Source: NCSU COOPERATIVE EXTENSION, 10/28/21

A Brief Historical Perspective

North Carolina soils are naturally acidic and deficient in phosphorus (P). Liming and P fertilization historically led to very positive impacts in crop yields, and these practices were considered critical for soil fertility improvement in North Carolina. Applied research from the early 1940s defined the economic optimum rates of fertilizers to maximize yields for a variety of crops on predominant soils, using soil analysis as the tool to guide fertility recommendations. With collaboration between the North Carolina Department of Agriculture and Consumer Services (NCDA&CS) Agronomic Division and North Carolina State University’s Department of Soil Science, soil test calibration studies were frequently conducted from 1950 to 1980. These studies focused on defining the economic optimum P rate for each soil test P level and crop species.

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