Author: mmh262

Manure Can Offset Nitrogen Fertilizer Needs and Increase Corn Silage Yield – Value of Manure Project 2023 Update

Juan Carlos Ramos Tanchez1, Kirsten Workman1,2, Allen Wilder3, Janice Degni4, Paul Cerosaletti4, Dale Dewing4, and Quirine M. Ketterings1

Cornell University Nutrient Management Spear Program1, PRO-DAIRY2, Miner Agricultural Research Institute3, and Cornell Cooperative Extension4

Introduction

              Manure contains all seventeen nutrients a plant needs, making it a tremendously valuable nutrient source for crop production. Applying manure to fields can also build soil organic matter, enhance nutrient cycling, reduce reliance on commercial fertilizer, and improve overall soil health and climate resilience. The Value of Manure Project of the New York On-Farm Research Partnership is funded by the New York Farm Viability Institute (NYFVI) and the Northern New York Agricultural Development Program (NNYADP). This statewide project evaluates nitrogen (N) and yield benefits of various manure sources and application methods to corn silage and corn grain crops. Eight trials were conducted in 2023, adding to three trials established in 2022. Here we summarize the findings of the trials conducted in 2023.

What we did in 2023

              Trials were implemented within commercially farmed corn fields in western (2 trials), northern (2 trials), central (3 trials), and southeastern (1 trial) New York. Each trial had three strips that received manure and three that did not, for a total of six strips per trial (Figure 1a). One trial (Trial B) received manure in spring of 2022. For this trial we tested carryover benefits into the 2nd year (2023). For all other trials, manure was applied in spring 2023 before planting corn. Manure source and application method varied across sites (Table 1).

Images of the manure plots for the study. Entire study area 1,200 ft by 120 ft, each study plot 200 ft by 120 ft.
Figure 1. Layout of a 2023 Value of Manure study plot. Three strips received manure before planting corn (1a). At the V4-V6 stage each of the six strips received six different inorganic N sidedress rates (1b).

              Strips were 1200-1800 ft long and 35-120 ft wide for all but one site, where strips were 300 ft long 35 ft wide. When corn was at the V4-V6 stage, each strip was divided into six sub-strips (Figure 1b) and subplots were sidedressed at a rate ranging from 0 up to 300 pounds N/acre. Sidedress rates were trial-specific, based on the expected N requirement of each field. For each trial, we measured manure nutrient composition, general soil fertility, Pre-Sidedress Nitrate Test (PSNT), Corn Stalk Nitrate Test (CSNT), yield, and forage quality.

Table describing the soil type, manure type, and manure application rate of the different trials in spring of 2023.
*Note: manure was applied in spring of 2022 in farm B, and we tested its carryover value for 2023.

              Soil test phosphorus (P) of the trials was classified as optimum (between 9 and 19 pounds P/acre), high, or very high (Table 2). Soil potassium (K) was optimum or very high for six of the trials while trials A and G tested medium in K. Magnesium soil test values were high (> 101 pounds Mg/acre) or very high. Soil test zinc (Zn) was medium for trials A and G (between 0.5 and 1.0 pounds Zn/acre) and high for all other trials. Manganese and iron were in the normal category (< 49 pounds Fe/acre, < 99 pounds Mn/acre).

Table describing the results of the Cornell Morgan test.
SOM = soil organic matter, P = phosphorus, K = potassium, Ca = calcium, Mg = magnesium, Zn = zinc, Mn = manganese, Fe = iron, Al = aluminum.

What we have found so far

              Similar to what we found in 2022, trials differed in their responses to manure and inorganic N (Figure 2). Trials D and E did not respond to manure or N sidedress application likely due to past N credits providing enough N to the crop. In trials A, B, C, G, and H, yield increased due to both manure and sidedress N application. Yields increased in manured plots beyond what could be obtained with fertilizer N by 0.3 to 4.6 tons/acre, and 5 to 21 bushels/acre (Table 3). In trials A and G, the ones with medium K and Zn classification, manure applications increased yield to such elevated levels (4.6 tons/acre for trial A and 21 bushels/acre for trial G), that it also increased the crop’s need for fertilizer N (in other words, the required sidedress N rate also increased). In both trials, manure application shifted soil K levels from medium to optimum and increased K content in silage, suggesting K was yield limiting at these locations.

Figure describing the MERN of different trials.
Figure 2. Most Economic Rate of Nitrogen (MERN) in eight trials. Orange text boxes are the MERN and yield at MERN for manured plots; gray text boxes are MERN and yield at the MERN for no manure plots. Corn silage yields are in tons/acre at 35% dry matter (DM), and corn grain yields are in bushels/acre at 84.5% DM.

Table describing the MERN for manure and no-manure plots.

              The PSNT levels of the manured plots were higher than their no-manure counterparts for all trials where liquid or digested manure was applied, showing that manure supplied crop available N to the soil (Table 4). In contrast, for farm A the PSNT-N was 15 ppm where compost had been applied versus 20 ppm without compost application, likely due to the high carbon content compared to N content of the compost used in that site. (Table 4). The impact of manure applications was also reflected in CSNT levels (Table 4). For trials D and E, CSNT levels of the plots that did not receive manure or sidedress fertilizer N were optimal or excessive, consistent with the lack of a yield response to N for those two sites. Similarly, for site F, the marginal classification suggested that limited (very little) to no N was needed, consistent with the lack of a manure-induced yield response and minimal fertilizer N response at that site. For the five trials where a crop response to N was determined (trials A, B, C, G, H), the CSNT’s of the zero N plots were low, accurately reflecting the need for additional N. For four trials, the CSNTs where manure but no N fertilizer was applied, were low (trials A, B, and G) or marginal (trial H), consistent with the response to sidedress N in the manured strips. For trials C, D, and E, the CSNTs were excessive in the manure strips without N fertilizer addition, consistent with the lack of a response to sidedress N (MERN = 0 pounds N/acre, Table 3). For trial F, the CSNT of the manured plots without sidedress N application was optimal. This trial showed a small response in yield to the addition of just over 30 pounds N/acre (Table 3).

Table describing the results of the Pre-Sidedress Nitrate Test.
*Note: Farm A applied compost that impacted PSNTs and had a very wet growing season (15 inches of rainfall higher than the 10-year average).

Conclusions and Implications (and Invitation)

              In 2023 we documented “yield bumps” resulting from manure application beyond what could be obtained with fertilizer only in five of the eight trial, consistent with observations for two of the three trials in 2022. For the sites with optimal or high fertility status, this yield increase shows that manure is not just supplying nutrients, but also benefits yield beyond nutrient contributions. The PSNT and CSNT results consistently reflected where N was needed and allowed for documentation of the N contributions of the various manure sources.
              The Value of Manure Project will continue in 2024. We will be testing additional manure types and manure application methods in various soil types and weather conditions. Join us in the Value of Manure Project in 2024 and obtain valuable insights about the use of manure in your farm! If you are interested in joining the project, contact Juan Carlos Ramos at jr2343@cornell.edu.

Additional resources

            The NMSP Value of Manure Project website and on-farm field trial protocols are accessible at: http://nmsp.cals.cornell.edu/NYOnFarmResearchPartnership/Value_of_Manure.html (project website),  http://nmsp.cals.cornell.edu/NYOnFarmResearchPartnership/Protocols/NMSP_Value_of_Manure_Protocol2024.pdf (protocol). Value of Manure phone app: https://valueofmanure-nmsp.glideapp.io/. For the 2022 project results: https://blogs.cornell.edu/whatscroppingup/2023/02/15/manure-can-offset-nitrogen-fertilizer-needs-and-increase-corn-silage-yield-value-of-manure-project-2022-update/.

Acknowledgments

              We thank the farms participating in the project for their help in establishing and maintaining each trial location, and for providing valuable feedback on the findings. For questions about this project, contact Quirine M. Ketterings at 607-255-3061 or qmk2@cornell.edu, and/or visit the Cornell Nutrient Management Spear Program website at: http://nmsp.cals.cornell.edu/.

Common Misconceptions about Concentrated Animal Feeding Operation (CAFO) Regulations and Comprehensive Nutrient Management Planning in New York State

Carly Bass1,7, Kirsten Workman2,3,7, Greg Albrecht4, Ron Bush4, Brendan Jordan4, Dale Gates5, Josh Hornesky5, Sara Latessa6, Kristan Reed7, Quirine M. Ketterings3,7

1Masters of Professional Studies in Animal Science, 2PRO-DAIRY, 3Nutrient Management Spear Program (NMSP), 4New York State Department of Agriculture and Markets (NYSAGM), 5United States Department of Agriculture Natural Resources Conservation Service (USDA-NRCS), 6New York State Department of Environmental Conservation (NYSDEC), and 7Department of Animal Science, Cornell University

Introduction

Farms that have more than 300 mature dairy cows (or an equivalent in other livestock animals) are required to operate under the New York State Pollutant Discharge Elimination System (SPDES) General Permit for Concentrated Animal Feeding Operations (CAFOs). The permit dictates that the farms follow environmental conservation practices and meet state standards designed to maintain the highest quality of water possible by mitigating the risk of pollution to New York waters. As only a small portion of our population is involved in agricultural production, it is not always understood what farms in New York State are required to do to stay in compliance. This article highlights and addresses some of the most common misconceptions surrounding New York CAFO farms and the CAFO permit.

Misconception 1:

“New York’s permit is less strict than the federal permit” 

New York works closely with federal agencies such as NRCS and the EPA to ensure their standards and permit satisfy or exceeds the federal requirements. New York takes the minimum guidelines set forth in the federal Clean Water Act (CWA) CAFO Rule and makes additional requirements for farms to follow within their Comprehensive Nutrient Management Plan (CNMP) to meet water quality and sustainability goals of the state. The following are examples where the New York CAFO permit is more environmentally protective, and thereby restrictive, than the federal CAFO rule.

  • New York CAFOs must maintain no discharge from their production areas (farmsteads) through a 100-year, 24-hour storm compared to the federal no discharge standard which is for a 25-year, 24-hour storm.
  • New York CAFOs must utilize an AEM Certified Planner, whereas no professional certification is required by the CWA CAFO Rule.
  • New York CAFO permitted farms must follow an integrated system of NRCS Conservation Practice Standards for management of nutrients throughout their farmsteads and fields; such engineering and management standards are not required by the CWA CAFO Rule.
  • Farms must sample soil for nutrient values every three years versus every five years.
  • Farmer fields need to be planned and managed to conserve soil and reduce erosion, whereas this is not a CWA CAFO Rule.
  • New York CAFO’s must develop and maintain facility specific winter and wet weather application procedures and identify low-risk fields to be used for winter application in the case of an emergency.
  • New structural practices need to be designed considering future flood risk due to climate change.
  • Farm staff must be present and monitor active waste transfers from the production area (farmstead) while material is being transferred.
  • The NRCS-NY 590 Nutrient Management Standard and associated Land Grant University Guidelines require New York CAFOs to account for nitrogen already present on the farm (soil, manure, crop rotation credits, etc.) when developing spreading recommendations.

Misconception 2:

“Manure storages are not safe and impact drinking water”

Manure storages located and operated on New York CAFOs are required to be designed and constructed by a trained, State of New York licensed professional engineer to meet national standards (Natural Resources Conservation Practice Standard – NY 313). The NRCS-NY 313 Standard requires that manure storages are designed, built, and operated to fully contain manure nutrients and any direct precipitation for future application to crops as fertilizer while remaining isolated and protected from ground- and surface waters. These standards require geological investigations, prior to the design, to properly site these structures and ensure an appropriate liner is selected to minimize any risk of leaking. To date, there has been no evidence of a certified manure storage contributing to an impact to groundwater in New York. In addition to the groundwater protections outlined in the standards, there are measures to ensure and protect against these structures overtopping. The standards themselves require maximum fill markers to help ensure that safety volume requirements are maintained. The New York CAFO permit also requires the final as-built plans, certified by a professional engineer, be maintained on site; fill levels be monitored and recorded; and operation and maintenance measures outlined by the professional engineer be followed. Finally, no farm in New York is allowed to impact the water resources of the state, no matter the size of the farm. Any impact to Waters of the State is considered a significant violation of the Environmental Conservation Law and is subject to substantial penalties and/or fines.

Misconception 3:

“Farmers can spread manure under any weather conditions”

All CAFO farmers are required to have a current Comprehensive Nutrient Management Plan (CNMP) developed by an AEM Certified Planner in accordance with the permit, NRCS standards, and guidelines. The CNMP must be updated annually and prescribes how much manure and fertilizer can be spread on each field, as well as the anticipated application method and timing. In addition to their individualized plans, the New York CAFO permit sets maximum single-application spreading rates. New York’s CAFO permit also contains specific requirements pertaining to winter and wet weather spreading, including a prohibition against spreading if the field is saturated or frozen-saturated.

New York does not have a calendar-based ban on winter spreading because calendar-based regulations do not take current weather and specific field conditions into account. Drivers of nutrient losses are based on specific field, soil, and weather conditions/forecasts. New York’s CAFOs must assess field conditions every time they spread and follow the specific guidance outlined in the “Revised winter and wet weather manure spreading guidelines to reduce water contamination risk”.

Misconception 4:

“New York regulations allow phosphorus to be applied to fields even when the crop does not need it”

Manure contains all 17 essential nutrients for plant growth and is a key to building soil health by providing organic matter and enhancing the soil ecosystem. Properly managed, use of manure can offset the need for purchased fertilizer, reducing the amount of imported nutrients onto farms and into a watershed. However, nutrients in manure aren’t necessarily present in the balance required by a specific crop grown on a specific field. Within a farm’s CNMP, the New York P-Index governs how much phosphorus can be applied to fields each year to ensure proper recycling of on-farm nutrients through crops and long-term, sustainable soil test levels for the benefit of water quality. In accordance with the New York P-Index, a farmer and AEM Certified Planner must assess the risk of phosphorus leaving the field. This needs to be done for all fields on the farm. Those assessments will determine how and how much manure may be applied and must be documented in the farms’ CNMP. Farmers implement beneficial management practices to further reduce P runoff risk to lower the New York P-Index rating for fields. Making the most of manure nutrients is critical for water quality, air quality, and crop production, and to reduce N and P imports into watersheds. Most soils in New York are currently deficient in phosphorus so proper phosphorus management is needed to maintain productive and healthy soils for food production.

Misconception 5:

“Farmers pay AEM Certified Planners, therefore plans are biased”

New York has strict rules for who can develop and update CNMPs. A farm’s CNMP needs to be written by a state-certified planner who has gone through extensive training, is required to keep certifications current through training sessions, and has signed a code of ethics. Such a certification is akin to other state certified professionals used across sectors, such as professional engineers, architects, accountants, etc. To become an AEM planner, an individual must first become a Certified Crop Adviser (CCA), which involves passing two exams (an international and a regional exam) and meeting further educational and experience requirements to demonstrate their knowledge in agronomy and environmental conservation in agriculture. The next step is satisfying participation in the state led CNMP Training. After completing these two steps, the individual’s first three CNMPs must be submitted to CNMP specialists at the New York State Department of Agriculture and Markets (NYSAGM) for review, revision, and acceptance. Once the three plans satisfy the CNMP requirements, the individual becomes an AEM Certified Planner. Certified planners must sustain their CCA status, maintain compliant work through ongoing quality assessments by NYSAGM staff, and satisfy 40 credit hours of continuing education every two years to maintain their certification. In addition to this rigorous certification and assessment process, the NYSDEC reviews CNMPs during regular CAFO inspections and pursues enforcement if deficiencies are identified.

Misconception 6:

“Only large dairy farms are regulated”

New York State laws and regulations require all animal feeding operations (AFOs) that meet certain animal thresholds, to obtain coverage under a State Pollutant Discharge Elimination System (SPDES) permit prior to operation. However, per Environmental Conservation Law Article 17, Title 5, Section 17-0501, no farm, regardless of size or permit coverage, is allowed to contribute to a water quality violation and impact New York’s water resources. New York also funds several programs that are available to all farms, including smaller AFOs. The AEM program, Dairy Advancement Program (DAP), and NRCS’s program help farms with conservation plan development (including CNMPs) and implementation of best management practices. To date, 13,500 practices on over 2,500 farms have been implemented through the AEM programs, the DAP has helped more than 300 non-CAFO farms develop CNMPs, and those NYS program accomplishments can be doubled when considering projects completed through USDA NRCS and the Farm Service Agency. These programs augment the substantial investment by farmers and ensure that farms of all types and scales have the resources to implement nutrient management practices on their farms to aid with environmental management. Roughly 1,000,000 acres of cropland are impacted annually in New York by nutrient management guidelines due to the various programs in place.

Additional Resources 

Acknowledgements

The information shared in this article comes from a larger extension document that outlines regulations and comprehensive nutrient management planning in New York State (see additional resources above). We thank the members of the Nutrient Management Spear Program advisory committees for their feedback on the larger document. For questions, contact Quirine M. Ketterings (qmk2@cornell.edu) or Kirsten Workman (kw566@cornell.edu).

 

Icons for the Nutrient Management Spear Program, Cornell University, Cornell CALS, and PRO-DAIRY