Warm‐season forage options in Northern Dryland Regions

Abstract

Rotating summer fallow with wheat (Triticum spp.) is done in dryland grain farming at upper latitudes to stabilize yields over time and to prevent crop failure. However, summer fallow is costly since weeds must be controlled and crops are not grown. Replacing summer fallow with grain crops can generate low economic returns. Previous research indicated that annual cool-season forages can be substituted for summer fallow in dryland cropping systems. Our objective was to determine if annual warm-season species were suited for forage production in monocultures and polycultures in the U.S. northern Great Plains. Dry matter (DM) production by 20 warm-and cool-season crop monocultures and 4 polycultures was determined across six environments during 2016, and by 25 warm-and cool-season crop monocultures and polycultures across four environments from 2016 through 2018. Maize (Zea mays L.) monoculture produced forage DM in amounts equal to, or greater than, those produced by other warm-and cool-season crop treatments (P < 0.05). Maize DM production averaged 2.5 to 5.7 Mg ha −1 , depending on the study and environment. Sorghum (Sorghum bicolor L.), foxtail millet [Setaria italica (L.) P. Beauv.] and sunflower (Helianthus annuus L.) also produced relatively large amounts of forage DM. Polycultures failed to produce more DM than monocultures consistently (P > 0.40). These results indicate that maize and other warm-season crops are adapted for dryland forage production in cool regions at upper latitudes. Additional research is needed to determine the impacts of annual warm-season forages on grain yield in a forage-wheat crop sequence.

Annual forage impacts on dryland wheat farming in the Great Plains

“…Carr, Boss, et al. (2020) reached similar conclusions in northern Montana where forage dry matter (DM) production by maize and other warm‐season species (e.g., sunflower and foxtail millet) was equal to, or greater than, cool‐season species. In more southern areas where warm‐season species dominate annual forage production (Anderson & Volesky, 2013; Roozebum, Shoup, Holman, Martin, & Blasi, 2008), triticale ( Triticosecale rimpaui Wittm.)…”

Cover crops to improve soil health in the North American Great Plains

“…Integration of CCs creates grazing opportunities for livestock (dual-use of CCs) and may provide economic benefit to producers to offset potential loss in revenue when water used by CCs results in yield decreases (Blanco-Canqui et al, 2020;Holman et al, 2018Holman et al, , 2021. Cover crop provide high quality feed for growing livestock (Carr et al, 2020;Holman et al, 2018Holman et al, , 2020. Integrated-crop livestock systems with CCs may be especially beneficial to farmers by helping to delay livestock grazing of native rangelands, providing longer rest periods between grazing.…”

Replacing fallow with warm‐season annual crops in dryland wheat systems

“…Nevertheless, preceding wheat with fallow remains a popular practice in the Great Plains and elsewhere (Carr et al, 2021;Christiansen et al, 2015;Whish et al, 2012). The replenishment of soil-water during the fallow period leads to wheat yield stability compared with continuous annual crop production over time (Carr et al, 2020). For example, wheat yields were reduced >50% following proso millet (Panicum miliaceum L.) compared with fallow in the central Great Plains (Anderson et al, 1999).…”

“…Cool-and warm-season crop monocultures, polycultures, and cultivarsin a dryland field study at the Central Agricultural Research Center in Montana (adapted fromCarr et al, 2020) …”