The effect of sowing date and cultivar on the yield and utilisation of kale: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science with Honours at Lincoln University

Abstract

'Caledonian' (Cale) and 'Regal' kale was sown at Lincoln, Canterbury, New Zealand m 2007/2008 on the 1 November (Nov) and 15 December (Dec). The maximum yield was 17.5 t DM/ha for Nov sowing date at the 16 June harvest date. Regal cultivar crop produced the lowest yield, 24% less than the maximum yield accumulating 13.4 t DM/ha at the same harvest date. The Dec sowing date reached at maximum yield of 13.5 t DM/ha and the Cale cultivar reached a maximum yield of 15.9 t DM/ha. The effect of sowing date and cultivar on leaf to stem ratio was analysed as a percentage of TDM. Once grazing started 9 June 2008, Regal cultivar showed a 11 % higher amount of leaf DM as a proportion of TDM compared with Caledonian. There was a significant difference between sowing dates at 9 June harvest with the Dec sowing date having 6% higher leaf DM as a percentage of TDM. One of the dominant drivers on animal performance and utilization was a high ME content throughout the study. The ME content stayed stable throughout all harvests and ranged between 11.5-11.7 MJ ME/kg DM and 12.1-12.5 MJ ME/kg DM for sowing date and cultivar treatments respectively for consumed kale crops. The %N showed a decreasing pattern down the stem fractions. The Caledonian cultivar showed a 42% decline in %n from the top of the stem to the bottom, 41 %, 36% and 35% for December and November sowing dates and Regal cultivar respectively. There were no differences in ADF, NDF and WSC content between both sowing date and cultivar throughout the trial period. The utilization across all treatments averaged 88% for the two week period of measurements. The highest utilization were in the December sowing date and Caledonian cultivar treatments during the week starting 16 June with 90% utilization for both treatments. Residuals ranged from 1.46 t DM/ha (90%) for December sowing for the week starting 16 June to the highest residual amount of 2.27 t DM/ha (86%) for December sowing for the week starting 9 June. Intake averaged 9.3kg DM of kale/day/cow, which was a 16% increase in daily intake. Increases in utilization can be associated to high crop quality and DM allocation.