The Spring Cereal Cultivar Evaluation Book for 2020/21 is now available to read.
Overall, in the 2020-21 season, irrigated spring wheat yields in Canterbury and the southern North Island were similar to the 4-year mean. On average, barley yields across Southland and Canterbury were also similar to the 4-year mean. However, at the Canterbury sites, irrigated crops were higher and dryland crops lower by around half a ton. In the lower North Island, barley yields were lower than the 4-year mean, with spring rainfall hampering some crops.
NIWA reported that Spring 2021 was New Zealand’s fifth warmest on record. Temperatures were above average across nearly all of the North Island and large portions of the South Island. The exceptions being parts of Wellington-Wairarapa, Marlborough, upper West Coast, interior Otago and Southland which recorded near average temperatures. Spring rainfall totals were also generally above normal across the lower half of the North Island, Nelson, Tasman, interior Otago, Fiordland, and coastal Southland, and this impacted the establishment and growth of some spring crops.
By the end of spring, soil moisture levels were higher than normal across most of the North Island south of Hamilton, as well as Nelson-Tasman. Much of Northland to northern Waikato and the southern half of the South Island recorded below average soil moisture levels due to below average spring rainfall and these areas remained below average throughout summer. While some drier regions did receive some summer rainfall, it was not always sufficient to improve soil moisture.
Summer solar radiation levels at the trial sites varied between average and below average, partly because of summer rainfall events in some regions and partly because of the humid cloudy days that continued into ripening. This prolonged harvest by up to a month in some areas. The average to below average solar radiation impacted yield potential in some locations. Summer temperatures were near average for the majority of New Zealand,
although above average temperatures did occur in parts of the North Island, Tasman, Canterbury and Otago. These would have hastened maturity and
reduced the grain fill period, especially for dryland crops.