Effects of Planting Method on Enhanced Stand Establishment and Subsequent Performance of Forage Native Warm-Season Grasses

Abstract

To develop strategies for successful establishment of forage native warm-season grasses (NWSGs) in southeastern USA, early agronomic performance of transplanted and seeded stands of big bluestem (BB, Andropogon gerardii Vitman), eastern gamagrass (GG, Tripsacum dactyloides L.), indiangrass [IG, Sorghastrum nutans (L.). Nash], and switchgrass (SG, Panicum virgatum L.) were compared. In early June, about 6-week old high tunnel grown seedlings were transplanted to assigned clean seedbeds. Plant spacing (cm) was 30-within and 45-between rows. Seeded plots received ≥ 11 kg seeds ha -1 planted at ≤ 2 cm deep in 45-cm wide rows, a month after transplanting to match rainfall availability. As needed, tall-growing broadleaf weeds were removed physically by cutting with a hand hoe. Plants were allowed uninterrupted first year growth with no fertilizer applied. Early in the following spring, dead standing biomass was mowed down to allow the emerging tillers more access to sunlight. During the second and third year after planting, plots were machine harvested twice between July and September for yield assessment. Percentage ground covered by plant material and species basal diameters were also recorded. Data were analyzed as a randomized complete block design for effects of planting method, species, and stand age. Except for GG, transplanting resulted in greater (>3,000 kg DM ha -1 ) forage yield and more so during the second harvest year. Total second year yields were similar for BB and GG and averaged 9,600 and 6,300 kg DM ha -1 for transplanted and seeded, respectively. Indiangrass and SG yields (kg DM ha -1 ) were 11,500 and 8,300 and 13,000 and 10,000 for transplanted and seeded plots, respectively. The NWSG ground cover was greater in the transplanted than seeded plots, while the reverse was true for weed cover. Data indicate that, in less than two years, transplanting under comparable growing conditions can produce harvest-ready uniform NWSG stands in weed infested areas. For practical recommendations, however, data on comparable responses of transplanted vs seeded stands to actual grazing at a similar timing is necessary.

Effects of Root-trimming and Cutting-heights on Growth Performance of Potted Native Warm-season Grasses

“…ready for transplanting as soon as field temperatures become favorable for growth. Use of transplants give the NWSGs a growing advantage over weeds at stand establishment, which enables them to finish their first growing season with energy-rich crowns and many dormant tillers for a robust spring growth (Temu, et al, 2016). However, the effectiveness of transplanting in NWSG establishment may depend on factors like seedling age, root biomass, root-covering at planting, soil moisture availability, weed challenges, and early defoliation management as well as their interactions.…”

“…Low seedling vigor makes them unable to compete with weeds for resources with low moisture and droughty conditions being frequently responsible for establishment failure (Blake, 1935). Following successful germination and seedling emergency, it usually takes at least two years for NWSG stands to be harvest-ready, and even longer if reseeding of failed patches is involved (Miller & Dickerson, 1999;Temu et al, 2016). Slow development of extensive root systems during early establishment phase is known to be responsible for delayed vegetative growth of NWSGs (Miller & Dickerson, 1999).…”

Early Forage Biomass and Sward Structures of Native Warm-Season Grasses Established at Different Seedling Densities

“…One alternative to seeded establishment of these NWSGs is raising seedlings in a weed-free environment and transplanting them onto clean seedbeds when growing conditions are optimum [2]. This is so because transplanting bypasses the most vulnerable seedling phases (germination, emergence and establishment) which gives the native grasses an edge over the annual weeds in competition for light, space, and soil-based resources.…”