What Are The Benefits Of Fall Soil Applications?
by Harold Schrock, AEA Staff Consultant
August 31, 2016
Many nutrients are locked in the soil and become available to plants only as they are digested by microbes. Phosphorus and calcium tend to bind to each other and be unavailable to plants. Minerals — iron, copper, zinc, manganese, molybdenum — are often found only in an oxidized state that’s almost completely unusable by plants. Soil microbes, primarily bacteria, will consume these elements to support their own life cycles; as they reproduce and die, the nutrients become available plant food.
This bacterial waste is also food for fungi and many other visible and microscopic soil-dwelling creatures, some of which compete with plant roots for nutrients. These soil dwellers play an important role in long-term soil building. Fungi, in particular, are directly responsible for the production of humus and stable humic substances.
We can encourage this soil-building process through the growing season by using foliar nutrition and good farming practices to keep crops healthy. A healthy crop exudes more sugars and feeds more bacteria and fungi than a struggling crop. More sugars and other root exudates equal more bacteria which equal more available nutrition to feed both the crop and beneficial soil organisms.
From fall to spring, when soil microbes are free of the nutritional demands of a crop, more food is available for microbes to attend to soil biology. Beneficial changes in soil structure can be impressive during these months. Farmers can kick start the process by stimulating soil biology with Rejuvenate™ and Sea Shield™, inoculating with Spectrum™ where necessary, establishing a cover crop wherever possible, and applying rock powders if needed.
Winter rest is as beneficial for soils as it is for growers. Here are some tips for preparing your soil for an off-season break.
Clean up fields. Applying Rejuvenate™ with Sea Shield™ and Spectrum™ as needed will speed digestion of crop residues, depriving insects and diseases of a winter home. Growers should weed perennial plantings and other no-till areas, and get any plastic mulch and other non-compostables out of the field.
Plant a cover crop. Crops that winter kill, such as oats and tillage radishes, simplify soil preparation in the spring, but having living, growing plant roots in the soil all year helps feed and maximize diversity of many beneficial soil-dwelling organisms. Using covers of multiple plant species broadens the soil food web and makes it more resilient in times of stress.
Add soil amendments. The best time to apply lime, solid manure, unfinished compost, or rock powders is after a killing frost and before snow cover. Giving these raw nutrients several months to assimilate into the soil food web will minimize potential nutrient imbalances during the growing season.
Whether your fields are in the world’s temperate zones, or under heavy snow cover and frost, the winter season of rest can bring about microbial regeneration that is beneficial to plant nutrients and soil structure. Following these steps will ensure your soil a period of healthy regeneration, and that will translate into better crop performance next season.