The Alchemy of Soil Amendments in Organic Farming

Leonardo Da Vinci once prophetically stated that “We know more about the movement of celestial bodies than about the soil underfoot.” Twelve hundred years later we are still uncovering the best inputs to nourish the soil that grows our food.Organic growers lead the way in discovering the perfect balance of nutrients, microbial activity and soil structure to create healthy living soils that enhance our planet.

Organic agriculture has always been a trailblazer in identifying soil amendments that improve the structure of the soil so it can best hold nutrients and retain moisture. When organic materials are added they act as alchemical fertilizers that provide nourishment to plants. Soil amendments balance out the PH levels, add beneficial microbes that hold oxygen and water and provide missing nutrients.

Since every furrow and field is different how does one go about determining the best amendments for your organic operation?  

According to Kevin Forney, product development manager, with Valent U.S.A. LLC, “The most important thing for a grower to understand as they choose their soil amendments is what the most yield-limiting factors present are. Examples are saline, compaction, nutritional status, etc.  Once a grower identifies the key problem(s), they can begin addressing them with the aid of crop/soil enhancement products.” 

The traditional list of organic soil amendments is a transformative brew including the likes of blood meal, bone meal, rock dust, bat guano and kelp.  There are new products emerging in organic amendments that are equally groundbreaking. Mycorrhizae fungi, humic acids, Trichoderma fungi, beneficial soil bacteria and biochar are just a few new products and trends emerging for organic growers.

Biochar isn’t actually that new to agriculture, it’s just been forgotten. As Biochar International points out “biochar is found in soils around the world as a result of vegetation fires and historic soil management practices. Intensive study of biochar-rich dark earths in the Amazon has led to a wider appreciation of biochar’s unique properties as a soil enhancer.” They claim the carbon in biochar resists degradation and can hold carbon in soils for hundreds to thousands of years which could help combat global climate change by displacing fossil fuel use and sequestering carbon in stable soil carbon pools.

 A recent biochar article in Civil Eats indicates “The jury is still out on the soil amendments, but early field trials suggest that burying charcoal in soil can increase yields, reduce water use, and capture carbon on the farm.”

Kevin Forney from Valent points to their innovative OMRI listed product “MycoApply” (mycorrhizal fungi). This product creates symbiotic relationships between fungi and plants where the fungi colonize the root system of the host plant, providing increased water and nutrient absorption while the plant provides the fungus with carbohydrates formed from photosynthesis.

 Trials have shown that Valent’s product has proven beneficial both in organic and conventional production with documented benefits of improved root and plant growth, enhanced nutrient uptake, improved drought tolerance, increased yield and quality.

Their “MycoApply” products have both short-term and long-term benefits associated with water use efficiency.  The mycorrhizal hyphae are able to better penetrate soil spaces to access moisture that is unavailable to the thicker root hairs.  Mycorrhizal fungi can also positively influence soil structure, by producing a substance called ‘glomalin’ that binds micro-aggregates of soil into stable macro-aggregates.

An interesting study recently published on Springer Link suggests that the co-composting of phosphate rock with organic materials improves the bioavailability of Phosphorus in the soil which can be hard to maintain in organic systems.  This promising news needs more field trials.

Employing the right soil amendments can create healthy soils which in turn reduce nutrient loading and sediment runoff and improve pollinator and wildlife habitat. Determining the correct inputs to address the needs of your site-specific soil is the key success.

We’ve come a long way in understanding the “soil underfoot” and organic growers are the modern alchemists’ moving soil amendment benefits to the forefront.