Geospatial analysis of soil property variability in cyclone-affected areas of southern Malawi

Tropical cyclones significantly alter soil through erosion, waterlogging, flooding, landslides, and changes in organic matter and microbial communities. While understanding these impacts is crucial for mitigation, the specific effects of recent cyclones in Malawi on soil remain poorly understood. This knowledge gap hinders our ability to predict long-term impacts on soil quality and ecosystem function, underscoring the need for further research. In this present study, 75 soil samples were collected at a depth of 0–30 cm on a regular grid in cyclone-affected areas of southern Malawi. The samples were analysed for pH, electrical conductivity (EC), total carbon (TC), total nitrogen (TN), available phosphorus (P), exchangeable bases, and particle size distribution. Topographic data was generated using an unmanned aerial vehicle (UAV), and a questionnaire survey was conducted to describe observed soil characteristics and land management practices. Descriptive and geostatistical analyses were used to examine the spatial patterns of soil properties and their relationships with topographic factors. The soil properties exhibited significant variability, as demonstrated by the coefficients of variation, with available phosphorus (P) showing the highest variability at 156.9%, followed by exchangeable potassium (K +) at 139.6% and electrical conductivity (EC) at 95.3%. Strong spatial dependency was found for pH, potassium, clay, total nitrogen, and sand, suggesting the influence of local-scale factors. Kriged maps revealed distinct spatial patterns, with lower pH values observed in the southern and northern parts of the study area and higher organic matter content in the central region. The cyclone's impact led to a decline in maize yield, dropping from nearly 3 to less than 2 tons per hectare. Cyclone Freddy significantly impacted soil properties and agricultural productivity in Southern Malawi. The findings highlight how critical it is to understand the effects of cyclone-induced spatial variability of soil properties. Specifically in this study, Tropical Cyclone Freddy affected soil quality across different regions in the study area, resulting in dynamic shifts in soil pH, soil texture and reduced overall crop productivity. This knowledge is essential for developing targeted land management strategies to mitigate cyclone-induced soil degradation and optimize land-use practices, ensuring long-term sustainability in cyclone-prone regions.