Transitional organic forage systems in the southeastern U.S.: Production and nutritive value

Abstract

Limited work has been done to develop organic forage programs in humid subtropical regions despite growing demand for high‐value forage and organic products. Alternative crops were compared for optimizing forage production and nutritive value under organic conditions in the southeastern United States. The study was conducted at the Middle Tennessee AgResearch and Education Center, in Spring Hill, Tennessee. Forage treatments consisted of (a) monoculture tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.], (b) monoculture bermudagrass [Cynodon dactlyon (L.) Pers.], (c) tall fescue and alfalfa (Medicago sativa L.) mixture, (d) bermudagrass and alfalfa mixture, and (e) an annual rotation of winter wheat (Triticum aestivum L.) mixed with winter pea (Pisum sativum L.) followed by sorghum–sudangrass [Sorghum bicolor (L.) Moench x S. sudanese (Piper) Stapf.] mixed with cowpea [Vigna unguiculata (L.) Walp.] mixture. Perennial treatments were established during the 2017–2018 growing season. Monthly production was measured in the 2018–2019 and 2019–2020 growing seasons. Botanical composition of forage mass fluctuated due to establishment dynamics and weed competition, affecting forage quantity and quality. The annual rotation was the highest‐yielding treatment, producing more than 6,000 kg−1, though each tall fescue and tall fescue–alfalfa treatments produced ∼4,000 kg ha−1. Nutritive value was sufficient for most livestock operations, with forage crude protein concentration averaging ∼150 g kg−1 across treatments and growing seasons. For transitioning organic producers, a perennial forage will likely favor long‐term sustainability, whereas the annual rotation may be useful during the transition period to reduce weed pressure before transitioning to a perennial forage system.

Economic outcomes for transitioning to organic forage production

“…A more detailed description of the experimental site and study design can be found in Kubesch et al. (2022).…”

“…Initial soil nutrient levels were similar across the experiment site and were determined by Mehlich 1 extract to be pH = 6.3, P = 63 ppm, K = 160 ppm, Ca = 1009 ppm, and Mg = 161 ppm. A detailed description of the experimental site and study design can be found in Kubesch et al (2022).…”

“…Dried subsamples were ground using a Wiley Mill (Model 4, Thomas Scientific) with a 1-mm screen, then scanned using a Unity SpectraStar XL-R near-infrared spectroscopy (NIRS) instrument and software InfoStar version 3.11.3 (Unity Scientific), for determination of crude protein (CP). A more detailed description of the experimental site and study design can be found in Kubesch et al (2022).…”

Water Stress Influences Phytoestrogen Levels in Red Clover (Trifolium pratense) but Not Kura Clover (T. ambiguum)

“…Red clover ( Trifolium pratense L.) is a globally important perennial legume widely utilized in temperate regions as forage for ruminants. It has high feed value due to its high digestibility and crude protein concentration. , Dairy diets containing legumes, such as red clover, increase milk yield and quality , and have been associated with reductions in methane yield (g/kg of dry matter intake) and methane intensity (g/kg of energy-corrected milk in dairy cattle) . Additionally, red clover fixes atmospheric nitrogen (N), thereby reducing the need for synthetic N fertilizers and their negative impacts on the environment including formation of the greenhouse gas N 2 O. − …”