The contribution of forage oats to annual feed production when grown after maize in a double cropping system

The cool season forage production of Florida oats (FO) was measured in a series of replicated small plot trials at the Ruakura Agriculture Centre over five successive seasons. The oats were grown as part of a double cropping system using maize as the complementary warm season crop. Combined annual forage maize/oats yields averaged 26 t dry matter (DM)/ha. Experiments in 1978 and 1979 showed that forage production of the earlier maturing FO was higher than that of New Zealand‐bred oat and wheat cultivars (11–13 t DM/ha v. 9–11 t DM/ha) when sown in April and cut in early October (‘ensiling’ yield). Subsequent experiments from 1980 to 1982 measured the yield response of FO to three rates of nitrogen (N) fertiliser (O, 35 and 70 kg N/ha) applied during tillering, following direct drilling into maize stubble. ‘Ensiling’ yields were high (9–13 t DM/ha) but yield responses to N fertiliser were small except in 1981 when June and July were warmer than average. FO was capable of consistently high yields when grown between successive maize crops. Tolerance to Barley Yellow Dwarf Virus probably contributed to the high yield potential of FO. The annual yield from the double cropping system was restricted by summer moisture stress affecting maize yields and severe frosts affecting winter cereal yields. Despite the high production level from the double cropping system, present costs of its implementation in dairy systems are prohibitive.