Don Reicosky: "Weather whiplash" requires new soil conservation
MORRIS -- Extreme weather events such as drought and powerful storms increasingly threaten our food security. Climate change may be the first “domino” to fall, setting off a series of crises related to soil degradation and loss of food security.
Minneapolis weatherman Paul Douglas has coined the phrase “weather whiplash” describing the extreme temporal volatility and variability of our weather. The quick changes in timing and intensity are providing more challenges to agricultural production.
"In the end, it doesn't matter one bit if climate change is a natural cycle or a man-made problem; we have to deal with it," said Fred Yoder, former president of the National Association of Corn Growers. We in agricultural will have to learn to mitigate and adapt to these extreme changes if we’re going to maintain food security for future generations.
Traditional soil conservation
Earth’s soils are complex and highly variable. Soil scientists and some farmers in the Midwest now say we are increasingly "exceeding the capacity" of traditional soil conservation methods. In other words, it's not enough anymore to just put in a terrace to keep soil from sliding down a hill.
Traditional conservation practices, in place since the Dust Bowl, such as contour strips, waterways, and terraces, were built to prevent sheet and gully erosion and have provided a degree of erosion control. More recently, we have transitioned to “conservation tillage” that results in somewhat better erosion control. Conservation tillage is defined by leaving 30 percent crop residue cover after the planting operation.
However, nothing has been said about the depth of tillage and the intensity of the mixing of soil and crop residue during the tillage operations prior to planting. Traditional conservation practices and conservation tillage methods are no longer able to control soil erosion with the recent extreme events in rainfall amounts and intensity. We have outgrown our traditional conservation practices. Conservation tillage is better than conventional inversion tillage, however, it is oversold for its conservation benefits. The concept is good, but the actual practice is bad for the soil.
New soil conservation is carbon management
Managing the complexities of climate and soil are a real challenge. It is commonly accepted that intensive tillage sets the soil up for wind and water erosion. If tillage is the culprit, then perhaps “less is more” – less tillage provides more soil protection and environmental benefits.
We need to protect our soils year-round and use reduced tillage to slow water movement, increase infiltration, and regenerate our soil organic matter. Methods like no-till farming, diverse rotations and cover crops not only help soil retain moisture, but also limit erosion, improve soil health and increase a field's capacity to grow high-yield crops. The no-till system, sometimes called direct seeding, which eliminates the use of full-width tillage equipment, provides both economical and conservation benefits to the producer. The promise of no-till with cover crop farming is that it not only can reduce soil erosion and agrochemical use, but also help keep the heartland churning out food, even as extreme weather events like droughts and floods become ever more common.
This summer, the USDA and the Conservation Technology Information Center released the results of a farmer survey showing that cover crops more than paid for themselves in the Upper Mississippi River watershed during the drought of 2012. Corn and soybeans planted in 2012 after cover crops had a 9.6 percent and 11.6 percent yield increase, respectively, when compared with fields that had no cover crops. While cover crops have proven themselves to increase soil organic matter and biological activity needed to improve soil health, many farmers have shied away from them because of concerns they will cut into maximizing yields of cash crops like corn and soybeans.
Cover crops are typically used for erosion control; however, the multiple benefits of increasing organic matter, nitrogen fixation, increasing water infiltration, better soil structure and improving the soil micro flora, all aid in sustaining or increasing yields through healthier soils. Evidence suggests that “C”arbon is the “C” that starts “C”onservation. The excitement about cover crops and carbon input stems from the potential for partially “drought proofing” a landscape.
It is hard to beat the synergistic simplicity of no-till (minimizes carbon and soil loss) and the use of diverse cover crop mixes (maximizes soil coverage and carbon input) for soil protection and regeneration. A few farmers are finding the environmental and economic benefits are going hand-in-hand with this system’s approach for food security.
By using these methods some farmers are finding that their soil actually has more available water for their cash crops when those crops really need it. With this inexpensive form of insurance against erosion and drought plus the associated environmental benefits, one has to ask why are so few farmers using no-till and cover crops?