Link: https://catalog.extension.oregonstate.edu/em9221
This publication describes how to use in-season soil nitrate testing to adjust sidedress N fertilizer application rate to match crop N requirements. Data to support our recommendations comes from field trials conducted in the Willamette Valley for vegetable crops produced during summer months.… Read the rest
This publication evaluates a broad spectrum of legume species and cultivars for their ability to thrive in an orchard environment and provide a significant nitrogen contribution.
Link: https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/wapmcsr12864.pdf… Read the rest
This publication assists western Oregon farmers and agricultural professionals in determining the nitrogen fertilizer replacement value of winter cover crops. Includes information on plant-available nitrogen (PAN) basics; a site-specific, step-by-step method to estimate PAN; Willamette Valley case studies; and appendices summarizing Willamette Valley cover crop research that supports these PAN estimates.
Link: https://catalog.extension.oregonstate.edu/pnw636
This Extension publication reviews baseline N mineralization which refers to plant-available nitrogen release that accompanies the decomposition of soil organic matter. The rate of baseline soil N mineralization is governed by the quantity and quality of soil organic matter, as modified by soil moisture and temperature. Baseline soil N mineralization typically supplies about half of crop N uptake. Soils that have been heavily manured for many years or are naturally very high in soil organic matter can supply most of the N required for crop production. Several laboratory tests for N mineralization are available, but most are useful only as … Read the rest