Cover crops have dollars invested in growing just as much as do wheat, sugar beet or potato crops. They take water, fertilizer, and labor, but don’t give back a product to sell at the end of the season to pay for those costly inputs. Pat Purdy, a farmer in Blaine County, sums up cover crops this way, “Growers are always hearing about cover crops in glowing terms of improved soil health, improved soil structure, improving soil pH, thriving microbiomes, and so on. At the end of the day, if I can’t make a profit, it isn’t a sustainable practice.”
On dryland acres, rainfall is “banked” in the soil for later when crop roots will mine the water to grow, flower and fill grain. Precious soil moisture is often accumulated over a growing season when the soil is left fallow. Dryland grain yields are typically 50% of irrigated yields and growers may only get one crop every two crop seasons. It is a stretch to see how cover crops are practical on dryland acres with less than 12 inches of rain per year.
Idaho Wheat commissioner Cory Kress pointed out, “For all the supposed benefits of cover crops, they just don’t work for everyone.” Some years, Cory’s dryland fields of wheat are seeded and waiting…for what? There isn’t enough soil moisture left to germinate the seed. Temperatures drop, the days get shorter, the crop isn’t established, and time is running out. “When it is dry, I plant shallow so what little rain there is will find the seed and germinate it. Then I hope there is still another two inches of moisture in the soil the root can mine to get a stand established before dormancy sets in. Some years, when rains have been consistent and soil moisture is plentiful, I could probably get a cover crop up after harvesting my earliest winter wheat, but then is there enough season left to get the biomass to make any contribution to the soil health?” No-till and direct seeding into the previous crop’s residue, as practiced on the Kress farm, achieves many of the benefits of cover crops, such as erosion control, improving water infiltration, and feeding the soil microbial community as roots and residue decay. On dryland acres in low rainfall zones, these practices are more profitable and come with fewer risks than cover crops.
“The profit in cover crops comes when they are used as forage for cattle,” explained Joel Packham, county extension educator for Cassia County. Grazing and cover crops are a winning combination when water is abundant and grazing animals are part of the farm ecosystem. “Cattle grazed on multi-species cover crops – fenced with temporary electric fencing into paddock-size areas – gain weight fast and don’t walk it off like cattle grazing the surrounding Bureau of Land Management lands.” The weight gain on the cattle more than makes up for the input cost of cover crops. But farmers are not generally cattlemen, nor are cattlemen generally farmers.
Pat Purdy partners with a local cattle operation in Blaine County, near his farm, to graze cattle on his cover crops and share the profits. Pat is experimenting with integrating cover crops, cattle grazing, and winter wheat in hopes of further stimulating the soil biology in his fields and making it profitable to do so.
“We lease some land that needs rehabilitation,” he explains. “The soil is very fine; it blows everywhere if the field is bare. Fertility is poor. We could put chemical fertilizers on it and get a crop, but that isn’t improving the soil.” The downside is, when the field is in a cover crop for the season it is not producing a cash crop. That cover crop is costing money to plant, grow and manage grazing. Purdy wondered if winter wheat could be added to the cover crop mix to provide a cash crop the following year. “The idea is to sow a multi-species cover crop in the spring, including winter wheat in the mix at 40-50%, then bring cow-calf pairs in to graze it in sections so they graze all the species evenly.” The cattle show a clear preference for the wheat over the other species. To counter this behavior, the paddock sizes were reduced, forcing the cattle to eat the other species in the mix after they had eaten the wheat to the ground. “The cattle guy will take them off in late fall, the annuals in the mix will freeze out, and the wheat goes dormant in winter. Next spring, if the wheat doesn’t winter kill, it should take off, head out, and we hope to harvest a cash crop of wheat in July 2021.”
Gordon Gallup, a wheat producer in Swan Valley, has been no-tilling and direct seeding for 30 years. He has the soil tests proving he has increased organic matter 1% over time. His acres are generally dryland, but at 6,000-feet of elevation he has plenty of soil moisture most years, especially now that his soil banks all the moisture it receives. Gallup wanted to experiment with cover crops to see if he could further improve the fertility in his soils by stimulating a more diverse microbiome. He learned you need to be very selective, choosing the species adapted to your altitude, climate, and crop rotation going into your cover crop mix.
Though he hoped to get rid of the cattle when his boys went off to college, Gallup quickly figured out he needed grazing in the cover crop system. Sustainable cover cropping requires careful reckoning with the base requirements: available water, length of season, residue management and adding a profit center through grazing. Gordon laughed, “One thing I learned is my cattle don’t like radishes planted alone, and rotting radish stinks to high heaven, so don’t plant it close to the house like I did! I found making cover crops work has been a thoughtful process of trial and error.”
