No-till cropping in seasonally dry environments
by Peter Donovan
Long-term success for no-till farming in dry-season (brittle) climates may require using livestock to speed nutrient recycling at the soil surface.
At the Pacific Northwest Direct Seed Association's January 2003 conference in Pasco, Washington, no-till farmers shared successes and challenges.
Dwayne Beck, one of the principal founders of the systemic approach to no-till cropping, said, "My goal is not to know anything about diseases, weeds, or insects."
"I'm not a scientist. I'm a systems guy. I throw a bunch of crap up against the wall, and see what sticks. Now a scientist, he will tell us why some of it doesn't stick, or why some that did stick should not have."
Beck has led the Dakota Lakes Research Farm near Pierre, South Dakota, since 1983, with farmer-scale, farmer-driven, and profit-supported research. Enhancing the profitability of farming was an overriding concern. He writes, "A holistic or systems approach was taken. There was not an adequate amount of knowledge available on the type of farming system needed for this situation. This meant that many of the component choices required to build the system could not be based directly on research data or producer's experience as is commonly done in agriculture. Consequently, many choices were based on fundamental agronomic principles using natural cycles and native vegetation as a guide."
"To be sustainable and profitable on a long-term basis the farming system must be designed such that natural cycles and principles become allies rather than enemies. Fertilizers and pesticides then become methods to augment or initiate natural cycles rather than being tools to stop processes that are natural." Farmers who visited Beck and saw what he was doing with rotations and cropping systems referred to the "brain transplant" that they experienced.
Don Reicosky of the USDA Ag Research Service in Minnesota gave the second keynote on carbon sequestration. He cited the Pendleton studies that showed substantial soil carbon losses from tillage, compared to gains with direct seeding. Permanent grass pasture showed even greater gains.
Reicosky suggested that soil carbon or organic matter is the hub of numerous ecological, economic, and social benefits, including a reduction of the risk of global climate change. (A number of Pacific Northwest Direct Seed Association member-farmers are receiving carbon credits based on their farming practices from Entergy, a Louisiana utility.)
The brittleness factor
One of the principal problems faced by Pacific Northwest direct seeders is the buildup of crop residue, and the difficulty of effective seeding through it. Several presentations focused on mechanical improvements and additions to no-till seed drills to deal with surface residue, and farmers several times cited it as a major concern. Though there is discussion of amount or season of rainfall, there appears to be little appreciation among direct seeders for what Allan Savory has termed brittleness--the seasonal distribution of moisture, and its implications for carbon cycling.
Direct seeding has been most popular and successful in areas that are relatively nonbrittle, such as the U.S. midwest, Argentina, and Brazil. In these areas the process of microbial decay has adequate moisture and warmth to deal with most crop residue. In the brittle Pacific Northwest direct seed areas of Oregon, Washington, and Idaho, however, summers are dry and hot, and soil-surface microbial decay comes to a screeching halt.
The cooperative efforts of the universities and farmers in starting and supporting systemic change, in the transition from tillage to direct seed systems, is a wonderful thing to see. But I am left with the question, Can direct seed cropping in this area be sustainable without the use of large animals to help cycle residue? In many areas the experience, infrastructure, and interest in livestock operations has all but disappeared. Incorporating livestock into the system would probably require mobile, entrepreneurial graziers, in what Joel Salatin calls stacked enterprises on the existing land base. Dwayne Beck commented that farmers with access to livestock operations have many more options in designing direct-seed rotations with the proper diversity and intensity.
Updated 15 January 2003