SOIL IS LIFE
2,500 billion tons of carbon is held in natural soil and with the nutrients that our plants need that feed us. So WHY ARE WE DESTROYING IT?
The importance of soil carbon — how it is leached from the earth and how that process can be reversed — is the subject of intensifying scientific investigation, with important implications for the effort to slow the rapid rise of carbon dioxide in the atmosphere.
According to Rattan Lal, director of Ohio State University’s Carbon Management and Sequestration Center, the world’s cultivated soils have lost between 50 and 70 percent of their original carbon stock, much of which has oxidized upon exposure to air to become CO2.
Absent carbon and critical microbes, the soil becomes mere dirt, a process of deterioration that’s been rampant around the globe. Many scientists say that regenerative agriculture and landscaping practices can turn back the carbon clock, reducing atmospheric CO2 while also boosting soil productivity and increasing resilience to floods and drought.
RELOCK OUR CARBON BACK INTO OUR SOILS AND AGRICULTURAL SYSTEMS
Humus and the Chemistry of Soil
DIFFERENCE BETWEEN HUMUS AND ORGANIC MATTER
The main difference between Compost and Humus is that the Compost is a organic matter that has been decomposed and recycled as a fertilizer and soil amendment whereas... Humus is organic matter that has reached a point of stability, formed from the chemical and biological decomposition of plant and animal residues and from the synthetic activity of microorganisms.
“Humus” is a general term that describes a group of separate but distinct humic substances. “Soil organic matter” is a material that is decomposing at various rates in the ground. Some of the most common substances we collectively refer to as “humus” include:
Fulvic acid: a yellow to yellow-brown humic substance that is soluble in water under all pH conditions and is of low molecular weight.
Humic acid: a dark-brown humic substance that is soluble in water only at higher soil pH values and is of greater molecular weight than fulvic acid. Humic acid may remain for centuries in undisturbed soil.
Humin: a black humic substance that is not soluble in water at any pH, has a high molecular weight and is never found in base-extracted liquid humic acid products.
We all know that compost is excellent for plants....BUT
compost and other sources of decomposing organic matter are not an efficient way to build soil humus levels. Compost rapidly decomposes and leaves its minerals behind, releasing carbon into the atmosphere as CO2. Humic substances, on the other hand, are stable, long-lasting biomolecules.
Components of humus have a mean residence time (based on radiocarbon dating, using extracts from non-disturbed soils) of 1,140 to 1,235 years, depending on the molecular weight of the humic acid.
WHY IS HUMIC ACID SO IMPORTANT?
The electronegativity factor of humic acids is key in developing and maintaining healthy and sustainable soil. Humic acids are extremely important as a medium for transporting nutrients from the soil to the plant because they can hold onto ionized nutrients, preventing them from leaching away. Humic acids are also attracted to the depletion zone of the plant root. When they arrive at the roots, they bring along water and nutrients the plant needs.
Positive ions are more easily absorbed by a plant’s root because the root has a negative charge. In other words, the positive (cation) is attracted to negative (the living root). Humic acids hold cations (positive ions) in a way they can be more easily absorbed by a plant’s root, improving micronutrient transfer to the plant’s circulation system. This works because humic acids (ulmic, humic, and fulvic) pick up positive ions and are then attracted to the root depletion zone and to the hyphae micro-tubes of mycorrhizae.
Since the root’s negative charge is greater than humic acid biomolecules’ negative charge, scientists theorize that the micronutrients are taken up by the plant’s root and are absorbed by the plant’s circulation system. Some of the micronutrients are released from the humic acid molecule as they enter the root membrane, but we are now realizing that the plant will also uptake some of the lighter molecular-weight humic acids as well. In essence, the humic substances are chelating such cations as magnesium (Mg2+), calcium (Ca2+), and iron (Fe2+). Through chelation, humic substances increase the availability of these cations to plants.
CARBON SEQUESTERING WITH HUMUS
If you really want to fix or rehabilitate a soil, increase its CEC, improve its tilth and porosity, improve water availability for conservation, and therefore make soil a healthier terrestrial biosphere for all plants, roots, microorganisms, you must depend on humus. Humus is a product of soil chemistry and is dependent upon a source of its precursor chemicals: amino acids.
Amino acids are the building blocks of protein. The best source of the amino acids in a natural ecotone is produced by the Glomus species of mycorrhizae. These are associated with any grass in a natural, undisturbed site. The tallgrass prairies of the Midwest exemplify this soil-building process better than any ecotone on earth because grasses utilize a Glomus-mycorrhizal relationship. This is why there is was so much humus-rich topsoil in the Tall Grass Prairies. Glomus makes a soil protein called glomalin, a substance that is rich in amino acids. Combined with humus, they create a huge carbon sequestering and banking factor.
“Humic Acids: Marvelous Products of Soil Chemistry” (The Journal of Chemical Education, December 2001) states, “Humic acids are remarkable brown to black products of soil chemistry that are essential for healthy and productive soils. They are functionalized molecules that can act as photosensitizers, retain water, bind to clays, act as plant growth stimulants, and scavenge toxic pollutants. No synthetic material can match humic acid’s physical and chemical versatility.”