West of the Cascades - Excel calculator for estimating costs, cover crop and fertilizer PAN and other fertilizer nutrients, with options for 1000sf or per acre calculations. Developed by OSU for western Oregon and Washington Mediterranean climate (Nick Andrews, Dan Sullivan, Jim Julian and Kristin Pool).
East of the Cascades - online cover crop PAN calculator. Developed by University of Idaho for irrigated fields in their arid climate (Amber Moore, Christi Falen, Lauren Hunter, Glenn Shewmaker and David Graybill).
Hawaii and their tropical climates - Excel cover crop PAN calculator under development at the University of Hawaii.
Information and resources
Quick Guide & Records Sheet for OSU's west of Cascades calculator - the quick guide illustrates the main steps used to use the calculator, the records sheet identifies the information needed to use the calculator.
Estimating plant available nitrogen release from cover crops (PNW 636) - this PNW Extension Publication explains how to sample cover crops, introduces a shortcut method for estimating cover crop plant-available nitrogen (PAN) release, describes the science behind cover crop PAN estimates, and uses on-farm case studies to address other frequently asked questions about cover crop PAN.
Research Background - these papers and eOrganic webinar provide more information about the research supporting the PAN estimates provided in OSU's calculator.