Arizona Climate-Smart Practices Explained: Conservation Cover & Cover Cropping
As the team behind the Arizona Climate-Smart Practices Program embarks on an ambitious effort to improve the health of the soil, conserve water, and sequester more carbon by helping farmers and ranchers transition to climate-friendly growing practices, consumers and communities can also join the journey by learning more about what these practices are, what they look like, and which Arizona farmers and ranchers are using them.
Two agricultural practices, conservation cover and cover cropping, may be new topics for many, but the practices used to grow our food and fiber directly impact us. Learning more about why they are used and the benefits they provide can help us better understand our landscapes and water cycles and get to know our Arizona farmers (and food!) better.
Conservation Cover
Keeping land covered with plants, trees, shrubs, and grasses provides many benefits, including providing habitat for pollinators and beneficial insects, increasing soil health and soil organic matter content, providing forage (feed) for livestock, and sequestering carbon. One climate-smart practice that does this is called conservation cover. This practice involves establishing and maintaining permanent vegetative cover by keeping the ground covered with native perennials, or plants that live more than at least two years and regrow each spring. Planting perennials is beneficial, as their roots systems can become extensive underground and this helps with establishing mycorrhizal fungi networks that support plant health, soil fertility, and sequestering carbon. Roots also help to capture and draw moisture into the ground and improve soil aggregates, which helps land absorb and retain more water, something that is needed in Arizona’s dry and hot landscapes.
It’s often said that drought doesn’t cause barren land, but barren land causes droughts. Keeping the soil covered with biomass from plants not only encourages more rain (via microbes), it also helps the soil infiltrate and hold more water. You may recall the Dust Bowl of the 1930s, which occurred partially because of the removal of native grasses that held soil in place and prevented erosion. Every one percent increase in soil organic matter can retain an inch of water (which is about 16,000-20,000 gallons of water per acre), so if we want to retain what little water we receive, soil needs to be built up by protecting its surface through practices like conservation cover.
Cover Cropping
Another similar climate-smart practice that provides many benefits is cover cropping. Cover cropping involves planting annual crops (plants that live for only one growing season and then die) for seasonal vegetative cover.
Planting diverse and seasonal cover crops, such ryegrass, barley, oats, teff grass, clovers, millet and legumes, protects the soil from extreme temperatures by keeping it cooler during the summer and warmer during the winter. Especially in the hot Arizona months, shielding the bare ground from heating up is important for supporting microbial activity, which is needed for soil health and growing nutrient-dense crops. Ideally, soil temperature should be in the 70° F range to support microbial growth. On a triple-digit Arizona day without protection, the surface soil temperature can easily reach above 130° F, at which point the soil microbiome can't survive. Shielding the soil surface from the blazing sun is critical, and cover crops do just that.
Selecting certain cover crops, such as legumes, can also add nutrients like nitrogen naturally back to soils, which can be important for areas that are growing crops requiring high amounts of nitrogen, such as corn fields. Also through selective cover cropping, a farmer can help to suppress the germination of “weeds,” or unfavorable plants. Overall, cover cropping prevents wind and water erosion, increases soil organic matter, and enhances soil carbon sequestration, which is key to helping mitigate climate change.
Arizona Climate-Smart Practices in Action: Oatman Farms
Yadi Wang, first-generation farmer and farm manager with Oatman Farms, gives an insightful answer when asked how he can tell if his land is healthy: “I know it is because I see dragonflies.”
“Dragonflies are an indicator species of healthy water cycles,” Wang explains. “They can only thrive in locations that have a significant amount of moisture and water content, or relative humidity. They are also a super-predator, so they feed on different diverse insect groups that help our farm with pest management.”
Wang has been farming at Oatman Farms for nearly four years. During the last two, he began to notice dragonflies arriving in late July and staying until November.
During July when the temperature is already 90 degrees by 5 a.m., Wang sees dew droplets in his fields, and the microclimate it creates has a cooling effect on his crops and prevents water loss from evapotranspiration. Under his current farming practices, which include conservation cover and cover cropping, nearly 350 million gallons of water are conserved annually on his farm.
In Arizona’s arid environment (receiving very little rain and having less vegetation), Wang grows heirloom White Sonora Wheat and other heritage grains using no chemicals or fertilizers and with water conservation in mind. He takes a holistic approach that incorporates regenerative and climate-smart farming practices; by implementing these, he has seen over 150 species return to the land in the last three years. His soil water retention and health have increased dramatically by keeping the ground covered.
Mesquite trees
Conservation cover & cover crop management plan
Conservation cover
In one of the fields where Wang is not actively growing row and cash crops – heritage varieties of wheat – he practices conservation cover by actively growing native perennial Mesquite trees. These trees are then used to grow Mesquite pods that are harvested, ground, and sold as Mesquite flour. The trees, as well other perennial shrubs and grasses in the field, can be also used as forage for livestock grazing, which he currently utilizes for sheep.
Multi-species cover cropping
Wang has been practicing conservation cover on this field for four years by planting dozens of different grasses, wildflowers and forbs, and shrubs. Keeping the ground covered with perennials has helped prevent soil erosion, increased microbial activity in the soil, provided a revenue stream with Mesquite flour, and supplied forage for livestock adaptive grazing operations.
Since arriving at Oatman Farms, Wang has been practicing cover cropping because he knew he needed to regenerate and preserve the land by keeping soil in place and creating a healthy micro water cycle, something that cover crops help achieve. He implements multi-species cover cropping and experiments with different species mixtures.
In the summer months when other farms are losing moisture and water vapor by having bare ground, Wang has been able to use cover crops to draw moisture down, increase microbial soil activity, cycle nutrients, and build organic matter. He has integrated over 14 cover crop species with his cash wheat crops; after harvesting wheat in June, Wang plants the multi-species of cover crops. Over the years he has noticed unfavorable plants, such as Bermuda grass and tumbleweeds, being phased out (slowly dying off) as his cover crops continue to help improve the health of the land and soil and the land becomes more productive.
Through implementing regenerative, climate-smart, and restorative farming practices, Wang is stewarding farmland, revitalizing ecosystem health, and offering Arizonans certified Regenerative, Organic heritage wheat to help feed communities nourishing and climate-friendly food.
To Learn More & Get Involved:
Want to learn more about the Arizona Climate-Smart Practices Program? Submit this simple contact form, and the team will reach out soon!
To apply for the program, fill out an application and send it in an email to Deborrah Smith at smith.aacd@gmail.com.The downloadable digital online application is here and a downloadable printable version is here.
Learn more about Oatman Farms and find their products here.