Impact of earthing up on groundnut (Arachis hypogaea L.) pod yield and its components

Groundnut is an important crop grown by smallholder farmers in West Africa for both domestic and market consumption. In groundnut cultivation, earthing up, or covering the plant's base and lower nodes with soil, is a common practice. However, there is no consistent evidence about its economic benefit. From 2016 to 2018, a three-year experiment was conducted to assess the benefits of earthing up and establish the best time to do so to increase groundnut yield, thus filling a knowledge gap in the region. The experiment was set up in a split-plot design, with the planting arrangement as the main plot (ridge vs flatbed planting) and the timing of earthing up as the subplot. The earthing up timing was divided into ten treatments, ranging from no earthing up (control) to earthing up at 70 days after planting. Data was collected on the number of matured pods per plant, dry pod yield, dry haulm yield, shelling percentage, and 100 seeds weight. The results for the time of earthing up revealed that there was no statistically significant difference in dry pod yield and dry haulm yield except in 2017. Similarly, for the number of matured pods per plant, 100 seeds weight, and shelling percentage, there was no statistically significant difference between times of earthing up except for 100 seeds weight in 2018 and shelling percentage in 2017 and 2018. The individual years and combined analyses across years revealed no statistically significant difference between the main plots for all the five traits. The combined analysis for the times of earthing up showed a significant difference only for shelling percentage. Therefore, in the Sudan Savanah agro-climatic conditions of the semi-arid tropics of West Africa, earthing up may not be economically beneficial during a typical rainfall season with appropriate planting time. Instead, it could raise production costs, reducing the profit.