Impact of changing weather on the crops yield stability in different cropping systems

Changes in weather conditions make it possible to change the schedule of agricultural works and introduce new crops and crop rotations in Northern Europe. It is important that the yield of the crops in the rotation are stable under highly variable weather conditions, which would ensure a high total yield for the rotation. One of the goals of this long-term field experiment (2008–2022) was to study the effect of weather conditions on the total yield and stability in the crop rotation; crops of the given crop rotation were grown in organic and conventional cropping systems. Compared to the pre-experimental period 1964‒2007, the annual average air temperature of the test period 2008‒2022 was higher by 1.1 degrees, whereas the increase in the annual average temperature was primarily due to the increase in winter and June–July temperatures. In the 3rd cropping cycle (2018–2022) the total yield of crop rotation as an average of fertilizer variants and experimental years was 21% and 24% lower than in the 1st (2008–2012) and 2nd (2013–2017) cropping cycles, respectively, which was mainly caused by the decrease in field pea yield. The effect of weather on yield stability was greatest for field pea. Fertilization with mineral fertilizers improved the stability of the total yield in the conventional cropping system. Correlation, factorial analyses of variance (ANOVA) and two-factor ANOVA were used to test the effect of cropping systems and climatic conditions on total and average DM yield of crop rotation, also each crop’s DM yield. Despite the negative impact of the weather, most of the yield loss can be prevented or the damage can be eased by careful planning and detailed knowledge about the influence of different weather factors. Further investigation is required to determine the change in growing season length, sowing dates and harvesting to provide farmers more detailed tools to predict and plan their actions.