Compost topdressing takes the product compost (once a waste stream) and applies it to the soil as an amendment to improve the soil structure, while significantly reducing maintenance input costs associated with expensive fertilizer, continuous irrigation schedules, and soil compaction problems necessitating pesticide applications as well as large physical renovations. The campus soil is a natural asset that should be included and managed as an asset in order to reduce expenses and maximize profits.
How Topdressing Works
Though fertilizing is technically a topdressing, I want to make a distinction based on the main objectives between topdressing and fertilizing. Fertilizing’s main objective is to provide plant nutrients in order to produce growth, and topdressing’s main objective is to improve the soil’s structure. It must be noted that they can each have an impact on the other in real life. For example, compost has nutritional benefits that also feed the plant like a fertilizer, as well as amendments to the soil structure. We should view compost topdressing as an amendment practice to a soil structure to better understand how it is an asset.
Soil structure is comprised of four basic materials: sand, silt, clay and organic matter (OM). From a topdressing amendment point of view, topdressing materials then are sand, silt, clay and OM (compost) or any blends of these materials.
Sand topdressing is used in leveling surfaces, improving soil porosity, covering up the roots of warm season grasses and supporting the grass blade stand. This application is performed on sports fields, golf greens and tees, and warm season lawns.
Silt and clay topdressings are often components to various blends in order to repair drainage issues or for specific purposes, such as the clay used on baseball diamonds and pitching mounds.
Compost topdressing, on the other hand, is used for the management of OM in the soil in order to preserve soil health. This application is used in agriculture and horticulture, on crop fields, lawns, sports fields and golf courses.
The basic three components of sand, silt, and clay make up the 12 soil classifications, and each soil classification has varying characteristics with inherent limitations. The unique OM component and its inherent adhesive property can make any soil type healthy and productive.
OM is better understood as the process of decomposition of biomass that ends in Humus formation, the asset in all soil type.
The OM percentage in a soil heavily improves the soil PH and CEC which are like the soil system’s horsepower. Though the OM percentage in the soil structure analysis is small in comparison to the three other components, the benefits are significant.
When the appropriate percentage of OM is preserved in a soil (5-10%), the soil is healthy and strong in terms of energy yet quite fragile when exposed to extreme weather conditions and human impacts, such as sporting activities along with routine cultural practices. It is imperative to understand that the OM level in the soil is the microbial habitat and sustenance, which serves as the soil’s protective buffer against stress caused by activities and routine horticultural practices.
For example the best mowing practice has established the 1/3 cut rule but when common circumstances lead to that rule being broken, the OM buffer in the soil can provide food energy to the grass plant (via the microbe). Mowing always causes stress on the grass plant that must be recovered from and reduces the photosynthesis leaf surface, the leaf ‘s energy production chamber.
Therefore, the management of OM is like an asset balancing out our normal, routine activities.
Reducing Costs And Maximizing Soil Assets
While compost topdressing is not a cure-all, it is a valuable tool for preserving and increasing the OM level in a soil. However, it would be an enormous task to increase OM levels by compost topdressing alone, taking nearly twenty tons of good compost just to raise the level by 1% on a one-acre field. Compost topdressing implementation should be a routine maintenance toward sustainability, and studies have found that light monthly compost applications had far better results than fewer heavier applications.
New root growth is the best way to increase soil OM, and compost is a great medium for germinating seed. New grass roots are also an excellent compacted soil aerator. This is nature’s way to produce and maintain OM in the soil. Every spring and every fall, nature goes to seed and then drops its leaves or allows part of a plant to die to serve as a topdressing amendment. Routine over-seeding combined with compost topdressing is a soil asset builder.
Ultimately, compost topdressing will greatly reduce input costs and maximize your soil asset to work for you. The only things increased by poor OM management are costly problems, due to increasing bulk soil density. Most importantly, compost topdressing can become the key that closes the cycle of sustainability.