Forage brassica can provide a near-concentrate type diet late in the grazing season. This allows for an extra grazing opportunity after annual row crops are harvested, and establishes forage to fill a gap in feed quality and supply. These crops can provide a high-quality feed in a short period of time, fitting well into rotations of other crops, extending the grazing season, and reducing reliance on expensive commercial feed inputs. In 2013, the University of Vermont’s Northwest Crops & Soils Program conducted a forage brassica variety trial to evaluate yield and quality of this annual crop

Burke, Conner

Cummings, Erica

Darby, Heather

Harwood, Hannah

Madden, Laura

Monahan, Susan

English

UVM ScholarWorks

University of VermontScholarWorks @ UVMNorthwest Crops & Soils Program UVM Extension2013Forage Brassica Variety TrialHeather DarbyUniversity of Vermont, heather.darby@uvm.eduLaura MaddenUniversity of VermontConner BurkeUniversity of VermontErica CummingsUniversity of VermontHannah HarwoodUniversity of VermontSee next page for additional authorsFollow this and additional works at: https://scholarworks.uvm.edu/nwcspPart of the Agricultural Economics CommonsThis Report is brought to you for free and open access by the UVM Extension at ScholarWorks @ UVM. It has been accepted for inclusion inNorthwest Crops & Soils Program by an authorized administrator of ScholarWorks @ UVM. For more information, please contactdonna.omalley@uvm.edu.Recommended CitationDarby, Heather; Madden, Laura; Burke, Conner; Cummings, Erica; Harwood, Hannah; and Monahan, Susan, "Forage Brassica VarietyTrial" (2013). Northwest Crops & Soils Program. 31.https://scholarworks.uvm.edu/nwcsp/31AuthorsHeather Darby, Laura Madden, Conner Burke, Erica Cummings, Hannah Harwood, and Susan MonahanThis report is available at ScholarWorks @ UVM: https://scholarworks.uvm.edu/nwcsp/31  2013 Forage Brassica Variety Trial    Dr. Heather Darby, UVM Extension Agronomist Laura Madden, Conner Burke, Erica Cummings, Hannah Harwood, and Susan Monahan UVM Extension Crops and Soils Technicians Visit us on the web at: http://www.uvm.edu/extension/cropsoil      © January 2014, University of Vermont Extension  2013 FORAGE BRASSICA VARIETY TRIAL Dr. Heather Darby, University of Vermont Extension Heather.Darby[at]uvm.edu  Forage brassica can provide a near-concentrate type diet late in the grazing season.  This allows for an extra grazing opportunity after annual row crops are harvested, and establishes forage to fill a gap in feed quality and supply. These crops can provide a high-quality feed in a short period of time, fitting well into rotations of other crops, extending the grazing season, and reducing reliance on expensive commercial feed inputs.  In 2013, the University of Vermont’s Northwest Crops & Soils Program conducted a forage brassica variety trial to evaluate yield and quality of this annual crop.  MATERIALS AND METHODS In 2013, a variety trial was conducted at Borderview Research Farm in Alburgh, VT, in order to evaluate seven forage brassica varieties (Table 1, Figure 1).  All varieties were purchased from King’s Agriseed, Ronks, PA. Table 1. Forage brassica varieties, 2013. Variety Species Appin Turnip Barkant Turnip Bonar Rape Nitro Radish Purple Top Turnip Rangiora Rape T-Raptor Brassica hybrid  The seedbed at Borderview Research Farm was prepared using standard local practices, including incorporating spring wheat residue with a moldboard plow and finishing with disk and drag harrows (Table 2). The soil was a Benson silt loam. The experimental design was a randomized complete block with three replications. Each plot was 5’ by 20,’ and a Great Plains grain drill was used to plant brassicas at a rate of 6 lbs per acre on 23-Aug.  Table 2. Agronomic and trial information for the 2013 forage brassica variety trial. Location Borderview Research Farm-Alburgh, VT Soil type Benson silt loam Previous crop Spring wheat Tillage operations Moldboard plow, disking, drag harrow Plot size (ft.) 5 x 20 Replicates 3 Planting date 23-Aug Seeding rate 6 lbs ac-1 Harvest date 5-Nov Figure 1. Appin turnip just before harvest.  All plots were hand harvested on 5-Nov to determine dry matter yields. Samples were dried and ground and a subsample was retained for chemical analysis. Forage quality was analyzed at Cumberland Valley Analytical Services in Hagerstown, Maryland using wet chemistry techniques. Plot subsamples were analyzed for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and 30-hour digestible NDF (NDFD).  The CP content of forages is determined by measuring the amount of nitrogen and multiplying by 6.25. The bulky characteristics of forage come from fiber. High fiber is negatively associated with forage feeding values since the less digestible portions of plants are contained in the fiber fraction. The detergent fiber analysis system separates forages into two parts: cell contents, which include sugars, starches, proteins, nonprotein nitrogen, fats and other highly digestible compounds; and the less digestible components found in the fiber fraction. The total fiber content of forage is contained in the neutral detergent fiber (NDF). Chemically, this fraction includes cellulose, hemicellulose and lignin. Because of these chemical components and their association with the bulkiness of feeds, NDF is closely related to feed intake and rumen fill in cows.  Recently, forage testing laboratories have begun to evaluate forages for NDF digestibility (NDFD).  Evaluation of forages and other feedstuffs for NDFD is being conducted to aid prediction of feed energy content and animal performance.  Research has demonstrated that lactating dairy cows will eat more dry matter and produce more milk when fed forages with optimum NDFD.  Forages with increased NDFD will result in higher energy values and, perhaps more importantly, increased forage intakes.  Forage NDFD can range from 20-80% NDF.   Variations in yield and quality can occur because of variations in genetics, soil, weather, and other growing conditions. Statistical analysis makes it possible to determine whether a difference among treatments is real or whether it might have occurred due to other variations in the field. All data was analyzed using a mixed model analysis where replicates were considered random effects. At the bottom of each table, a LSD value is presented for each variable (e.g. yield). Least Significant Differences (LSDs) at the 10% level (0.10) of probability are shown. Where the difference between two treatments within a column is equal to or greater than the LSD value at the bottom of the column, you can be sure in 9 out of 10 chances that there is a real difference between the two values. Treatments listed in bold had the top performance in a particular column; treatments that did not perform significantly worse than the top-performer in a particular column are indicated with an asterisk. In the example at right, treatment A is significantly different from treatment C, but not from treatment B. The difference between A and B is equal to 400, which is less than the LSD value of 500. This means that these treatments did not differ in yield. The difference between A and C is equal to 650, which is greater than the LSD value of 500. This means that the yields of these treatments were significantly different from one another.   RESULTS Using an onsite Davis Instruments Vantage Pro2 Weather Station at Borderview Research Farm in Alburgh, VT, weather data are summarized for the 2013 forage brassica growing season (Table 3).  August and September were slightly cooler than the historical average (1981-2010), while October was slightly warmer.  The warm October resulted in 98 more growing degree days than the 30-year average, Variety Yield A 1600* B 1200* C 950 LSD (0.10) 500 as calculated with a base temperature of 32°F. The 2013 fall growing season was also drier than the historical average, with 4.32 fewer inches of rain than normal between August and October.  Table 3. Summarized weather data for 2013 – Alburgh, VT. Alburgh, VT August September October Average temperature (°F) 67.7 59.3 51.1 Departure from normal -1.1 -1.3 2.9     Precipitation (inches) 2.41 2.20 2.22 * Departure from normal -1.50 -1.44 -1.38     Growing Degree Days (base 32°F) 1112 825 600 Departure from normal -27 -33 98 Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT. *October 2013 precipitation based on National Weather Service data from cooperative stations in South Hero, VT.   Average plant height differed significantly between varieties (Table 4, Figure 2).  The tallest variety was Rangiora at 38 cm.  This was statistically similar to Bonar (36.0 cm), Appin (33.3 cm), and Barkant (32.8 cm), but statistically different from T-Raptor (26.6 cm), Nitro (25.7 cm) and Purple Top (23.8 cm).   Figure 2. Average plant height for seven forage brassica varieties, Alburgh, VT, 2013.Treatments with the same letter did not differ significantly from one another (p=0.10). 0510152025303540Purple Top Nitro T-Raptor Barkant Appin Bonar RangioraAverage height (cm) Variety a a a ab bc c c Brassica varieties did not differ significantly in forage quality characteristics, yield or harvest dry matter (Table 4).  The average yield for the brassica trial was 2243 lbs of dry matter per acre. The CP concentrations average 21.6%. The low fiber levels and high fiber digestibility are characteristic of this crop.  Table 4. Yield, dry matter content and forage quality characteristics for seven forage brassica varieties, Alburgh, VT, 2013. Variety Plant height Harvest dry matter DM yield Forage quality characteristics    (DM)  CP ADF NDF NDFD      % of % of % of % of   cm % lbs/ac-1 DM DM DM NDF Appin 33.3* 16.5 2762 21.5 18.8 20.1 64.9 Barkant 32.8* 16.3 2346 20.5 18.1 19.5 70.2 Bonar 36.0* 16.8 2474 20.9 17.0 18.0 71.0 Nitro 25.7 16.0 1968 24.5 19.5 20.5 71.0 Purple Top 23.8 16.8 2050 19.8 19.3 21.5 68.7 Rangiora 38.0* 16.1 2030 25.3 17.6 19.5 73.7 T-Raptor 26.6 14.0 2073 18.6 15.8 17.1 71.8 LSD (0.10) 6.4 NS NS NS NS NS NS Trial mean 30.9 16.1 2243 21.6 18.0 19.5 70.2 Treatments indicated in bold had the top observed performance. * Treatments indicated with an asterisk did not perform significantly lower than the top-performing treatment in a particular column. NS – No significant difference was determined between treatments. DISCUSSION  Forage brassicas have great potential as an additional grazing crop in the Northeast. With average dry matter yields of over a ton, this study demonstrated that any of the trialed forage brassica varieties could be a strong addition to a feeding plan, providing valuable nutrition during seasonal feed shortages and reducing the need for imported feed. While statistically insignificant, the turnip species Appin had the highest dry matter yield (2762 lbs per acre).   Forage brassicas are known for the high CP content, energy and level of digestibility.  The variety with the highest CP was the rape species Rangiora.  However, this did not differ significantly from any of the other varieties.  The average CP for this trial was 21.6%.  The average ADF for this trial was 18.0%, the average NDF was 19.5%, and the average NDFD was 70.2%.  While the top varieties for these characteristics were Nitro, Purple Top, and Rangiora respectively, these varieties did not differ significantly from other varieties.  Yield and quality should both be taken into consideration before selecting a variety. The high overall levels of crude protein show that most forage brassicas have the potential to be a welcome addition to a fall grazing system. This highly digestible feed should be complemented with a more fibrous feed. This brassica crop would likely be grazed in short time increments to reduce the potential for herd health issues associated with highly digestible feed.  It is important to note that the data presented here reflect results from only one season and one location. This research should be combined with experience managing dairy animals and research from other regions and across years, as well as recommendations from nutritionists.   ACKNOWLEDGEMENTS   UVM Extension would like to thank Roger Rainville at Borderview Research Farm in Alburgh for his generous help with this research trial.  We would also like to acknowledge Katie Blair and Ben Leduc for their assistance with data collection and entry.  The research was funded in part by the NRCS Conservation Innovation Grant (CIG) and Organic Valley’s Farmers Advocating for Organics (FAFO) Fund and USDA NIFA Organic Research and Education Initiative grants.  This information is presented with the understanding that no product discrimination is intended and no endorsement of any product mentioned, nor criticism of unnamed products, is implied.  UVM Extension helps individuals and communities put research-based knowledge to work.    Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. University of Vermont Extension, Burlington, Vermont. University of Vermont Extension, and U.S. Department of Agriculture, cooperating, offer education and employment to everyone without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or familial status.     

Forage Brassica Variety Trial

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Forage Brassica Variety Trial

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