Soil Biology Revolution
Charlie Walthall and Jerry Hatfield are rebels with a cause. As top-tier researchers with the USDA Agricultural Research Service, they are part of what Walthall describes as a revolutionary approach to plant health and productivity. It is one that could be key to meeting present and future food, fuel and fiber needs. If so, it will also be key to full-service ag retailers, independent crop consultants and other agronomic service providers meeting their customers' needs.
"We are approaching soil now as a living entity, examining the feeding, care and health of the soil," said Walthall, national program leader, USDA ARS. "If the soil is healthy, it will be able to sustain healthy plants and good yields. Genetics and genomics are an important part of the equation, but it is clear that how we care for and manage the soil is an even bigger part."
Jerry Hatfield, director, National Laboratory for Agriculture and the Environment, (formerly Soil Tilth Lab), Ames, Iowa, points to variations in crop yield across any given field as evidence of a need to look deeper than genetics, tillage or traditional nutrient applications. "When we watch a yield monitor as a combine crosses a field, we can see yield variations from 75 bushels to 100 bushels to 250 bushels," said Hatfield. "A lot of that is due to poor soils in parts of the field. If all that was missing was nitrogen (N), phosphorus (P) and potassium (K), then adding them should alleviate the yield difference. But we need to approach the problem from a more holistic viewpoint."
The viewpoint suggested by Walthall and Hatfield is one of soil biology. Rather than viewing soils as an amalgamation of clay, sand and nutrients, they advocate including the biological activity, bacteria, fungi and other subsurface life forms that feed plant root systems.
"The bottom line is that by promoting a healthy biological system in the soil, we are adding the glue that holds the sand and clay together in a more resilient state," noted Hatfield. "We need to build up the aggregate stability of the soil in order to increase aeration and the capacity of the soil to increase water infiltration and absorption and decrease erosion. Then we can incorporate the best genetics and nutrients."
Examining Biotic Fertilizer
The two researchers are not alone in their interest in soil biology. Walthall noted that a number of companies have approached him or made him aware of work they are doing in this area. Researchers, some of them private and some USDA ARS scientists, are looking at everything from manures and compost to soil inoculants and the impact of biochar on soil quality and productivity. One commercial product being examined is Perfect Blend biotic fertilizer ("Manure Based Fertilizers," AgProfessional, Aug., 2008). Introduced originally as an organic fertilizer, the chicken litter based product is processed into a uniform chelated product with added mycorrhizal inoculants and select micronutrients.