Geospatial Analysis of Soil Property Variability in Cyclone-Affected Areas of southern Malawi

Tropical cyclones significantly influence soil variability through various mechanisms, including erosion, waterlogging, flooding, landslides, changes in organic matter content and soil microbial communities. Understanding these impacts is essential for developing strategies to mitigate the negative effects of cyclones on soil resources and ecosystem health. However, the specific effects of recent tropical cyclones in Malawi on soil variability remain poorly understood. This knowledge gap hampers the ability to predict the long-term impacts of such cyclones on soil quality and ecosystem functioning, highlighting the need for further research in this area. 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 analyzed 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 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 dynamical 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.