Inconsistent yeild response of forage sorghum to tillage and row arrangement

Authors: Nieman, Christine; Franco, Jose; RAPER, RANDY - Oklahoma State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Biomass from warm-season grasses such as sorghum-sudangrass (Sorghum bicolor L.) are promising, sustainable alternatives to ethanol produced from corn grain. For small, pasture-based cow-calf operations in the mid-South, warm-season grasses, such as sorghum-sudangrass, may have the potential to be utilized as a biofuel crop, while also providing timely and high-quality forage during the summer months for grazing. Introducing a potential biofuel crop that is multi-use and low risk, may help persuade small farmers to adopt biofuel crops as the crop may be used for other purposes as necessary. Before dual-use sorghum-sudangrass systems can be recommended to small beef farmers, research is needed on successful tillage methods that both allow for as minimal tillage as possible while also supporting productive establishment of sorghum-sudangrass on pasture lands. Intense tillage, such as disking and rototilling, can be expensive for farmers because of additional equipment, fuel, and labor costs, and can also have detrimental effects on soil health and structure. However, because tillage produces an even seed bed with low weed competition, seed germination and early seeding growth may be better on land that is tilled, versus planting directly into sod. Row arrangement, the distance between rows or sets of rows can also effect sorghum-sudangrass yield by increasing or decreasing competition from plants. Our overall objective was to evaluate tillage type and row configuration on sorghum-sudangrass yield in a 3-cut system. Three tillage treatments ranging from high intensity, low intensity, to no tillage were tested with two row arrangements, twin rows, or rows with 7 in between a set and 30 in between sets of rows, and single 30 in rows. The study was repeated on two sites in Booneville, AR, for three years (2010-2012). Sorghum-sudangrass yields were variable, and no-till establishment resulted in reduced yields in some instances, but not consistently, and twin rows did not result in greater yield compared to sing row arrangement. Management and weather, and their interactions are important drivers of forage production as they directly impact plant establishment, plant growth, and plant community composition. In this study, the authors found that these factors and their interactions and the variability of these factors from year to year, greatly affected sorghum-sudangrass yield and may challenge producers interested in utilizing dual-use sorghum-sudangrass.

Technical Abstract: Forage sorghum is an alternative source for biofuel feedstock production and may also provide forage for livestock operations. Introducing biofuel feedstock as a dual-use forage to livestock operations has potential to increase adoption of biofuel feedstock production. However, additional technical agronomic information focusing on tillage, row arrangement, and harvest date for forage sorghum planted into pasturelands intended for dual-use is needed. Three tillage treatments, disking and rototilling (RT), chisel plow (CP), and no tillage (NT), and two row arrangement treatments, single row planting with 76.2-cm rows and twin-rows of 17.8-cm on 76.2-cm centers, were tested for effects on forage sorghum yield in a 3-cut system. The study tested two sites in Booneville, AR from 2010-2012. Several interactions with year were detected, likely due to large precipitation differences within and among years. Year greatly affected yield, with greater (p < 0.05) yields in year 1 compared to years 2 and 3 at both locations. No-till resulted in lower yields in some years and harvest dates, though no clear trend was detected among tillage treatments over years. Twin-rows generally did not improve yield, except for the third harvest date at one location. No strong trends for tillage or row arrangement effects were observed in this study. Inconsistencies may have resulted from the strong influence of year or interactions of multiple factors, which may challenge producers interested in utilizing forage sorghum for biofuels and livestock feed.