How much rain did you keep?
MEDIA CONTACT:
Paul Jasa, NSHC Board Member
Email: pjjlnk@gmail.com
Phone: 402-450-6331
Ask a producer “how much rain did you get” and he’ll tell you, usually followed with a “but”. Either “but we need more as it’s been dry” or “but it came too fast and most of it ran off”. What really matters is “how much rain did you keep”. Producers with well structured, healthy soils will respond “all of it”.
I grew up in northeast Nebraska and my dad, like most producers in the 1960s, did a lot of tillage. With no residue remaining after the tillage, there was considerable runoff and erosion. To reduce these problems, he adopted reduced tillage in the 1970s, a one pass tillage system. With this background in farming, I went to the University of Nebraska in 1974 and started working with soil and water conservation.
I learned that crop residue management, no-till crop production, and cover crops are important methods to reduce erosion, runoff, and evaporation and to improve soil health. Improved productivity and profitability follow as soil health improves, making production systems more resilient while reducing risks to the environment. This became the focus of my Extension programs and why I’m working with the Nebraska Soil Health Coalition to help producers adopt practices to improve soil health.
The Importance of Plants and Residue
Growing plants and residue protect the soil from water erosion and crusting by absorbing the energy of raindrop impact, reducing soil particle detachment, surface sealing, and runoff. They also protect the soil from the sun and wind, reducing wind erosion and soil moisture losses through evaporation. In addition, they keep the sunlight energy off the soil surface, reducing temperatures in the heat of the growing season, further reducing evaporation. The living roots feed the soil biology by transferring sunlight energy and carbon (sugars in the root exudates) into the soil, improving soil health.
Using no-till can save far more than fuel, labor, and equipment costs. The savings in soil moisture can be just as important, especially in a year when soil moisture and precipitation are short or when irrigation is costly. UNL research in irrigated conditions at North Platte showed that no-till corn yields in residue-covered plots were 17-25 bushels higher and no-till soybean yields were 8-10 bushels higher than in plots where the residue had been removed. For the four years of the study, the estimated water savings was 2.5 to 5.0 inches per year for the residue-covered plots compared to bare-soil plots.
In southwest Kansas, KSU research at Garden City had similar results with soil water evaporation being as much as 30% of the total evapotranspiration (ET) during the irrigation season without residue. Evaporation from a corn residue-covered or wheat straw-covered no-till soil surface amounted to 15% of the total ET, translating to a water savings of 2.5 to 4.0 inches. Both studies indicated that crop residue should be left in the field to save water and reduce irrigation costs.
No-till Reduces Runoff and Improves Infiltration
Tillage breaks up soil structure and pulverizes the soil surface, creating a condition that seals the soil, resulting in more runoff and less effective rainfall or irrigation. UNL research with a rainfall simulator at Sidney demonstrated that effect in a wheat-fallow rotation. More than 3.75 inches of water was applied in 90 minutes on continuous no-till before runoff started, compared to only 1.0 inch of water applied in 20 minutes on plowed ground.
With the improved soil structure of continuous no-till, infiltration also improves, reducing runoff even more. Research at the UNL Rogers Memorial Farm near Lincoln showed a much greater infiltration rate for no-till, over 4 inches per hour, than for tilled conditions, only 0.4 inches per hour, after 25 years of continuous tillage system evaluation. Similar results were measured at the UNL South Central Ag Lab near Clay Center after 30 years of continuous tillage system evaluation. With better infiltration, storms of greater intensity will have less runoff and can provide more water in the soil profile for use later in the season.
This was illustrated nicely in June when a heavy rainfall event caused flooding in the Grand Island area. A producer near Dannebrog shared a video of him walking in his field about six hours after a 7 inch rainfall event. He has been using practices to improve his soil health for several years.
By adopting continuous no-till and using residue management, more water is available for crop production, and the soil system becomes more resilient to extreme events, including drought. Cover crops will “grow” any water and nutrients that would otherwise be lost to leaching into a biological form while feeding the soil system. The improved soil structure and healthier soil will enhance productivity and profitability.
About the Nebraska Soil Health Coalition
We are a collaborative effort to increase sustainable agricultural production and thriving rural communities. As part of that vision, we support Nebraska’s community newspapers. Our mission is to advance producer-centered education, outreach, and adoption of soil health principles to build resilient farms, ranches, and communities across Nebraska. You can learn more at www.nesoilhealth.org
