Irrigated Tall Fescue–Legume Communities in the Southern Rocky Mountains

Abstract

Short‐term testing of perennial forages may not determine their long‐term persistence and productivity. A study initiated in 1994 at New Mexico State University's Sustainable Agriculture Science Center at Alcalde was continued from 1998 to 2001, comparing irrigated monoculture tall fescue (Festuca arundinacea Schreb.) and tall fescue in binary mixtures with each of alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), cicer milkvetch (Astragalus cicer L.), or kura clover (Trifolium ambiguum M.B.) in three randomized complete blocks. Percentage of harvested grass in mixtures declined in midseason, but grass dry matter (DM) yield increased across the season. Grass DM yield averaged 7.78 and 4.79 Mg ha−1 yr−1 for the monoculture and mixtures, respectively. Seasonal distribution of kura clover and combined (kura + fescue) DM yield differed from other treatments causing year × harvest × treatment interactions. Cicer milkvetch–tall fescue performed poorly compared with the other treatments (mean annual yield 5.2 Mg ha−1). Mean annual yield (12.7 Mg ha−1) of the alfalfa–tall fescue mixtures was enough to enhance its usefulness over monoculture grass through reduced fertilizer inputs. The birdsfoot trefoil–tall fescue mixture also provided the benefit of reduced fertilizer requirements, but mean annual yield (8.2 Mg ha−1) equaled fertilized monoculture tall fescue. Kura clover–tall fescue average annual yields (14.1 Mg ha−1) equaled alfalfa–tall fescue. Stand longevity, reduced fertilizer inputs, and high yield and quality enhance the usefulness of kura clover in the southern Rocky Mountains. But, irregular seasonal distribution of kura clover between years may make forage budgeting difficult.