The latest study about the use of cover crops on the Great Plains has been released, this time focusing on Nebraska. And while the news about their impact on yields and soil-moisture use is mixed at best, that’s only part of the story.
Five no-tillers worked with the Nebraska On-Farm Research Network in 2014 to assess the use of covers on their farms. Specifically, they were concerned with the impact of cover crops on yields for the subsequent cash crops — a common concern in the semi-arid Plains states.
You can read the full compliment of information and results of this study by clicking here. The sites for this study ranged from south-central Nebraska, near Loomis, to Ithaca, Neb., 37 miles west of Omaha.
Soybeans, wheat and corn were the crops involved. Soils ranged from silt loam to silty clay loam, and at one site the effects of grazing or not grazing covers after wheat, and ahead of soybeans, was analyzed. Two of the sites were center-pivot irrigated, and all farms were seeing cover crops for the first time.
These trials showed negative net returns associated with cover crops that ranged from $25 to $154 per acre, which certainly isn’t great news. But near Ithaca, where cover crops were grazed for 48 days, results showed a net return of $765.53 per acre, higher than both the cover cropped acres ($601.73) or check plot ($643.80). ?
Yields for soybeans were 62-64 bushels. The net return was based on $10-per-bushel soybeans, $22 an acre to seed covers, a $13.37-per-acre drill application cost, a cost of fencing and labor at $12.50 per calf, and a net income for the calves of $178.50.
The fact that yield hits occurred at three sites, and didn’t occur at two sites, illustrates there is a “critical need” for additional research, say Extension educators Laura Thompson, Chuck Burr, Keith Glewen, Gary Lesoing, Jenny Rees, and Gary Zoubek. “Despite yield losses in some cases, the farmers are interested in repeating the studies in the future,” they said.
Those with an interest in participating in this project can e-mail Keith Glewen, or call 402-624-8005.
I think University of Nebraska Extension should be commended for reaching out to farmers to do the research, put pencil to paper and start answering these questions, in a variety of geographical areas and under different farm systems.
The only problem I see is that cover crops — which have been used by farmers around the world for 2,000 years — are being measured here only to the point of yield. Of course, yield is what pays the bills, and cover crops aren’t a silver bullet for every challenge in farming.
But what about the potential effect of cover crops on soil organic matter, water-holding capacity and nutrient cycling? How much less fertilizer will these farmers be applying if cover crops were used over many years? How much less compaction would there be?
Long-term study studies need to be done, at as many farms as possible, so growers and all ag stakeholders can see the entire picture.