What’s Cropping Up? Volume 29 Number 3 – July/August 2019

Nitrogen Management for Forage Winter Cereals in New York

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.

Forage winter cereal most economic rates of N (MERN) and yield at the MERN
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.
Decision tree for forage winter cereal most economic rate of N (MERN) at spring green-up
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.
Forage winter cereal crude protein as impacted by N rate applied at spring green-up
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

Cornell, Nutrient Management Spear Program, and Pro-Dairy logosThis 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/.

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Best Timing of Harvest for Brown Midrib Forage Sorghum Yield, Nutritive Value, and Ration Performance

Sarah E. Lyonsa, Quirine M. Ketteringsa, Greg Godwina, Debbie J. Cherneyb, Jerome H. Cherneyc, Michael E. Van Amburghb, 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. Since it requires a soil temperature of at least 60°F for planting, the recommended planting time for New York is early June, unlike corn which is usually planted earlier in the spring. This would allow time for a forage winter cereal harvest in mid- to late-May prior to sorghum planting. Forage sorghum also has comparable forage quality to corn silage for most parameters except for starch, which is typically lower in forage sorghum. The main question for this research was: can forage sorghum be harvested in time for establishment of a fall cover crop or winter cereal double crop in New York? To answer this question, we conducted seven trials in central New York from 2014 through 2017 to evaluate the impact of harvesting at the boot, flower, and milk growth stages versus the traditional soft dough stage on the yield and forage quality of a brown midrib (BMR) forage sorghum variety.

Trial Set-Up

The seven trials were planted between early June and early July on two Cornell research farms in central New York. The sorghum was planted at a 1-inch seeding depth and 15-inch row spacing (15 lbs/acre seeding rate). Two N-rates as urea treated with Agrotain® (Koch Agronomic Services, LLC, Wichita, KS) were broadcast at planting (100 and 200 lbs N/acre) with the goal of having a non-N limiting scenario for these sites. Alta Seeds AF7102 (Alta Seeds, Irving, TX) was used for all trials. Forage sorghum was harvested at the boot, flower, milk, and soft dough stages. Harvest was done using a 4-inch cutting height. Measurements included dry matter (DM) yield and forage quality, including total digestible nutrients (TDN), neutral detergent fiber (NDF) analyzed on an organic matter basis with amylase, 30 hour NDF digestibility (NDFD30), non-fiber carbohydrates (NFC), acid detergent fiber (ADF), dry matter (DM), crude protein (CP), and starch content. Forage quality parameters were entered into the Cornell Net Carbohydrate and Protein System (CNCPS) version 6.55, a ration formulation software, for predicting how sorghum harvested at various growth stages would perform in a typical dairy total mixed ration (TMR) compared to corn silage. Forage sorghum, at each of the different growth stages, was substituted for 0, 25, 50, 75, and 100% of the corn silage fraction of the diet, and metabolizable energy (ME) allowable milk and metabolizable protein (MP) allowable milk were predicted.

Results

Timing of forage sorghum harvest impacted both yield and forage quality. Yield did not increase beyond the flower stage for four trials or beyond the milk stage for one trial. For two trials yield continued to increase until the soft dough stage. Averaged across all trials, yield increased from 4.8 tons DM/acre at the boot stage, to 6.0 tons DM/acre at the flower stage, and 6.8 and 7.1 tons DM/acre at the milk and soft dough stages, respectively (Figure 1). These results suggest that, in most cases, forage sorghum can be harvested at the flower or milk stage without losing a substantial amount of yield. With later harvests forage quality parameters of DM, starch, and NFC were increased while CP, NDF, and NDFD30 were decreased.

Graph of summary of yield and forage quality of BMR brachytic dwarf forage sorghum
Figure 1: Summary of yield and forage quality of BMR brachytic dwarf forage sorghum as impacted by growth stage at harvest. These are averages of seven trials in central New York from 2014-2017. Quality parameters include total digestible nutrients (TDN), neutral detergent fiber (NDF) analyzed on an organic matter basis with amylase, 30 hour NDF digestibility (NDFD30), non-fiber carbohydrates (NFC), acid detergent fiber (ADF), dry matter (DM), crude protein (CP), and starch.

Without adjusting for DM intake, 100% inclusion of forage sorghum harvested at the soft dough stage resulted in predicted ME allowable milk (90 lbs) that was similar to the 100% corn silage TMR (92 lbs) across sorghum inclusion amounts (Fig. 2A). The lower starch content of less mature sorghum resulted in reduced ME allowable milk at greater inclusion in the diet, averaging 87, 88, and 89 lbs for 100% inclusion of sorghum at the boot, flower, and milk stages, respectively. Predicted MP allowable milk for all sorghum growth stages was similar to that of corn silage (Fig. 2B).

Graph of metabolizable energy allowable milk and metabolizable protein allowable milk of forage sorghum
Figure 2: Metabolizable energy (ME) allowable milk (A) and metabolizable protein (MP) allowable milk (B) of BMR brachytic dwarf forage sorghum predicted with the Cornell Net Carbohydrate and Protein System (CNCPS) version 6.55. Harvest took place at four growth stages, and sorghum was substituted for different percentages of corn silage in a typical dairy total mixed ration. Values are averages of seven trials in central New York from 2014 to 2017.

Conclusions and Implications

Forage sorghum can be a good alternative to corn silage in double-cropping rotations with winter cereals grown for forage in New York. The BMR forage sorghum in this study could be harvested as early as the late-flower to early-milk growth stage without losing significant amounts of yield. However, early harvesting did affect forage quality, resulting in greater NDFD30, NDF, ADF, and CP, and less NFC, starch, and DM. Forage sorghum could replace corn silage in a dairy TMR but energy supplements are needed if sorghum is harvested before the soft dough stage due to a lower starch content at the earlier harvest dates. Additional forage may also be needed in a sorghum-based TMR due to changes in fiber digestibility at different growth stages. The higher moisture content of less mature sorghum may also call for adjustments in chop length and/or silage additives, such as inoculants, for proper fermentation.

Additional Resource

Lyons, S., Q.M. Ketterings, G. Godwin, D.J. Cherney, J.H. Cherney, J.J. Meisinger, and T.F. Kilcer (2019). Nitrogen Management of Brown Midrib Forage Sorghum in New York. What’s Cropping Up? 29(1):1-3.

Acknowledgements

Cornell University logo, Nutrient Management Spear Program logo, and Pro-Dairy logoThis 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/.

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What’s Cropping Up? Volume 29, Number 2 – March/April 2019

Warm-Season Grass Binary Mixtures for Biomass in the Northeast

J.H. Cherney1, D.J.R. Cherney2, and M. Davis3
1Section of Soil & Crop Sciences, 2Dept. of Animal Science, Cornell University, and 3Farm Manager, Cornell Willsboro Research Farm, Willsboro, NY

Over five million acres of marginal agricultural land in the Northeast USA are no longer in use and have great opportunities for grass biomass production, although environmental or other supplemental compensation may be required for profitable production on low-yielding marginal land. Warm season grasses are considered a viable herbaceous second generation biofuel feedstock but are better suited to marginally productive cropland Future selection through breeding should have a significant focus on low-input types of environments.

Additional environmental benefits may accrue when mixtures are used instead of monocultures. Studies have suggested that polycultures sequester more carbon in the soil profile and have less N leaching compared to monocultures. Profitability in biomass production, however, is most strongly influenced by yield, and we focused on yield potential in this study.

Experimental layout

A long-term plot study was sown in 2010 in Ithaca (central NY, Williamson fine sandy loam soil) and Chazy (northern NY, Roundabout silt loam soil), and was completed in 2018. A goal was to determine if binary mixtures of warm-season grasses would result in increased yield over pure stands.

Three replicates of 12 treatments compared pure species with binary mixtures (Fig. 1). Binary mixtures had one species seeded in one direction, and the second species seeded perpendicular to the first. Pure species also were seeded twice, with one half the total seed sown perpendicular to the other half. Pure switchgrass and Atlantic coastal panic grass plots were seeded at 10 lbs pure live seed (PLS)/acre. Pure big bluestem plots were seeded at 12 lbs PLS/acre. Mixtures contained half the seeding rate of pure species plots for each species in a binary mixture. All entries were commercially available varieties, with the exception of RC Big Rock switchgrass, which was an experimental selection from Cave-In-Rock (REAP-Canada, Ste-Anne-de-Bellevue, QC). Insufficient seed was available of Timber switchgrass to seed at both sites.

Fig. 1. Plot layout at the two NY sites.

Plots (15’ x 15’) were fertilized with 50 lbs N fertilizer/acre at spring green up each year. Roundup was sprayed in the spring prior to warm season grass green up to control weeds after 2013. A few weeds were resistant to Roundup and remained, such as milkweed. Plots were well established by the 2013 growing season. Plots were harvested for yield determination each year in early October generally after first frost at a 4” stubble height using a flail harvester, harvesting 78 sq. ft. of plot area (3’ x 13’ twice per plot). Samples were collected for dry matter (DM) determination.

Yield

The more southern, generally wetter, Ithaca site averaged 22% greater yield across all years and species combinations. Ithaca long-term average precipitation is 4.5” per year more than Chazy (Plattsburgh, NY weather station), and Ithaca averaged 5.5” more per year during the experiment. Although Chazy is considerably farther north than Ithaca, long-term average heat units are very similar. Over the 2013-2017 period from May 1 to Oct. 1, both sites averaged 4916 GDD per growing season (base 32F). Warm season grass mixtures behaved differently on different sites. At Chazy, big bluestem (BB) tended to compete very well in mixtures with switchgrass (SW), while at the Ithaca site switchgrass tended to be the major component.

Big bluestem was the slowest species to become fully established, but Prairie View BB pure stands were the highest yielding at the Chazy site, averaged over five years. RC Big Rock switchgrass selection had the greatest yield in Ithaca for pure SW stands, averaging 6.6 tons DM/acre over 5 years. Cave-in-Rock SW (CAV) and the CAV-Prairie View BB mixture both yielded 13% less at Chazy than Ithaca, but pure Prairie View stands produced similar yields at both sites. Upland switchgrass mixed with Prairie View BB tended to produce the best overall results and was the most compatible mixture (Fig. 2). Other mixtures tended to become mostly monocultures over time.

Fig. 2. Average yields of pure switchgrasses (SW) vs. SW mixtures with big bluestem (BB).

Atlantic coastal panic grass (ACP) was promising the first year, but quickly deteriorated to a weak stand after the first year, and had significant weed invasion in later years, particularly at Chazy. BoMaster switchgrass struggled in pure stands and became a very minor component of mixtures. In later years, big bluestem and switchgrass tended to invade plots with weaker stands, as ripe seed was scattered each year during harvest with a flail harvester.

Mixtures

At both sites, mixtures of Cave-in-Rock SW and ACP quickly became pure switchgrass stands. By the end of the trial, mixtures of Cave-in-Rock and Suther BB were pure switchgrass at Ithaca, and averaged 10% BB at Chazy. BoMaster SW and ACP, as well as mixtures of these two, tended to be weak stands at both sites, with up to 25% weeds observed in the summer of 2018. Prairie View BB and BoMaster SW mixtures were essentially pure big bluestem stands in 2018 at both sites. Suther BB and Cave-in-Rock SW mixtures were pure switchgrass in Ithaca, and averaged 10% big bluestem in Chazy. Prairie View BB and Cave-in-Rock SW mixtures averaged 15% bluestem in Ithaca and 35% bluestem in Chazy, at the end of the trial.

Ground cover

Plots in Ithaca were observed for ground cover in the spring of 2018 (Fig. 3). The three replicates were very consistent in ground cover. Switchgrass provided the most ground cover early in the season, with RC Big Rock SW appearing to have the greatest ground cover. BoMaster was the weakest switchgrass, typically with weed infestations. Approximately 50% of the ground area was bare in BB plots, but open areas were generally free of weeds. Even less surface area was covered by ACP, and open areas tended to be infested with weeds annually. With the exception of ACP at both sites, and BoMaster SW at Chazy, other species and species combinations developed into a closed canopy by mid to late summer, regardless of the ground cover observed in spring.

Summary

The only mixtures with a significant contribution from both species were Prairie View BB and Cave-in-Rock SW mixtures. These mixtures had considerably more switchgrass at the Ithaca site compared to the Chazy site. Our results agree with other studies suggesting that species mixtures will be largely influenced by environmental variation. Results from a single location may not be applicable to other environments. Mixtures can improve yields mainly in the establishing years, with the potential for better yield stability over the life of the stands. Farmers should consider planting adapted cultivar mixtures of big bluestem and upland switchgrass for enhanced yield and yield stability. Improving seedling establishment of big bluestem should be an important breeding priority for more widespread adoption of this crop.

Acknowledgments

This work was supported by the USDA National Institute of Food and Agriculture, Multistate project 218756. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the National Institute of Food and Agriculture (NIFA) or the United States Department of Agriculture (USDA).

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What’s Cropping Up? Volume 28, Number 4 – September/October 2018