Einfluss von Niederschlägen im Vegetationsverlauf und hohen Temperaturen im Frühjahr sowie Pflugeinsatz auf den Kornertrag von Winterweizen in Niederösterreich

Winter wheat is grown on a large scale in the state of Lower Austria, and yield losses are expected due to climate change, both as a result of increasing drought all year round and high temperatures in the generative phase. The influence of precipitation in winter is particularly questionable. Based on large data sets from six different districts in Lower Austria and 14 harvest years 2006 to 2019, which also included information on soil cultivation before wheat sowing, the influence of precipitation (in four periods during wheat development), the influence of high temperatures (in spring and early summer) and the effect of ploughing on grain yield were examined. An influence of winter precipitation (November 16 to February 28/29) was not detectable, nor was that of spring or early summer precipitation (March 01 to July 15). The autumn precipitation (July 16 to November 15) and the total precipitation of a harvest year (July 16 to July 15) showed a positive, although minor, influence on wheat yield. In contrast, the number of hot days with a maximum temperature of above 27 °C in spring and early summer and high daily average temperatures in the generative phase (May 01 to July 15) had a negative effect on wheat yield. The results underline the great impact of heat stress on wheat crops in spring and early summer, while precipitation only had a positive effect in the annual total and in autumn. The evaluation of ploughing before sowing showed, with the exception of the Mistelbach district, a significantly negative influence of the use of the plough on grain yield, with a lower yield of around 500 kg ha⁻¹ on average in all districts. This result confirms the advantage of reduced soil tillage on relatively dry sites.