Nick Maravell’s Talking Points
Addressing Agriculture’s Role in Reducing Climate Change by
Building Healthy Soils
“Scenario 300: Making Climate Cool” Conference,
sponsored by Biodiversity for a Livable Climate
WHEN: April 20, 2017 (the day after the
People’s Climate March in DC)
WHERE: Washington, DC, at the law offices of
Steptoe & Johnson LLP
Most of these principles have been practiced for many centuries of recorded agricultural history, because they are all part of a natural system—they were just not stated explicitly because humans lived closer to nature and did not question it. – Nick Maravell
The terms “healthy soils” and “soil health” have a long research history, and there is no consensus on how to scientifically measure healthy soil—at least how to measure it at reasonable cost. Items that have been hard to measure include: long-term stability and the capability to be resilient, the amount of biological activity (especially singling out the most desired biological actors), and the effects of organic matter additions to various soil carbon fractions (i.e., how do you encourage the most stable long-lasting humus compounds?).
If you get soil scientists to weigh in on soil health, you could get dizzy rather quickly! Soil structure, water permeability, and topsoil erosion are much easier to measure “mechanically” and are often used as proxies for overall soil health. These are the most likely measures that NRCS (the US Department of Agriculture’s Natural Resource Conservation Service) and MDA (the Maryland Department of Agriculture) would refer to. Measures of soil organic carbon (organic matter) are very gross and not always accurate—especially depending on sampling techniques, sampling depth, and what the field history has been. The gross amount of soil carbon does not tell the whole story—the actual composition of the soil carbon remains unknown. Some types of soil carbon are more beneficial in the long run—“more valuable,” more complex carbon chains—than others. The distribution of the soil carbon in the soil profile also plays a role in water retention, nutrient availability, biological activity, and longevity of carbon sequestration in the face of tillage.
On nutrient availability of the food produced at Nick’s Organic Farm:
- Beef is higher in Omega 3s and CLAs and vitamin E due to being grass-fed;
- Eggs are higher in Omega 3s and beta carotene due to pasturing;
- Food-grade corn is higher in protein (more nutrient dense), due to the heirloom varieties planted.
I have used soil health regenerative principles for the past 40 years, including:
- Reducing tillage, using shallow cultivation. Using plants and animals for tillage (alfalfa, rye grain, forage radish, earthworms, etc.). Emphasizing no-till could lead to more support for chemical intensive practices—think GMOs and Round Up. However, I use organic no-till planters and drills also.
- Keeping living roots in the soil as long as possible—the rhizosphere is where we see the maximum biological soil activity. (I try to reduce my exposure to no living roots to less that one month on 20-25% of my acreage each year. The rest of the acreage has living roots all year long.)
- Integrating animals with crops.
- Keeping the soil covered with cover crops and organic matter residues as long as possible to reduce soil erosion.
- Building organic matter content of the soil by returning as much previously living organic matter to the soil, adding compost, and by “fixing” carbon from the air by growing abundant high-yielding nutrient dense healthy plants and cover crops, and allowing animals to leave manure on the soil.
- Reducing off-farm fertility inputs to a minimum. Phosphorus, potassium, and calcium and trace elements may have to be brought in for some soils, but feeding animals a mineral mix and rotating the grazing to all fields can often reduce the need for mineral rock powder additions.
- Emphasizing bio-diversity by integrating multiple plant varieties (interplanting) and multi-species grazing.
- Rotating crops and animals—in general, the longer the rotation the better. Note that you can build soil organic matter with or without animals in your system—without animals the dynamics and timeframe can be quite different.
Most of these principles have been practiced for many centuries of recorded agricultural history, because they are all part of a natural system—they were just not stated explicitly because humans lived closer to nature and did not question it.