The Soil, Water and Forage Analytical Laboratory (SWFAL) was established by the Oklahoma Cooperative Extension Service to provide soil testing, plant, animal waste and water analyses for the State of Oklahoma and anyone who needs agricultural testing services. Each year over 60,000 samples are submitted for analyses by thousands of farmers, ranchers, homeowners, consultants, governmental agencies and researchers. Interpretations and recommendations are made based on many years' field calibrations conducted in Oklahoma. Here's how to submit a sample for testing.