No-Till Alfalfa Paired With Italian Ryegrass Companion Crop Works

By Jane Fyksen, Crops Editor
Thursday, February 22, 2007 11:36 AM CST

2005-2006 Dry Matter Yield

Due to cold wet springs and heavy ground, forage growers in some parts of Wisconsin are "understandably skeptical" about no-till alfalfa, concedes Clark County Crops and Soils Agent Nick Schneider.

However, recent research reveals no-till alfalfa planted with Italian ryegrass to be an intriguing combination - even on north-central Wisconsin's generally heavier soil.

Ever-increasing emphasis on saving time, reducing tillage costs and keeping soil in place for compliance with 590 Nutrient Management Plans have alfalfa producers exploring no-till. Schneider has, too, as a field demonstration during the 2005 Farm Technology Days at Malm's Rolling Acres north of Loyal in which alfalfa was no-tilled - either solo-seeded or with Italian ryegrass - in either grain-corn or soybean residue. He shared the findings at last month's joint symposium of the Midwest Forage Association, Wisconsin Customer Operators and the Professional Nutrient Applicators Association of Wisconsin.

While the soybean stubble wasn't sprayed, the corn ground was sprayed with glyphosate. Planting took place May 5 with a Great Plains 10-foot no-till drill. Two alfalfa varieties were compared, one conventional, the other potato leafhopper resistant (PLH). First and second cuttings were made June 28 and Aug. 18. Second-crop was analyzed for crude protein and NDF.

The alfalfa was either straight-seeded at 12 pounds to the acre or with the Italian ryegrass variety Monarque at a rate of 5, 10 or 20 pounds.

Schneider continued the research last year to evaluate yields in subsequent years. The alfalfa was harvested June 2, July 8 and Aug. 15 and evaluated only for yield. Potato leafhopper populations did hit economic treatment thresholds in July last year, but no insecticide was applied.

Comparing the two alfalfa varieties - conventional to PLH - protein and NDF weren't significantly different, reports Schneider. But, he notes, when mixed with Italian ryegrass, the grass component influenced quality and yield more than the alfalfa variety.

"Final yield was the same between the conventional and PLH variety throughout 2005 and the June harvest in 2006," he reports. "Due to potato leafhopper presence in the summer of 2006, the PLH variety had a higher yield for the year by 105 pounds of dry matter." The two-year yield averages were the same for varieties.

As for crop rotation, it had a measurable influence on yield, protein and NDF during the establishment year.

Alfalfa and Italian ryegrass mixtures averaged 515 more pounds of DM per acre going into soybean stubble over corn residue. Most of the additional yield resulted from growth in June collected during the first harvest in the seeding year.

Quality was also better following soybeans, with higher protein (18.7 percent protein versus 17.3 percent on corn stubble) and lower NDF (47.7 percent, versus 52.2 percent where corn was the last crop).

Italian ryegrass influenced protein, NDF and final yield. Solo-seeded alfalfa had crude protein 5 to 7 percent higher than mixes with Italian ryegrass, and not surprisingly, it had lower NDF. But, notes Schneider, Italian ryegrass quality in his research was lower than other studies he's seen because it initiated seed heads. His advice? Select Italian ryegrass varieties that don't head out.

While the alfalfa alone turned in crude protein of 22.7 percent and a 38.2 percent NDF, adding in five pounds of Italian ryegrass dropped protein marginally to 17.3 percent but raised NDF to 51.6 percent. Still, adding 10 pounds of grass dropped protein further to 16.1 percent and raised the NDF to 54.6 percent. Upping ryegrass to 20 pounds resulted in 15.7 percent protein and 54.9 percent NDF forage.

He says the five-pound seeding rate resulted in higher protein and more digestible forage than the two higher rates of Italian ryegrass (which had essentially no quality differences).

In the seeding year, no-till alfalfa had a lower final yield than when it was seeded with Italian ryegrass. The combination of legume and grass resulted in anywhere from 303 to 464 more pounds of dry matter in the seeding year. However, in the following year, the more Italian ryegrass planted, the less the yield.

"As anticipated, there were very few Italian ryegrass plants randomly scattered among the alfalfa plants," says Schneider. "In the plots with Italian ryegrass in 2005, some of the seed production contributed to Italian ryegrass germination in 2006, however, the alfalfa competition prevented this Italian ryegrass from establishing." In 2006, the yield of alfalfa established alone was 655 pounds of DM higher than alfalfa established with five pounds of Italian ryegrass.

"The yield of the established alfalfa decreased even further as the Italian ryegrass planting rate increased. When Italian ryegrass was seeded at 20 pounds per acre with alfalfa in 2005, in 2006 the yield was 1,406 pounds less than alfalfa alone. This reduction of 2006 yield was likely caused by a reduction in alfalfa stem density," says Schneider.

Alfalfa stem counts per square foot were 63, 42, 36 and 30 when Italian ryegrass was seeded at 0, 5, 10 and 20 pounds per acre respectively.

The final two-year cumulative yields show that alfalfa seeded alone or with five pounds of Italian ryegrass yielded statistically similar - and better than with higher rates of grass. The two-year DM yields are: 8,383 pounds of DM for no-till alfalfa alone; 8,032 for alfalfa with five pounds Italian ryegrass; 7,921 for alfalfa and 10 pounds grass; and 7,286 for alfalfa and 20 pounds grass.

Schneider also used the UW's SNAP Plus software to estimate soil loss with fall chisel plowing versus no-till for Loyal silt loam with a 4 percent slope. The two-year average soil loss was reduced by about a half-ton per acre by going no-till. Adding the grass reduced topsoil erosion even further - by one-tenth to two-tenths of a ton per acre.

So what has this Clark County agent concluded from his exploration of no-till alfalfa, with or without a companion crop of Italian ryegrass?

He says when leafhoppers hit, there was a yield advantage to having planted a PLH variety. But with no potato leafhopper pressure, the two varieties - conventional and PLH - yielded similarly.

No-tilling into soybean stubble (as opposed to where corn for grain had been the prior crop) resulted in modest yield and quality improvement in the forage stand during the seeding year. However, there was no rotation-generated yield difference in the first established-stand year - or in combined two-year yields.

As noted, if you're going to establish alfalfa with Italian ryegrass, be sure to pick a variety that typically doesn't set seed heads in the planting year. Schneider believes that the Italian ryegrass quality in this research was lower than in other studies because of seed head initiation in 2005.

"As the seeding rate of Italian ryegrass increased, quality decreased and yield in the established stand the following year decreased," he reports, thus noting that going beyond five pounds of Italian ryegrass with alfalfa is "detrimental."

The UW recommends seeding Italian ryegrass as a cover crop at 2 to 4 pounds to the acre. If you're using Italian ryegrass for renovating an existing forage stand, Schneider says to go with 5 to 10 pounds to the acre. Plant pure ryegrass for forage at 20 to 25 pounds.

He suggests using a burndown herbicide before planting. "No-till planting is a viable option for establishing alfalfa," he maintains, stressing that a burndown is needed to control perennials, winter annuals and early emerging spring annuals like common lambsquarters.

Pure alfalfa will have a slightly lower yield in the seeding year than with Italian ryegrass as a companion. The following year, established-stand yield was less the higher the ryegrass seeding rate had been.

Other lessons? Italian ryegrass quality drops as it heads out. There's higher yield and better quality in the seeding year when forage goes into soybean ground, versus where corn for grain had been.

"Too much grass can crowd out alfalfa," he warns. But an Italian ryegrass companion for no-till alfalfa checks erosion. He suggests going with a high-seeding-year-yielding alfalfa and seed it at 15 pounds to the acre.

To maximize alfalfa yield in the seeding year, Schneider suggests: Seeding early; select your variety carefully; consider mixing in Italian ryegrass; cut 60 days after seeding and subsequently at the appropriate stage; and take a late fall cutting if you planted a variety with a winter survival rating of two or less.

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