Soil Nitrate Testing for Willamette Valley Vegetable Production (2019) EM9221

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

Estimating Plant-Available Nitrogen Release from Cover Crops

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

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Baseline Soil Nitrogen Mineralization: Measurement and Interpretation (2020) EM9281

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