This Oregon State University fact sheet explains the basics of plant-available nitrogen (PAN); when to kill cover crops for the maximum PAN benefit; step-by-step instructions on how to perform site-specific measurements to predict PAN from your cover crop; and case studies from the Willamette Valley about cover crop management, PAN and the value of cover crops as a nitrogen fertilizer substitute.
The field sampling approaches described in this fact sheet to determine cover crop N uptake are applicable to a wide variety of cropping systems. Information related to the timing of cover crop termination is applicable to western Oregon and western Washington. Equations used to predict PAN are expected to be applicable in most locations.
The authors of this fact sheet also developed an Excel-based calculator for estimating the nutrient value of organic fertilizers, cover crops, compost and synthetic fertilizers.
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This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture through the Sustainable Agriculture Research and Education (SARE) program. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.