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♩ (guitar music) ♩

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<i>(narrator) We hear a lot about[br]climate change and carbon dioxide.</i>

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<i>What can farmers do about it?</i>

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<i>"A lot," says Australian soil scientist[br]Dr. Christine Jones,</i>

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<i>"and get better crops as a result."</i>

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It's all about getting light energy,

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transforming it to biochemical energy,

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getting that biochemical energy[br]into the soil,

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to drive the soil ecosystem[br]to make nutrients available.

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<i>Well, the reason carbon is important</i>

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<i>is because all living things[br]contain carbon.</i>

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<i>So as things live and die,[br]they give up their carbon</i>

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<i>and then something else lives[br]and takes up that carbon.</i>

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<i>I guess what we're talking about [br]with climate change is,</i>

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<i>we're talking about that cycle[br]getting out of balance.</i>

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<i>So for thousands of years,[br]it's been in balance...</i>

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<i>the atmosphere[br]and the plants, and the soil,</i>

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<i>and all the living creatures.</i>

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♩ (guitar music) ♩

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<i>(narrator) But in modern times, people [br]have dug up and burned fossil fuels,</i>

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<i>and exposed soil for farming.</i>

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<i>In fact, over a third of the carbon</i>

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<i>added to the atmosphere since 1850</i>

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<i>has come from deforestation and exposing,</i>

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<i>and oxidizing[br]the rich carbon deposits in our topsoil.</i>

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<i>U.S. soil scientist[br]Dr. Elaine Ingham says,</i>

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<i>"We can put it back though,</i>

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<i>and in a way[br]so that much of it will stay."</i>

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So, carbon sequestration,[br]we're talking about putting CO2

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from the atmosphere back into the soil

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in a form that's not going to be lost.

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♩ (guitar music) ♩

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<i>(narrator) How do we do this?</i>

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<i>The same way nature did[br]in the first place.</i>

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♩ (guitar music) ♩

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We've got to be photosynthesizing,

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so we've got to be[br]growing plants in that soil,

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so CO2 and sunlight[br]will be bound back into sugar structures.

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As those sugars go down[br]into the root system,

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picking up all the nitrogen, phosphorus,[br]sulfur, magnesium, calcium

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from the soil.

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Building that plant material.

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The plants are putting[br]exudates out into the soil,

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"cakes and cookies" out into the soil,

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and the bacteria and fungi[br]utilize that material

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and build the organic matter[br]back in the soil once again.

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♩ (guitar music) ♩

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<i>(narrator) Those sugar water exudates[br]are the key.</i>

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<i>This photo shows liquid carbon[br]flowing from a plant root above,</i>

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<i>along a fungal hypha or two,</i>

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<i>to feed the fungus below.</i>

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<i>In exchange for that carbon,</i>

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<i>soil microbes, including fungi,</i>

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<i>bring water[br]or micro nutrients to the roots,</i>

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<i>causing the plant to release more carbon.</i>

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In order to build that soil carbon,

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you have to be looking after the microbial

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or supporting[br]the microbial communities in the soil

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that join all the little[br]carbon atoms together

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to form humus polymers.

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♩ (guitar music) ♩

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<i>I can't grow as well unless[br]those microbes are there.</i>

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<i>They won't have as many [br]trace elements in them</i>

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<i>if those microbes aren't there.</i>

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<i>And when the plants don't have [br]those trace elements in them,</i>

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<i>they become vulnerable[br]to insect attack and fungal attack,</i>

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<i>pathogens of all kinds.</i>

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♩ (guitar music) ♩

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Finally, we're now seeing[br]the light as it is

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and realizing that we are light farmers.

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And that what we need to do

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is to harvest as much[br]sunlight energy as possible

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by having as much green leaf as possible.

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Therefore, as much[br]of the year as possible.

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♩ (guitar music) ♩

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<i>(narrator) Because photosynthesis[br]drives the whole system,</i>

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<i>soil should always be covered with plants,</i>

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<i>either crop plants or cover crops.</i>

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♩ (guitar music) ♩

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Farmers here in the United States

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started experimenting with two-way covers,

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and then five-way covers,[br]and then ten-way covers,

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and now they're sort of aiming[br]for 20-way covers.

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In other words, 20 different varieties[br]of plants in a cover crop.

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<i>And realizing that the more diverse[br]they make the cover crop,</i>

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<i>the faster they can build soil,</i>

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<i>and the more-- less reliant[br]they are on any chemicals at all.</i>

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<i>(narrator) Farmers are finding[br]that building soil biodiversity</i>

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<i>builds plant health.</i>

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And they're finding they don't have[br]to use any synthetic fertilizers anymore,

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they don't have to use pesticides,[br]they don't have to use insecticides.

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Not only are they producing food [br]that's higher in nutrients,

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but it's also lower in toxic chemicals.

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And they're taking CO2[br]out of the atmosphere

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and storing it in the soils.

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<i>(narrator) We also[br]want resilience in our fields.</i>

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<i>Carbon builds[br]a good, clumpy soil structure,</i>

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<i>holding on to rainwater.</i>

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And the other thing is how quickly,[br]when the rain does absorb,

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how quickly does it evaporate?

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So when it gets into the soil,[br]we want it to stay there.

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So we want to have aggregates in the soil,

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<i>which are little lumps,[br]like pea-shaped lumps in the soil</i>

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<i>that have a much higher moisture content</i>

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<i>on the inside of the aggregate[br]than on the outside.</i>

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♩ (guitar music) ♩

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And we see the greatest increases[br]in carbon sequestration,

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through what I call[br]<i>the liquid carbon pathway</i>--

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when it's being fixed in green leaves,[br]translocated through the plants,

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exuded by roots[br]into microbial communities in the soil,

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and forming aggregates,

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and leading to the process of unification,

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which is the "holy grail" for soil,

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to have an increase in humus in the soil.

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<i>(narrator) So our job,[br]as Dr. Ingham says, is to farm</i>

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<i>so we are working with nature.</i>

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♩ (guitar music) ♩

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<i>(Elaine) So don't till.</i>

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Could we have a list of those farmers

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that are no-till or zero till

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and really let people know that

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they're the ones doing the work?

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<i>(narrator) And, as Dr. Jones says, this[br]kind of farming is a win for everyone.</i>

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<i>(Christine) If we can take more[br]of the carbon that's in the atmosphere</i>

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<i>and store it in our soil,</i>

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<i>then our soils[br]and our food production systems</i>

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<i>are going to be more resilient.</i>

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♩ (guitar music) ♩

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<i>But we could produce the same meal[br]with much higher quality,</i>

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<i>with much lower cost,</i>

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<i>and building soil at the same time.</i>

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<i>I think the fundamental shift[br]in thinking that we have to make</i>

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<i>is that farming is about harvesting light.</i>

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<i>Through the process of photosynthesis,</i>

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we're going to change light energy[br]to biochemical energy,

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and then that biochemical energy[br]becomes our plants, our animals.

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So, you know, through the carbon compounds

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that are made by that process.

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We are fundamentally light farmers

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and when we make that realization,[br]then the sky's the limit.