Category: Nutrient Management

Characterization of phosphorus balances in corn silage fields from eight New York dairies

Agustin J. Olivo1, Laura Klaiber2, Kirsten Workman1,3, Quirine M. Ketterings1

1 Department of Animal Science, Cornell University, Ithaca, NY, United States; 3William H Miner Agricultural Research Institute, Chazy, NY, United States; 3PRO-DAIRY, Department of Animal Science, Cornell University, Ithaca, NY, United States

Introduction

              Optimizing phosphorus (P) application in corn silage production systems to align with crop P requirements while sustaining soil test P (STP) levels can help mitigate environmental risks and enhance farm profitability. Nutrient balances (supply minus uptake) can be an effective strategy to monitor P management in fields (Fig. 1). Sustained negative P balances (uptake > supply) can lead to a reduction in STP and negative impacts on crop productivity over time. Conversely, regular nutrient applications beyond crop removal can lead to increases in STP, which may be desirable in the short term to raise low STP, but undesirable if continued once soils reach optimum levels.

A graph with two bars.
Fig. 1. Phosphorus (P) pools considered for P supply and P uptake when calculating field-level P balances.

              Data on P balances from 994 corn silage field observations across eight New York dairies were analyzed to characterize this metric and identify drivers that may point towards opportunities for improved management. Data on manure management practices that affect field P dynamics and nitrogen (N) availability for the crop were also evaluated, as well as the relationship between P balances and STP for four of the farms.

Key findings

Phosphorus balances were low, but with a wide range across farms and fields

              On average, P balances across all fields were low (median of 7 lbs/acre), partially reflecting reductions in P surpluses on NY dairy farms over the last two decades as farm nutrient management has improved. However, there was a wide range across farm averages (-10 to 27 lbs/acre) and individual fields (-48 to 122 lbs/acre) (Fig. 2).

Two bar graphs.
Fig. 2. Relative frequency distribution for phosphorus (P) balances per acre (A), and area-weighted average P balance per acre (B) for Farms 1-8 across all years analyzed in the study.

Manure P supply was the main driver of balances

              Phosphorus supply was a more relevant driver of balances than P removed with harvest. Manure was the main source of P for all farms (Fig. 3), and farm to farm differences explained the largest portion of the variability in P supply. Higher P supply across farms was associated with higher manure application rates (driven partially by farm animal density) and higher manure P content connected to higher P rations.

A bar graph.
Fig. 3. Area-weighted average P supply from fertilizer and manure in Farms 1-8 across all years analyzed in the present study.


Phosphorus was applied at higher rates to fields with adequate STP than to lower STP fields

A b
Fig. 4. Phosphorus (P) supply (A) and P balances per acre (B) for individual observations in the dataset across agronomic soil test P categories in Farms 1, 3, 4 and 5 for all years analyzed in the study. Numbers in the top row represent means for each category. Values with different letters are statistically different.

              Morgan-extracted STP levels varied across farms and fields, with averages of 9, 13, 22 and 22 lbs P/acre for Farms 1, 3, 4 and 5, respectively (the only ones analyzed in the study for Morgan-extracted STP). These values corresponded to sub-optimal (<9 lbs P/acre), optimal (9-19 lbs P/acre), and high (20-39 lbs P/acre) agronomic P levels, according to land-grant university guidelines. Across the entire database, P was applied at higher rates to fields with adequate STP levels, indicating potential opportunities to re-allocate P within farms (Fig. 4).

P-based manure applications could cover a large fraction of crop N requirements

              Under management practices currently implemented by the farms assessed in the study, application of manure at N-based rates to corn would lead to large P balances for all farms, if utilized, due to a mismatch between manure available N to P ratio and corn N to P ratio needs. Similarly, P-based applications would cover only 51% of corn N requirements, on average. Increasing the rate of spring manure injection/incorporation or in-season injection on these farms could cover an average of 66 to 85% of corn N requirements, respectively, illustrating the greater N value of manure when more is incorporated/injected.

Conclusions

Results across the dataset showed low P balances on average, reflecting continued efforts from farms to efficiently manage manure nutrients and limit use of fertilizer P. Farms with large P balances may improve their performance by optimizing diet formulation to lower P excretion, reducing animal density, and/or exporting manure to move excess P off-farm. The data also showed potential opportunities to better allocate P within farms, re-allocating P from high or very high testing fields to P deficient fields. Combining appropriate rates of manure and N fertilizer or implementing manure treatment technologies that conserve N during storage and/or remove P, could help reduce P overapplication with N-based manure use. Similarly, spring or in-season manure incorporation or injection at P-based rates could recover a larger fraction of manure N, enough to cover almost all corn N requirements in some cases.

Full citation

This article is summarized from our peer-reviewed publication: Olivo A.J., L. Klaiber, K. Workman, and Q.M. Ketterings (2024). Characterization of phosphorus balances in corn silage fields from eight New York dairies. Agronomy Journal. https://doi.org/10.1002/agj2.21710.

Acknowledgements

We thank farmers and their certified crop advisors who shared farm data. This research was funded by a USDA-NIFA grant, funding from the Northern New York Agricultural Development Program (NNYADP), and contributions from the New York Corn Growers Association (NYCGA) managed by the New York Farm Viability Institute (NYFVI), and the Department of Animal Science, Cornell University. For questions about these results, contact Quirine M. Ketterings at qmk2@cornell.edu, and/or visit the Cornell Nutrient Management Spear Program website at: http://nmsp.cals.cornell.edu/.

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New York state, regional and county level nitrogen and phosphorus balances for harvested cropland

Olivia Godber1, Kirsten Workman1,2, Kristan Reed3, and Quirine Ketterings1

1Nutrient Management Spear Program, 2PRODAIRY, 3Department of Animal Science, Cornell University, Ithaca, NY 14853

Introduction

              New York (NY) state is one of five states that collectively produce more than 50% of the annual milk supply within the United States. The local environment allows farmers to integrate crop and livestock systems, facilitating cycling of manure nutrients back to cropland. Thus, dairy farming provides NY with benefits, opportunities, and challenges in terms of environmental sustainability and climate resiliency. Improved balancing of crop needs for nitrogen (N) and phosphorus (P) with supply from manure is key for a circular agricultural economy. The objectives of this study were to calculate and evaluate (1) regional and county level N and P balances of harvested cropland; and (2) the contribution of manure to a circular agricultural economy for NY. 

              Nutrient balances were calculated for 2017 (most recent USDA Census of Agriculture year at the time) as the difference in nutrient inputs through purchased fertilizer and recoverable manure, and nutrients removed in harvested crops. Atmospheric N deposition, legume N fixation, and manure nutrient losses during collection, transfer, storage, and treatment were also estimated.

Key Findings!

              The 2017 NY State P balance was 9 lbs P/acre. The N balance was between 35 and 85 lbs N/acre, depending on the proportion of legume cropland assumed to have received manure (Figure 1). 

2 bar graphs with a key.
Figure 1: Breakdown of the inputs and crop removal of (A) phosphorus (P), and (B) nitrogen (N) at the New York state level in 2017. Estimated N losses of manure N during storage through volatilization and denitrification are identified.

              For P balances at the regional level, a small range of 5 to 10 lbs P/acre was seen (Figure 2). Chemung County was the only county with a negative balance (-3 lbs P/acre).

Image of New York State sectioned off by region. Each region has a corresponding small bar graph indicating phosphorus input and crop phosphorus uptake. A few counties in gray are excluded.
Figure 2: Breakdown of phosphorus (P) inputs and crop P uptake at the regional level, and P balance at county and regional level for New York in 2017; counties in gray were excluded.

              For N balances at the regional level, a small range of N balances from 17 to 41 lbs N/acre was seen (Figure 3A) when balances were calculated assuming that manure and purchased fertilizer N were applied to all cropland, and no N fixation occurred. Under the assumption that no manure or purchased N fertilizer was applied to legume cropland, and additional N inputs were included as a result of N fixation on legume cropland, a higher but still small range in N balances from 60 to 94 lbs N/acre was seen (Figure 3B). Under both assumptions the balances were calculated before storage and application losses of N.

              Redistribution and application of manure to meet P-removal on only the non-legume cropland left a surplus of 3 lbs P/acre at the NY state level. Applying surplus manure to legume and non-legume cropland resulted in a slight, state-level, P deficit. In both scenarios, the large N deficit that cannot be met through legume N fixation alone indicates N fertilizer is required to meet crop needs under the reported yield and manure supply conditions. These results show NY’s ability to capitalize on the value of manure.

Two maps of the state of New York, sectioned off by region, with excluded counties colored in gray. Each map has small bar graphs corresponding with each region indicating the nitrogen input and crop uptake of nitrogen of the region. The map on top includes manure and purchased nitrogen being applied to all cropland, whereas the one on the bottom refers to non-legume cropland only. The maps are each purple.
Figure 3: Breakdown of nitrogen (N) inputs and crop N uptake at the regional level, and N balance at county and regional level for New York in 2017, assuming manure and purchased N was applied to (A) all cropland (assumes no legume N fixation) versus (B) non-legume cropland only (assumes legumes received N through fixation). Counties in gray were excluded.

              Manure has value to cropland beyond N and P and consideration of these factors at the field level, in combination with field management history and soil test results, could help to prioritize where manure should be applied, and where purchased N and P inputs are required. Development and adoption of advanced manure treatment, storage, and application practices, with consideration of how livestock feeding practices can influence manure characteristics, could all help to further improve the value of manure, improve balances, and increase circularity and sustainability of the agricultural sector in NY.

Next Steps?

              As updated manure excretion rates and the amount of nutrients lost during storage and application of manure become available, combined with an expected continuation in the upward trend of both cow numbers and milk production for NY, it will be important to continue assessments of nutrient balances and animal densities, and explore manure treatment options to allow for transport of manure nutrient throughout NY to avoid creating nutrient “hotspots” within the state. With the recent release of the 2022 USDA Census of Agriculture data, we aim to evaluate these scenarios in more detail for the 2022 state balances.

Full Citation

              This article is summarized from our peer-reviewed publication: Godber O.F., Workman K., Reed K., and Ketterings Q.M. (2024) New York state, regional and county level nitrogen and phosphorus balances for harvested cropland. Frontiers in Sustainability 5:1352296. https://www.frontiersin.org/journals/sustainability/articles/10.3389/frsus.2024.1352296/full.

Acknowledgements

              This research is funded primarily by a gift from Chobani, in addition to Federal Formula Funds and grants from the New York State Department of Agriculture and Markets (NYSAGM) and New York State Department of Environmental Conservation (NYDEC). For questions about these results, contact Quirine M. Ketterings at qmk2@cornell.edu, and/or visit the Cornell Nutrient Management Spear Program website at: http://nmsp.cals.cornell.edu/.

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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/.

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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

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Tillage Intensity Classification for Greenhouse Gas (GHG) Emission Estimations

Corrine Brown1, Olivia Godber1, Kirsten Workman1,2, Kitty O’Neil3, Josh Hornesky4, Quirine Ketterings1

1Nutrient Management Spear Program, 2PRODAIRY, Cornell University, Ithaca, NY 14853, 3Cornell Cooperative Extension North Country Regional Ag Team, 4USDA-Natural Resources Conservation Service, NY

Introduction

Tillage practices can impact soil greenhouse gas (GHG) emissions, soil carbon (C) sequestration and overall soil health. Tools are available to estimate whole farm GHG inventories (N2O, CO2, and CH4 emissions), field-based emissions, and C sequestration or loss. These tools often require a user to classify tillage intensity. The Natural Resources Conservation Service (NRCS) GHG accounting system uses the Revised Universal Soil Loss Equation (RUSLE2) to calculate a Soil Tillage Intensity Rating (STIR) that can be used to classify the intensity of various tillage practices. This tool also classifies tillage intensity based on percent residue surface cover and soil disturbed. This article explains what a STIR factor is, describes how to determine percent surface residue cover, and categorize different tillage practices into tillage intensity classifications.

Soil Tillage Intensity Rating (STIR)

The STIR value of a field can range from 0-200 with high values for intense tillage (Table 1). The STIR is based on four components: tillage type, depth of operation, operational speed, and percent of soil surface area disturbed.

    • Tillage type: This describes how a tillage pass mixes soil and crop residue. Tillage disturbance operations can include inversion and some mixing of soil, mixing and some (limited) inversion, lifting and fracturing, mixing only, and soil compression.
    • Depth of operation: The depth to which soil disturbance and residue incorporation occur.
    • Operational speed of tillage: This is the recommended operating speed of each tillage operation. The forward speed of a tillage implement impacts soil disturbance and mixing; faster speeds result in more significant forces and broader disturbance.
    • Percent of soil surface area disturbed: The percentage of surface soil disturbed by the tillage pass.

Estimating Percent Residue Cover

Percent residue cover remaining on the surface following a tillage operation can be determined using the RUSLE2 equation or measured in the field using the line transect method. The line transect uses a line measuring tool (a rope or tape measure) that has 100 equally distributed and easily viewed marks (Figure 1). Typically, the measuring tool is 100 feet long with markings at 1-foot intervals or 50 feet long with marking at 6-inch intervals. To determine the percent residue surface cover of a field, stretch the tool diagonally across crop rows in a direction that is at least 45 degrees off the row direction and count the number of markings that have crop residue directly present beneath. Residue smaller than 1/8 inch in diameter should not be counted. The total count (markings with residue beneath them) is the percent residue cover for the field. This process should be repeated at least three times in different areas of the field and percentages should be averaged.

Agricultural field with residue and tape measure
Fig. 1: A simple measuring tape can be used to easily determine percent residue surface cover of a field (Picture credit:
https://www.sdsoilhealthcoalition.org/ soil-health-assessment-card/).

NRCS Tillage Intensity Classes

The NRCS tool groups tillage practices into six categories; intensive, reduced, mulch, ridge, strip, and no-till:

    • Intensive tillage is full width tillage that inverts soil with high disturbance. Common equipment includes a moldboard plow.
    • Reduced tillage occurs at full width without soil inversion, using a point chisel plow, field cultivator and/or tandem disk.
    • Mulch tillage a single pass across the field using tools such as a tandem disk followed by field or row cultivator or similar implement.
    • Ridge tillage creates soil ridges in the field that are rebuilt during cultivation by disturbing up to 1/3 of the row width. The soil is then undisturbed from harvest to planting.
    • Strip tillage leaves the soil between crop rows undisturbed (Figure 2). To create a seedbed, up to 1/3 of the row width is disturbed.
    • No-till operations plant crop seeds directly through residue of the previous crop using a no-till planter or drill.
Agricultural field with strip tillage
Figure 2: Strip tillage leaves the soil between crop rows undisturbed.

Full vs. Reduced vs. No-Till

Some GHG footprint assessment tools categorize tillage practices differently, using three main categories; full, reduced, and no-till:

    • Full tillage contributes to significant soil disturbance, fully inverting the soil (as is done with moldboard plowing) and/or performing tillage operations frequently in the same year using tools like chisel plows or row cultivators.
    • Reduced tillage also disturbs the soil but does not fully invert the soil. Examples include onetime use of chisel plows, field cultivators, tandem disks, row cultivators, or strip-tillers.
    • No-till practices directly drill crop seed through the residue layer with little to no disturbance to the soil. Minimal disturbance occurs in the area where seeds are planted. Common operations use a no-till planter.

In Summary

Tools available to assess whole-farm and field-based GHG inventories and C sequestration or loss require the user to classify tillage intensity. Choosing the tillage description that best fits the producers’ management practices is essential for accurately assessing GHG emissions.

Additional Resources

Acknowledgements

This article is available as part of the Cornell Nutrient Management Spear Program (NMSP) Factsheet Series: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet126.pdf. Corrine Brown was an undergraduate intern with NMSP, funded by a gift from Chobani. For questions, contact Quirine M. Ketterings (qmk2@cornell.edu) or visit the NMSP website at: http://nmsp.cals.cornell.edu/.

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Manure Can Offset Nitrogen Fertilizer Needs and Increase Corn Silage Yield Value of Manure Project 2022 Update

Juan Carlos Ramos Tanchez1, Kirsten Workman1,2, Allen Wilder3, Janice Degni4, and Quirine Ketterings1
Cornell University Nutrient Management Spear Program1, PRO-DAIRY2, Miner Agricultural Research Institute3, and Cornell Cooperative Extension4

Introduction

Manure is a tremendously valuable nutrient source. When used appropriately (right rate, right timing, right placement method), it can help build soil organic matter, enhance nutrient cycling, and improve soil health and climate resilience. Sound use of manure nutrients can decrease the need for synthetic fertilizer, thus, lowering whole farm nutrient mass balances and contributing to reduced environmental footprints.

Current guidance for nitrogen (N) credits from manure recognize that N availability depends on the solids content of the manure (lower first year credits for manure with >18% solids than for liquid manure). It also recognizes that the amount of N in manure is affected by how it is collected, stored, treated (solid liquid separated, composted, digested, etc.), and land-applied (timing and method). Higher shares of manure N will be available to crops when manure is applied closer to when crops need it and if manure is injected or incorporated into the soil right after it is applied versus left on the surface.

In the past two decades since manure crediting systems were developed, many different manure treatments technologies have been implemented on farms and re-evaluation of the N crediting system for manure is needed. Furthermore, recent studies have shown that manure can increase yield beyond what could be obtained with N fertilizer only. Thanks to funding from New York Farm Viability Institute (NYFVI) and the Northern New York Agricultural Development Program (NNYADP), we initiated the “Value of Manure” statewide project to evaluate the N and yield benefits of various manure sources and application methods. Three trials were conducted in 2022. Here we summarize the initial findings.

What we did in 2022

Trials were implemented on three farms. Each trial had three strips that received manure and three that did not, for a total of six strips (Figure 1a). Strips were 1200-1800 ft long and 50-80 ft wide. When corn was at the V4-V6 stage, each strip was divided into six sub strips (Figure 1b) and sidedressed at a rate ranging from 0 to up to 192 pounds N/acre, depending on the farm. All three farms applied liquid untreated manure, ranging from 7,525 to 15,000 gallons/acre in the spring.

color coded images showing how plots were laid out in research trial
Figure 1. Layout of a Value of Manure study plot. Three strips received manure before planting (1a). At the V4-V6 corn stage each of the six strips received six different inorganic N sidedress rates (1b).

Soils on farm A were Lima and Honeoye (Soil Management Group [SMG] 2), farm B had a Hogansburg soil (SMG 4), and farm C had Valois and Howard soils (SMG 3). The farms implemented and harvested the trial. The Cornell team sampled for general soil fertility, Pre-Sidedress Nitrate Test (PSNT), Corn Stalk Nitrate Test (CSNT), and silage quality. Each trial was harvested with a yield monitor.

What we have found so far

Corn silage had a different response to manure and inorganic N sidedress in each of the study farms (Figure 2). Farm A responded to both the application of manure and inorganic N fertilizer. In that farm manure application was able to offset 58 lbs N/acre and presented a 0.6 ton/acre yield advantage at the Most Economic Rate of N (MERN), the rate of N that maximizes economic returns, compared to plots with inorganic N fertilizer application only (Figure 3). The application of inorganic N fertilizer and manure had no impact on the yield of farm B, showing that the field already had enough N and did not need any N addition (fertilizer or manure). At farm C, yield did not respond to the application of inorganic N sidedress (the field by itself provided enough N to the crop), but yield was higher when manure was applied: on average manured plots yielded 1.5 ton/acre higher than the no-manure plots. The MERN for farms B and C was 0 lbs N/acre both with manure and without it.

The PSNT and CSNT levels of the manured plots were higher than their no-manure counterparts for all three studies, showing that manure supplied N (Table 1). Both manure and no manure plots in farm A had optimum CSNT levels at the MERN, showing that manure was able to offset 58 lbs N/acre.

Figure 2. Effect of manure application and different nitrogen sidedress rates on corn silage yields in three New York farms. Error bars are standard deviations.
Figure 3. Most economic rate of N (MERN) in farm A. Without manure, the MERN was 114 lbs N/acre with a yield at the MERN of 28.5 tons/acre. With manure, the MERN was 56 lbs N/acre, with a yield at the MERN of 29.1 tons/acre.

Conclusions and Implications (and Invitation)

The trials of 2022 show the range of possible responses, with one trial not showing a yield or N benefit of the manure, one trial showing a yield increase when manure was applied that was not due to N addition, and one showing both a yield and N fertilizer benefit from manure. This shows the importance of targeting manure application to fields with low past N credits, where it will be most likely to cause a yield respond. Additional trials are needed with various manure sources (raw manure, separated liquids, solids, digestate, etc.) before we can draw conclusions about the N and yield benefits of manure. Join us for the 2023 Value of Manure project and obtain valuable insights about the use of manure in your farm! If you are interested in joining the project, contact Juan Carlos Ramos Tanchez 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  (website) and  http://nmsp.cals.cornell.edu/NYOnFarmResearchPartnership/Protocols/NMSP_Value_of_Manure_Protocol2023.pdf (protocol).

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/.

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