Understanding soil health

摘要

A Cornell University scientist advocates a more proactive and holistic approach to soil health. In the past, growers considered soil health in terms of the limiting factor. For example, nitrogen is the most limiting factor when it comes to yield potential. Once there's sufficient nitrogen in the soil, the next most limiting factor is phosphorus. And the next one is calcium, and so on (see Figure 1). "The idea was that these different chemical components more or less function independently," Dr. Harold van Es, soil scientist at Cornell University, New York, explained during aWashington State University soil workshop last winter. In the past, growers have relied on reactive management—using short-term responses to immediate problems and relying mostly on external interventions. For example, if the nitrogen was low, fertilizer would be applied. The solution to compacted soil was to use a subsoiler. Van Es said this is somewhat like a person taking a pill for an illness.