A recent article on the Union for Concerned Scientists website, titled “How Healthier Soils Help Farms and Communities Downstream Deal with Floods and Droughts,” was particularly timely given the recent hurricane damage that much of the southeast faced in late August and early September. It is no news to farmers and ranchers how devastating these events can be.
In the United States, floods and droughts together have done damage worth an estimated $340.4 billion since 1980 and taxpayers have paid $38.5 billion in crop insurance payouts from 2011 to 2016 (not to mention all the flood damage numerous cities have had to face). Luckily, the knowledge that soil can be a huge sponge to soak up rainfall is becoming more widespread as people learn about soil health and the power of soil carbon.
The full report noted in the article shares some of the key points learned from the Union’s review of scientific data. They also note that the key practices that increase soil health and resilience are:
- Ecological grazing (planned grazing)
- No-till cropping
- Cover crops
- Integration of livestock and cropping
- Perennial cropping
The Union performed a rigorous review of prior field studies (150 experiments on six continents) that used any of those practices and focused on soil properties that improved water infiltration rate and water availability in the soil. Here’s some of the key findings:
- Water infiltration rates improved by 59% with perennial crops, 35% with cover crops, and 58% with improved grazing practices.
- The largest and most consistent improvements came from practices that keep live roots in the soil year round, such as cover crops, perennial crops, and planned grazing.
- Heavy rainfall events – more than one inch of rain per hour – can be significantly offset with some of these practices, particularly perennials. In more than half (53%) of the experiments that compared perennial crops to annual crops, water entering the soil not only increased, but did so at a rate higher than a one-inch per hour rain event.
Based on these findings the Union then modeled what would happen if the most erodible or least profitable croplands in Iowa were planted in cover crops and perennials. The outcome would likely be:
- Up to 20% less runoff in historic flood events
- Flood frequency (the number of months reaching flood stage) reduced by approximately one-fifth in some regions
- Up to 16% more crop water use during droughts as severe as those experienced in 1988 and 2012
They also noted that Holistic Management practitioner Tom Frantzen had found great benefit in his hybrid rye crop which helped protect his soil so that there was no soil erosion during a damaging three-inch rain event. They also quoted a report from No-Till Farmer that mentioned a soil scientist observing water infiltration down to eight feet during a heavy downpour. In that way the power of soil to store carbon and water is past most people’s comprehension.
One Holistic Management practitioner, Gene Goven showed an increase of 800% in water infiltration rates on his ranch after practicing Holistic Management. Likewise, Gabe Brown noted the increase of water infiltration rates on his ranch after combining livestock on his cover crop fields. A 12-inch rain in a 24-hour period was mostly absorbed by his land.
Visit HMI’s Soil and Conservation page to learn more how other Holistic Management practitioners are improving soil health.
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