Effect of climate change adaptation options on maize yield across different agro-climatic zones in South Asia: A meta-analysis

Maize (Zea mays L.), despite being a crucial and versatile crop, faces up to 30% yield loss due to climate-induced hazards such as heat and drought. To mitigate climate risks, various adaptation strategies has been suggested. However, the effectiveness of these strategies may vary significantly across different agro-climatic zones (ACZ), depending on the local conditions, making adoption decisions challenging. This study synthesises and evaluates the linkage of regional climatic hazards to potential adaptation options, and assess their suitability across different ACZs, soils and seasons in South Asia (SA). Additionally, we strengthen our work by using local literature from SA countries to introduce granularity and enhance the contextual relevance of our findings. Meta-analysis involving subgroup analysis and meta-regression was conducted to capture the influence of ACZ, soil textures, and seasonal conditions (rainfall and temperature) on yield benefits. Among 1114 observations reviewed for meta-analysis, 62% reported a positive yield response. In-situ moisture conservation, nutrient management and zero tillage showed mean yield benefits of 6.8%, 6.2% and 4.3%, respectively, over conventional practices across SA. ACZ significantly influenced the performance of the adaptation option, with central-western zone and north-eastern plain zone showing greatest yield benefits. Fine-textured soils had a significant positive impact of adaptation options in both wet and dry seasons while coarse-textured soils had a notable positive effect only in dry season. Performance of adaptation options were strongly influenced by rainfall and temperature, underscoring the need for region-specific technologies. Our findings improve the understanding of suitability and effectiveness of adaptation options across different regions, soils and climate, thereby supporting selection of appropriate adaptation options for greater benefits. We conclude by emphasizing the need for localized adaptation options that addresses the regional climatic risks and are productive in local soil and season to enhance maize resilience in SA.