Spatial frameworks for robust estimation of yield gaps

Abstract

Food security interventions and policies need reliable estimates of crop production and the scope to enhance production on existing cropland. Here we assess the performance of two widely used ‘top-down’ gridded frameworks (Global Agro-ecological Zones and Agricultural Model Intercomparison and Improvement Project) versus an alternative ‘bottom-up’ approach (Global Yield Gap Atlas). The Global Yield Gap Atlas estimates extra production potential locally for a number of sites representing major breadbaskets and then upscales the results to larger spatial scales. We find that estimates from top-down frameworks are alarmingly unlikely, with estimated potential production being lower than current farm production at some locations. The consequences of using these coarse estimates to predict food security are illustrated by an example for sub-Saharan Africa, where using different approaches would lead to different prognoses about future cereal self-sufficiency. Our study shows that foresight about food security and associated agriculture research priority setting based on yield potential and yield gaps derived from top-down approaches are subject to a high degree of uncertainty and would benefit from incorporating estimates from bottom-up approaches.

Progress in research on site-specific nutrient management for smallholder farmers in sub-Saharan Africa

“…Excellent methodologies have been developed for that in recent years (e.g. Rattalino et al, 2021 ) and it is now necessary to apply them more widely across SSA. This must also guide the representative selection of field sites used for collecting critical data and evaluating specific SSNM solutions ( Ten Berge et al, 2019 ).…”

Combined Application of Compost, Zeolite and a Raised Bed Planting Method Alleviate Salinity Stress and Improve Cereal Crop Productivity in Arid Regions

“…Moreover, the integrated effect of composting, zeolite application and raised bed growing has received less attention thus far. Despite the fact that cereal crops, particularly wheat and maize, are considered strategic crops for ensuring food security, most countries in arid regions rely heavily on imports due to land degradation, poor management of salt-affected soils, and climatic changes [22][23][24][25]. As a result, proper saline soil management is an urgent need for improving cereal crop production and closing the food gap in arid regions.…”

Southeast Asia must narrow down the yield gap to continue to be a major rice bowl

“…However, the regional extent of our study, together with the level of detail in relation to spatial and temporal variation in yield gaps and specificity in terms of cropping systems is unique, providing a basis for prioritizing agricultural research and development and investments at regional, national and subnational levels 32 . These regional and seasonal differences in yield gaps would not have been detected using top-down modelling approaches that ignore the complexity and diversity of rice systems in Southeast Asia 33 . For example, while rainfed rice exhibits a larger yield gap, our study shows that closure of yield gaps in irrigated rice can lead to a larger impact on annual rice production due to higher cropping intensity.…”