Target populations for direct-drilled ryegrass and tall fescue.

摘要

Establishment, botanical composition and production of direct-sown Lolium perenne and Festuca arundinacea were compared for 2 sowing rates in a grazed, autumn field trial located at No. 1 Dairy Farm, Massey University, Palmerston North on an alluvial soil. F. arundinacea cv. AU Triumph was sown at either 17 or 31 kg/ha and L. perenne cv. Grasslands Supernui was sown at 12 or 23 kg/ha in autumn 1990 with Trifolium repens cv. Grasslands Pitau (3 kg/ha). Measurements of herbage mass and botanical composition during the ensuing 2-year period indicated that there was no advantage in terms of the suppression of weed species or the accumulation of herbage mass of the sown species from sowing more seed than that required to achieve a population of 450-500plants/m2 6 weeks after sowing of either L. perenne or F. arundinacea. A population of 150 T. repens plants/m2 appeared to be adequate for development of a balanced sward. Establishment of F. arundinacea was slower than that of L. perenne but both species developed to productive swards after infrequent but close defoliation with dairy cattle in the first spring and subsequent rotational grazing by lactating dairy cows. Pasture establishment in Northland is difficult because of shallow topsoils. It is suggested that direct sowing may preserve fragile topsoil and successfully establish alternative species such as F. arundinacea as long as attention is paid to their establishment requirements. It is concluded that alternative species may offer a solutionto the low feed availability in the summer, and poor survival in poorly drained areas during the winter, of L. perenne.