How will farmers feed 9 billion people by the close of this century? That is the question posed to six renowned leaders in the field of conservation farming during the Conservation Ag Systems Innovation conference tour (CASI)
On August 28th, 29th and 30th,
Jeff Mitchell, University of California Cooperative Extension Specialist, gathered together some of the world’s great visionaries to sell conservation farming practices to California farmers, students, and agency staffpeople. Conservation farming, a term used to refer to no-till, minimum tillage and controlled traffic farming practices, is popular in the midwestern US because it saves water and cuts fuel costs while preserving soil organic matter, which has many benefits to soil fertility. No-till is also popular in South America, particularly in Brazil, while controlled traffic farming (with conventional tillage) is practiced in Tasmania, an island off the coast of Australia, for the purpose of reducing soil compaction on the cropped rows while improving traction on the trafficked rows.
Don Reicosky from Morris, MN, a retired USDA ARS employee, explained the nuts and bolts of tillage and likened it to natural disasters for soil microorganisms. The best tillage is no-till, he explained.
Rolf Derpsch from Paraguay, who has worked in Brasil, Argentina, Somalia and Germany, explained why conservation tillage not only saves water but also reduces the need for fertilizer because soil microbes and organic matter act as a slow release fertilizer, protecting ground and surface water from contamination. He said that early adoption of no-till in South America was easier to support than here in the US because there was no initial attachment to what we call conventional tillage, and the yield increases with less gas and less fertilizer inspired the spread of conservation farming there.
Clay Mitchell from Geneseo, IA grows corn and soybeans alternating in a north-south direction to maximize profitability based on market prices for those two commodities, but that is not all. This farmer has combined controlled traffic farming with satellite GPS (Global Positioning System) technology, and an awe inspiring data collection protocol which allows him to micromanage the fertilizer application based on things like prior yield in a particluar square foot of field. Tillage has long been considered the primary way to get rid of weeds and make the fertilizer applications and rooting depth more uniform. With no-till, surface application of soil ammendments like lime (calcium or calcium-magnesium carbonates) could be inconsistent and will only reach a depth of a few centimeters during a growing season, so Mr. C. Mitchell advises crop rotations rather than tillage to incorporate surface applied lime at depth, and he relies on satellites to position his fertilizers exactly where they are most needed rather than tilling for greater uniformity. This is a real engineering problem solving strategy, but weed control
Jerry Hatfield spoke about what the EPA and the California Air Quality Control Board want from soil, and how much more food we will need to produce on the same land. These two ideas do not conflict–by keeping more carbon on the ground, soil water holding capacity goes up, meaning that less irrigation water is needed and droughts are less severe. Water use efficiency increases as does productivity per unit fertilizer, giving us some hope for the future, when worldwide land area will decrease while demand will be as high in the next 10 years as in the previous 100 years.
John McPhee of Burney, Tasmania explained how GPS technology can aid in controlled traffic farming which reduces erosion and compaction, improving drainage and allowing cultivation and planting sooner after rain events. He said that tillage was an integral part of his operation and it was not popular to consider no-till systems in Tasmania. He likened the soil microbes to an elephant per acre, and the residue left in the field as food for the elephant -FEED the Elephant!
I would like to suggest that there was another elephant in that room. Herbicides. There is no such thing as organic no-till. Tillage is a wonderful alternative to herbicides and with all the hype about overuse of Roundup and other easily available potent herbicides, which results in herbicide resistance in common weed species such as Palmer Amaranth. Mr. Clay Mitchell of Iowa explained that he rotated his herbicides by rotating his GMO corn and soybeans from Roundup Ready varieties to Liberty Link varieties (the first can tolerate lots of the herbicide Roundup, or Glyphosate, and the second can handle a lot of Glufosinate, an herbicide with a different mode of action. Rotating modes of action is smart to prevent resistance in weed species, but mechanical control is the only option for organic growers, so if we stop plowing, we protect the environemnt from carbon dioxide and particulate matter but this system depends on constant innovation of herbicide chemistries to keep up with herbicide resistance, and constant new developments in the world of GMO’s to allow excessive herbicide applications. The herbicide question looms large in my mind, particularly for the developing world, where transportation infrastructure increases the cost of everything from fertilizer to herbicide to parts for fancy GPS directed no-till equipment. So feed the soil microbial elephant, and give that herbicide elephant a few peanuts too, while you’re at it–the future of humanity and food security depend on it!