Planting density is a key driver of sorghum yield gaps and variability in smallholder farms of northern Nigeria: Results of an integrated panel survey and crop cutting experiment

Abstract Understanding the drivers of crop yields and variability is fundamental to closing yield gaps and ensuring global food security, especially in smallholder farming systems. This study identified the major socio-economic, soil and crop management factors contributing to sorghum yield variability and yield gaps in the sorghum belt of northern Nigeria. Data on socio-economic indicators, agronomic practices, soil fertility characteristics and yields were collected through integrated agronomic panel and crop cut surveys. These surveys were conducted in two agroecological zones (i.e., Sudan and Sahel savanna zones), the sorghum production belt in Nigeria, among 144 sorghum-producing households using a multistage balanced acceptance sampling procedure. Our results showed that sorghum productivity was relatively higher (43% more) in Sudan compared to the Sahel agroecological zone. Additionally, planting density was the main factor in reducing sorghum productivity across the two zones, with a 68% and 40% yield reduction for the Sudan and Sahel Savanna agroecological zones, respectively. This suggests innovative technologies that promote optimal planting density should be encouraged in farmer extension services to close the persistent sorghum yield gaps under smallholder farming conditions in the two agroecological zones.