The Earth's Way
Though the achievements of NPK fertilizers
in modern horticulture and agriculture are undisputed, they are not enough. That's because there's more to soil than the macronutrients nitrogen, phosphorus, and potassium. Micronutrients (such as zinc, sulfur, copper, iron, and numerous trace elements), along with oxygen, organic carbon, and beneficial microbes all contribute to the living micro-environment that plants need to thrive.
That's where compost comes in. It is the original soil management tool as it rebuilds the soil from the ground down, improving its physical, chemical, and biological properties. Over time, soil becomes depleted of nutrients and living organic matter. It becomes inert dirt. Simply stated, compost turns dirt back into soil.
Adding compost makes soil more crumbly and workable. As a result, the problems associated with soil compaction
(poor aeration, difficulty cultivating, poor drainage) are significantly alleviated. With improved soil structure, vegetation develops strong, healthy root systems, which is key to protecting soils from wind and water erosion.
Compost's organic matter acts like a thirsty sponge, holding water within the soil matrix. That means fewer runoff problems and less susceptibility to drought. In addition, fewer irrigations are required, so water costs are held in check.
Compost can raise or lower soil's pH, providing just the right acid/alkaline balance for a variety of plants. It also buffers the pH, stabilizing it against change. To determine your soil's pH level, the University of Hawai's College of Tropical Agriculture and Human Resources (CTAHR)
has put together an instructional brochure on why and how to take a soil-test sample.
In addition, compost improves the cation exchange capacity
of soil. This increases its ability to hold nutrients, thereby increasing its fertility and maximizing its usage of fertlizer, often allowing for reduced applications.
Because nutrients are released by microbial action as soil temperatures rise, plants benefit from a built-in "time release" feature that matches their increased nutrient demands as warm weather accelerates growth. The result is higher yields from the same soil. Increased populations of certain microbes may suppress plant diseases, such as phythium
and fusarium, as well as nematodes