Establishment of Switchgrass and Big Bluestem in Corn with Atrazine

Abstract

Switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) provide abundant forage for livestock and wildlife during hot summer months when cool‐season grass species may decline in production. Little biomass production for grazing may result during warm‐season grass establishment because of weed competition. Chemical methods of weed control are now limited, because application of atrazine [6‐chloro‐N‐ethyI‐N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] to switchgrass and big bluestem is no longer allowed according to the label. Using corn (Zea mays L.) as a companion crop could provide potential for high biomass production during warm‐season grass establishment, and allow the use of atrazine for weed control. This study investigated the ability of switchgrass and big bluestem to establish in a corn companion crop. The effects of corn hybrid (short‐ vs. long‐season), population density, row spacing, and harvest date on switchgrass and big bluestem stands and on corn production were quantified. Establishment of switchgrass and big bluestem in corn was successful. Switchgrass mean stands were 26.3 plants m−2 in 1995 and 46.4 plants m−2 in 1996. Big bluestem stands were similar to switchgrass in 1995 (31.7 plants m−2), but were much lower in 1996 (5.2 plants m−2). Long‐season corn hybrids and higherdensity corn populations increased corn silage and grain yield without reducing warm‐season grass stands. Within a season, no difference existed between corn grain yields when grown with either switchgrass (6.7 Mg ha−1 in 1995, 5.3 Mg ha−1 in 1996) or big bluestem (6.9 Mg ha−1 in 1995, 5.7 Mg ha−1 in 1996). Silage dry matter yield was not different between corn grown with switchgrass (12.6 Mg ha−1 in 1995, 16.1 Mg ha−1 in 1996) and corn grown with big bluestem (13.1 ha−1 in 1995, and 16.6 Mg ha−1 in 1996) for a given year. Switchgrass and big bluestem grown in corn with atrazine reduced land production losses during the establishment year, yet allowed adequate establishment of these grasses for future forage production.

The Mycorrhizal Fungus, Sebacina vermifera, Enhances Seed Germination and Biomass Production in Switchgrass (Panicum virgatum L)

“…Due to these limitations and because S. vermifera can easily be propagated on a large scale in axenic culture in the absence of a host plant (unlike AMF), we are currently investigating alternative inoculation techniques, including the feasibility of seed coating. As with many warm-season perennial grasses, switchgrass can be difficult or slow to establish, particularly in unmanaged stands [2,14,17,20]. There are several factors affecting the productivity of a stand in the field [20], and some of those are inherent to the species, such as seed dormancy [24].…”

Biomass Production in Northern Great Plains of USA – Agronomic Perspective

“…However, atrazine is only labeled for roadside and CRP lands in some states, not for large area of switchgrass except for a special use in Iowa [17]. Alternatively, switchgrass was companion-planted with corn or sorghum-sudangrass using atrazine [59][60].…”

A collection of cytochrome P450 monooxygenase genes involved in modification and detoxification of herbicide atrazine in rice (Oryza sativa) plants

“…Crop contamination with herbicides not only affects the cereal production, but also serves as a food chain pollutant, threatening to human health (Hintz et al, 1998;Arora et al, 2008;Lu et al, 2014). There is an urgent need to assess the possible modification and degradation of atrazine in rice crops and to develop a strategy to minimize its accumulation in edible part (e.g.…”