NRCS area conservationist Mike Collins examines soil on Scott Wolf's farm during Wednesday's tour.
Courier photos by Lauren Krizansky
Courier staff writer
MOSCA — Underfoot is a world that holds the keys to human survival, and Valley farmers, ranchers and scientists are exploring its minute corners looking for answers to respond to and prevent environmental challenges.
On Wednesday, the San Luis Valley Soil Health group and the Natural Resources Conservation Service (NRCS) connected 50 producers and soil health supporters at its Fall Planted Cover Crops into Small Grain Stubble tour. The tour visited four farms in Alamosa and Saguache Counties and focused on in-situ organic matter buildup, residue decomposition, carbon/nitrogen ratios, potato yield quality, no till planting and sequential cropping.
“Soil is meant to be covered,” said NRCS area conservationist Mike Collins. “We have to get the soil to start living the way it was meant to be.”
A cover crop is used for a variety of purposes. In some systems, it is used for reducing erosion from wind and water; increasing soil organic matter content; capturing and recycling or redistributing nutrients in the soil profile; and promoting biological nitrogen fixation. Other uses include reducing energy use; increasing biodiversity; suppressing weeds; managing soil structure; minimizing and reducing soil compaction; reducing pest pressure and encouraging pollination.
“How you till and how you plant is your choice,” Collins said. “We can make stable changes.”
In the Valley, producers and researchers are using cover crop rotations to improve the soil’s health, reduce irrigation and for livestock nutrition. Potato growers are finding the technique a replacement for conventional farming measures including non-organic fertilizer applications and till regiments. Ranchers are exploring cover crops for replacement feed through forage production and windrow grazing. Scientists are experimenting with green manure crops to prevent nematode problems commonly found in the field.
When small grain cover crops are planted in the fall between harvest and the coming spring’s planting, they increase surface cover, anchor residues and increase water infiltration, according to the United States Department of Agriculture (USDA). Turnips and radishes, two crops Valley producers are incorporating into their rotations, are also suitable for livestock and wildlife grazing.
Lyle Nissen's fields play many roles in his mixed farming system. This year, he planted two cover crops. In one field, a winter rye and sweet yellow clover crop for winter cattle grazing and, in the other, turnips into the barley stubble.
The rye acreage was not tilled and the cover crop was drilled in to the previously grazed rye that had reached its productive stage. The rye has a deep root that catches available nitrogen and the sweet yellow clover fixes nitrogen, making it available for other plants. After 80 pairs of cattle graze the crop, a sorghum/sudan grass mix will enter the rotation in preparation for the next season’s potato planting. The acreage has had 12 inches of water and the field should provide two and one-half spring grazes.
“He opted to keep the ground in the best shape he knew how to do,” said Agro Engineering agronomist Patrick O’Neill in Nissen’s absence. “This is the start of (soil) structure.”
In the opposing field, turnips broadcasted with ammonium sulfate are rooted in the soil. The broadleaves will also become cattle feed and the herd will become part of the system through nutrient recycling and ground stimulation.
“You are probably much better off doing this than cutting it (the cover crop) and sending it far away from here,” O’Neill said. “Then we just have to buy that fertilizer back.”
Instead of turnips, Scott Wolf broadcasted radishes into a tilled barley field that are now growing alongside the small grain volunteer grain a few miles down the road. The radishes have nematode management qualities, have been cultivated with three inches of water and will help prepare the fields for a coming potato crop. It won’t go to feeding livestock, but that’s not the only herd roaming for food on any farm.
“We are adding live plants and adding cool season broadleaves because Mother Nature wants diversity in the soil,” Collins said after arriving on a Sunny Valley Farms field in Saguache County. “We are trying to feed the herd under the soil.”
Sunny Valley Farms’ Ernie Ford drilled peas, radishes and turnips into no tilled barley stubble splitting the middles of the original grain drill rows. The peas behave similar to clover and will help prepare the soil for next year’s potato crop. The mix should help the field’s carbon and nitrogen ration and assist in the barley stubbles decomposition.
The final fields of the tour belonged to Rob Jones, a certified organic farmer in Mosca. Jones has tried a number of cover crop combinations to benefit his potato production, the soil’s health and to pasture a herd of sheep. He has been averaging two cover crops a year using combinations of peas, oats, rye, clover, radishes, vetch and buckwheat and has not needed more than 12 inches of water to keep the rotation alive.
In addition to the fields, the tour stopped to look at Indian rice grass planted to prevent erosion and add organic matter to a dry pivot corner.