Month: March 2025

Stalk Nitrate Test Results for New York Corn Fields from 2010 through 2024

Sanjay Gami¹, Juan Carlos Ramos Tanchez¹, Mike Reuter², and Quirine M. Ketterings¹

¹Cornell University Nutrient Management Spear Program (NMSP) and ²Dairy One

Introduction

            The corn stalk nitrate test (CSNT) is an end-of-season evaluation tool for N management for corn fields in the 2nd or more years after a sod. It allows for identification of situations where more N was available during the growing season than the crop needed (CSNT>2000 ppm). Results can vary from year to year but where CSNT values exceed 3000 ppm for two or more years, it is highly likely that N management changes can be made without impacting yield. 

Findings 2010-2024

            In 2024, 47% of all tested fields had CSNT-N greater than 2000 ppm, while 37% were over 3000 ppm and 28% exceeded 5000 ppm (Table 1). In contrast, 20% of the 2024 samples were low in CSNT-N. Two years of CSNT monitoring is recommended before making management changes unless CSNT’s exceed 5000 ppm, in which case one year of data is sufficient.
            Some of the variability in CSNT distribution over the years may be reflect differences in growing season (Figure 1). The percentage of samples testing excessive in CSNT-N across 2010-2024 was most correlated with the total precipitation in May-June with droughts in those months translating to a greater percentage of fields testing excessive. The year 2024 was classified as normal based on these criteria although some areas experienced drought conditions for parts of the season, possibly contributing to a higher percentage of stalks testing excessive in CSNT.

            Within-field spatial variability can be considerable in New York, requiring (1) high density sampling (equivalent of 1 stalk per acre at a minimum) for accurate assessment of whole fields, or (2) targeted sampling based on yield zones, elevations, or soil management units. The Adaptive Nitrogen Management for Field Crops in New York lists targeted within-field CSNT sampling as one of five end-of-season evaluation tools. Samples received in more recent years may also reflect more targeted field sampling. 

A bar graph.
Figure 1: In drought years more samples test excessive in CSNT-N while fewer test low or marginal. The last 15 years included six drought years (2012, 2016, 2018, and 2020 through 2023), three wet years (2011, 2013, and 2017), and five years labelled normal (2010, 2014, 2015, 2019, and 2024) determined by May-June rainfall (less than 7.5 inches in drought years, 10 or more inches in wet years). Weather data are state averages; local conditions may have varied from state averages.

            Because crop and manure management history, soil type and growing conditions all impact CSNT results, conclusions about future N management should consider the events of the growing season. This includes weed and disease pressure, lack of moisture in the root zone in drought years, lack of oxygen in the root zone in wet years, and any other stress factor that can impact crop growth and N status. 

Relevant References

•   Instructions for CSNT Sampling: http://nmsp.cals.cornell.edu/publications/StalkNtest2016.pdf.
•.  Agronomy Factsheets #31: Corn Stalk Nitrate Test (CSNT); #63: Fine-Tuning Nitrogen Management for Corn; and #72: Taking a Corn Stalk Nitrate Test Sample after Corn Silage Harvest. http://nmsp.cals.cornell.edu/guidelines/factsheets.html.
•.  Adaptive Nitrogen Management for Field Crops in New York (2025): http://nmsp.cals.cornell.edu/publications/extension/AdaptiveNitrogenManagement2025.pdf. 

Acknowledgments

We thank the farmers and farm consultants that sampled their fields for CSNT over the years.

For questions about these results 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/. 

Profitability of contrasting organic management systems from 2018-2021 in the Cornell Organic Cropping Systems Experiment

Kristen Loria1, Allan Pinto Padilla2, Jake Allen1, Christopher Pelzer1, Sandra Wayman1, Miguel I. Gómez2, Matthew Ryan1

1School of Integrative Plant Science, 2Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY 14853.

About the Cornell Organic Cropping Systems Experiment

The Cornell Organic Cropping Systems (OCS) experiment was established in 2005 at the Musgrave Research Farm in Aurora, New York to serve as a living laboratory for organic field crop management systems and provide practical insights to farmers. This ongoing long-term experiment compares four management systems along a dual spectrum of external inputs and soil disturbance over a multi-year crop rotation. An advisory board consisting of a dedicated group of organic farmers provides guidance on management decisions. The four systems are compared in terms of several sustainability indicators including yield, profitability, soil health and greenhouse gas emissions.

Both external input and soil disturbance gradients of the four treatment systems range from an extensive approach (low input) aimed at maximizing profitability by reducing costs via efficient resource use, to an intensive approach (high input), aimed at maximizing profitability by maximizing yield. Risk associated with low input management includes reduced crop production from inadequate soil fertility or weed competition, which can lead to decreased returns despite low input costs. Risk associated with high input management include diminishing returns where productivity increases are insufficient to justify additional cost.

The four management systems of OCS are: 1) High Fertility (HF), 2) Low Fertility (LF), 3) Enhanced Weed Management (EWM), and 4) Reduced Tillage (RT). In 2018, the crop rotation was modified from a three-year rotation to a  four-year rotation based on advisor input.: This article includes an economic analysis of the complete four-year crop rotation cycle from 2018-2021, which consisted of: 1) triticale / red clover, 2) corn / interseeded cover crop mix, 3) summer annual forage mix / cereal rye cover crop, 4) soybean (Figure 1).

Figure 1. Four-year crop rotation for the OCS phase 2018-2021.

Looking back: key takeaways from past OCS cycles

Caldwell et al. (2014) compared the yields and the profitability during and after the initial phase of organic transition in OCS following two three-year rotation cycles (corn-soybean-winter spelt/red clover) from 2005-2010. The first three years were considered as transitional production years in which crops could not be sold as certified organic, while crops produced from 2008 to 2010 could be sold as such. They used flexible interactive crop budgets to calculate relative net returns based on crop yields, tillage, weed management and fertility practices and, after the three-year transition period, compared relative net returns of organic production with concurrent organic price premiums to Cayuga County yield averages with conventional crop production inputs and prices. With a 30% organic price premium, the relative net return of organic production in all systems except RT was positive. The RT system was excluded from most analyses due to major challenges with experimental ridge-till practices resulting in decreased crop competitiveness. For both corn and soybean phases averaged across entry points, relative net return in the HF system was significantly lower than LF or EWM, due to higher input costs without corresponding higher yields in the HF system. For the spelt phase averaged across entry points, relative net return was higher in HF than LF and EWM (though not significantly so), with increased input cost in the HF system corresponding with a yield increase. The HF system led to higher weed biomass over time than the EWM and LF systems.

Trial design and system differences

The Cornell Organic Cropping Systems experiment uses a split-plot randomized complete block design with four blocks. The main plot treatments are the four management systems, whereas subplot treatments are two crop rotation entry points (A and B) . Entry points A and B represent different phases of the crop rotation. For example, in 2018 entry point A was planted to triticale while entry point B was planted to soybean.

Treatment systems are arranged along a fertility gradient as well as a soil disturbance gradient (Figure 3). For triticale, summer forage, and corn, the HF system had a 50% higher fertilization rate than RT and EWM. LF received fertilizer rates 50% lower than RT and EWM on the same crops. Intermediate fertilizer rates were applied to both EWM and RT. With respect to soil disturbance, EWM received additional weed management operations in several crops, while RT and LF incorporated an organic no-till soybean phase. Overall number of primary tillage events was not substantially different between systems, though mechanical cultivation was reduced in the soybean phase for RT and LF.

Figure 2. Contrasting management approaches in four systems.

Crop yields across management systems

No matter the management system, crop yield is a key component of profitability. Yields across all four years of the cycle comprising five harvested crops are summarized below. Ryelage was only harvested in EWM and HF systems as the cereal rye cover crop was rolled-crimped for no-till soybean in LF and RT systems. Triticale was grown as a grain crop in EWM and HF and taken for forage in the LF and RT systems. Organic no-till practices were implemented in RT and LF systems only, with soybean planted into tilled soil in HF and EWM. In entry point A soybean yields were comparable across systems, but in entry point B organic no-till soybean yields were nearly half of cultivated yields, likely due to dry conditions in the soybean phase in 2018.

Table 1. Mean yields for all harvested crops across four management systems and crop rotation entry point from 2018-2021. Within an entry point, systems sharing a letter were not significantly different (p < 0.05). Means were not compared between entry points. Triticale in RT and LF systems was harvested as forage (lbs DM/ac) while in HF and EWM it was harvested as grain (lbs/ac). Means were not compared.

Net return of management systems

Net return subtracts total variable costs (TVC) of production (inputs + labor + equipment-associated costs) from gross income (crop yield x price). Prices for corn and soybean were obtained from the USDA organic grain report (USDA National Organic Grain and Feedstuffs Report, February 4, 2022). As commodity price references for triticale grain, cereal rye forage and summer annual forage were unavailable, prices were based those typically fetched for organic forage in NY (MH Martens and P Martens, personal communications, 2022). All operation-related costs were taken from Pennsylvania’s 2022 Custom Machinery Rates (USDA NASS 2023). To correct the absence of an inflation adjustment, crop prices and input costs used in this study were converted to real values using the U.S. Consumer Price Index (CPI), with 2016 as the reference year.

All values are denominated in U.S. dollars and represent the average annual revenue, production costs, and net return over four years. In the case of crop rotation entry point A, the LF cropping system exhibited the lowest Total Variable Cost (TVC). Conversely, the HF system had the highest TVC, which despite higher grain and forage yields, resulted in lower net return than LF, EWM and RT systems (Figure 4).

Overall, across four years of the crop rotation and in both crop rotation entry points (i.e., temporal replications of the trial) the EWM system maximized net return via intermediate fertility rates and relatively high yields, though the HF system yielded higher in both entry points Net return for RT and LF systems was more variable between crops and entry points, possibly indicating higher weather-related risk associated with those system approaches, i.e. reliance on cover crops for fertility in LF, and use of organic no-till management for LF and RT (Figure 4).

Figure 4. Comparison of net return and components across four systems in entry point A.

In entry point A, LF demonstrated higher net return than both HF and RT despite lower yields due to reduced input costs. Net return in RT narrowly surpassed HF due to lower input costs as well. In entry point B, LF ranked lowest in net return due to low grain yields across the rotation. HF ranked second and RT ranked third, with RT characterized by intermediate to low yields with intermediate input costs.

Figure 5: Comparison of net return and components across four systems in entry point B.

When net return of each management system is summarized by entry point, high variability in profitability was observed across entry points, largely due to yield differences between growing seasons of the same crop. Because management was nearly identical for each crop within each system across entry points, temporal variation in net return can be attributed to yield response from seasonal environmental or climatic factors either directly or in interaction with management. This highlights the complexity of systems experiments given year-to-year variation (Figure 6).

Figure 6: Net return comparison of all four cropping systems and two entry points.

Conclusions

Differences in yield and subsequent net return between systems varied significantly across entry points, making it difficult to draw conclusions on the most profitable system overall. However, the HF system had the lowest net return across entry points, indicating that input levels were likely higher than optimum and yield gains to justify increased inputs were not realized. EWM had the highest net return across entry points, indicating that intermediate levels of fertility combined with additional cultivation passes in the row crop phases and full tillage soybean production “paid off” as a management strategy, with increased labor or fuel costs outweighed by increased yields. Of course, this assumes availability of labor required which may be out of reach for some farms, and can be challenged by finite weather-related windows conducive to field operations.

Variability in net return between entry points was particularly high for the LF and RT systems, largely driven by yield variation in the soybean phase between temporal replications. For entry point B, intermediate corn yields and low organic no-till soybean yields drove low profitability in LF, while relatively high corn yield in RT partially made up for low organic no-till soybean yield. This variation in soybean yield highlights a challenge with an organic no-till management approach that dry conditions can reduce yields to a greater extent compared to a tillage-based approach. However, in an extremely wet year where adequate weed control was not possible, no-till management may pay off.

By accounting for system profitability only, this article does not consider other tradeoffs between systems such as soil health outcomes or greenhouse gas emissions from contrasting management, additional sustainability metrics to evaluate organic production system success.

References

Caldwell, B; Mohler, CL; Ketterings, QM; and DiTommaso, A. (2014). Yields and profitability during and after transition in organic grain cropping systems. Agronomy Journal, 106(3):871–880.

Gianforte, L personal communication. 2022.

Jernigan, A. B., Wickings, K., Mohler, C. L., Caldwell, B. A., Pelzer, C. J., Wayman, S., and Ryan, M. R. (2020). Legacy effects of contrasting organic grain cropping systems on soil health indicators, soil invertebrates, weeds, and crop yield. Agricultural Systems, 177:102719.

USDA National Organic Grain and Feedstuffs Report, February 4 2022. Agricultural Marketing Service.

Martens, MH personal communication. 2022.

Martens, P personal communication. 2022.

Pennsylvania’s 2022 Machinery Custom Rates. USDA NASS.

For more results from the Cornell Organic Systems Experiment visit the Sustainable Cropping Systems Lab website.

New York Dairies Show the Way to Reduce Greenhouse Gas Emissions

Olivia F. Godber¹, Karl J. Czymmek², Michael E. van Amburgh³ and Quirine M. Ketterings¹

¹Nutrient Management Spear Program, ²PRO-DAIRY, and ³Dairy Nutrition, Department of Animal Science, Cornell University, Ithaca, NY 14853

Introduction

              In a recent study, 36 medium to large dairy farms (>300 cows) located across New York state were assessed for greenhouse gas (GHG) emissions for the 2022 calendar year using The Cool Farm Tool. Cows were predominantly Holstein. Dairies ranged in animal density from 0.71 to 1.96 animal units per acre (one animal unit is 1000 pounds of live weight). Herds produced an average fat and protein corrected milk (FPCM) yield of 29 000 lbs per cow per year using 64% homegrown feed. Total FPCM production was 1.92 billion lbs, sold to four dairy cooperatives. This milk production represented approximately 12% of total NY milk production in 2022. 

Findings

              The GHG emission intensity ranged from 0.63 to 1.06 lb CO₂eq per lb of FPCM (mean GHG emission intensity = 0.86 lb CO₂eq per lb FPCM). Methane was the biggest contributor, accounting for 60% of total GHG emissions on average, with enteric methane as the largest contributor (45% of total farm emissions). With several studies suggesting the US average GHG intensity of around 1lb CO₂eq per lb FPCM, this study shows these New York dairies to be leaders in sustainability.  

              The relatively low GHG emission intensity achieved by the farms in this study reflect high quality and quantity of home-grown feed, careful nutrient management, quality nutrition and high animal productivity, and for several of the farms also the installation of more advanced manure management systems such as solid-liquid separation with cover and flare, and anerobic digesters. These characteristics allow optimization of milk production through high feed efficiency, demonstrate the recognition of the value of manure offsetting synthetic fertilizer use, and the farm’s ability to take advantage of the dilution of maintenance concept through high milk yields and components. 

              Another important finding of the study is that many of the key drivers of GHG emission intensity for these farms were related to homegrown feed production and manure management, two main areas of management that also impact whole farm nutrient use efficiency. Reducing fertilizer and feed purchases not only benefits the GHG emission intensity of the farm but also contribute to improvements in whole farm nitrogen and phosphorus balances and improves farm economics. 

Highlights

•  Medium to large New York dairy farms in a recent study averaged a GHG intensity of 0.86 lb CO₂eq per lb of fat and protein corrected milk, much lower than the national average.  

•  Manure management system (implementation of solid-liquid separation with cover and flare, and anaerobic digesters), was a major driver of lower GHG emissions on the farms.

•  Homegrown feed (both total amount and quality), heifer/cow ratio, and feed efficiency all impacted emissions with reduced emissions for integrated farms that grow a large portion of the forages fed to the cows on the farm itself, have lower heifer/cow ratios, and for farms that implemented precision feed management. 

Invitation

              The farms in this study represent a considerable proportion of New York’s milk production but expansion of the database will be needed to develop additional understanding of drivers of emissions and opportunities for improvements over time. Many of the farms that participated with 2022 data are continuing to participate now with 2023 and 2024 data. We welcome additional farms to join and would particularly also invite more farms with under 300 cows to participate to better represent the diverse New York dairy industry.  

Full Citation

              This article is summarized from our peer-reviewed publication: Godber, O.F., K.J. Czymmek, M.E. van Amburgh, and Q.M. Ketterings (2025). Farm-gate greenhouse gas emission intensity for medium to large New York dairy farms.  Journal of Dairy Science.  https://www.journalofdairyscience.org/article/S0022-0302(25)00124-9/fulltext.

Acknowledgments

              We thank the farmers and farm advisors and coops that participated in the assessment. For questions about these results or inquiries about participating, 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/. 

Logos of associated partners, from left to right, NMSP, Cornell University, Cornell CALS and PRO-DAIRY.

Manure Continues to Offset Nitrogen Fertilizer Needs and Increase Corn Silage and Grain Yields: Value of Manure Project 2024 Update

Juan Carlos Ramos Tanchez¹, Carlos Irias¹, Allen Wilder², Janice Degni³, Paul Cerosaletti³, Dale Dewing³, Kirsten Workman¹𝄒⁴, and Quirine M. Ketterings¹ 

¹Cornell University Nutrient Management Spear Program, ²Miner Agricultural Research Institute, ³Cornell Cooperative Extension, and ⁴PRO-DAIRY

Introduction

              Manure contains all seventeen nutrients a plant needs, making it a tremendously valuable nutrient source. In addition, manure can help build soil organic matter, enhance nutrient cycling, and improve soil health and climate resilience when managed appropriately. Previous research in New York State indicates that these manure benefits contribute to crop yield beyond just the fertilizer value of manure.  The Value of Manure Project, part 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), with additional support from the New York State Departments of Agriculture and Markets and Environmental Conservation, and the US Department of Agriculture’s National Institute for Food and Agriculture. This statewide project evaluates nitrogen (N) and yield benefits of various manure sources and application methods to corn silage and corn grain. Eight trials were conducted in 2024, adding to eleven trials conducted in 2022 and 2023. Here we summarize the findings of the 2024 trials.

What we did in 2024

              Trials were implemented within commercially farmed corn fields in western (1 trial), northern (2 trials), central (4 trials), and southeastern (1 trial) New York. Each trial had three strips that received manure and three that did not, for six strips per trial (Figure 1a).

Figure 1. Layout of a 2024 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).

              Four trials (D, E, F, G) received manure in spring 2023 but not in 2024. For these trials, we tested yield and fertilizer offset carryover benefits of 2023 manure into the 2nd year (2024) after manure application. For all other trials, manure was applied in spring 2024 before planting corn. Dairy manure treatment and application methods varied across trials (Table 1).

*Note: manure was applied in the spring of 2023 in trials D, E, F, and G so we tested its carryover value for 2024. For all other trials, manure was applied in the spring of 2024. SMG = soil management group (http://nmsp.cals.cornell.edu/publications/factsheets/factsheet19.pdf).

              Strips were 1200-1800 ft long and 35-120 ft wide for all but one trial where strips were 300 ft long. 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 to 200 pounds N per acre. Sidedress rates were trial-specific, based on the expected N needs for that field stemming from its specific characteristics and history. For each trial, manure was analyzed, and samples were taken for general soil fertility, Pre-Sidedress Nitrate Test (PSNT), Corn Stalk Nitrate Test (CSNT), yield, and forage quality. Soil test phosphorus (P) levels in the trials were in the medium to very high category (Table 2). Soil test potassium (K) was optimum or very high for five of the trials, while trials D, F, and G tested medium in K. Magnesium soil test values were high or very high for all trials. Soil test zinc (Zn) was medium for trials C, D, and G and high for all other trials. Manganese (Mn) and iron (Fe) were in the normal category.

What we have found so far

              As we also found in 2022 and 2023, trials differed in their responses to manure and sidedress inorganic N (Figure 2). Common among all trials in 2024 was that yield responded to N sidedress application in all eight trials. In seven of the eight trials (A to G), manure increased yield to levels not achievable with fertilizer alone by 0.3 to 2.7 tons/acre and 13 bushels/acre (Table 3). Out of these seven trials, in one of the trials with medium levels of K (F), manure applications increased yield to such elevated levels (2.3 tons/acre) that it also increased the crop’s need for fertilizer N, similar to what was observed for two trials in 2023. Yield in trial H only responded to manure in the lower N rates, likely reflecting the low application rate of this trial and low manure N contribution (3,840 gallons/acre, surface applied without incorporation). In trials A, C, and E manure did not replace inorganic N fertilizer, but still resulted in a yield increase.

Figure 2. Most Economic Rate of Nitrogen (MERN) in eight Value of Manure trials conducted in 2024. 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). Corn grain yields are in bushels/acre at 84.5% DM.
*Note: manure was applied in the spring of 2023 in trials D, E, F, and G so we tested its carryover value for 2024. For all other trials, manure was applied in spring 2024.

              The PSNT levels where liquid or digested manure was applied in 2024, were higher than their no-manure counterparts for all but one trial, showing that manure supplied crop available N to the soil (Table 4). The exception was trial C, where the application rate was relatively low (5,200 gallons/acre), which may have contributed to a lack of a response in PSNT. The PSNT results in the no-manure plots incorrectly identified trials B, C, and E as not needing additional N. In the manure plots, PSNTs also incorrectly suggested trials A, C, E, and H did not need sidedress N. For the manure carry-over trials (D, E, F, and G), PSNT levels were similar in manure and no-manure strips (Table 4), suggesting limited to no carryover into the second year, although each of these trials had a yield increase where manure was applied the previous year. 

              In all eight trials, CSNT levels of the plots that did not receive manure or sidedress fertilizer N were low, consistent with the yield response to N. In the plots that received manure but no N fertilizer, only trial B was in the excess category, consistent with the lack of a sidedress-induced yield response in trial B manured strips (trial B manure MERN = 0 pounds N/acre, Table 3). In the other trials (A, C, D, E, F, G, H) the manure strips without N fertilizer addition were in the low CSNT category, accurately reflecting the need for additional N.

              In 2024 we documented “yield bumps” resulting from manure application beyond what could be obtained with fertilizer only in seven of the eight trials, consistent with observations for seven of the eleven trials in 2022 and 2023. These yield bumps were also present in all four “carry-over” trials, signaling that manure applied in 2023 continued to be beneficial to crop yield in 2024. Those yield increases in the trials with optimal or high fertility status show that manure has additional benefits beyond its nutrient contributions. The CSNT results consistently reflected where N was needed and allowed for documentation of the N contributions of manure. The PSNT results showed inconsistencies this year with five trials where corn yield still responded to sidedress N even though the PSNT values were high. 

Next steps in 2025

              To re-evaluate the current N crediting system and learn how to predict and take into account yield bumps, the Value of Manure project requires the addition of more trials beyond the nineteen trials completed so far. Thus, the Value of Manure Project will continue in 2025. We will be testing additional manure types and application methods in various soil types and weather conditions. Join us and obtain valuable insights about the use of manure on your farm! If you are interested in joining the project, contact Juan Carlos Ramos Tanchez at jr2343@cornell.edu.

Additional resources

Acknowledgments

              We thank the farms participating in the project and their collaborators 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/.