Growth and development of early sown cereals under grazing

Abstract

A field experiment was conducted to investigate the biomass production and regrowth of wheat (Triticum aestivum L.), triticale (× Triticosecale), oats (Avena sativa) and rye corn (Secale cereale) as dual-purpose crops at early sowing dates in Canterbury, New Zealand. A successful dual-purpose crop was defined as a cereal that was able to provide high quantities of biomass for grazing by stock ant times of feed deficit, without developing in such was that grain yield could be expected to differ from that of an un-grazed crop. This experiment examined biomass production, apical development and Zadocks’ growth stage of eight wheat, three triticale, one rye corn and two oat cultivars sown at three sowing dates between 20th December 2013 and 3rd April. Biomass available was greatest prior to the first grazing of each plot. Prior to the first grazing oat cultivars had higher average available biomass than the other species at TOS 1 and 3 producing 8716 and 1414 kg DM (dry matter) ha⁻¹ respectively at TOS 2 rye corn had marginally higher biomass, producing 4082 kg DM ha⁻¹. Biomass production was greatest for cultivars in TOS 1 decreasing with each subsequent grazing, average accumulated biomass removal was 4791, 2804 and 1027 kg DM ha⁻¹ at TOS 1, 2 and 3 respectively. Oat and triticale cultivars generally reached Zadocks’ growth stage 30 prior to grazing treatment in most cases (exceptions ‘Prophet’ in TOS 2 and ‘Empero’ in TOS 3), this meant they received grazing damage, preventing crop regrowth. Grazing damage made the oat and triticale cultivars unsuitable for dual-purpose use. At TOS 1 all cultivars appeared to be damaged by grazing, this would have resulted in poor grain yield. At TOS 2 development habits (time to growth stage 30) were most suitable in the cultivars ‘KWW42’ and ‘Phoenix’, these cultivars however had lesser accumulated biomass removal from grazing than other cultivars in the trial, producing an average of 2476 and 2558 kg DM ha⁻¹ respectively. The wheat cultivars ‘Empress’ and ‘KWW47’ had the best combination of late maturity (time to GS 30) and accumulated biomass removal producing 3882 and 3372 kg DM ha⁻¹ respectively. ‘Empress’ and ‘KWW27’ were the most suitable dual purpose cultivars at TOS 2, balancing biomass production and potential grain yield. AT TOS 3 there were no difference is accumulated biomass removal from grazing and time to GS 30 between wheat cultivars, therefore all wheat cultivars were equally suitable. This experiments indicate significant opportunity for wheat cultivars to be sown up to 3 months earlier than grain only crops and grazed throughout the autumn and winter period. Subsequent grain yields were not examined in this study and remain an area of further research in New Zealand.