Establishment of Rhizoma Perennial Peanut with Varied Rhizome Nitrogen and Carbohydrate Concentrations

Rhizoma perennial peanut (RPP; Arachis glabrata Benth.) is a vegetatively propagated forage legume characterized by inconsistent establishment, possibly related to the chemical characteristics of RPP rhizomes used for propagation. This field study evaluated effects of chemical composition of 'Florigraze' rhizome planting material on emerged shoot number at 80 d after planting (DAP), rhizome and shoot mass accumulation at 180 DAP, percent RPP cover at season end, and herbage yield in June of the second growing season. The soil was a loamy, siliceous, hyperthermic Grossarenic Paleudult. Rhizome planting material was obtained from grazed pastures which, through varied defoliation management, produced rhizomes with a range of total nonstructural carbohydrate (TNC) (62-383 g kg−¹) and N (12.7-25.8 g kg−¹) concentrations. In 1990, a drought year, rhizomes with TNC ranging from 260 to 300 g kg−¹ and N = 21 g kg−¹ produced maximum responses for shoot number (39 m−²) and rhizome (530 kg ha−¹) and shoot mass (1040 kg ha−¹) accumulation. During the wetter than normal spring of 1991, rhizomes with TNC and N concentrations similar to those in 1990 supported 40 to 55% greater shoot counts and almost double (1050 kg ha−¹) the rhizome mass accumulation. Because much RPP production occurs on nonirrigated sandy soils, and rainfall constraints are prevalent following planting in most years, assessment of rhizome planting material quality should be based on the 1990 results. In that year, rhizomes with TNC of 230 to 250 g kg−¹ and N of 20 to 20.5 g kg−¹ performed well, about 70 to 90% of the maximum responses indicated above. Rhizomes with TNC of 190 to 220 g kg−¹ and N of 18 to 19 g kg−¹ performed at about 40 to 65% of maximum responses. Planting rhizomes with TNC ≤ 180 g kg−¹ and N ≤ 17 g kg−¹ is not recommended unless irrigation is available, since establishment performance was ≤ 40% of maximum predicted responses. Fla. Agric. Exp. Stn. Journal Series no. R-04438. Research supported in part by USDA Special Grant no. 90-34135-5173, administered by the Caribbean Basin Advisory Group.