From April to Sep. 2018 the trial location received 198 mm of rain, which was 184 mm less than the year before and very low for the region. At the same time the temperature of these five months were on average 2 ℃ higher than in 2017 with max temperatures in summer 2018 reaching 32 ℃ in July compared to 25 ℃ in 2017. No irrigation was possible in the field, as the need was not expected.
The very dry conditions made the standard herbicide application program difficult. The weeds developed a thick wax layer and was less susceptible than under normal conditions. Especially, volunteer oilseed rape and Chenopodium album was difficult to control with the normal herbicide program consisting of metamitron, ethofumesate and phenmedipham. The bandspraying in strategy 2 and 3 had the same actives as the standard confined to the crop row. The ALS-tolerant variety was treated with foramsulfuron and thiencarbazone, which are less inhibited by the wax layer. Because of the poor efficacy of the herbicides a weed harrowing was added in all strategies. This means that a weed harrowing was conducted twice in strategy 2 and 4 and once in strategy 1 and 3. Strategy 3 was sown 2 weeks later than other strategies and the first weed harrowing (strategy 2 and 4) was obsolete.
In the end, the yield was poor due to drought, but some differences was observed among strategies.