As plants gather energy from their “soil panels” and exudate, or secrete, that energy through their root systems into the soil, microorganisms use this energy to improve soil fertility. Root exudation is a fundamental process in building organic matter in our soils, and we’re learning more about its importance every day. Root mucilage, a studied root exudate, is believed to alter the surrounding soil as it is secreted from continuously growing root cap cells.
We’re discovering that root border cells and their extracellular matrix can contribute up to 98% of the total weight of root exudates dedicated to the development of the rhizosphere (Griffin et al. 1976). In the past, many thought of border cells as irrelevant, sloughed-off root caps, but according to Dr. Martha Hawes, these cells are able to “trap” fungi and other potential pathogens, which are then detached from the root surface leaving the root tip free of disease. How great is that — this very vulnerable region of the root is protected from infection by the root border cells. Plants are truly remarkable.
Border cells can contribute 90% or more of the carbon released from young roots, and a single border cell can trap hundreds of bacteria (Hawes, 2014). An increase in bacteria has been shown to protect plants from root disease by maintaining root border cells on a root tip. Border cells can stimulate protozoa, nitrogen-fixing bacteria and other soil organisms.
Vesicular-arbuscular mycorrhizae (VAM) are fungi that symbiotically exist with plants and feed on root exudates. In return, they can absorb up to 80% of the water and nutrients for the plant and provide protection from parasitic fungi and nematodes – a real symbiotic relationship. Arbuscular mycorrhizal fungi also appear to be the only producers of glomalin. Glomalin is the glue that holds the house together, or in this case, the soil structure. It contains 30-40% carbon and is capable of forming clumps of soil granules called aggregates, the foundation of soil structure and carbon storage. A recent study by Kristine Nichols of the University of Maryland found that glomalin accounts for 27% of the carbon in soil, far surpassing the 8% accounted for by humic acid, which was previously thought to be the major holder of carbon in soil.
Rich, organic, carbon-laden soil, is a huge benefit to the plant world, and to farmers. When there are sufficient levels of organic matter, plants are able to tolerate drought better by soaking up any extra water and releasing as the plant requires. Plants with access to higher carbon levels grow larger and are able to receive a slow release of nutrients naturally cycled throughout the seasons.
Soil health relies on a balance of energy, macronutrients and micronutrients, as well as microbial health, which creates a harmonious marriage between soil and plant. Andaman Ag’s approach to plant health follows a strategy of both soil and foliar products to stimulate the exudation process and improve crop production and health.