The Dirty Little Secret… Soil

June 11th, 2014 | Simcha Weinstein | Comments Off on The Dirty Little Secret… Soil

Organic SoilThose of us in the organic foods industry, in whatever capacity we serve, find ourselves frequently in a position to explain why organic foods are beneficial, both to human health and the health of our environment. We typically understand, and are comfortable to articulate the clear advantages of organically raised food – no pesticides, herbicides, or chemical fertilizers. And it’s pretty easy to understand that if we are not ingesting chemicals or spreading them across our fields, then naturally we benefit from that. This is the easy part of the organic story, and certainly the information that is most frequently shared. And with good reason – it makes sense. It’s easy to understand. It’s the low hanging fruit when it comes to both telling and understanding the organic story. And while it’s become the mainstay, and certainly the headline of why choose organic, there is an aspect to organic farming that is less frequently discussed when touting its benefits, that may very well be one of the key factors in mitigating climate change – which according to most scientists is the key planetary issue that we will face in the twenty-first century. And it’s certainly an attribute of organic food and farming that we should be sharing as ambassadors of the organic foods industry. This attribute? Very simply – it’s our soil. It doesn’t sound sexy and it probably doesn’t even sound that interesting, but if we can help consumers understand the importance of how organic farming creates healthy soils, which in turn significantly reduces our greenhouse gas emissions, we have essentially added a completely new chapter to the organic story – and one that is vital for people to understand.

Scientists know that simply reducing our greenhouse gas emissions is not enough; we must also pull carbon out of the atmosphere in the form of CO2. Soil carbon sequestration (soil storage) is the process of moving CO2 from the atmosphere into the soil, where it can no longer contribute to the warming of our planet. In case you’re doing a double take here, you read that last line correctly. Our soil actually grabs carbon out of the atmosphere and brings into the soil, where in addition to reducing the carbon in the atmosphere, it also provides huge benefits to the health of our soil and therefore to our food.

So here’s how it works: Plants pull CO2 out of the atmosphere through photosynthesis, so as plants grow, carbon is captured in their roots. When the plant dies, its roots remain in the soil, serving as a storage unit for carbon. Very simply – this is the process of building healthy soils.

Soil organic matter is approximately 50 percent carbon. As we increase soil carbon, we build soil. Over the past 150 years more than a third of the CO2 we have added to the atmosphere has come from the impact of conventional farming practices – changes in land use and poor land management – not from burning fossil fuels. During this time, we have lost 50-80 percent of our topsoil worldwide. Positive changes in land use could sequester significant amounts of carbon in the soil. Restoring even a portion of the lost carbon in our soils would represent a significant reduction in atmospheric greenhouse gases, an effective tool to curb global warming. And, organic farming is the best method for restoring carbon to our soil.

There’s more carbon in soil than there is in the atmosphere and the global biomass combined. Soil contains about 3 times as much carbon as the atmosphere and 5 times as much as forests. And about 60% of this is in the form of organic matter in the soil, which sounds incredible, but it’s true. Soil subject to organic farming methods sequesters far more carbon than conventionally-farmed soil – this according to just about every scientific study ever published, but specifically according to the Food and Agriculture Association of the United Nations, (FAO). Increasing the amount of carbon naturally stored in soils could provide the short-term bridge to reduce the impacts of increasing carbon emissions until low-carbon and sustainable technologies can be implemented. According to the FAO, 86% of agriculture’s potential for climate change mitigation lies in carbon sequestration in soils; that organic farming results in 20%-28% higher levels of soil carbon compared to non-organic farming; and that a global conversion to organic farming could sequester up to 11% of global greenhouse gas emissions. That’s significant!

And here are a few more key points detailing the importance of soil carbon store and how it impacts climate change:

– Soil carbon losses account for 1/10th of all the CO2 emissions by human activity since 1850. However, unlike the losses from burning fossil fuels, the soil carbon store can be recreated to a substantial extent. This would remove large amounts of previously emitted carbon from the atmosphere, offsetting current greenhouse gas emissions.

– The principal component of the soil carbon store is humus, a very stable form of organic carbon, with an average lifetime of hundreds to thousands of years.

– Soil carbon sequestration also provides a rapid and timely greenhouse gas emission mitigation win since climate sequestration starts as soon as the positive practices (organic farming techniques) are adopted and about half of the total amount that will be sequestered occurs within the first 20 years. This is critically important, as drastic greenhouse gas emission reductions are required in the next 20 years to mitigate the rapidly growing impact of climate change.

Organic farming typically highlights it’s soil advantages including better plant nutrient content, increased water retention capacity, and less soil erosion; but now it’s time to highlight a tremendous attribute of organic farming that often goes unmentioned. It’s time to highlight carbon soil storage as a key benefit to organic farming – and one that may be key to mitigating the impact of climate change . . . and that’s a big deal.