Effects of climate change on key soil characteristics and strategy to enhance climate resilience of smallholder farming: an analysis of a pomegranate-field in a coastal Tunisian oasis

Climate change may affect soil fertility because it can alter various soil physicochemical characteristics through different mechanisms. Currently, a better understanding of its effect on soil physicochemical characteristics is required for sustainable soil management. Therefore, the main purposes of this study were to assess the effect of climate change on key soil physicochemical characteristics (i.e., soil moisture, organic carbon content, and macro-nutrients) and to develop a suitable soil management strategy to enhance climate resilience of smallholder farming in a Tunisian oasis, called Gabes Oasis. An investigation methodology was developed based on future climate projection and simulation of climate change effects on key soil physicochemical characteristics from 2019 to 2050 using the HP1 model. The HP1 model was calibrated and validated based on intensive field measurements over four years (from January 2015 to December 2018) in a pomegranate-field in Gabes Oasis. The results showed that the HP1 model could simulate soil physicochemical characteristics under the baseline scenario. Compared to the no climate change scenario, significant effects of climate change (i.e., RCP8.5, RCP6.0, and RCP4.5 scenarios) on the investigated key soil characteristics were predicted by 2050. Among the investigated soil characteristics, it was predicted that soil organic carbon content was most critically affected. By 2050, it is expected that this content will decrease by 14% for RCP4.5 scenario, 16% for RCP6.0 scenario, and 23% for RCP8.5 scenario. Finally, it is recommended to apply the following cow manure amount to enhance soil characteristics resistance to future climate change: 3748 kg ha−1 year−1. However, more experiments on fields are necessary to investigate the sustainability of the proposed level of cow manure.