Skip to main content
Geosciences LibreTexts

8.4: OMRI Approved

  1. Last updated
  2. Save as PDF
  • Page ID
    34630

    • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)

    OMRI and Organic Fertilizers

    The Organic Materials Review Institute (OMRI) is a web-based site to visit for information about whether or not a product--be it a fertilizer, soil amendment, animal vet product, or cleanser--is “approved for use in organic systems”. OMRI is used and trusted by the organic industry, certifiers, inspectors, and farmers. http://www.omri.org/about-omri-listed-products

    Here is what the site looks like on the internet. You can search the site for all kinds of great information.

    Screenshot of OMRI home page

    The OMRI website changes periodically so you may not see a site that looks exactly like what is shown here. As a farmer or commercial gardener, you should be able to explore, navigate, and find products in which you are interested. Most farmers I know do not “subscribe” to OMRI. I recommend that level of involvement only for those who want to sell products or get products certified.

    Here is the kind of information you can get from the OMRI website:

    • the function of a product
    • the status of a product
    • exceptions or any restrictions on the use

    This is a sampling of a few fertilizers and amendment products that we use on our farm (Full Circle Farm) and those described on the OMRI website. The information includes the purpose of the function and whether or not they are “OMRI approved.” If something is OMRI-approved, you can be confident it is OK to use on your organic farm.

    Potassium Fertilizers

    Their function is to supply potassium.

    • Potash. Status: It is OMRI allowed as described in the OMRI information. “Only from mined sources.”
    • Potassium Chloride (KCl). Status: Allowed with Restrictions. Class: Crop Fertilizers and Soil Amendments. Origin: Non-synthetic. Muriate of potash (potassium chloride) must be applied in a manner that minimizes chloride accumulation in the soil. NOP Rule: 205.203(d)(3) & 205.602(e) A mined substance of high solubility. [Prohibited] unless derived from a mined source and applied in a manner that minimizes chloride accumulation in the soil.

    Blood meal

    The collected blood of slaughtered animals after it has been dried. The major nutrients supplied are nitrogen and additional trace elements, including iron. It is allowed as described below.

    • Status: Allowed. Class: Crop Fertilizers and Soil Amendments. Origin: Non-synthetic.
    • Description: Animal material. See website glossary for the definition of "blood meal." NOP Rule: 205.105(a)

    Dolomitic Lime

    Dolomite does not contain a major nutrient but does serve a primary function in adjusting pH with magnesium carbonate and calcium carbonate (alkaline.) It is allowed, as described:

    • Dolomite: naturally mined. Status: Allowed. Class: Crop Fertilizers and Soil Amendments.Origin: must be non-synthetic.
    • Description: Magnesium carbonate and calcium carbonate. May cause a build-up of magnesium. See also MINED MINERALS – UNPROCESSED. NOP Rule: 205.203(d)(2) A Mined substance of low solubility.

    Gypsum

    Gypsum fertilizer is calcium sulfate. It must be mined (synthetic gypsum is about 30% of the market). This fertilizer provides calcium and sulfur, is used in the case of excessive phosphorous, and can be a correction for salinized soil. It is superior to lime because it reaches subsoil and lime does not. The mined form is allowed as described below.

    • Status: Allowed. Class: Crop Fertilizers and Soil Amendments. Origin: Non-synthetic.
    • Description: Calcium sulfate; only mined forms are acceptable. See also GYPSUM BY-PRODUCTS and MINED MINERALS – UNPROCESSED. NOP Rule: 205.203(d)(2) A mined substance of low solubility.

    Tennessee Brown Rock Phosphate

    This is non-synthetic and contains total phosphate of 21-25%, calcium 20%, and trace elements. It is allowed as described below.

    • Status: Allowed. Class: Livestock Feed Ingredients, Livestock Health Care. Origin: Non-synthetic.
    • Description: May be supplied by: calcite, chalk, rock, ground clam shells, gypsiferous shale, ground limestone, dolomitic limestone, oyster shell flour, ground phosphate rock, soft phosphate rock, or shell flour. NOP Rule: 205.237(a)

    K2SO4 Potassium Sulfate

    This is also non-synthetic with the major nutrient supplied being potassium. It is allowed upon the conditions described below (non-synthetic origin.)

    • Status: Allowed. Class: Crop Fertilizers and Soil Amendments. Origin: Non-synthetic.
    • Description: Only if from langbeinite or other nonsynthetic sources. See also MINED MINERALS – UNPROCESSED.
    • NOP Rule: 205.203(d)(3) A mined substance of low solubility.

    Poultry Litter

    Poultry is the richest animal manure source of N-P-K, all major nutrients. It is organic allowed when composted, as described below.

    • Compost – windrow (plant and animal materials). Status: Allowed. Class: Crop Fertilizers and Soil Amendments. Origin: Non-synthetic.
    • Description: Plant and animal materials are composted through a process that establishes an initial C:N ratio of between 25:1 and 40:1 and maintains a temperature of between 131°F and 170°F for 15 days, during which period the composting materials must be turned a minimum of five times. Acceptable feedstocks include, but are not limited to, animal manure, by-products of agricultural commodities processing, and source-separated yard debris or "clean green." Compost must not contain more than 1x10³ (1,000) MPN fecal coliform per gram of compost sampled and must not contain more than 3 MPN Salmonella per 4 grams of compost sampled. See also MICROBIAL PRODUCTS for information on compost starters, other COMPOST listings, SEWAGE SLUDGE, and MUSHROOM COMPOST. See the website glossary for the definition of "compost."
    • NOP Rule: 205.203(c)(2)(i) & (iii) Composted plant and animal materials.

    Compost

    Compost provides nitrogen-fixing in many cases, as well as organic matter, and improves microbial activity. Allowed as described below.

    • Compost – other (plant and animal materials). Status: Allowed. Origin: Non-synthetic.
    • Class: Crop Fertilizers and Soil Amendments
    • Description: Compost is acceptable if (i) made from only allowed feedstock materials; (ii) the compost undergoes an increase in temperature to at least 131ºF (55ºC) and remains there for a minimum of 3 days, and (iii) the compost pile is mixed or managed to ensure that all of the feedstock heats to the minimum temperature for the minimum time. Compost must not contain more than 1x10³ (1,000) MPN fecal coliform per gram of compost sampled and must not contain more than 3 MPN Salmonella per 4 grams of compost sampled. This does not include Compost Tea. See other COMPOST listings. See the website glossary for the definition of "compost."
    • NOP Rule: 205.203(c)(2)

    Cattle Manure

    Provides N-P-K. Allowed as described below.

    • Composted – other (plant and animal materials) Status: Allowed. Origin: Non-synthetic.
    • Class: Crop Fertilizers and Soil Amendments
    • Description: Manure compost is acceptable if (i) made from only allowed feedstock materials; (ii) the compost undergoes an increase in temperature to at least 131ºF (55ºC) and remains there for a minimum of 3 days; and (iii) the compost pile is mixed or managed to ensure that all of the feedstock heats to the minimum temperature for the minimum time. Compost must not contain more than 1x10³ (1,000) MPN fecal coliform per gram of compost sampled and must not contain more than 3 MPN Salmonella per 4 grams of compost sampled. This does not include Compost Tea. See other COMPOST listings. See the website glossary for the definition of "compost."
    • NOP Rule: 205.203(c)(2)

    References

    This page titled 8.4: OMRI Approved is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Valerie Dantoin (Northeast Wisconsin Technical College).