White clover and chicory production from four sowing dates with five rates of ryegrass: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science With Honours at Lincoln University

Abstract

Low lamb growth rates are attributed to less than 30% dicotyledonous species in a pasture. In this study germination, emergence, herbage production, botanical composition of the pastures and root and shoot weight of chicory (Cichorium intybus L. c.v 'Puna'), sown on four sowing dates (4/2, 26/2, 19/3, 9/4), with 0, 4, 8, 12 or 16 kg ha⁻¹ rates of ryegrass (Lolium perenne L. c.v 'Ruanui') and 3 kg ha⁻¹ white clover (Trifolium repens L. c.v. 'Le Bons') and 1.5 kg ha⁻¹ chicory were examined. All species emerged after a similar thermal time (ca 172 °Cd), and temperature did not effect (p<0.05) the maximum percentage germination of ryegrass or white clover. Maximum percentage germination of chicory declined (p<0.05) from 79% to 34% at 24°c and 10 °C respectively. Dry matter production by 25 September decreased for each delay in sowing date (p<0.01) from 672 g/m² from pastures sown on 4 February to 203 g/m² from pastures sown on 9 April, due to decreases in the amount of photosynthetic PAR intercepted and temperatures. Delay of sowing date when soil temperature 13 °C, resulted in no white clover and chicory all ryegrass sowing rates and increase in winter annual weeds. There was no advantage in terms of dry matter production or weed suppression from sowing more than 12 kg ha⁻¹ of ryegrass. Ryegrass sowing rates greater than 12 kg ha⁻¹ sown on all sowing dates resulted in a maximum of 15 % white clover/chicory in the pasture. A pasture containing 30% or more white clover and chicory was only obtained by sowing into a seedbed of 18 °C on 4 February with less than 8 kg ha⁻¹ of perennial ryegrass. To maximise chicory production in the spring after defoliation root weight must be maximised this is only achieved by a 4 February sowing with less than 8 kg ha⁻¹ of perennial ryegrass.