Effect of potassium and seed density on potato production Solanum tuberosum Group Phureja var. Criolla Guaneña

Potassium is a macronutrient that can improve the growth of crops. A randomized complete block design was used to evaluate the influence of four planting densities (50,000, 41,667, 33,333, 31,250 plants ha-1) and three potassium levels (300, 250, 200 kg of K2O ha-1) on leaf area (AF), leaf area index (LAI), crop growth index (CCI) and harvest index (CI) in potato Solanum tuberosum Phureja var. Criolla Guaneña grown in an area of Botana, Altiplano de Pasto, Nariño, Colombia. All evaluations were measured every 20 days until 120 days after sowing (das), except for the IC at the end of the cycle. Analysis of variance, comparison of Tukey means (P<0.05) and regression among the evaluated variables was performed. The physiological variables presented a significant adjustment to the polynomial models of third degree, quadratic and Hoerl, with coefficients of determination higher than 0.6, indicating that with 31,250 plants ha-1 and 250 kg K2O ha-1 increments were achieved in AF of 6000 cm2 and with 200 kg K2O ha-1 in IAF and ICC of 2.0 and 40 g m2 day-1 between 60 to 80 and 80 to 100 das, respectively; However, with 33,333 plants ha-1 and 250 kg K2O ha-1 the IC (0.70) was increased (P<0.05). Although the regressions showed a tendency to increase the LAI and ICC with the production management practices carried out by the farmers (41,667 plants ha-1 and 250 kg K2O ha-1) between 60 to 80 das, it is not recommended since a lower IC (0.60) was obtained at the end of the cycle.