Coffee productivity and root systems in cultivation schemes with different population arrangements and with and without drip irrigation

•We examine five years of production of irrigated coffee at different spacings.•Increasing yields were obtained with the use of irrigation, even in years of low production.•Dense spacings cause higher yields of coffee in the first five years.•Root mass is increased with the use of irrigation, especially in less dense tillage. This study addressed the vegetative development, yield, and root development of coffee during cultivation in the absence and presence of drip irrigation and in different population arrangements over five years. A 6×2 factorial experimental scheme was used with a randomized block design and four replications. The six plantation densities were 1.60×0.50m; 1.60×0.75m; 1.60×1.00m; 3.20×0.50m; 3.20×0.75m; and 3.20×1.00m. These plantation densities were divided into irrigated and non-irrigated treatments. The analysis of variance of the interaction between planting density and irrigation revealed absence of synergism in changing the biometric parameters. However, the isolated analysis of the factors showed significant effects of plantation densities, with the arrangement of 1.60×0.50m getting the highest values of plant height and the smallest crown diameter, over the cycles. The adoption of irrigation caused significant effects on biometric parameters, with the irrigation of coffee causing increase in plant height, crown diameter and stalk diameter. The irrigated coffee in the four cycles resulted in a higher processed coffee production, especially when coffee was grown with small row spacing. The irrigated coffee obtained the average yield of 2623kgha−1, while the coffee without irrigation had an average yield of 1026kgha−1. The irrigated treatments had greater root concentrations as compared to the non-irrigated treatments. In addition, the root concentration was greater in the 0–0.5-m layer when smaller row spacing was used.