Increasing zinc concentration in maize grown under contrasting soil types in Malawi through agronomic biofortification: Trial protocol for a field experiment to detect small effect sizes

Summary

This trial protocol describes a multi-site field experiment designed to evaluate whether application of zinc-enriched fertilisers can increase zinc concentration in maize grain across contrasting soil types in Malawi, addressing widespread micronutrient deficiency in rural populations. The study employs power analysis informed by pilot data to detect a minimum 10% increase in grain zinc concentration at the highest fertiliser rate, and tests the hypothesis that agronomic biofortification effectiveness differs between Lixisols and Vertisols soil types. The research will generate evidence on whether such interventions can create sufficient zinc gains to improve dietary supplies whilst accounting for soil-dependent variation.

Regional applicability

The findings have limited direct applicability to UK agricultural contexts, where zinc deficiency in staple crops is not a recognised public health priority and soil zinc status is generally adequate. However, the methodological approach to detecting small effect sizes in agronomic interventions across soil types may be relevant to UK research on micronutrient optimisation in cereal production.

Key measures

Grain zinc concentration (primary); grain mass (yield), stover mass, and stover zinc concentration (secondary); comparison across three zinc fertiliser rates (1, 30, 90 kg/ha) and two soil types (Lixisols and Vertisols)

Outcomes reported

The study protocol describes measurement of grain yield, stover mass, and both stover and grain zinc concentrations across three fertiliser rates applied to two soil types at three agricultural research stations. A second cropping year will assess residual effects on grain zinc concentration.

Topic tags