Agronomic and economic responses of the potato (Solanum tuberosum subsp. andigena) to differential fertilization in four environments in Nariño, Colombia

Abstract

Due to the importance of potato cultivation in Nariño, Colombia and the high participation of fertilizer in production costs (25%), as well as the great variability of soils in the region, we evaluated three fertilizer levels for six cultivars of Solanum tuberosum subsp. andigena in four homogeneous production environments. We recorded physiology and yield of the potatoes in experimental plots in a randomized complete block design with three replications in each environment. Analysis of variance, comparison of means for yield components, and discriminant analysis of principal components were performed for all variables. For the economic analysis we used the partial budget net benefit methodology. The environments generated differential responses in the cultivars. Between fertilization levels there were significant differences; however, there was no interaction between levels and environments. The cultivars ‘ICA Única’, ‘Pastusa Suprema’, ‘Parda Bilingüe’, and ‘Roja Huila’, showed the highest yields with the application of 262, 600, and 538 kg ha^-1 of N, P₂O₅, and K₂O (level L3). ‘Diacol Capiro’ and ‘Superior’ did not show yield differences between levels. Economically, the alternative that would generate the highest return on investment was fertilization with level L2 (N 180, P₂O₅ 400, K₂O 358 kg ha^-1) in ‘Diacol Capiro’, ‘Superior’, and ‘ICA Única’ cultivars. For ‘Roja Huila’ and ‘Parda Bilingüe’ the highest return was level L1 (N 150, P₂O₅ 200, K₂O 100 kg ha^-1). In the case of ‘Pastusa Suprema’ the marginal rate of return was 18.5% with the L2 fertilization level.