Annual Ryegrass Forage Mass Distribution as Affected by Sod‐Suppression and Tillage

Early‐season forage mass production of annual ryegrass (Lolium multiflorum Lam.) is reduced in the southeastern USA when ryegrass is established no‐till rather than with conventional tillage. Two studies were conducted to evaluate forage mass distribution of annual ryegrass established under tillage vs. no‐till. One evaluated the effect of sod‐suppression, and the other evaluated past and current tillage practices. In the sod‐suppression study, no‐till plots established with herbicides produced 27% more forage mass at first harvest than did no‐till plots that were mowed. However, tilled plots produced 55% more forage mass at first harvest than no‐till plots established with herbicides. After January, no‐till plots produced as much or more forage mass than tilled plots in both studies. In the 1994–1995 growing season, forage mass produced at first harvest was positively correlated (P = 0.01) with stand count in both the sod‐suppression (r = 0.62) and the tillage history (r = 0.73) studies. After the first harvest, stand count was not correlated (P > 0.11) with forage mass production. In the tillage history study, current seedbed preparation had a much greater impact than past seedbed preparation on early‐season production of annual ryegrass. When combined over both studies, ryegrass established with tillage (4.9 tons/acre) and established no‐til with herbicides (4.6 tons/acre) produced more season total forage mass than no‐till ryegrass established without herbicides (4.3 tons/acre). In annual ryegrass establishment systems, tillage does more than reduce competition from warm‐season grasses. However, suppression of warm‐season grasses with herbicides is still important for no‐till establishment of annual ryegrass. Research Question Annual ryegrass is a common cool‐season forage crop in the southeastern USA. Having ryegrass available as early in the growing season as possible is important to dairy farmers and producers with growing animals. Producers have traditionally used tillage to establish early planted ryegrass. High erosion potential and regulations in recent farm bills make critical the establishment of minimum tillage guidelines for the establishment of annual ryegrass. Two research trials were conducted, one evaluating the effect of sod‐suppression and one evaluating the effect of tillage history on annual ryegrass forage mass distribution. Literature Summary Early season annual ryegrass forage yield is generally reduced in no‐till systems, compared with tilled systems. Since the warm‐season annual grasses that tend to volunteer after ryegrass in early‐establishment systems can be suppressed with herbicides, early season ryegrass production may be improved with adequate suppression of summer grasses. In addition, tillage history of a site and current tillage practices may also affect early‐season annual ryegrass production. Study Description Field experiments were conducted at the Louisiana Agricultural Center Louisiana Agricultural Experiment Station near Franklinton. Soils: Tangi silt loam. Ryegrass variety: ‘Jackson’, 30 lb/acre pure live seed. Plots were harvested when ryegrass reached 10 to 12 in. Exp. 1 Annual ryegrass was established with tillage or no‐till with mowing, paraquat, or glyphosate to suppress warm‐season grasses. Exp. 2 Short‐ and long‐term effects of tillage and no‐till for annual ryegrass production were compared. Applied Questions Can similar early season and total forage yields be produced from ryegrass established with tillage and established no‐till with herbicides? No‐till plots established with herbicides produced more forage at first harvest than no‐till plots that were mowed but with no herbicide applied. However, tilled plots produced more forage at first harvest than did no‐till plots established with herbicides. After January, forage mass production in tilled and no‐till plots tended to be similar. Tilled plots produced more season‐total forage mass than did no‐till plots during the 1994–1995 growing season. However, when averaged over years, season‐total forage mass was similar between tilled and no‐till plots established with herbicides in both studies. In the study evaluating sod‐suppression methods, no‐till plots established without herbicides produced less season‐total forage mass than tilled plots or no‐till plots established with herbicides. These results indicate that some factor in addition to competition is reducing early‐season annual ryegrass production in no‐till systems. However, control of competing vegetation in no‐till systems increases early‐season and season‐total forage mass production compared with ryegrass established no‐till without herbicides. Thus, control of competing vegetation for no‐till annual ryegrass establishment is important. What effects do short‐ and long‐term tillage practices have on annual ryegrass forage yield? How a site was prepared just prior to planting was more important than tillage history. Ryegrass established with tillage during this study produced more forage mass at the first harvest than ryegrass established no‐till. Early‐season and total forage mass production were similar for ryegrass planted no‐till for six consecutive years and in the first 2 yr of no‐till establishment. This indicates that although soil loss is great with tillage systems on these sites, no‐till establishment of ryegrass for six consecutive years did not reduce early season forage mass production differences between ryegrass established no‐till and with tillage.