Variability in soil quality among smallholder macadamia farms in Malawi

Summary

This cross-sectional survey of 63 smallholder macadamia farms in Malawi documents widespread soil fertility constraints, with sandy loam soils, strong acidity (mean pH ≤5.1), low organic matter (>50% of samples ≤1%), and inadequate cation exchange capacity (mean 1.67 cmol(+) kg−1). The findings establish an evidence base for site-specific soil fertility restoration interventions, highlighting that poor agronomic practices and long-term nutrient depletion by tree and annual crops have driven these deficiencies. The research underscores the need for sustainable nutrient management strategies tailored to macadamia production systems in resource-limited contexts.

Regional applicability

These findings are of limited direct applicability to UK farming, as macadamia cultivation is not practised commercially in the UK climate. However, the methodological approach to characterizing nutrient variability across smallholder farms and the emphasis on site-specific fertiliser recommendations may inform UK policy discussions on precision nutrient management and reduced input efficiency in diverse farm contexts.

Key measures

Soil texture; pH; cation exchange capacity (cmol(+) kg−1); soil organic matter content (%); concentrations of essential nutrients; mean pH ≤5.1; proportion of soils with organic matter ≤1%

Outcomes reported

The study characterized soil fertility status across 63 smallholder macadamia farms in central and southern Malawi, measuring soil chemical properties (pH, organic matter, nutrient concentrations, cation exchange capacity) from 189 soil samples at 0–15 cm depth.

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