Response of Soil Microarthropods to Drought in Arable Fields

Abstract

In the face of current as well as projected increased frequencies and severities of droughts the interest in responses of the belowground system to such profound changes in environmental conditions has risen. The heavily disturbed soils of agricultural fields deserve special attention since they seem especially vulnerable and are of crucial importance for future crop production. Soil organisms mediate a number of functions in soil, hence, in order to develop strategies for mitigating detrimental drought effects on agricultural systems, it is essential to better understand their response to drought and how this may be modulated by interactive factors. GENERAL INTRODUCTION1.1 CLIMATE CHANGE Droughts are the result of several forces that are altered by global climate change. During the last decades temperature increased and precipitation became more variable, hence, it is no surprise that droughts have become more frequent and intensive (IPCC 2021). In the future, even under conservative scenarios for climate change, drought is predicted to further increase in frequency and severity within the current century. For Europe models using differently weighted indices consistently project increasing duration, frequency and affected area of drought (Samaniego et al. 2018). However, the magnitude of this increase is spatially and temporally different. Generally, extreme dry, but also extreme wet years are projected to become more frequent with more pronounced dry years in Southern Europe and more pronounced wet years in Northern Europe (Russo et al. 2013; Spinoni et al. 2015). Yet, drought is predicted to increase in spring and summer all over Europe under a moderate climate change scenario (Spinoni et al. 2018). Drought is still not uniquely defined; thus, different modelling approaches focus on different indicators. For belowground systems soil moisture is likely to be the most crucial measure, which is projected to decrease in all seasons in Southern Europe, in summer in Western and Central Europe and in spring in Northern Europe (Ruosteenoja et al. 2018). Generally, episodes with anomalously low moisture are expected to become more frequent in all regions of Europe. Such, in part, profound effects on environmental conditions in the belowground systems are likely to also affect soil organisms with potential differences between different regions of Europe.