Taking soil samples for laboratory analysis. Photo by Karl Hakanson.
Row Crop, Pasture, Fodder, Rice, Small Grains, Animal Confinement, Palm Oil
Temperate, Semiarid, Tropical
North America, South Asia, Europe
Nitrogen, Phosphorus, Sediment
Soil testing is used before planting to determine the characteristics of the soil, including nutrient content, pH, moisture, and composition. Soil testing is an important component for determining the right balance and right rate of nutrient application on the field. The soil testing process is based on soil samples being taken from representative areas in a field, analyzed using a chemical extraction appropriate for the soils in the region, and either correlated with plant nutrient uptake or calibrated with crop yield. Resulting fertilizer recommendations would be based on how a particular crop responded to a nutrient, using the average response from a multi-year and multi-site data set. 2
Soil should be tested every 3-5 years. One sample should be taken for every 20 acres at a depth of approximately 8 inches. In the U.S. a soil test costs between $7 and $10 per sample. Applicability of this practice will depend on proximity to qualified soil testing laboratories and extension services.
Scalable to small farms?
1 Wortman, Charles S. "Agricultural Phosphorus Management and Water Quality Protection in the Midwest." The Heartland Regional Water Coordination Initiative. University of California, Division of Agriculture and Natural Resources. Web. July 2014. http://extension.missouri.edu/explorepdf/regpubs/ncr187.pdf .
2 "Best Management Practices, Today's Agriculture: A Responsible Legacy." Nutrient Best Management Practices. Web. Aug. 2013. http://dda.delaware.gov/nutrients/D17762BestMgmtbklt.pdf .