomes concentrated in the surface layer of the soil. Even though no-till reduces soil runoff and erosion—which carries phosphorus bound to soil particles into waterways—the resulting high phosphorus concentration at the soil surface leads to runoff of dissolved reactive phosphorus. The algal blooms that result from this are exacerbated by heavy rainfalls, which wash more phosphorus into the lake, and which are predicted to become more frequent in the region as global warming proceeds,” Gurian-Sherman wrote.
He suggests the use of phosphorus fertilizer, which makes runoff possible, is a waste of a natural resource, and he thinks “occasional tillage will help alleviate this problem by burying the phosphorus.” He admits he is “unclear” whether cultivators or chisel plows that do not invert the soil would do any good. He has no real opinions about “rotational tillage or ridge till.”