A SURVEY OF CRP LAND IN MINNESOTA .1. LEGUME AND GRASS PERSISTENCE

The federal Conservation Reserve Program (CRP), which had goals includ ing reduced soil erosion and increased wildlife habitat, funded divers ion of land from annual crops into permanent vegetation, The survival of grasses and legumes planted in CRP fields was not known, Our object ives were to assess the persistence and coverage of grasses and legume s in 6- to 8-yr-old CRP fields and to determine changes in soil pH, P, and K levels, We studied 151 CRP fields chosen from 10 counties in fo ur geographical regions of Minnesota: 108 in the conservation practice 1 (CP-1) cover type (planted cool-season perennial grasses and legume s); 17 in the CP-2 cover type (planted warm-season native grasses); an d 26 in the CP-10 cover type (existing vegetation), Statewide, legumes persisted in 82% of CP-1 fields planted to legumes, with 23% groundco ver. Grasses persisted in 90% of the planted CP-1 fields with 47% grou ndcover. Alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus cor niculaturs L.), the most persistent legumes, persisted in 90 and 67% o f the planted fields with 21 and 32% groundcover, respectively, Smooth bromegrass (Bromus inermis Leyss), reed canarygrass (Phalaris arundin acea L.), and switchgrass (Panicum virgatum L.) persisted in over 90% of the planted fields and had 50% groundcover or more, Other legumes a nd grasses persisted in 50% or less of the planted fields and had 10% groundcover or less, To maintain legumes in CRP fields, clipping is re quired or cultivars should be developed that persist without defoliati on. Generally, soil pH, P, and K levels did not change from initial to final samples and should be adequate to obtain low levels of forage p roduction.