Agronomic Responses of Two Major Perennial Forage Arachis Species in the Tropics as Affected by Stubble Height

Abstract

The use of forage legumes in pasture systems has been proposed as an option not only for enhancing herbage nutritive value, but also as a tool to aid in the recovery of degraded/degrading grass pastures and an important provider of a variety of ecosystem services. Perennial peanuts (Arachis spp.) comprise a group of species whose potential has been widely demonstrated in forage systems in warm areas of the globe, but comparisons across species are scarce in the literature. The objective was to explain the impact of two stubble height on the herbage accumulation (HA), plant-part composition and canopy structural traits of ‘Belmonte’ pinto peanut (PP; Arachis pintoi Krapov. W.C. & Greg cv. Belmonte) and ‘Florigraze’ rhizoma peanut (RP; Arachis glabrata Benth cv. Florigraze) in a tropical environment of southeastern Brazil. Irrigated small plots were harvested at 4 and 8 cm height every 42 days, during both rainy/warm and dry/cool seasons from March 2020 to March 2022 in Piracicaba, Brazil. In the warm season, PP had 46% greater HA than RP (6470 kg DM ha⁻¹). In addition, PP had 88% and 37% greater leaf area index and leaflet proportion than RP (2.6% and 47%, respectively) in the harvested herbage. Weed proportion was greater in RP (28%) than in PP (2.8%). During the warm season, the 8-cm stubble height resulted in greater canopy height (16 vs. 12 cm) and stolon proportion (16% vs. 14%), but lower specific leaflet area (228 vs. 243 cm² g⁻¹) compared to the 4-cm stubble height. In the cool season, at 4 cm stubble height PP had 17% greater petiole proportion (8.8%) and 82% greater stolon proportion (2.8%). Regardless of stubble height and season, PP is a superior option than RP for warmer tropical areas.