Malheur Experiment Station Information for Sustainable Agriculture

Third Year Results of the 1999 to 2003 Alfalfa

Forage Variety Trial

Eric P. Eldredge, Clinton C. Shock, and Lamont D. Saunders

Malheur Experiment Station

Oregon State University

Ontario, OR, 2001

Introduction

With increasing dairy herds in Oregon and Idaho and increasing exports of alfalfa cubes, compressed bales, and pellets to nations across the Pacific, a marketing opportunity has developed for premium quality hay. Quality hay can be obtained by cutting alfalfa early, when buds are fully formed but before the first flowers open. Total yield will be lower than it could be with later cuttings. When there is strong demand for premium quality hay, the increased market value may more than compensate for lower yield.

Producing premium quality hay involves increased risk. Repeated early cutting reduces stored carbohydrate in the roots, and can result in thinning stands or a shorter life of the stand. Alfalfa stressed by repeated early cutting is more susceptible to pests and diseases that may be present in the field. Varieties can vary in their ability to withstand frequent cutting, diseases, and insects.

In this 5 year trial, 12 proprietary varieties are being compared to 2 public check varieties for production of high quality hay. The purpose of this trial is to identify alfalfa varieties that remain productive when cut early for high quality hay. The trial is being grown on marginal soil with sprinkler irrigation, characteristic of soils and irrigation practices available for alfalfa hay production.

The trial was established in September 1998, on Nyssa silt loam that has not been deep plowed. Details of this trial's establishment are in a previous annual report (Eldredge, et al., 2000) or on the internet at www.cropinfo.net/annualreports/1999/alf99a2est.htm.

Plots were 20 ft long by 5 ft wide, separated at their ends by 3-foot alleys, with each variety replicated five times in a randomized complete block design. Fall regrowth was cut with a flail mower on December 19, 2000, to reduce soil cover to improve herbicide spray penetration and effectiveness. Soil cover during winter can also promote rodent colonization of the alfalfa stand. A tank mix of Gramoxone at 0.23 lb ai/acre plus Sencor at 0.46 lb ai/acre was applied on March 15 to control winter annual weeds and to provide residual soil active herbicide. On August 10, annual grasses and broadleaf weeds were controlled with an application of Pursuit at 2 oz/acre plus Select at 10 oz/acre.

The alfalfa was harvested on May 22, June 26, August 3, and September 24, 2001. The first cutting was slightly late, as some plants were in bloom. Second cutting was at bud stage. Third cutting was also at bud stage, and fourth cutting was in early bloom. At each cutting date, a 3-ft by 20-ft swath was cut from the center of each plot using a flail mower, and the alfalfa was weighed. Ten random samples of alfalfa were collected over the entire field before each cutting, dried in a forage drier at 140°F with forced air, and re-weighed to determine the alfalfa moisture content at each cutting. Yield was reported based on alfalfa hay at 88 percent dry matter.

Forage quality samples of approximately 20 stems per plot were taken at second cutting at bud stage. The second cutting forage quality samples were dried, ground to pass a 1-mm screen, sub-sampled, and sent to the Oregon State University Forage Quality Lab at Klamath Falls, Oregon, where they were reground to pass a 0.5-mm screen. Near infrared spectroscopy (NIRS) was used to analyze percent crude protein, percent acid detergent fiber (ADF), and percent neutral detergent fiber (NDF). Relative feed value (RFV) was calculated by the formula:

Quality standards based on RFV are Prime, RFV higher than 151; No. 1, RFV 151 to 125; No. 2, RFV 124 to 103; No. 3, RFV 102 to 87; No. 4, RFV 86 to 75; and No. 5, RFV less than 75 (Undersander et al. 1991). A higher RFV means less grain or feed concentrate is required to formulate the dairy ration.

The average total hay yield was 5.68 ton/acre (Table 1). There were no significant differences in hay yield between varieties in the first, second, or third cuttings. The fourth cutting was delayed into September because regrowth was too slow after the third cutting. In the fourth cutting, 'W-L 325HQ' produced 1.35 ton/acre, which was significantly more hay than the lowest five varieties in the fourth cutting.

The crude protein, which averaged 23.3 percent in the second cutting, ranged from 24.1 percent for 'Multi-5301' to 22.2 percent for 'Lahontan'. Crude protein for 'Multi-5301' was significantly higher than the lowest four crude protein values of varieties in the second cutting. ADF averaged 28.9 percent. NDF averaged 39.4 percent. All varieties except 'Gold Plus' and 'Lahontan' produced Prime quality hay, with RFV higher than 151, in the second cutting.

The 3-year hay yield averaged 5.75 ton/acre/year (Table 2). Information on the disease, nematode, and insect resistance of the varieties in this trial was provided by the participating seed companies and/or the North American Alfalfa Improvement Council (Table 3). Most of the varieties have some resistance to diseases and pests that could limit hay production in our area. Growers should choose varieties that have stronger resistance ratings for disease or pest problems known to be present in their fields. The yield potential should be evaluated based on performance in replicated trials at multiple sites over multiple years.

Eldredge, E.P., C.C. Shock, and L.D. Saunders. 2000. First year yield of the 1999-2003 alfalfa forage variety trial. Oregon State University Agricultural Experiment Station Special Report 1015:12-15.

Undersander, D., N. Martin, D. Cosgrove, K. Kelling, M. Schmitt, R. Becker, C. Grau, and J. Doll. 1991. Alfalfa management guide. ASA-CSSA-SSSA, Madison, WI.

Table 1. Alfalfa variety hay yields and second cutting crude protein*, ADF*, NDF*, and relative feed value for 2001. Malheur Experiment Station, Oregon State University, Ontario, OR.

*Based on % of dry weight.

^†ADF: acid detergent fiber.

^‡NDF: neutral detergent fiber.

^§Yield at 88% dry matter.

^¶DW: dry weight. ^††NS: not significant.

*Yield at 88 percent dry matter

Table 3. Variety source, year of release, fall dormancy, and level of resistance to pests and diseases for 14 varieties in the 1999-2003 forage variety trial. Malheur Experiment Station, Oregon State University, Ontario, OR 2001.

*Pest Resistance Rating: >50% = HR (high resistance), 31-50% = R (resistant), 15-30% = MR (moderate resistance), 6-14% = LR (low resistance)

^†FD: fall dormancy, BW: bacterial wilt, FW: Fusarium wilt, VW: Verticillium wilt, PRR: Phytophthora root rot, AN: Anthracnose, SAA: spotted alfalfa aphid, PA: pea aphid, SN: stem nematode, AP: Aphanomyces, RKN: root knot nematode (Northern)

^‡Fall Dormancy: 1 = Norseman, 2 = Vernal, 3 = Ranger, 4 = Saranac, 5 = DuPuits, 6 = Lahontan, 7 = Mesilla, 8 = Moapa 69, 9 = CUF 101

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Last updated  Tuesday July 30, 2002 .