What's Cropping Up? Blog

Articles from the bi-monthly Cornell Field Crops newsletter

June 6, 2018
by Cornell Field Crops
Comments Off on What’s Cropping Up? Vol. 28 No. 2 – May/June 2018

What’s Cropping Up? Vol. 28 No. 2 – May/June 2018

June 5, 2018
by Cornell Field Crops
Comments Off on More Rapid Emergence but Lower Early Plant Densities (V1 Stage) in Organic Compared to Conventional 2018 Soybean

More Rapid Emergence but Lower Early Plant Densities (V1 Stage) in Organic Compared to Conventional 2018 Soybean

Bill Cox, Eric Sandsted, and Phil Atkins

Fig. 1. Organic soybean emerged in about 8 days after planting in 2018.

We initiated a 4-year study at the Aurora Research Farm in 2015 to compare different sequences of the corn-soybean-wheat/red clover rotation in conventional and organic cropping systems under recommended and high input management during the transition period (and beyond) to an organic cropping system. Unfortunately, we were unable to plant wheat after soybean in the fall of 2016 because green stem in soybean, compounded with very wet conditions in October and early November, delayed soybean harvest until November 9, too late for wheat planting. Consequently, soybean followed corn as well as wheat/red cover in 2018 so we are now comparing different sequences of the corn-soybean-wheat/red clover rotation with a corn-soybean rotation (Table 1). This article will focus on soybean emergence (days) and early plant densities (% early plant establishment) at the early 1st node stage (V1 stage) in 2018.  

Fig. 2. Conventional soybean emerged in about 9.5 days after planting in 2018 so is further behind organic soybean 11 days after planting.

The fields were plowed on May 17 and then cultimulched on the morning of May 18, the day of planting. We used the White Air Seeder to plant the treated (insecticide/fungicide) GMO soybean variety, P22T41R2, and the non-treated non-GMO variety, 921A20, at two seeding rates, ~150,000 (recommended input) and ~200,000 seeds/acre (high input). P21A20 is a not an isoline of P22T41R2 so only the maturity of the two varieties and not the genetics are similar between the two cropping systems. We treated the non-GMO, 921A20, in the seed hopper with the organic seed treatment, Sabrex, in the high input treatment (high seeding rate). We used the typical 15” row spacing in conventional soybean and the typical 30” row spacing (for cultivation of weeds) in organic soybean. Consequently, the soybean comparison is not as robust as the corn or wheat comparisons in this study because of the different row spacing and genetics between the two cropping systems.

Warm conditions (64.7 F average temperature and 0.81 inches of precipitation) during the 10 days following planting resulted in fairly rapid emergence. Organic soybean required about 8 days for emergence but conventional soybean required about 9.5 days (Table 2). The more rapid soybean emergence in the organic system is similar to previous years (http://blogs.cornell.edu/whatscroppingup/2017/06/06/soybean-emergence-and-early-plant-densities-v1-v2-stage-in-conventional-and-organic-cropping-systems-in-2017/). In previous years, however, variety differences rather than cropping system differences probably influenced days to emergence with P92Y21, the variety used in the organic system from 2015-2017, with a higher field emergence score (8 out of 10 rating) compared with P22T41R2 (7 out of 10). In 2018, however, we had to switch to P21A20 (P92Y21 no longer available), which had the same field emergence rating (7 out of 10) as P22T41R2. So variety differences probably did not contribute to emergence differences between the two cropping systems. The organic cropping system also was planted in 30 inch rows so there were 8.5 to 11.5 seeds emerging per 1 foot of row in the organic system compared with 4.25 to 5.75 seeds emerging in 1 foot of row in the conventional system. In 2018, however, there was no real soil crust because of intermittent rains after planting so seed spacing within the row was probably not a factor. The final factor to consider is that the insecticide/fungicide seed treatment may have delayed emergence in conventional soybean, as it seemed to delay wheat emergence (http://blogs.cornell.edu/whatscroppingup/2017/12/01/organic-compared-with-conventional-wheat-once-again-has-more-rapid-emergence-greater-early-season-plant-densities-and-fewer-fall-weeds-when-following-soybean-in-no-till-conditions/).

We estimated soybean plant densities at the early V1 stage (June 1), about a week after the rotary hoeing operation in organic soybean. Conventional soybean generally had higher plant establishment rates (78-91%) compared with organic soybean (67 to 76%, Table 2). In previous years, conventional vs. organic soybeans had greater early plant establishment (2016), lower early plant establishment (2017), or similar early plant establishment rates (2015). We did note some damage, but relatively low damage, to organic soybean from the rotary hoe operation, which occurred 6 days after planting. Based on previous data, however, we do not think that rotary hoe damage was totally responsible for the 10 to 15% lower plant establishment rate in organic soybeans. The higher compared with recommended input treatment of organic soybean had higher early plant establishment rates in fields with corn and soybean as the 2014 crops so perhaps the use of the Sabrex seed treatment improved early plant establishment.

In conclusion, early plant populations in conventional soybean (15-inch rows) in the recommended input treatment exceeded the 114,000 plant/acre threshold limit for maximum soybean yields in NY. Consequently, both high and recommended input treatments in conventional soybean have similar yield potential at this stage of development. We have not really established a plant/acre threshold limit for organic soybeans in New York (because very few soybeans are grown in 30-inch rows) so it is not clear if early plant stands of 100,000 to 105,000 plants/acre are adequate for maximum yield. Conceivably, more plants will emerge after our stand counts to increase early plant establishment rates in organic soybean. On the other hand, future cultivations, especially the close to the row cultivation, could decrease organic soybean stands by another 5%. Furthermore, lower stands in the recommended input treatment of organic soybean may allow for increased weed interference, which has the potential to reduce yields. Ironically, the year that organic compared with conventional soybean had greater early plant establishment rate was the only year (2017) that organic soybean yielded lower. It will be interesting to see how the 2018 soybean growing season plays out.

 

Print Friendly, PDF & Email

May 25, 2018
by Cornell Field Crops
Comments Off on No-Till Organic Wheat Continues to Have Low Weed Densities in Early Spring (April 9) at the Tillering Stage (GS 2-3)

No-Till Organic Wheat Continues to Have Low Weed Densities in Early Spring (April 9) at the Tillering Stage (GS 2-3)

Bill Cox and Eric Sandsted, Soil and Crops Sciences Section, School of Integrative Plant Science, Cornell University

From left to right: Organic wheat with high inputs, organic wheat with recommended inputs, 10 foot border, conventional wheat with recommended inputs, and conventional wheat with high inputs.

We initiated a 4-year study at the Aurora Research Farm in 2015 to compare the corn-soybean-wheat/red clover rotation in different sequences under conventional and organic cropping systems during and after the transition to an organic cropping system. This article will discuss weed densities in conventional and organic wheat.

We provided the management inputs for wheat in both cropping systems under high and recommended input treatments in a previous article (http://blogs.cornell.edu/whatscroppingup/2017/12/01/organic-compared-with-conventional-wheat-once-again-has-more-rapid-emergence-greater-early-season-plant-densities-and-fewer-fall-weeds-when-following-soybean-in-no-till-conditions/), but we will briefly review them. We used a John Deere 1590 No-Till Grain Drill to plant a treated (insecticide/fungicide seed treatment) Pioneer soft red wheat variety, 25R46, in the conventional cropping system; and an untreated 25R46, in the organic cropping system on September 27 at two seeding rates, ~1.2 million seeds/acre (recommended management treatment for a September planting date) and ~1.7 million seeds/acre (high input treatment). The wheat was no-tilled in both cropping systems because of the paucity of visible weeds after soybean harvest (9/23). We also applied Harmony Extra (~0.75 oz/acre on 10/27) to the high input conventional treatment at the tiller initiation stage (GS 2-October 27) for control of winter annuals (chickweed, henbit, and common mallow) and winter perennials (dandelion).

We also reported in the above article that we walked along the entire wheat plot (~100 feet X 10 feet) to count all the weeds on 10/27 just prior to the Harmony Extra application to the high input conventional wheat plots. As in 2015, organic compared with conventional wheat generally had lower weed densities in the fall, especially in the field in which corn was the 2014 crop (Table 1). Weed densities, however, were very low so we speculated that yields would probably not be compromised. Dandelion was the dominant weed specie in the fall in all plots. Apparently, the last cultivation of soybean on July 20 removed existing or late-emerging dandelions, whereas the observed weeds in the conventional cropping system apparently emerged after the June 21 Roundup application.

Weather conditions were extremely warm in October (6 degrees above normal) so wheat (and weeds) got off to an excellent start. Ensuing weather conditions, however, were much colder than normal with November, December, January, March, and April averaging more than 2.5 degrees below normal. In fact, March 1-April 30, was the 3rd coldest period on record at the Aurora Research Farm (34.20 average temperature) (http://climod.nrcc.cornell.edu/runClimod/cb248220aa6e4a42/10/), only eclipsed by the infamous 1975 and 1978 early springs (average temperatures of 34.10). Consequently, winter wheat greened up about 2 weeks later than normal in 2018. It is not clear on how the cold winter and early spring conditions affected winter annual and perennial weed development but probably it was delayed.

Early spring weed densities were taken at the GS2-3 stage on 04/10, about 10 days after green-up, again by counting all the weeds along the entire length of the plots. Dominant weeds included dandelion, common mallow, and chickweed. As in the fall, weed densities were extremely low and probably would have no significant effects on yield (Table 1). There was a cropping system by input interaction in the field with corn as the 2014 crop because of very low weed densities in conventional wheat with high inputs (Harmony Extra application) and higher weed densities in organic wheat with high inputs (seeding rates and N rates).

High input management in organic wheat did not reduce weed densities, which agrees with the 2016 data (http://blogs.cornell.edu/whatscroppingup/2016/04/05/no-till-organic-wheat-continues-to-have-low-weed-densities-in-early-spring-march-31-at-the-tillering-stage-gs-2-3/). Some organic growers believe that wheat should be planted at a higher seeding rate to reduce weed densities, but our study does not support that speculation. Our data does support the idea that if weed densities are low in organic soybean (<2.5 weeds/m2), organic wheat growers can no-till wheat into soybean stubble without fear of high weed densities. More research, however, should be conducted to compare no-till and conventional tillage organic wheat.

In conclusion, no-till organic and conventional wheat had very low spring weed densities about 10 days after green-up. The cool conditions in April prevented rapid shading by the wheat canopy so perhaps the weeds that were present in early April may interfere with wheat yields, but impacts should be minimal because of the low densities. On April 15, organic wheat looked as good as conventional wheat (picture). It remains to be seen, however, if Kreher’s composted chicken manure, the N source for organic wheat (60 lbs. /acre of actual N pre-plant +50 lbs. /acre of actual N on 3/21 in high input and the single 75 lbs. /acre of actual N as a spring application in recommended management) can provide enough available N for maximum yield in organic wheat.

Print Friendly, PDF & Email

May 2, 2018
by Cornell Field Crops
Comments Off on Spring N Management is Important for Triticale Forage Performance Regardless of Fall Management

Spring N Management is Important for Triticale Forage Performance Regardless of Fall Management

Sarah E. Lyonsa, Quirine M. Ketteringsa, Greg Godwina, Jerome H. Cherneyb, Karl J. Czymmeka,c, and Tom Kilcera,d
a Nutrient Management Spear Program, Department of Animal Science, Cornell University, Ithaca, NY, b Soil and Crop Sciences Section of the School of Integrative Plant Science, Cornell University, Ithaca, NY, c PRODAIRY, Department of Animal Science, Cornell University, Ithaca, NY, and d Advanced Agricultural Systems, LLC, Kinderhook, NY

Introduction

Including a cool-season crop like triticale in a forage rotation can be a rewarding enterprise for dairy farms in the Northeast. Double cropping with winter cereals can provide environmental advantages such as reduced risk of erosion and nutrient loss, enhanced soil fertility, and improved rotation diversity, in addition to increased total season yields. Planting before September 20th was shown to increase nitrogen (N) uptake and biomass in the fall (see Lyons et al., 2017), but the impact of fall management on spring performance was unclear. To evaluate the effect of planting date and fall N availability on triticale forage yield and quality, three trials were conducted from 2012-2014.

Trial Set-Up

The three trials were planted with triticale (King’s Agri-Seeds Trical 815 variety) from late August to early October on research farms in eastern NY (Valatie) and central NY (Varna). None of the fields had a recent manure history. Each trial had two planting dates (one before and one after September 20). Triticale was planted at a 1-inch seeding depth and 7.5-inch row spacing (120 lbs/acre seeding rate). To create a range in soil nitrate availability, 5 N rates were applied at planting in the fall (0, 30, 60, 90, and 120 lbs N/acre; main plots). Biomass was sampled in the fall (see Lyons et al., 2017). In the following spring, the same 5 N rates were applied at dormancy break (0, 30, 60, 90, and 120) for each fall N rate (sub plots). All plots were harvested at flag leaf stage in May of each year (from May 14-21) at a 4-inch cutting height. Measurements included dry matter yield, crude protein (CP), the most economic rate of N (MERN), the ratio of fall biomass to spring yield at the MERN to see if fall biomass can predict spring yield, and “Nitrogen Use Efficiency” (NUE). The NUE is the measure 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 (at 30, 60, 90, or 120 lbs N/acre), 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 triticale.

Results

We found that when no N was applied in the spring, N applied at planting the previous fall increased spring yield only when triticale was planted by September 20 (Figure 1a). Across all trials, yields with no fall or spring N applications averaged 0.8 tons DM/acre. With fall N applications ranging from 30-120 lbs/acre (no spring N), yields ranged from 1.4 to 1.9 tons DM/acre. Yields trended upward with increasing fall N rates, but the only significant yield response to N was at the 30 lbs N/acre treatment. Where triticale was planted after September 20, fall N did not significantly increase spring yield (1.2 tons DM/acre average) (Figure 1b). Crude protein at spring harvest followed a similar trend as yield, but it took a fall application of 120 lbs N/acre to see a significant difference in CP (9.4 versus 10.7%) in the spring (no N applied at green-up) and that occurred with early planting only. Because fall uptake of N does not seem to greatly influence forage protein content in the spring, these results suggest that proper spring fertilization management for optimal nutritive performance is most important.

Figure 1: Effect of fall N application on triticale yield and crude protein concentrations in the spring. Triticale was seeded on two planting dates: before September 20 (A), and after September 20 (B). No N was applied at green-up in the spring N. Data are averages for three locations.

Although fall N application and planting date had some impact on spring yield, neither treatment affected spring MERN (Figure 2a), yield at the MERN (Figure 2b), or NUE at the MERN (17.6 lbs DM/lbs N average). Additionally, the ratio between fall biomass and spring yield was not impacted by the treatments. The earlier planted sites had higher ratios (closer to 1) because with earlier planting there was more fall biomass and the relative gain in yield in the spring was smaller.

Figure 2: Spring most economic rate of N (MERN, A) and yield at the MERN (B) for different fall N fertilizer rates and planting dates of triticale.

Conclusions and Implications

Winter cereals like triticale grown for forage in double crop rotations can provide environmental benefits and additional harvestable forage for dairy producers in the Northeast. When no N was applied in the spring, a small fall N application at planting (30 lbs N/acre) increased yields in the spring if the stand had been planted before September 20. There was no benefit of fall N when the stand was planted later in the fall. Crude protein was only increased when a large amount of fall N (120 lbs N/acre) was applied at a planting date before September 20 and when no spring N had been applied. The MERN and yield at the MERN for each trial were not influenced by fall N or planting date, suggesting that spring N management is by far the most important management consideration for achieving optimum yields. A larger sample size than just three locations may be needed to detect any differences but this research suggests that on fields without recent manure histories, triticale forage requires 60-90 lbs N/acre at dormancy break to achieve optimum yields. Work is ongoing to determine N needs for forage winter cereals under a variety of management scenarios, including manured fields.

Reference

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/.

 

Print Friendly, PDF & Email

May 2, 2018
by Cornell Field Crops
Comments Off on Soil Nitrate at Harvest of Forage Winter Cereals is Related to Yield and Nitrogen Application at Green-up

Soil Nitrate at Harvest of Forage Winter Cereals is Related to Yield and Nitrogen Application at Green-up

Sarah E. Lyonsa, Quirine M. Ketteringsa, Greg Godwina, Karl J. Czymmeka,b, Sheryl N. Swinka, and Tom Kilcera,c
a Nutrient Management Spear Program, Department of Animal Science, Cornell University, Ithaca, NY, b PRODAIRY, Dept. of Animal Science, Cornell University, Ithaca, NY, cAdvanced Agricultural Systems, LLC, Kinderhook, NY

Introduction

Double cropping with winter cereals provides many benefits to forage rotations, including soil erosion control, addition of soil organic matter, nutrient recycling, and boosting home-grown forage inventory. Previous work on winter cereal cover crops (green manure, not harvested for forage) in New York suggested that, in most cases, 20-30 lbs nitrogen (N)/acre can be credited to the next crop (see Ort et al., 2013). When the winter cereal is harvested for forage instead of terminated as a cover crop, about 50 lbs N/acre is removed for every 1 ton DM/acre harvested, but some N remains in the crop stubble and roots. For a winter cereal yielding about 2 tons DM/acre there will still be an estimated 0.7 tons DM/acre in the root and stubble biomass (see Long et al., 2013), meaning about 20-30 lbs N/acre could become available over the growing season as the residue decomposes. Due to the time it takes to decompose this biomass, residual N from winter cereal roots and stubble is not likely sufficient to offset starter N needs if the next planting occurs shortly after the winter cereal is harvested. However, when fertilizer N is applied to winter cereals at dormancy break, there is usually some nitrate remaining in the soil as it is likely that not all of the N applied is taken up by the winter cereal. In some situations, the residual nitrate from a spring topdress fertilizer application may meet early season corn needs and substitute for a starter N application. This summary aims to address how to credit N to the next corn crop from fertilized winter cereals harvested as forage.

Field Research

As part of a state-wide study investigating spring N needs of winter cereal forages, 63 on-farm trials were conducted in New York from 2013-2016. Trials 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). The forages were harvested at flag-leaf stage in May each year. For seven of these trials in central New York (in 2015 and 2016; two cereal rye, five triticale) we took soil samples (0-8 inches) at green-up and at harvest and analyzed them for soil NO3-N (KCl extractable NO3-N). While nitrate exists in the soil as NO3,  we measure it in the lab as nitrate-N, or NO3-N, which represents the total amount of N in the nitrate molecules, not the total nitrate in the sample. Planting dates for the seven trials ranged from September 15 to October 10, and harvest dates ranged from May 11 to 21. All seven sites had a manure history and were in corn prior to planting of the winter cereal. Winter cereals were drilled at seeding rates ranging from 100 to 125 lbs/acre. Here we report on the NO3-N levels in the soil at harvest of the winter cereal as an indicator of spring starter N needs for corn.

Results

Figure 1. Nitrate-N at harvest of two cereal rye trials and five triticale trials in New York (2015-2016). Nitrogen fertilizer at the indicated rates was applied at dormancy break. Different letters indicate significant differences between N rate treatments.

Across all seven trials, soil NO3-N following harvest increased with fertilizer N applications at green-up (Figure 1 and Table 1). On average, NO3-N levels at harvest were 12, 13, 18, 27, and 40 lbs NO3-N/acre for the 0, 30, 60, 90, and 120 lbs N/acre treatments, respectively. For the two trials that had yields of 1 ton DM/acre or less (#58 and #62), left-over soil NO3-N was considerably higher, especially when N was applied above the MERN (Table 1). The trial that had the highest yield at 3.1 tons DM/acre (#63) had the lowest residual soil NO3-N at harvest for all N rates even though the MERN for this site was 0 lbs N/acre (crude protein increased with N addition). These data suggest that residual soil NO3-N is related to yield; the higher the yield, the lower the left-over soil NO3-N at harvest. Applying N at rates above the MERN can also result in elevated soil nitrate concentrations.

Conclusions and Implications

Nitrate as represented by NO3-N in the soil at harvest ranged (averaged across sites) from 12 lbs NO3-N/acre for the 0 lbs N/acre treatment to 40 lbs NO3-N/acre for the 120 lbs N/acre treatment. Based on the results here, when N applications are close to the MERN for the site, soil NO3-N at harvest is approximately 10 lbs NO3-N/acre, the level typically measured at the start of the growing season at sites without winter cereals in the rotation. Left-over NO3-N in the soil is related to yield of the winter cereal; higher yield means lower residual soil NO3-N at harvest, while low yield (less than 1 ton DM/acre) can result in high soil NO3-N levels. The basic recommendation for corn is to apply a small amount of starter fertilizer at planting (20-30 lbs N/acre). This is under the assumption that there is not a significant amount of NO3-N available from other sources at that time. This winter cereal research suggests that there can be a sufficient amount of soil nitrate at harvest that could be available to the subsequent corn crop, especially when winter cereals are fertilized at green-up at levels that exceed crop needs and/or where yields are depressed for other reasons. The most direct way of determining soil nitrate at winter cereal harvest is to soil sample for NO3-N. Fields that will be planted to corn where soil nitrate levels exceed 20 lbs NO3-N/acre following a winter cereal forage harvest may not respond to starter N. Test strips can help improve these decisions over time.

References

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/

Print Friendly, PDF & Email

May 1, 2018
by Cornell Field Crops
Comments Off on Forage Quality of Spring Growth

Forage Quality of Spring Growth

J.H. Cherney and D.J.R. Cherney
Soil & Crop Science Section, and Dept. of Animal Science, Cornell University

As we are rapidly approaching another spring season of forage growth, it may be useful to consider some of the issues that affect the assessment of spring forage growth. Since most of the forage in NY is alfalfa-grass mixtures, and most of the forage becomes dairy cattle feed, we are focusing on the optimum timing for harvest of mixtures for high quality dairy feed. High quality alfalfa and grass forage will significantly increase milk production and increase the proportion of homegrown feeds in rations. Fiber digestibility (NDFD) is the most important forage factor affecting milk production.

For high producing dairy cows, an increase of one-percentage unit NDFD may increase milk production as much as one pound of milk per cow per day. Higher NDFD in forages can be achieved by harvesting earlier, or by selecting higher NDFD alfalfa and grass varieties. Almost all alfalfa seed companies have a “high quality” alfalfa variety, although there is likely a considerable range in quality among “high quality” varieties. There have been very few attempts to breed grass varieties for high quality, but there are some differences among grass species.

Optimum spring harvest should not be based on NDFD, however, but needs to be based on the optimum total fiber content (NDF) of the forage. Rations can be easily balanced for protein and energy, not so easy to balance for fiber.

Spring 2017 Sampling of Forage Quality

We monitored first production year spring growth of alfalfa and grass in 2017. Alfalfa varieties sown were: HarvXtra-1, HarvXtra-2, Hi-Gest 360, LegenDairy HXD, N-R-Gee, SW315LH, and Pioneer 55H94. Grass varieties sown were: Driftless meadow fescue, Bariane tall fescue, Barlegro orchardgrass, Dividend VL orchardgrass, sparse-heading orchardgrass, Fojtan festulolium, and Perseus festulolium. Alfalfa and grass were grown separately with three field replicates, and grass was fertilized with 100 lbs N at spring green up.

Protein

Alfalfa quality does not appear to be affected by the presence of grass in the stand, such that evaluation of alfalfa in pure stands should produce similar results to evaluating alfalfa grown in mixtures. In general, grass quality also is not greatly affected by alfalfa in a mixed stand, with one exception. From previous studies, we conclude that grass crude protein (CP) content in alfalfa-grass mixtures is directly proportional to the percent alfalfa in the mixed stand.

In a pure stand, grass CP will decline linearly (Fig. 1). In a mixed stand that is predominantly alfalfa, grass CP will not decline as quickly as in a pure grass stand, because of a continuous supply of N from alfalfa. In several previous alfalfa-grass studies in NY conducted on dairy farms, a spring harvest around May 25 consistently resulted in grass with over 17% CP, when the stands were 30% grass. Total alfalfa+grass CP in a 30% grass stand generally exceeds 20% CP at spring harvest.

Fig. 1. Crude protein content of alfalfa and grass grown separately in spring 2017.

Note: Beware, this article contains differences between varieties sometimes expressed as a percentage unit change (e.g. NDFD difference of 54% to 50% = 4 percentage unit drop in NDFD) and sometimes appropriately expressed as a percent change (e.g. lignin difference of 6% to 5% = 17% drop in lignin).

Pattern of Forage Quality in Spring

In a normal spring, forage quality of both alfalfa and grass will generally fluctuate until around May 10. There may not much to be gained by collecting forage samples for analysis (e.g. scissors-cut samples) the first week of May. After about May 10, NDF and NDFD often show linear patterns of increase or decrease (Fig. 2 & 3). Grass typically gains about 1 percentage unit of NDF per day in the spring, and was relatively normal in 2017 in spite of somewhat abnormal temperatures. Alfalfa, on the other hand, matured faster than normal the last half of May. Alfalfa typically gains about 0.6 to 0.7 percentage units of NDF per day prior to spring harvest.

Fig. 2. Below normal temperatures in early May, followed by average and above average temperatures, resulted in alfalfa maturing faster than normal in the second half of May.

Fig. 3. Grass NDFD declined at a relatively normal rate in spring 2017, while alfalfa NDFD declined much faster than normal.

Although alfalfa was maturing at a faster rate than normal in late May, maturity at spring harvest was similar to a normal year. On May 25, a typical spring harvest date for alfalfa-grass in central NY, alfalfa averaged 37% NDF, compared to 57% for grass. NDFD on May 25 averaged 49% for alfalfa and 72% for grass. High NDFD in grass is the primary reason that alfalfa-grass mixtures can result in an excellent forage for high producing dairy cows.

Alfalfa Variety Differences

We have found in other studies that HarvXtra (Hx) types tend to be slightly later in maturity than other alfalfas, when measuring mean maturity stage. This leads to a slightly lower NDF content in Hx on any given date (Fig. 4). Hx also has a slightly lower rate of NDF accumulation. On May 11, Hx is about 1 percentage unit lower, while on May 29 it is a little over 2 percentage units lower than other alfalfas.

Fig. 4. NDF accumulation in HarvXtra types, compared to other alfalfa varieties.

NDFD of Hx types was consistently higher than other alfalfas (Fig. 5), with a slightly faster rate of decline in NDFD/day. On May 11, Hx was 4 percentage units higher, and on May 29 it was 3 percentage units higher in NDFD than the average of other alfalfa varieties.

Fig. 5. Fiber digestibility of HarvXtra type alfalfa, compared with other varieties.

As we have found in a number of other trials, Hx is consistently much lower in lignin content than other alfalfa varieties (Fig. 6). Hx also had a slightly lower rate of lignin accumulation. On May 11, Hx was 12% lower, and on May 29 it was 14% lower in lignin than the average of other alfalfa varieties.

Fig. 6. Pattern of lignin accumulation in spring alfalfa growth.

Grass Species Differences

In grasses, NDF typically accumulates around 1 percentage unit/day in spring growth (Fig. 7). Grass species in this trial were all similar in NDF content and rate of NDF accumulation with one exception. Perseus festulolium is a ryegrass-type of festulolium very different from fescue-type festuloliums (e.g. Fojtan). Total fiber content is very low in Perseus spring growth, and NDF accumulates at a slightly lower rate in Perseus compared to other grasses. A May 25 spring harvest of Perseus was over 9 percentage units lower in NDF than other grasses. The serious problem with Perseus and probably all festuloliums, however, is the tendency to head out quickly in regrowth, making second harvest festulolium forage much lower in quality than other grasses. Festuloliums are not a particularly good option as a companion crop with alfalfa for dairy cow forage for that reason.

Fig. 7. Rate of NDF accumulation in grasses in spring growth.

As it is less mature and much lower in NDF, Perseus is also considerably higher in NDFD than most grasses in spring growth, except for meadow fescue (Fig. 8). Perseus is significantly lower in NDFD than other grasses in regrowth, however, due to rapid heading in regrowth. Meadow fescue NDFD appears to decline at a slower rate than with other grasses. At the time of a typical spring harvest, meadow fescue is similar in NDFD to Perseus festulolium, and is 11% higher in NDFD than other grasses.

Fig. 8. Fiber digestibility of grasses in spring growth.

Lignin content of meadow fescue and Perseus festulolium did not differ, but both were significantly lower than all other grasses (Fig. 9). Also, lignin accumulates at a slower rate for meadow fescue and Perseus, compared to other grasses. On May 20, meadow fescue was 22% lower in lignin than other grasses, excluding Perseus.

Fig. 9. Lignin content of grasses in spring growth.

We have collected 19 meadow fescue varieties from North America and Europe that will be sown as pure grass stands in Ithaca, NY and Burlington, VT this spring. Heading dates and quality data will be gathered in 2019. We will also plant these meadow fescue varieties in binary mixtures with one alfalfa variety in Ithaca and in Lewis County, to evaluate competition and grass percentage of mixtures.

Summary

On May 25, 2017, a typical central NY date for spring harvest, grass averaged 20 percentage units higher NDF than alfalfa, but also averaged 23 percentage units higher NDFD. Among alfalfa varieties, HarvXtra types were slightly lower in NDF, somewhat higher in NDFD, and much lower in lignin content than other alfalfa varieties. Being a predominantly ryegrass-type of festulolium, Perseus was very low in NDF and high in NDFD in spring growth, but typically heads out in regrowth, resulting in relatively low quality regrowth forage.

Meadow fescue is high in NDFD and the decline in NDFD per day is not as great as with other grasses. On May 25, this resulted in meadow fescue NDFD being 11% higher than other grasses, except Perseus. While meadow fescue is consistently higher quality than other grasses commonly sown in the Northeast, it is not necessarily better in some other regions of the country, particularly if the location is near the southern limit of meadow fescue’s productive range. The relatively rapid decline in forage NDFD in spring growth (nearly 1 percentage unit/day) makes a timely spring harvest critical for high forage quality.

Print Friendly, PDF & Email

Subscribe By Email

Get a weekly email of all new posts.

Please prove that you are not a robot.

Skip to toolbar