Sowing strategies for slow-establishing pasture species on a North Otago dairy farm

Abstract

Slow-establishing, high quality, pasture species are frequently added to standard ryegrass-white clover seed mixtures in an effort to improve pasture nutritive value. However, intense competition during establishment can suppress these species. Four alternative sowing strategies (Treatment 1: temporal separation of species (clovers sown in November 1998 before ryegrass direct-drilled at 10 kg/ha in March 1999); Treatment 2: substitution of ryegrass with slower-establishing timothy; Treatments 3 and 4: physical separation (alternate drill rows) of slower-establishing species from lower than average ryegrass seeding rates (3.5 kg/ ha or 8 kg/ha)) were used on a commercial North Otago dairy farm. Total dry matter (DM) production after 16 months was greater from pastures initially sown with ryegrass (19.1 t DM/ ha) (Treatments 3 and 4) than when ryegrass sowing was delayed or substituted with timothy (15.2 t DM/ha) (Treatments 1 and 2). The percentage of red plus white clover was similar in all pastures at 16 months of age and averaged 54%, compared with less than 1% for caucasian clover. Timothy sown without ryegrass contributed 42% of production (Treatment 2), compared with 7% when sown with ryegrass (Treatments 3 and 4). Ryegrass composition was similar (43%) regardless of sowing rate (Treatments 3 and 4) and sowing date (Treatment 1). This on-farm study demonstrated successful establishment of red and white clover in all four treatments but timothy and caucasian clover were suppressed by the inclusion of low rates of ryegrass. Keywords: botanical composition, competition, dry matter production, Lolium perenne, Phleum pratense, seeding rates, Trifolium ambiguum, T. pratense, T. repens