Vegetative Establishment of Dwarf Elephantgrass: Effect of Defoliation prior to Planting Stems

Abstract

AbstractCattle (Bos spp.) gains on ‘Mott’ dwarf elephantgrass (Pennisetum purpureum Schum.) have averaged 1 kg d−1 during 3 yr of summer grazing in Florida, but vegetative establishment of this cultivar has been problematic. The objective of this research was to determine the effect of defoliation prior to harvesting stems for vegetative planting on number of shoots produced, percentage of planted stems producing shoots, and shoot and root dry matter (DM) accumulation during 6 wk postplant. Responses were quantified for mid‐ and late summer planting dates in 2 yr on a Smyrna sand (sandy, siliceous, hyperthermic Aeric Haplaquods). Previously undefoliated plants were (i) grazed to remove 70 to 90% of leaf blade (grazed), (ii) grazed to remove the apical meristem and leaf blade of individual stems (meristem), (iii) not grazed, but leaf blades were stripped manually from stems (stripped), (iv) not grazed, but all herbage above the collar of the most recently expanded leaf was clipped manually (topped), or (v) not defoliated (undefoliated). More shoots emerged per row from undefoliated stems than from all other treatments except topped. Defoliation had no effect on percentage of planted stems that produced at least one shoot. Shoot DM was greater for undefoliated than for all but stripped stems, and root DM was greatest for undefoliated stems. Stems from the meristem treatment initiated shoot but not root growth during the first 2 wk postplant, and shoot and root DM production was low through 6 wk. Undefoliated stems produced little shoot DM by 2 wk, but root growth started soon after planting. Root and shoot growth responses were consistent with theories regarding apical dominance and auxin effects on early plant development from stem cuttings. Results suggest that successful establishment of Mott elephantgrass is most likely if undefoliated stems are planted.