MANAGEMENT OF TRIUMPH BARLEY FOR HIGH-YIELD AND MALTING QUALITY ON LIGHT SOILS IN CANTERBURY, NEW-ZEALAND

This 4-year study was initiate to formulate a management package for producing high yields of high quality malting barley and involved large-scale trials comparing the levels and interactions of nitrogen (N), irrigation, and disease and pest control on yield and quality. One ha each of autumn and spring sown crops were sown in mid Canterbury each year. In the first 3 years, low and high levels of irrigation (flood irrigation when gravimetric soil moisture in die top 150 mm of soil fell to either 15% or 20%) and two levels of disease and pest control (curative and preventative) were compared at different levels of N fertiliser (100, 200, and 300 kg N/ha in Year 1, and 0, 50, 100, and 200 kg N/ha in Years 2 and 3). In the fourth year, four levels of disease control (nil, curative, half preventative, and preventative) were compared along with four levels of N fertiliser (0, 50, 100, and 150 kg N/ha). The treatment means from all eight trials (but only the first six trials in the instance of malt extract, ears/m2, and grains/ear) were then analysed together to determine the overall effect of treatments and treatment combinations. This combined analysis showed that N fertiliser significantly increased yields (from 4.5 to nearly 7 t/ha), particularly at the high irrigation treatment and in autumn sowings (up to 8 t/ha). N fertiliser also increased percentage screenings (from 5 to 16%), particularly under curative disease and pest control. Grain N percentage was also increased with increasing N fertiliser levels (from 1.3 to 1.6%), especially in the spring sowing and under low irrigation. Malt fine extract was reduced by increasing N fertiliser (from 84.4 to 81.3% at 200 kg N/ha). Ears/m2 increased by up to 50% with increasing N, especially in autumn sowings and under high irrigation. Grains/ear increased by 1.6 with increasing N fertiliser especially under curative disease and pest control.