Low lignin alfalfa trial data shows differences
SEYMOUR - A lot of numbers were collected from harvests at alfalfa plots on two farms in Outagamie County during the summer of 2016, but whether the differences between low-lignin and conventional varieties are statistically significant is still awaiting professional analysis.
Plots involving one of the two commercially available varieties of low-lignin trait alfalfa were conducted on Randy Dorow's Triple T Dairy farm near Hortonville and the Nick Van Wychen crops farm near Freedom. They were overseen by Outagamie County Extension Service crops, soils, and horticulture agent Kevin Jarek.
The project had strong support from the Outagamie County Forage Council, Dave Taysom at Dairyland Labs in Arcadia and Dairyland Seeds fieldman Kevin Naze although the company didn't have a product in the trial plots, Jarek reported. The venture would ordinarily have cost about $10,000 in fees for services, but it was carried out with a contribution of only about $2,800 by the forage council, he told attendees at recent annual meetings of county forage councils.
Low-lignin plot basics
The purpose of the plots was to compare the low-lignin Alforex Hi-Gest 360 variety with other popular conventional varieties that the farm cooperators were growing, Jarek pointed out. Samples of the forages were taken weekly for the six weeks from May 10 through June 14.
On the Dorow farm, the comparison was with Pioneer's 55V50 variety included only three cuttings because of a delay with the first cutting due to wet field conditions, Jarek noted. Five cuttings were taken on Van Wychen farm, where WL 363 HQ was the conventional variety, resulting in a total yield of very close to 7 dry matter tons per acre for both varieties during a nearly ideal growing season — more than double the average in Wisconsin for 2016.
In addition to yield tabulations and forage quality evaluations, tests were run at Dairyland Labs for the nutritional components and values such as fiber and its digestibility, potential milk per ton of dry matter, milk per acre and ash content. Jarek presented the raw numbers to attendees at the forage council meetings.
Jarek acknowledged that the three alfalfa varieties were not truly scientifically comparable in their traits but he did emphasize that there were three repetitions of the trial plot on both farms. One factor that could have made a difference is the fact that the Alforex has a 5 rating for fall dormancy, while the other two have ratings of 3 and 4 on that scale.
With the significantly higher cost of low-lignin alfalfa seed, Jarek said that another element of its evaluation should be in terms of economics. Spreading the seed cost over a four-year stand of the crop is another factor in the economic formula, he added.
As the weekly comparisons were recorded, the raw numbers stood very consistently in favor of the Alforex low-lignin in terms of relative feed quality and relative feed value, Jarek noted. But the numbers began to tighten by the fourth and fifth week and were virtually no different by the sixth week on most of the comparatives.
There were also some deviations on the individual cuttings, particularly on the Van Wychen farm, where the numbers for the 3rd cutting tipped in favor of the WL 363 HQ, Jarek indicated. Dorow, who has a milking dairy herd (the Van Wychen farm does not), told Jarek that the low-lignin alfalfa had a higher percentage of leaves and that milk production appeared to be a bit better when it was being fed.
Company research data
The statistical findings and anecdotal reports are in line with what Alforex Seeds, which is based in Woodland, CA with a research site near West Salem, WI, is reporting from its own research data. On particular items, its research shows a 7 to 10 percent (not percentage points) reduction in lignin (measured as acid detergent fiber), 5 to 10 percent less undigestible fiber, 5 to 10 percent increases in the total digestibility of nutrients score and in the rate of fiber digestion in a cow's rumen along with a 3 to 5 percent (again, not percentage points) increase in crude protein.
According to the company, even better average numbers were tabulated for four of those categories (testing was not conducted for the faster rate of fiber digestion) on data which was collected in 2015 from 33 growers, who accounted for a portion of the approximately 10,000 acres of Alforex Hi-Gest 360 in production that year. With the faster rate of digestion, Jarek suggested that forage testing laboratories might have to consider changing the timing for analyzing the forage samples from low-lignin alfalfa, which also includes HarvXtra from Croplan.
One of the premises for the development of the lower lignin alfalfa varieties is their ability to maintain desired quality and nutritional traits for a longer growing period, thereby extending the cutting window from the traditional 28 to 30 days after the first cutting by up to seven days without sacrificing the beneficial traits. In some cases, this could reduce the number of cuttings per year by one, thereby saving on costs for equipment, fuel and labor.
Alfalfa seeding rates
Jarek has also been involved in a multi-county alfalfa seeding rate trial which began in 2015. In addition to Outagamie, other participating counties include Calumet, Shawano, Clark, Chippewa and St. Croix.
On participating farms, alfalfa plant and stem counts are taken a month after the establishment of the crop and then again in the autumn and the following spring. Comparisons are being recorded for up to three different seeding rates to determine if they make a difference in stand counts after various periods of time, Jarek explained.
At the various sites, the per acre seeding rates for live seeds have ranged from 12 to 30 pounds, Jarek reported. Among the seed companies whose alfalfa is grown at one or more sites are Legacy, Latham, Dekalb, Kussmaul, Renk, Dairyland and Alforex.
Evaluating the data
As the reports have been filed, the prevailing trend is that alfalfa mortality rates are high across the board in the first and second year of stands and that higher seeding rates do not result in higher plant totals or stems per square foot, Jarek indicated. Where three seeding rates were used, the middle amount has sometimes fared the best over time.
Knowing that should guide growers on the economics of seeding rates because they can save money while sacrificing little in plant and stem count, Jarek stated. He suggested that the adequacy of phosphorus and potassium in the field might be a greater factor in alfalfa plant viability and mortality than seeding rates in meeting the Extension Service's recommendation of a minimum of 55 alfalfa stems per square foot to keep an alfalfa stand.
Jarek explained that it is natural for alfalfa to self-thin through the process of auto-toxicity while other losses may be due to diseases, lack of fertilization, and damage from harvesting equipment. One benefit from the loss of plant density is the ability of the remaining plants to grow more stems each, he noted.
Advice for 2017
As they complete their purchases of alfalfa seed for 2017 and prepare to plant, Jarek urges growers to be aware of the pure seed rating provided on the label and to convert it to the potential for plant establishment.
Having a fairly high portion of “hard seed” indicated on the label might not be bad in some cases, Jarek observed. In the seeding rate trial with Latham's 9600 HY on the Adam Faust farm in Calumet County, the autumn square foot count of plants was 10 higher than the spring count — perhaps due to the later germination by the hard seed, he suggested.
Coatings on the seed as rhizobia, fungicide and colorant must also be accounted for when determining how much pure seed there is per bag, Jarek emphasized. As he showed samples of two versions of coating and one of seeds without a coating, Jarek explained that a true comparison of the effects of coating materials can be made only with alfalfa with the same genetics.