Karl J. Czymmek1,2, Quirine M. Ketterings2, Mart Ros2, Sebastian Cela2, Steve Crittenden2, Dale Gates3, Todd Walter4, Sara Latessa5, and Greg Albrecht6
1PRODAIRY, 2Nutrient Management Spear Program (NMSP), Department of Animal Science, Cornell University, 3United States Department of Agriculture Natural Resources Conservation Service (USDA-NRCS), 4Department of Biological and Environmental Engineering, Cornell University, 5New York State Department of Environmental Conservation (NYSDEC), 6New York State Department of Agriculture and Markets (NYSDAM)
After more than 15 years of field use, version 1 of the New York Phosphorus Index (NY-PI) has been updated. The new version (NY-PI 2.0) incorporates new science and does a better job of addressing P loss risk while still giving farm managers options for recycling manure nutrients. The process of updating the NY-PI was led by the NMSP at Cornell in partnership with NYSDAM, NYSDEC, and NRCS and in consultation with certified planners and farmers. Farms that are regulated as concentrated animal feeding operations (CAFOs) will need to start using the new NY-PI when the CAFO Permit is updated (current permits are due to be renewed in 2022). Farms that are in state or federal cost share programs will need to use the tool based on NRCS determination. Agency discussions are in progress to make sure the roll-out is as smooth as possible.
Figure 1: the new NY-PI has a transport × BMP approach.
Here is how it works: a farm field is rated based on an assessment of its runoff risk-related transport features, including those observed directly during a field visit and others from normal soil survey information (most of these factors are the same as those used in the old NY-PI). For example, being close to a stream or watercourse, poorly drained soil, or higher levels of soil erosion are some of the risk factors that can lead to a high transport score. For fields with a high transport score, manure and P fertilizer application practices can be selected to reduce the transport risk. These best/beneficial management practices (BMPs) cover a combination of changes in application timing (close to planting) and method (placing P below the soil surface), and more vegetation on the soil surface when P is applied. Thus, implementation of BMPs will reduce the final PI score. Field practices include setbacks, ground cover (sod or cover crops) or placing manure below the soil surface (injection or incorporation). Combined with information about soil test P levels, the final NY-PI score results in a management implication: if risk is classified as low or medium, manure may be used at N-based rates; if classified as high, manure rate is limited to expected P uptake by the crop, and if very high, no P from manure or fertilizer may be applied. This transport × BMP approach is shown in Figure 1.
Coefficients were set for the new NY-PI using a database of more than 33,000 New York farm fields supplied by certified nutrient management planners and a second dataset that included data for PI assessment and whole-farm nutrient P balance assessments for 18 New York AFO and CAFO farms. While some farm fields had to have manure diverted, in almost all situations, the NY-PI 2.0 provided a pathway for farms with an adequate land base to both reduce risk and apply the manure generated from their herd. The full NY-PI 2.0 can be seen in Table 1.
Sarah E. Lyonsa, Quirine M. Ketteringsa, Shona Orta, Gregory S. Godwina, Sheryl N. Swinka, Karl J. Czymmeka,b, Debbie J. Cherneyc, Jerome H. Cherneyd, John J. Meisingere, and Tom Kilcera,f
a Nutrient Management Spear Program, Department of Animal Science, Cornell University, Ithaca, NY, b PRODAIRY, Department of Animal Science, Cornell University, Ithaca, NY, cDepartment of Animal Science, Cornell University, Ithaca, NY, dSoil and Crop Sciences Section of the School of Integrative Plant Science, Cornell University, Ithaca, NY, eUSDA-ARS Beltsville Agricultural Research Center, Beltsville, MD, fAdvanced Agricultural Systems, LLC, Kinderhook, NY
Introduction
Forage double-cropping, or growing two forage crops in a single growing season, can be a beneficial practice for dairy farmers in New York. Double-cropping corn silage with forage winter cereals, such as triticale, cereal rye, or winter wheat, can add additional spring yield on top of numerous environmental benefits including preventing soil erosion, nutrient recycling, and increased soil organic matter over time – which all promote increased soil health. Winter cereals intended for forage harvest require nitrogen (N) management to reach optimum yield and forage quality. This study was aimed at identifying field and management characteristics that can estimate yield and N needs for winter cereals harvested for forage in the spring.
Field Research
A state-wide study with 62 on-farm trials investigated the spring N needs of forage winter cereals across New York from 2013 to 2016. Each trial had five rates of N (0, 30, 60, 90, and 120 lbs N/acre) applied to farmer-managed forage triticale, cereal rye, or winter wheat at green-up in the spring to determine the most economic rate of N (MERN). All forages were harvested at the flag-leaf stage in May each year. Soil samples were taken at green-up before fertilizer was applied. Farmers supplied information about management practices and field characteristics, such as past manure applications, planting date, and soil drainage. This information, in addition to soil fertility analysis results, was used to develop a decision tree model for predicting MERN classification.
Results
About one-third of the trials did not require additional N (MERN = 0), while the remainder responded to N and most required between 60 and 90 lbs N/acre (Figure 1). Yields at the MERN across trials ranged from 0.4 to 3.0 tons DM/acre (1.8 tons DM/acre average). Yield could not be accurately predicted based on information gathered, but the lower-yielding sites (< 1.0 tons of DM/acre) tended to be poorly or somewhat poorly drained and not have a recent manure history.
Farmer-reported soil drainage, manure history, and planting date were the most important predictors of the MERN (Figure 2). Most of the winter cereals grown on fields that were described as well-drained by the farmers did not require additional N at green-up. For the fields reported as somewhat poorly- or poorly-drained, 60 to 90 lbs N/acre were required if the field had not received manure the previous fall. If manure had been applied recently, 60 to 90 lbs N/acre were required for stands that were planted after October 1 versus 0 lbs N/acre if planting had taken place before October 1.
Figure 1. Forage winter cereal most economic rates of N (MERN) and yield at the MERN for 62 N-rate trials in New York from 2013 to 2016. Fertilizer N was applied at spring green-up and forage was harvested at the flag-leaf stag in May.Figure 2. Decision tree for forage winter cereal most economic rate of N (MERN) at spring green-up. If the indicated site or history factor in the blue box is true, move to the left branch in the tree; if false, move to the right branch. The predicted MERN is listed in the red boxes. Recent manure history refers to manure applied within the last year (either spring or fall). This decision tree correctly predicted MERN classifications for 78% of the trials included.Figure 3. Forage winter cereal crude protein as impacted by N rate applied at spring green-up for 62 trials in New York from 2013 to 2016. Forage was harvested at the flag-leaf stage in May.
Most forage quality parameters were not impacted by N rate. Neutral detergent fiber (NDF) at the MERN ranged from 42 to 60% of DM (52% average), in vitro true digestibility (IVTD) at the MERN ranged from 81 to 94% of DM (88% average), and NDFD digestibility (48-hour fermentation) at the MERN ranged from 67 to 84% of NDF (78% average). However, crude protein (CP) increased with N rate for most trials, even those with MERNs of 0. Crude protein averaged 13% of DM for the 0 lbs N/acre treatment and 20% of DM for the 120 lbs N/acre treatment (Figure 3). On average, CP increases by 1% for every 15-20 lbs of N applied. These findings suggest that additional N beyond the MERN can increase the CP levels of the forage while not impacting other forage quality parameters.
Conclusions and Implications
Results from this study emphasize the importance of growing conditions for optimum forage winter cereal performance. In fields that have poor drainage and lack recent manure histories, forage winter-cereals may not yield well and will likely require additional N inputs, while fields with well-drained soil conditions and better soil fertility will support higher yields and better forage quality without needing additional N in the spring. Planting date is also a critical management consideration. Planting late in the fall (after October 1 in this study), may result in lower yields (see also Lyons et al., 2018a). Timely planting (before October 1) in fields with good soil fertility and/or recent manure histories more often resulted in MERNs for N at green-up of 0 lbs N/acre, which would save farmers time and costs in the spring. Nitrogen management at green-up did not greatly affect forage quality except for CP, which increased with N addition even if the additional N did not increase spring yield.
Additional Resources
Lyons, S.E., Q.M. Ketterings, G.S. Godwin, J.H. Cherney, K.J. Czymmek, and T. Kilcer. 2018a. Spring N management is important for triticale forage performance regardless of fall management. What’s Cropping Up? 28(2): 34-35.
Lyons, S.E., Q.M. Ketterings, G.S. Godwin, K.J. Czymmek, S.N. Swink, and T. Kilcer. 2018b. Soil nitrate at harvest of forage winter cereals is related to yield and nitrogen application at green-up. What’s Cropping Up? 28(2): 32-33.
Acknowledgements
This work was supported by Federal Formula Funds, and grants from the Northern New York Agricultural Development Program (NNYADP), the USDA-NRCS, and Northeast Sustainable Agriculture Research and Education (NESARE). We would also like to thank participatory farmers and farm advisors for assisting with the trials, including Cornell Cooperative Extension educators, consultants, NRCS staff, and SWCD staff. 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/.
Sarah E. Lyonsa, Quirine M. Ketteringsa, Greg Godwina, Debbie J. Cherneyb, Jerome H. Cherneyc, John J. Meisingerd, and Tom F. Kilcere
a Nutrient Management Spear Program, Department of Animal Science, Cornell University, Ithaca, NY, b Department of Animal Science, Cornell University, Ithaca, NY, c Soil and Crop Sciences Section of the School of Integrative Plant Science, Cornell University, Ithaca, NY, d USDA-ARS Beltsville Agricultural Research Center, Beltsville, MD, and e Advanced Agricultural Systems, LLC, Kinderhook, NY
Introduction
Forage sorghum is a drought and heat tolerant warm-season grass that can be used for silage on dairy farms. It can be a good alternative to corn silage in New York particularly during drought years or in the case of delayed planting in the spring. Forage sorghum requires soil temperatures of at least 60°F for planting, which normally occurs in early June in New York. Forage sorghum could also be a good fit for double cropping rotations because its later planting date gives time for an early May harvest of a forage winter cereal. Between 2013 and 2017, we conducted 13 N-rate trials across three regions of New York to evaluate nitrogen (N) needs for a brown midrib (BMR) forage sorghum variety (Alta Seeds AF7102).
Trial Set-Up
The trials were planted between early June and early July in central New York (eight trials) and northern New York (five trials). Of the northern New York trials, three were on commercial farms. The other trials were on Cornell research farms. Two of the three trials on commercial farms were conducted on fields with recent manure or legume histories. For eleven of the trials, sorghum was planted at a 1-inch seeding depth and 15-inch row spacing (15 lbs/acre seeding rate). The remaining two trials were planted either with a 30-inch or 7.5-inch row spacing. Five N-rates as Agrotain®-treated urea (Koch Agronomic Services, LLC, Wichita, KS) were broadcasted at planting (0, 50, 100, 150, and 200 lbs N/acre) with two additional N rates (250 and 300 lbs N/acre) for one of the central New York locations. The forage sorghum was harvested at the soft dough stage, which occurred between September 20 and October 14. Harvest was done using a 4-inch cutting height and dry matter (DM) yield was measured. This allowed for determination of the most economic rate of N (MERN), the N use efficiency (NUE), and the apparent N recovery (ANR). The NUE and ANR are measures of N efficiency. The NUE is the amount of N taken up in relation to yield, and is calculated by subtracting the yield when no N was applied in the spring from the yield when N was applied, and dividing that value by the N rate applied (NUE [lbs DM/lbs N] = [Triticale yieldN rate – Triticale yield0 N]/N rate). A higher NUE means that more of the N that was applied was taken up by the sorghum. The ANR is the amount of fertilizer N recovered, calculated by subtracting the N in the forage when no N was applied from the N in the forage when N was applied, and dividing that value by the N rate applied (ANR [%] = [Forage N of Nrate – Forage N of N0]/N rate).
Results
The crop yield response to N could be separated into three yield response groups: (1) no response to N addition (MERN = 0; two trials), (2) no yield plateau (MERN > 200 kg N ha-1; four trials), and (3) a yield plateau between the lowest and highest N rates (seven trials) (Figure 1). The two trials on fields at commercial farms with a recent manure or legume history did not respond to N addition (group 1 trials, panel A). The trial in group 1 with the lowest yield (5.3 tons DM/ac) was planted with a 30-inch row spacing, which resulted in weed issues that likely impacted crop performance. Trials in group 2 (panel B) were either very responsive to N addition or had N uptake limitations, most likely reflecting weather or soil drainage issues. The trials in group 3 (panel C) had MERNs ranging from 134 to 234 lbs N/acre, averaging 181 lbs N/acre. Yields at the MERN for group 3 trials ranged from 6.7 to 10.4 tons DM/acre and averaged 8.9 tons DM/acre. On average, for responsive sites (so excluding group 1 trials), forage sorghum required approximately 20 lbs N/acre per ton DM. On average, for each ton of DM, 25 lbs of N was taken up by the sorghum. For group 3, higher N rates led to lower ANR and NUE (Figure 2). For these trials, NUE at the MERN averaged 56 lbs DM/lbs N and ANR at the MERN averaged 83%.
Figure 1: Impact of N application on forage sorghum yield for 13 trials from 2013 to 2017. Sorghum was harvested at the soft dough stage. Two trials did not respond to N (A), four trials did not have a yield plateau (B), and seven trials had a yield plateau between the lowest and highest N rates (C). Differences are likely due to sites native N supply, weather conditions, agronomic practices, and/or soil properties (see text for further details). Different symbols represent different sites within each group.Figure 2: Forage sorghum nitrogen use efficiency (NUE, A) and apparent N recovery (ANR, B) as impacted by N application rate for seven trials with a most economic rate of N between the highest and lowest N rates. Different shapes represent different trials within each group.
Conclusions and Implications
Forage sorghum can be a good alternative to corn silage in years of drought, delayed corn planting, or as part of a double crop rotation with forage winter cereals. The BMR forage sorghum in this study, grown on N-limited sites, needed around 180 lbs N/acre, or around 20 lbs N per ton of DM, and yielded between 7 and 10 tons DM per acre. Fields with recent manure or legume histories supplied sufficient N, resulting in no crop response to additional N for the forage sorghum. Applying N beyond the N needs of the crop will result in reduced N use efficiencies. In addition, stands with row spacing greater than the recommended 15 inches may result in weed or other stand issues that could impact performance.
Acknowledgements
This work was supported by Federal Formula Funds, and grants from the Northern New York Agricultural Development Program (NNYADP), New York Farm Viability Institute (NYFVI), and Northeast Sustainable Agriculture Research and Education (NESARE). 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/.
Quirine Ketterings1, Karl Czymmek1,2, Sanjay Gami1, Mike Reuter3 Cornell University Nutrient Management Spear Program1, PRODAIRY2, and Dairy One3
Introduction
The corn stalk nitrate test (CSNT) is an end-of-season evaluation tool for N management for 2nd or higher year corn fields that allows for identification of situations where more N was available during the growing season than the crop needed. Where CSNT results exceed 3000 ppm for two or more years, it is highly likely that N management changes can be made without impacting yield.
Findings 2010-2018
The summary of CSNT results for the past nine years is shown in Table 1. For 2018, 54% of all tested fields had CSNTs greater than 2000 ppm, while 44% were over 3000 ppm and 26% exceeded 5000 ppm. In contrast, 15% of the 2017 samples were low in CSNT-N. The percentage of samples testing excessive in CSNT-N was most correlated with the precipitation in May-June with droughts in those months translating to a greater percentage of fields testing excessive. As crop history, manure history, other N inputs, soil type, and growing conditions all impact CSNT results, conclusions about future N management should take into account the events of the growing season. In addition, weed pressure, disease pressure, lack of moisture in the root zone in drought years, lack of oxygen in the root zone due to excessive rain, and other stress factors can impact the N status of the crop.
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 2018 expansion of adaptive management options for nutrient management now includes targeted CSNT sampling. Work is ongoing to evaluate use of yield to CSNT-N ratios to identify situations where yield was limited by factors other than N supply. Two years of CSNT data are recommended before making any management changes unless CSNT’s exceed 5000 ppm (in which case one year of data is sufficient).
Figure 1: In drought years (determined in this analysis by May-June rainfall below 7.5 inches; which occurred in 2012, 2016, and 2018), more samples test excessive in CSNT-N while fewer test low or marginal.
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.
Acknowledgments
We thank the many farmers and farm consultants that sampled their fields for CSNT. 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/.
