Figure 4.
What if? Carbon in the soil combines with
oxygen to become CO2 , the greenhouse
gas that contributes greatly to global warming. Common agricultural practices like plowing and tilling mix oxygen with soil carbon. Lately there has been tremendous attention examining reversing this process via carbon sequestration. Te intent is to reduce CO2
levels in the atmosphere. Fifty years
ago, few had heard of or cared about the concept. Carbon sequestration has suddenly become a hot topic. Important questions are being
addressed. How to best capture CO2
from the atmosphere? What organisms facilitate moving CO2
from
the atmosphere to carbon in the soil, where it improves plant productivity? A good, natural process is to enhance incorporating carbon into the soil via arbuscular mycorrhizal fungi on millions of acres of farmland (Fig. 4 shows Rodale Institute Long-term farming systems trial: the soils on the right were grown with organic methods and mycorrhizal fungi: on the left conventional practices). Research indicates that current agricultural practices release
20 FUNGI Volume 14:4 Fall 2021
25 to 35% of all carbon dioxide into the atmosphere, more than all types of transportation combined. Moreover, many farming practices such as intensive tillage and over-fertilization not only release carbon to the atmosphere but result in erosion and nutrient pollution of steams, lakes, and oceans. But “what if” we could change farming from a destructive force to a regenerative force? Te knowledge and know-how for
regenerative farming exist today. For example, we know that minimal or no tillage, fewer chemical fertilizers, and pesticides, cover cropping, and the addition of organic amendments are ways to increase soil-carbon content, so less carbon dioxide is returned into the atmosphere and instead deposited in the soil (Pimintel et al., 2005). Rates of carbon increase in the soil can exceed 1,000 pounds per acre per year. It’s not an expensive process to add
carbon to soils. But it does take large numbers of people to participate. When managed appropriately on millions of acres of farmland, this approach can make a real difference in CO2
levels in
the atmosphere. For example, increasing the carbon content of the world’s soils (outside of permafrost areas) by just
a few parts per thousand (0.4%) each
year would remove an amount of CO2 from the atmosphere equivalent to the fossil-fuel emissions of the European Union (around 3–4 gigatonnes (Gt). It would also boost soil health: in studies across Africa, Asia and Latin America, increasing soil carbon by 0.4% each year enhanced crop yields by 1.3% (Soussana et al., 2019). Governments are beginning to
recognize the importance of adding carbon to soil. Te Paris Agreement, also known as the Paris Climate Accord, is an agreement among the leaders of over 180 countries to reduce greenhouse gas emissions and limit the global temperature increase to below 2 degrees Celsius (3.6o
F) above pre-
industrial levels by the year 2100. Te Paris Agreement includes the voluntary “4p1000 initiative,” which was launched under the framework of the Lima-Paris Action Plan in Paris on December 1, 2015. Te name of the initiative reflects that a comparatively small proportional increase (0.4%) of the global soil organic carbon content in the top 0.3–0.4 m would store a significant amount of the global annual carbon emissions (Rumpel et al., 2018). Te message is simple:
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
