Gabe Brown's five keys to soil health

Gabe Brown from North Dakota is one of the most influential farmers in the developed world. Insights from his property are inspiring commercial farmers to understand soil health from a whole new perspective and scientists are catching on to his success.

Brown recently visited Australia to rub shoulders with communities of farmers pioneering low input farming and looking to enjoy benefits of greater profits and less stress.  His message is simple: To change what you do on-farm, make little changes; to change what you see on-farm, make big changes. 

Sustainability as seen by most agronomists and policy makers simply means to sustain a degraded resource like soil.  As Brown argues, unless soil is regenerating there is little hope for farmers and their communities to improve water quality.  Right now US farmers are being sued by cities for contaminating drinking water with nitrogen.

Three things made Brown question industry advice: Four years of no income from drought and hail; pioneering soil scientists pointing out how agrichemicals degrade soil function; being a keen observer of native prairie grasslands. 

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His cash crops now yield 25 per cent above his county average without any inputs except very occasional herbicide and he is looking to cut that completely, too.

Now scientists, and even National Geographic magazine, are banging on his door to study how soils are improving on his 2000-hectare property.  Their studies find increasing NPK and organic carbon despite no inputs used. To anybody looking in, it's not just his use of cover crops which is eliminating fertiliser use. 

Brown promotes five keys to soil health. The first is least amount of soil disturbance possible, preferably no-till. 

Brown sold all his cultivation gear in 1993 to buy a John Deere direct drill.  After 20 years of no-till his soils absorb over 200mm of rainfall an hour, whereas his neighbours are less than 15mm (in a 400mm annual rainfall).  Soil that captures and holds more rainfall lengthens growing seasons and lifts fertility, allowing crops to yield more and be healthier without technology.  For this to occur, soil surfaces must look like black cottage cheese, says Brown.

The second key is no bare soil.  The role of plants is to cover soil whether dead or alive.  It's litter (or as Brown refers "armour") which insulates soil surfaces against weather, preventing drying out and erosion of sediment.  Litter also stimulates soil fungi which pull litter into soil and stop movement.  This provides a bed and breakfast for other organisms to enhance soil function, including earthworms. 

When farmers first try this approach, he suggests 50 per cent legumes in a seed mix to lift nitrogen levels to help break down accumulating litter on soil surfaces.  As soil health improves drop the legumes to 20 per cent.

Key three is diversity; nature never has monocultures.  Many farmers are aware of companion planting but Brown goes to another level.  Dr Ademir Caligari a Brazilian scientist and a leading expert on cover crops inspired Brown to go beyond 2-3 species mixes to sowing 15-25 simultaneously.  

Every plant sown has a role to improve soil health and the new skill for farmers is knowing which plant combinations improve soil function and reduce reliance on synthetic chemicals.  Unfortunately, most farmers see plants as simply crops for harvesting or forage for livestock and completely miss significant cost savings over time. 

Brown documented that during drought multispecies pasture tripled biomass production compared to monocultures of the same species.  A decade on, many North American farmers are experimenting with combinations on their own properties.

Fourth, keep a living root in the ground for as long as possible.  With the climate extremes of North Dakota, Brown looks to extend his 100-day growing season by sowing species from all four groups - cool season grasses and broadleaves, warm season grasses and broadleaves.  He identifies forage shortages then fills forage gaps by timing sowing to maximise growth habits of plant species.  Living plants produce exudates to feed soil life which renew soil particles that normally break down after four weeks. This is the secret to good soil structure.

Brown and son Paul plant all their experiments near roadsides so neighbours and travellers have plenty to talk about. 

The final key is livestock integration lifts availability of nutrients for pastures and crops.  Researchers again have documented that livestock grazing significantly increases the availability of major nutrients versus crop land where livestock are absent. 

On top of this, his property is inside Bismarck city limits so he has 100,000 neighbours peering over fences.  It means being mindful that his 350 cattle can't drift into housing developments and swimming pools during blizzards.  His livestock graze outside all year round and calve late spring after weaning early spring.  Cows and calves do fine in winter grazing corn stalks where the climbing legume hairy vetch provides valuable crude protein.

- John King is a consultant in regenerative agriculture based in Christchurch.  You can contact him john@succession.co.nz or 027 6737 885.