N-ST*R- Exemplifying the Need for Soil Test Development, Correlation and Calibration In the 21st Century and Beyond.

The University of Arkansas directs one of the few remaining “free” soil testing programs in the United States and has long been a leader in the development, correlation and calibration of soil testing methods for Mid-South row-crops such as rice, soybean, corn and wheat. Arkansas’ soil test laboratory processes over 150,000 soil samples annually and provides routine analysis for pH and extractable nutrients; P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, B, and S free of charge. Correlation and calibration of soil test P and K have been the focus of the soil fertility program and have led to the release of updated recommendations for rice and soybean with on-going work in wheat and corn. Researchers at the University of Arkansas have led the way in the development of the first soil-based N test for rice; N-ST*R. Soil-based N tests have been the focus of soil fertility research programs for the past 50 years and the recent success of N-ST*R highlights the importance of continually developing new soil test methodologies and ensuring current methods provide the proper rate recommendations. In a world of rising commodity and fertilizer prices coupled with the increase in potential environmental impact the identification and application of proper nutrient rates has never been more important.