InfoAg 2017 Presentation
Advances in VR Nutrients

Regency C
Wed, Jul 26, 2017
8:00 AM to 10:00 AM

Advances in VR Nutrients (Repeat)

Regency C
Wed, Jul 26, 2017
1:20 PM to 3:20 PM


Much of the phosphorus (P) fertilizer applied across the US is applied using a variable rate (VR) strategy. Often we interpolate soil P data and use standard soil test interpretations to develop VR prescriptions. We need to critically examine this approach. Can traditional soil test critical values (the soil P concentration below which we expect P fertilizer response) and fertilizer recommendation systems be used under a VR management strategy? How precise are interpolated soil test maps? These questions and others will be examined as we discuss ongoing research into VR-P.

Josh McGrath
Associate Professor & Extension Specialist
University of Kentucky
Lexington, KY 40546-0091
Dr. Josh McGrath joined University of Kentucky’s faculty in 2014 after spending eight years at the University of Maryland focused on agriculture and the Chesapeake Bay. Josh’s research and extension activities concentrate on agricultural productivity, with emphasis on water quality, nutrient use efficiency, and precision agriculture. Dr. McGrath routinely speaks throughout the United States on issues related to agriculture and the environment as well as precision agriculture. Dr. McGrath was born and raised in Smyrna, Delaware, graduated with a BA from Johns Hopkins University, earned his Ph.D. from University of Delaware, and conducted post-doctoral research at Virginia Tech. When not talking about or researching soil fertility Josh enjoys hunting and fishing and has been a volunteer firefighter for over 25 years.