Follow-up on the Danish winter wheat demonstration trial 2017/18, WP3

After the problematic weather conditions at sowing with very wet conditions, the winter did not let Denmark go before April followed by a sudden shift to very high temperatures and no rain. 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.

This might one of the explanations for differences in the best performing strategy in early season compared to final yield. Even with the poor conditions for establishment, the directly sowed strategies had a higher crop plant number per row meter than the standard row width strategies. In June, however, there was a lower crop biomass than in other strategies. The strategies sowed at wide row distance had the highest crop biomass at this time of the season. At harvest, however, the directly sowed strategies yielded much better than all other strategies and the strategies with wide rows gave the lowest yield. The standard strategies had intermediate values for biomass of crop in June and yield.

Weed biomass in June was sampled at the same time as crop biomass, but the amounts of weeds in all the strategies were very low. The dry summer inhibited any new weed flushes after control measures in spring. It is difficult to conclude on the results regarding strategy performance, but there was an indication of better conditions in the directly sowed strategies during the drought. The ploughed strategies with wide rows showed promising establishment and early summer biomass production, but was least resilient during the drought. The difference in yield between strategy 4 and 6 is hard to explain as both had very low weed biomass and the only management practice to differ in spring was a tine harrowing in strategy 6.

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