In the West, a lack of water persists. Precipitation for this water year — which began Oct. 1 — has averaged less than 50% of normal across eastern Oregon and Washington state, Northern California and the Great Basin. The lack of precipitation during April adversely affects dryland farming in these areas.
Retaining moisture in the soil creates resiliency for drought. Organizations are looking at new ways to hold moisture for crops, while at the same time offering a chance to diversify income.
The key is understanding the role cover crops and cattle can play in your crop mix. This “pasture cropping” — integrating crops and livestock to regenerate soil health — maintains perennial grasses in a pasture for livestock to graze while simultaneously growing annual crops.
Dryland cover crops for grazing
In eastern Washington, dryland farmers work with the Okanogan Conservation District and the Washington State Department of Agriculture to integrate cover crops and livestock grazing. Cash crops, such as wheat, triticale and barley, are grown in a fallow system around Okanogan, Wash., in zones with 8 to 11 inches of annual rainfall.
In the fallow system, farmers plant wheat in August and harvest it in July of the next year. The ground lies fallow until summer of the following year. During the fallow period, the soil’s organic matter decreases, which makes holding moisture more difficult.
WINTER FOOD: Dryland farmers near Okanogan, Wash., intercrop a cover crop with their cash crop for winter livestock grazing.
Leslie Michel, WSDA soil scientist, knew the organic matter from cover crops would help retain soil moisture. Soil’s organic matter holds 18 to 20 times its weight in water. If the top 6 inches of soil contains 1% organic matter, 1 acre will retain 27,000 gallons of water.
In 2017 and 2018, Michel and the Okanogan Conservation District piloted, through funding from Western Sustainable Agriculture Research and Education, growing cover crops in the fallow year for livestock to graze.
After the last frost in late May, a cover crop of millet, sorghum-sudangrass, sunflowers, turnips and Austrian winter peas was planted in fallow fields. Cattle grazed the cover crop in late summer. When the cattle were removed, the farmers left the cover crop residue in the fields through the winter. The following spring, they planted triticale, barley or wheat.
There was no statistical difference in the cash crop yields between the cover crop fields and the fallow control fields. Soil tests showed that the cover crops retained more soil moisture through increased organic matter and plant residue that held winter recharge. The cow-calf pairs were weighed before and after grazing the cover crop. Calves averaged 2.5 pounds of gain per day while pastured on the cover crop.
All of the farmers involved in the pilot project continue to integrate cover crops and livestock, and they’ve also added fallow-crop planting in the fall. Essentially, the new crop grows through winter even as cattle graze.
“Now, farmers put the cover crop in with a cash crop,” Michel says. “They plant the same type of cover crop mix, adding corn that works really well for winter grazing.”
She adds that the farmers plant in June to cover the ground earlier in the season, to conserve moisture. The cover crop grows good biomass during the summer, and the cash crop of winter wheat or triticale “hangs out” below.
Livestock graze the cover crop biomass the following winter. The next spring, the cash crop is already planted and takes off. Intercropping with cover crops provides additional livestock forage when producers need it the most while increasing soil organic matter and plant diversity.
Livestock pasture cropping
On Calder Farm in Gunnison, Colo., Blaine and MJ Pickett are experimenting with pasture cropping. The concept was pioneered by Australian farmer Colin Seis, and another way to describe it is to plant annual crops directly into perennial grassland.
The annual crop is no-till-drilled when the perennial grasses are in dormancy, or after livestock grazing removes the competitive advantage of the established pasture. This maintains living plants in the soil to increase nutrients and moisture, and it decreases capital inputs — adding to farm profitability.
Gunnison receives 11 inches of annual rainfall. The Picketts raise hogs on pasture, and grow vegetables and cut flowers for direct-to-consumer sales. “We have a 32-day growing season here,” MJ Pickett says. “We experimented this year with planting 3 to 5 acres of potatoes within an established pasture. We’ll use portable electric fence to graze our partner’s cattle on strips of pasture grasses between the potatoes.”
To plant the potatoes, the Picketts will till minimally. “We’ll cut the sod with a chisel plow, just enough for a two-wheel tractor with a rotary plow to turn a trench to plant the potatoes,” Blaine Pickett explains. “It is much less disturbance than plowing a whole section of pasture. We want to lessen the impact on the microbial networks that the grasses established in the soil, which will benefit the potato crop.”
The Picketts have found that the rooting action of their pastured pigs invigorates the grass rhizomes to increase forage yield and diversity the following season. “Our theory with pasture cropping the potatoes,” Blaine says, “is that the minimal tillage will generate the same effect. If so, we’ll bump the strips of potatoes over 2 feet in a rotation. This will provide more plant diversity and stronger grass growth across the whole pasture.” It also increases the soil’s organic matter to soak up moisture, and it reduces evapotranspiration.
As the West tends toward longer dry spells, soil moisture retention must be considered along with irrigation efficiencies and precipitation forecasts. Integrating crops and livestock is a way to increase soil’s organic matter to retain moisture and diversify land use for more profitability. Holistically managing water requires healthy soil.
Environmental monitoring remote sensing tools
As producers plan how to integrate crops and livestock for soil moisture retention, the National Drought Mitigation Center and National Oceanic and Atmospheric Administration offers several tools to assess current, and forecast, moisture conditions:
Vegetation Drought Response Index (VegDRI). The VegDRI tool shows the current conditions on the date the map was generated. It’s a combined indicator of drought-related stress on vegetation, climate data, environmental characteristics (land cover, irrigated or rain-fed, soil’s capacity to hold water for vegetation to use), elevation and ecological setting.
GRACE-based Shallow Groundwater Indicator. The GRACE (NASA gravity recovery and climate experiment) tool estimates anomalies in root zone soil moisture, surface soil moisture and groundwater to capture current water availability.
Grassland Production Forecast. This forecast, also known as Grass-Cast, combines current weather data with seasonal climate outlooks inside a grassland projection model to predict total pounds per acre of forage biomass. The new tool is only available for the Great Plains region right now, but it will expand to the Western U.S. soon.
Western Water Supply Forecasts. This NOAA map shows current river flow and reservoir inflow rates with a forecast and percentage comparison to normal levels.
4 principles for soil health
Here are the USDA Natural Resources Conservation Service’s four tenets of soil health:
• Use plant diversity to increase diversity in the soil.
• Manage soils more by disturbing them less.
• Keep plants growing throughout the year to feed the soil.
• Keep the soil covered as much as possible.
Hemken writes from Lander, Wyo.