Editor's Note: This article was published by the Minot Daily News.
The future of agriculture lies in the concept of intercropping, which cultivates two or more crops in the ground simultaneously with the intent of producing an agronomic benefit like increasing yield or reducing pests, says Joao "Juca" Carlos de Morales Sa.
Sa, who has studied soil fertility, organic matter dynamics and carbon sequestration in no-till farming systems in the United States and South America for more than 30 years, told Manitoba-Dakota Zero-Tillage Farmer's Association conference attendees that the use of an intensified crop rotation as a tool to keep the soil permanently covered can increase carbon sequestration, profitability of crops and overall soil quality.
To illustrate his point, he told a story about Brazilian farmers who engaged in a monoculture of cotton. Harvest data showed that over the previous 5 years, average cotton yields were declining due to imbalances in the soil. To fix the problem, farmers were encouraged to add another crop, but they were reluctant — a trend also seen in the U.S. with corn.
"People need to put aside the concept of 'I am a corn grower' or 'I am a soybean grower,'" Sa says. "If you do that, more money will go into your pocket than to the bank."
Martin Entz, professor of Natural Systems Agriculture at the University of Manitoba, discussed the feasibility of using cover crops in the Northern Plains and the different application methods that are available to producers depending on their environmental conditions.
Using winter wheat as the main focus, Entz said historical weather data indicated that there was enough heat and rainfall to grow a cover crop using either the relay or double-cover crop method.
Relay cropping involves seeding a cover crop before the main crop is harvested, while the double-cropping method involves seeding the cover crop after harvest of the main crop.
Using several different species of legumes as a cover crop, Entz says their research shows that nitrogen supplied by late-season cover crops following a winter cereals crop can range from 0 to 60 pounds of nitrogen per acre, which would enable farmers to apply less fertilizer for the following crop and has negligible negative effects on grain yields.
Other benefits highlighted by the research include the moderation of soil surface temperatures, the feeding of beneficial fungi called mycorrhiza and the reduction of leached nutrients.
While there are several benefits to using cover crops, there are also several economic, environmental and management factors that need to be considered.
Yvonne Lawley, a research agronomist at the North Dakota State University Carrington Research Extension Center, addressed the issues of soil compaction and salinity, herbicide carryover, labor and time constraints, seed availability and equipment needs.
With the cost of cover crops averaging $14 per acre, Lawley says farmers need to have specific goals for their cover crops to manage weeds, to use for grazing and increase organic matter, as well as a management plan to make it worth the cost.
"How you manage these cover crops and the decisions you make will greatly influence (how) they work in your fields," she says. "That's why it's so important to get the right species in at the right time and in the right place."
Other topics addressed Tuesday include the application, management and economics of fertilizer and the different management techniques no-tillers can use against insect and biological foes.
Dave Franzen and Andy Swenson, both NDSU researchers, addressed new fertilizer recommendations and the economic effect of different application methods.
Tweaking a model used by Corn Belt states that shifts the focus from maximizing yields to maximizing profits, Franzen, a soil scientist, created a model that uses producer-specific information like soil type, productivity level, crop rotation, nitrogen and wheat price, level of organic matter and the crop cultivation method to come up with a fertilizer application recommendation with a margin-of-error window of 30 pounds of nitrogen. This window enables producers to use their own personal experiences and judgment to gauge their unique fertilizer needs.
Researchers from NDSU and Agricultural Research Service addressed insects and disease management issues.
Although insect populations are naturally regulated by the effects of predators, pathogens and parasitoids, the intensity of modern cropping systems creates a lack of biodiversity — which is needed by the natural enemies of pests to survive — creating an insect management issue for farmers, says Jonathan Lundgren, a research entomologist with the Agricultural Research Service.
Lundgren discussed the use of vegetational diversity in fields to encourage natural enemies and reduce pest pressure. The research found that the use of winter grass cover crops can increase predator populations and the predation they inflict, and reduce rootworm densities and crop damage.