NO-TILL PASTURE RENOVATION AFTER SWARD SUPPRESSION BY HERBICIDES

Abstract

Four experiments were conducted to investigate methods for establishing legumes without cultivation in a pasture of low productivity because of nitrogen and phosphorus deficiencies on the Pathlow Community Pasture in northeastern Saskatchewan. Glyphosate applied at 2.2 kg ha−1 in strips 36 cm wide in early fall 1983 and 1984 was used as a standard vegetation control method. Other treatments were applied the same way. Alfalfa (Medicago media Pers. ’Beaver’) and cicer milkvetch (Astragalus cicer L. ’Oxley’) were seeded in the sprayed strips in late fall 1983 and spring 1985 using a triple-disk range drill. The degree of establishment was assessed initially by seedling counts and later by cover estimates each year until 1988. Legume establishment was best in strips where the vegetation was killed. The addition of 5% wt/vol ammonium sulphate to glyphosate did not improve establishment of the legumes significantly. Fluazifop-butyl, quizalofop-ethyl, and haloxyfop-methyl had little effect on the resident vegetation and legume establishment was poor. Sethoxydim tested at 0.8 kg ha−1 appeared to provide less suppression of vegetation than was achieved with glyphosate at 1.1 kg ha−1 but legume establishment was similar. There was no benefit to drilling phosphorus at rates up to 60 kg ha−1 with the seed.Key words: Pasture, renovation, no-tillage seeding, alfalfa, cicer milkvetch, sward suppression