First Year Results of the 2006-2011 Furrow-irrigated Alfalfa Forage Variety Trial

Malheur Experiment Station

Information for Sustainable Agriculture

First Year Results of the 2006-2011 Furrow-irrigated Alfalfa Forage Variety Trial

Eric Eldredge, Clinton Shock, and Monty Saunders
Oregon State University
Malheur Experiment Station
Ontario, OR, 2006

Introduction

The purpose of this trial is to compare the productivity and hay quality of alfalfa varieties in the Treasure Valley area of Malheur County. The trial also provides information about the adaptation of alfalfa varieties to furrow irrigation for hay production. In this 5-year trial, eight proprietary varieties are being compared to two public check varieties.

Methods

The trial was established on Owyhee silt loam where winter wheat was the previous crop and alfalfa had not been grown for more than 10 years. A soil sample taken on September 6, 2005 showed 57 lb N/acre in the top 2 ft of soil. The soil in the top foot had pH 7.7, 1.3 percent organic matter, 18 ppm P, 437 ppm K, 10 ppm sulphate, 1,851 ppm Ca, 351 ppm Mg, 1.4 ppm Zn, 0.5 ppm Cu, 4 ppm Mn, 4 ppm Fe, and 0.5 ppm B. The field was plowed, and fertilizer was applied to supply 100 lb P₂O₅/acre, 300 lb S/acre, 5 lb Zn/acre, 8 lb Mn/acre, 4 lb Cu/acre, and 1 lb B/acre.

The field was ground-hogged and corrugated on 30-inch furrow spacing using a spike-tooth bed harrow. Eptam^® at 4 pt/acre plus Balan^® at 1.5 lb/acre was applied on September 19 and incorporated with two additional passes, in opposite directions, with the bed harrow. On September 20, 2005, seed of each variety was planted in plots 60 inches wide by 20 ft long, replicated five times. Seed was planted at a rate of 20 lb/acre using a cone seeder with a spinner divider feeding three double-disk furrow openers per 30-inch bed.

This trial was established and grown with furrow irrigation from gated pipe. The field was irrigated for 24 hours on September 21, 2005 to promote rapid, uniform emergence, and cotyledons emerged on September 26, 2005. The field was hand weeded on April 20, 2006 and alleys were cut between plots on May 21. The first irrigation in 2006 was applied on June 1, after the first cutting. Irrigation was applied for approximately 24 hours once per week with the final irrigation applied on September 1. The field was recorrugated on October 24.

The entire trial area was mowed and the clippings were removed to reduce rodent cover and expose more of the soil for herbicide application, and Maki^® rodenticide pellets were applied in vole (“field mice”) tunnels using a probe type applicator on November 15. On November 16, the soil-active selective herbicides Kerb^® 50WP at 1.5 lb/acre and Sinbar^® 80WP at 1.5 lb/acre were applied, and a follow-up treatment of Maki rodenticide was made on December 5.

In 2006, the first cutting was taken on May 31. A 32-inch by 20-ft swath was cut from the center of each plot with a flail mower, and the alfalfa was weighed. The alfalfa was harvested three more times, on June 30, August 8, and September 25. Ten samples of alfalfa were cut by hand from border areas of plots over the entire field on the same day just before each cutting; they were quickly weighed, dried, and reweighed to determine the average alfalfa moisture content at each cutting. Yield was reported as tons per acre of alfalfa hay at 88 percent dry matter.

Samples of alfalfa from approximately 1 ft of row per plot were taken mid-morning on August 8, before the third cutting, to measure forage quality. The forage quality samples were dried, ground in a Wiley mill (Thomas Scientific, Swedesboro, NJ) to pass through a 1-mm screen, and sent to the Oregon State University Forage Quality Lab at Klamath Falls, Oregon, where they were reground in a UDY mill (UDY Corp., Ft. Collins, CO) to pass through a 0.5-mm screen. Near infrared spectroscopy (NIRS) was used to estimate percent dry matter, percent crude protein, percent acid detergent fiber (ADF), percent neutral detergent fiber (NDF), percent fat, and percent ash. Relative forage quality (RFQ) was calculated by the formula:

RFQ = (DMI *TDNL) / 1.23

where:

DMI = Dry Matter Intake (for alfalfa hay), and

DMI = (((0.120 * 1350) / (NDF/100)) + (NDFD - 45) * 0.374)) / 1350 * 100, and

NDFD = dNDF48 / NDF * 100, and

dNDF48 = Digestible NDF as a percentage of Dry Matter, as determined by a 48-hour in vitro digestion test,

TDNL = Total Digestible Nutrients [for Legume (alfalfa hay)]

TDNL = (NFC * 0.98) + (Protein * 0.93) + (Fat * 0.97 * 2.25) + ((NDF-2) * (NDFD/100))

NFC = 100 - ((NDF - 2) + Protein + 2.5 + Ash), and 1.23 was chosen as the denominator to adjust the scale to match the RFV scale at 100 = full bloom alfalfa.

Quality standards based on RFQ are: Supreme, RFQ higher than 185; Premium, RFQ 170-184; Good, RFQ 150-169; Fair, RFQ 130-149; and Low, RFQ below 129. RFQ estimates voluntary energy intake when the hay is the only source of energy and protein for ruminants. Hay with a higher RFQ requires less grain or feed concentrate to formulate dairy rations.

Results and Discussion

During winter the seedlings were dormant and did not achieve much additional growth. March was cool and exceptionally wet with 3.57 inches of rain. The rain hammered the alfalfa seedlings and covered some seedlings with mud. The first cutting was delayed by rainy weather in May to bloom stage on May 31. The second cutting was taken June 30 at late bud to early bloom stage. Third cutting, when forage quality samples were taken, was on August 8, at early bloom stage. The fourth cutting was taken on September 25, at late bud to early bloom stage.

The average first year total hay yield was 6.9 ton/acre, with no significant differences in hay yield among the entries (Table 1). The first-cutting average yield was 2.5 ton/acre. In the second cutting the average yield was 1.7 ton/acre. In the third cutting, the average yield was 2.2 ton/acre. The average yield was 1.5 ton/acre for the fourth cutting.

The crude protein averaged 20.6 percent in the third cutting, and ranged from 19 percent for ‘Lahontan’ to 21.8 percent for ‘WL 319 HQ’. Acid detergent fiber, ADF, averaged 34.8 percent, and ranged from 32 percent for WL 319 HQ to 38 percent for Lahontan. Neutral detergent fiber, NDF, averaged 40 percent, and ranged from 36 percent for WL 319 HQ to 44 percent for Lahontan. Relative feed quality averaged 147, in the “Fair” quality category and ranged from RFQ = 129, “Low” for Lahontan to RFQ = 167, “Good” for WL 319 HQ.

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 2). Most alfalfa varieties have some resistance to the diseases and pests that could limit hay production. Growers should choose varieties that have stronger resistance ratings for disease or pest problems known to be present in their fields. The yield potential of a variety should be evaluated based on performance in replicated trials at multiple sites over multiple years.

Table 1. Alfalfa variety hay yields and third cutting crude protein, ADF, NDF, and relative forage quality for 2006. Malheur Experiment Station, Oregon State University, Ontario, OR.

	Cutting date								2006	Crude			Relative
Variety	5/31			6/30		8/8		9/25	total	protein	ADF^a	NDF^b	forage quality
		------------------ton/acre^c----------------								-------% of DW^d-------			RFQ
DKA-42-15		1.50	1.75		2.28		1.54		7.08	20.0	36.2	41.6	135.8
Rustler II		1.58	1.75		2.17		1.57		7.06	21.6	34.0	39.0	152.0
Masterpiece		1.60	1.75		2.17		1.52		7.04	21.4	33.4	38.6	155.8
WL 319 HQ		1.57	1.83		2.23		1.37		7.00	21.8	32.0	36.4	167.2
FC 2055		1.49	1.67		2.13		1.64		6.92	21.0	34.6	39.6	148.6
WL 357 HQ		1.46	1.69		2.29		1.46		6.91	20.4	35.0	40.6	143.8
FC 1045		1.49	1.73		2.08		1.55		6.85	20.0	36.0	41.2	140.4
Lahontan		1.46	1.65		2.12		1.56		6.80	18.8	37.6	43.6	129.4
FC 1055		1.46	1.63		2.17		1.46		6.72	21.0	34.0	38.4	153.6
Wrangler		1.52	1.55		2.14		1.30		6.51	20.2	35.4	41.0	143.8
Mean		1.51	1.7		2.18		1.50		6.89	20.6	34.8	40.0	147.0
LSD (0.05)		NS^e	NS		NS		NS		NS	NS	NS	NS	NS

^aADF: acid detergent fiber. ^bNDF: neutral detergent fiber.
^cYield at 88 percent dry matter.^dDW: dry weight.
^eNS: Not significant at the alpha = 0.05 level.

Table 2. Variety source, year of release, fall dormancy, and level of resistance topests and diseases for alfalfa varieties in the 2006-2011 furrow-irrigated forage variety trial, Malheur Experiment Station, Oregon State University, Ontario, OR, 2006.

Release

Pest resistance rating^b

Variety

Source

year

FD^a

PRR

SAA

RKN

Lahontan

public

1954

6^c

Wrangler

public

1984

Rustler II

Andrews Seed

1995

Masterpiece

Simplot

2000

DKA-42-15

Eureka Seeds

2001

WL 319 HQ

W-L Research

2002

WL 357 HQ

W-L Research

2003

FC 1045

Andrews Seed

2005

FC 1055

Andrews Seed

2006

FC 2055

Andrews Seed

2006

^aFD: 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: Northern root knot nematode. ^bPest resistance rating: >50 percent = HR (high resistance), 31-50 percent = R (resistant), 15-30 percent = MR (moderate resistance), 6-14 percent = LR (low resistance).^cFall dormancy: 1 = Norseman, 2 = Vernal, 3 = Ranger, 4 = Saranac, 5 = DuPuits, 6 = Lahontan.