Building Soils with Min-Till, Biochar and Compost (FSFS182)

Farmer and Soil Consultant James Hutchinson joins Diego to talk about his method for building soils on his Tasmanian farm.  He utilizes minimum tillage alongside composting, cover cropping and biochar to build soil in his bio-intensive permabed system.

Soil Management Principles for Success

On Longley Organic Farm James has soil testing regime done every 2 years with an agronomist. His best advice to new farmers;

 

“ Get testing done, and follow it!”

 

 You may have a problem with your soil if…

  • You don’t have it tested.
  • You make the common mistake of only adding dolomitic limestone. “The Mg ends up locking up your nutrients.”
  • You use crappy compost – Nitrogen drawdown is common; it comes with unfinished compost and woody food-based composts. Always ask for compost tests.

Your main goal?

Try to make sure your soil will hold and release moisture, store oxygen, and be a beneficial environment for beneficial microbes.

How to get there?

Add a lot of stable carbon with:

  • Leonardite
  • Brown coal: Composted from 20M y/o rainforest, mined. 97% pure humate. 
  • Biochar. 

Benefits of Stable Carbon

They form a ‘soil scaffold’ that has a high cation and ion exchange capacity for holding onto nutrients. The structure is microporous so it holds a lot of O2 and humidity. Roots can be insulated and watering can be less frequent. Fungal growth will make its way deeper into the soil and become stable carbon at depth.

 

“We’re amending the microbes as much as the plants.”

 

How to Take a Soil Sample

  1. In a 25x25m take 18-22 core samples.
  2. Take a core sample using a 40-50mm PVC pipe, and whack it into the ground at 140-150mm. This is the depth paramount to amend for feeding plant roots and microbial life.
  3.  Make sure the samples are representative of beds; take from the end of beds, middle, anything that results in a representative sample. 
  4. Mix all the cores together in a bucket
  5. Spread over a tarp to ½” thick puddle, raking out flat with a rake.
  6. Remove two opposite triangles of soil and then bring the other two triangles of soil together until you have one pile.
  7. Make another puddle out of that pile and then reduce it down (remove triangles), over and over, until you have a pint of soil. 
  8. Send ½ pint of soil to get tested. 

Aerobic, or Hot, Compost Recipe 

Aerobic compost is hot compost using;

  • Ingredients:  3 Parts Staw, 2 Green Waste, 1 Manures (as many varieties as you can get), and leaf litter from the forest (have a lot of cellulose digesting fungi) 

The point of the compost is to make humates. You only get humates right at the end of the compost cycle. The humates are the bodies of the bacteria and fungi that become a stable carbon. 

  • Process: Heat the compost; Use a 36” compost thermometer (moved whenever you have the manpower, roughly 3-10d). In the Tasmanian climate after 3-5wk, we get final humification, this is when it has cooled down. For most of the process 50-60C, don’t want it above 60C, toss like a salad to bring back down. After 4-6wk it should cool down, when completely cool we use it. It will still improve easily for another 12mo. after that, but it must be cool before using it. 

Anaerobic, or Cold, Compost Recipe

Cold compost takes over a year. Broken down by lactobacillus. 

  • Ingredients: 1L molasses, 1L EM, 18L water
  • Process:  Put on a beer mat to heat for a few weeks. Look for fungi on the surface. Use rebar to make holes and pour in pile 1L at a time. 

Utilize 15cu.meters across 100 beds.

Purchasing Compost

When making compost, utilize what you can, you don’t always need to have the perfect ingredients on hand, or need to make a particular cold/hot compost. If you plan to buy compost instead, be aware, there are a lot of sellers who will give you an unfinished or poor product, which is why…

 

“Market gardeners use too much crap compost.” 

 

When buying commercially look for records that it has been above 60C for at least 3 days and to see how many times it has been turned. Look for the sticky feel; indicates humates or sugars. Be careful of it being finished as pH can be as high as 13 if not finished. Often compost will have too much Mg has been overheated, or is just not the best quality.  

If you have tested your soil for stable carbon you know how much compost to add. For heavy feeder beds generally, add 10L of compost per sq. meter. If the stable carbon level is really low, then go as high as 15-20L/sq.Meter. If it’s good only 5L/sq.meter. Roughly a ¼ inch on top of the soil. 

Considering Biochar

Biochar is a delivery system. It will slowly impart nutrients to plant. If you have a good C:N ratio, you will see the soil clinging to plant roots when you pull it out. It also retains C out of the atmosphere.

James takes 1hr to make 100L of Biochar in cone kilns. To reduce particle size before use he puts it in a sack and drives over it. Or cement mixer with 3 fist-sized rocks.

Low-Till Integration

How do you integrate amendments in the soil in a low-till system? 

To target regenerative soils, make sure stable carbon is mixed in soil down to a depth of 150mm. Broadfork down 30cm and then only pull back to crack soil. You do not need to turn over soil with the broadfork.  In light feeding beds, with shallow-rooted crops (that result in more compact soil during the season) might need to fork 2-3x per year. Amendments sitting on top of the soil will fall down cracks and remaining is integrated with tilther. In beds that have become compacted over years and are flat the Berta plow will reestablish paths. This is a good time to get biochar in. Or use a power harrow every 2-3 years.

Additional Techniques for Fertility

James uses green manures after every allium crop. When starting new beds use potatoes to break up compaction. Then follow with green manure.

Australian, New Zealand and Pacific Island Residents

Visit James online farm store to find products for small scale farms not otherwise available. Their mission is to provide all the up to date equipment being developed globally to Australians, NZ, and Pacific Islanders.

Follow James:

https://www.instagram.com/longleyorganic

https://www.instagram.com/activevistagram/

James’ online Farm Store:

https://www.activevista.com.au/

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