Summary Table

IAMP-Compost and Manure Application Practice
(within NRCS 590)

Description

Compost and manure are carbon-based amendments derived from animal byproducts with or without plant materials. Compost is a product created through the controlled aerobic, biological decomposition of plant and animal materials. Manure can also be composed of both plant and animal materials that have not been managed for biological decomposition (e.g. fresh scraped manure or stockpiled manure). Both products have plant-available nutrients, such as nitrogen, phosphorus, and potassium, that need to be accounted for in a nutrient management plan. The emphasis in IAMP is on the reduction of synthetic N fertilizers, a greater reliance on organic sources of N and improving N use efficiency. Incentives are provided for management that replaces at least 15% of the typical baseline synthetic inorganic N demand with organic compost and/or manure sources without exceeding the Idaho State Department of Agriculture Phosphorus (P) limits on cropland.

Benefits

Compost and manure supply nutrients to plants and microbes in addition to carbon. They can reduce soil bulk density and overall soil structure.

Soil Carbon Impacts

Manure and compost additions will likely lead to increased soil carbon.

Greenhouse Gas (GHG) Impacts

During the composting process, microbes aerobically consume organic matter and release CO2 and other gasses. Composting significantly reduces GHG emissions compared to other low-tech, low-input manure management techniques and stockpiled manure or raw manure land application. Very low GHG emissions come from compost if properly managed. Most GHGs, mainly methane (CH4) and nitrous oxide (N2O), can be produced within the first 60 days of composting. Formation of all GHGs and other gasses during composting is biologically driven. Management of the composting process impacts GHG emissions. For example, a lower than ideal C:N ratio increases ammonia (NH3) and CH4 emissions but does not affect N2O; an optimal C:N ratio for reducing GHG emissions is 30:1. Compost pile aeration reduces GHG emissions. The larger the compost pile, the more intensely it must be managed to reduce emissions because anaerobic conditions quickly redevelop after turning. However, when N2O and CH4 emissions are reduced, NH3 volatilization is increased, which is not ideal for compost meant to supply nutrients for crop production.

Considerations for Success

  • If equipment is not already owned or readily available, growers may need to hire a custom applicator to apply compost/manure.
  • If the field is located far from a composting facility and/or higher application rates are used, the cost of compost could exceed incentive payment.
  • Application plan must consider and avoid the accumulation of excess soil salts, P, and Potassium (K).

Options

See NRCS Nutrient Management (590) guide and/or NRCS Soil Carbon Amendment (Codes 336 or 808).

IAMP Preferences/Considerations

The IAMP project incentivizes practices that result in a net reduction in GHG and increase in soil carbon. Practices that optimize phosphorus or other nutrients that do not have any clear direct impact on GHG, and soil carbon would be better supported by other programs (e.g. EQIP and CSP). Manure and compost additions to cropping systems should focus on the four R’s (Right Source, Right Rate, Right Timing of Application and Right Place). Developing a nutrient management plan for a field and implementing these plans, can require yield maps, remotely sensed imagery including near-infrared technology (NDVI/NDRE), soil testing. The IAMP project will provide some level of technical support and training to assist in developing these nutrient management plans, however we encourage producers to work with crop consultants or NRCS planners with experience developing these plans to assist in the development of these plans appropriate for the particular field identified for this program.

Specific Details

IAMP has several requirements for this compost/manure replacement nutrient management practice to ensure fertilizer application rates are not excessive as well as document the effectiveness of the practice from the current nutrient management strategies employed in the field. The cost of analysis of any required soil, crop, or manure/biomass sampling and analysis will be covered by the IAMP project. For an overview of all required sampling for each IAMP practice, see IAMP_required_sampling. Implementing partners will be assisting with the collection of any sampling related to the practice. Each of these requirements is described below.

  1. Baseline strip: Producers will maintain a minimum strip of 80 ft in length and a minimum width of 20 ft where the full baseline synthetic fertilizer rate will be applied as a comparison to the rest of the field. The actual dimensions of the strip can vary to be compatible with the width of implements used to manage the field.
  2. Soil Carbon sampling: Paired soil sampling points in the baseline strip and in the treated field at the start of the project and at the end of the project is required to track the changes in soil carbon over the duration of the project, see the IAMP Soil Sampling Protocol.
  3. Soil Nutrient sampling: Paired soil sampling points in the baseline strip and in the treated field prior to planting and after harvest every ft down to 3 ft is required (down to 5 ft is preferred) to set fertilizer rates, assess the impacts of the practice on available soil nitrogen, and identify any nutrient deficiencies/benefits from the implemented practice, see the IAMP Soil Sampling Protocol.
  4. Crop Biomass sampling: Paired above ground crop biomass measurements at the paired soil sampling locations will be required prior to harvest and will be evaluated for total dry biomass weight as well as the percent carbon and nitrogen, see the IAMP Crop Biomass Sampling Protocol.
  5. Compost/Manure sampling: Compost or manure samples will be sent in for analysis prior to application each year, see IAMP required sampling for information on where to send the sample.
  6. Nutrient Management Plan: Using the following NRCS spreadsheet 590_ID_GD_Nutrient_Management-Spreadsheet.xlsx to demonstrate both the baseline and proposed fertilizer management strategy. The proposed nutrient management application rates must not exceed University of Idaho fertility guides. The initial agreement will be approved based on grower provided historic fertilizer rates, actual or estimated pre-plant soil nitrogen. Each year following implementation of the practice planners will ensure nitrogen reduction was at least 15% based on actual soil tests taken as a part of the IAMP practice and that the actual fertilizer rates did not exceed University Idaho fertility guides.
  7. Water Quality Risk Assessment: Use the INTRA (Idaho Nutrient Transport Risk Assessment) tool INTRA_041514.xlsm to ensure the proposed practice does not pose a risk to water quality. Any recommendations by the INTRA analysis need to be addressed to meet NRCS compliance and must be included in the plan.
  8. Grower supplied field management information:
    • Any specific crop (e.g. potatoes) used to set in-season fertilizer applications such as tissue, petiole, or sap testing.
    • Variable rate prescription and as-applied fertilizer rate maps, if applicable.
    • Statements or other documentation of fertilizer rate, application dates and materials applied.
    • Crop yield maps (if available for both the baseline strip and the remaining field).
    • Fertilizer and pesticide application information (type, timing, rates, methods of application). As applied fertilizer maps are ideal. Include information on any biological amendment or nitrification inhibitor or slow N release products.

Criteria/Verification

  • Confirmation that State requirements and regulations have been followed when applying nutrients near areas prone to contamination, such as designated water quality sensitive areas, (e.g., lakes, ponds, rivers and streams, sinkholes, wellheads, classic gullies, ditches, or surface inlets) that run unmitigated to surface or groundwater.
  • Soil testing for nutrient management confirmations:
    • Provide geo-referenced pre-plant and post-harvest soil sampling results for the baseline strip and the remaining land parcel that will receive the reduced rates.
    • Statements or other documentation (e.g. as-applied maps, receipts) that demonstrate fertilizer rates and materials applied where within the recommendations described in the nutrient management plan for the field (e.g. at least 15% replacement of synthetic fertilizer application rates with manure or compost).
    • If applicable, provide in-season tissue, petiole, or sap testing results that were used to adjust in-season applications of nutrients.
  • Manure testing and application rate confirmations:
    • Provide manure testing lab results with carbon and nutrient analysis.
    • Manure/compost application rates, date of application, methodology, and manure testing results.
  • Water quality risk assessment using INTRA (Idaho Nutrient Transport Risk Assessment) tool (INTRA_041514.xlsm) completed and recommendations addressed to meet NRCS compliance.
  • Crop yield maps (if available) and geo-referenced biomass samples at geo-referenced soil sampling locations (work with implementing partners/UI on scheduling the collection of these samples).

Incentive Payments

$60/acre for compost or manure, in each case to replace 15% of inorganic N applications from baseline rates. An additional $1 per acre for every additional 1% replacement of inorganic N applications beyond 15% up to a maximum of 50% (i.e. maximum payment of $95 per acre at a 50% replacement). Incentives will also be added to include funding to cover the additional soil and manure lab analysis costs.

Stacking or Companion Practices

Manure and compost fertilizing is compatible with other incentive IAMP practices: Cover crops, Conservation crop rotation (>2 crops), Intercropping, No tillage from conventional, Reduced tillage from conventional, Prescribed grazing, Soil carbon amendment (Biochar). A caveat for stacking with the no-tillage practice is that only compost should be used (N losses from unincorporated manure would be high), and only at lower rates and in areas not prone to runoff. Stacking as part of a reduced total N application is encouraged.

Sources