The North Carolina Department of Agriculture & Consumer Services’ Agronomic Services Division announced on Apr. 2 the release of a new step-by-step guide aimed at helping farmers measure the nutrient value of their cover crops and reduce fertilizer inputs.
The new resource comes as fertilizer costs have risen and more growers are adopting soil health practices. The guide is designed to give practical instructions for collecting cover crop biomass samples, submitting them for analysis, and calculating their nutrient value per acre. Growers can use these guidelines before terminating their cover crops each spring to adjust fertilizer plans based on actual nutrient content.
“There has been a growing interest in the nutrient value of cover crops in recent years,” said Dr. Kristin Hicks, lab director of the Plant/Waste/Solutions/Media Lab. “With recent spikes in fertilizer prices, we expect that interest to increase significantly. We created this quick guide with the goal of making it as easy as possible for growers to determine how much a cover crop could offset the need for fertilizer inputs.”
A notable recommendation from the guide is that farmers should submit samples through the Waste and Compost Analysis service rather than Plant Tissue Analysis. “In the case of cover crops, you aren’t growing it for harvest but as a fertilizer for eventual land application or incorporation, similar to manure or compost,” Hicks said. “The Waste Analysis is designed to report nutrient concentrations on a per acre basis for this purpose.” She also said that quantifying nutrients helps growers make informed decisions: “Growers want to get the most out of the cover crops they invest in. By giving them straightforward sampling methods and quick nutrient calculations, we hope to empower them to reduce input costs while improving their soil’s long-term productivity.”
Cover crops offer various benefits beyond supplying nutrients: legume species such as crimson clover, hairy vetch and Austrian winter peas fix atmospheric nitrogen; cereal species like barley, oats and rye retain leftover nutrients; all contribute by increasing soil organic matter, suppressing weeds, reducing erosion and improving water retention.
Step-by-step guidelines along with a printable field guide are available online at www.ncagr.gov/Agronomic-Services under “Determining the Nutrient Value of Cover Crops.”
