Efecto del guano de isla en el rendimiento de dos variedades de Quinua (Chenopodium quinoa Willd) en suelo degradado Effect of island guano on the yield of two varieties of Quinoa (Chenopodium quinoa Willd) on degraded soil

, with the objective of evaluating the yield of four varieties of cassava in three harvest intervals. The experimental design was randomized blocks, with four treatments (Seda, Pomberi, Sa'yju and Tacuara) and five repetitions. The spacing was 0.8 x 0.7 m, with a population density of 17,870 plants per hectare. Root quantity per plant, root weight per plant, amount of commercial and non-commercial root, weight of commercial and non-commercial root, yield per hectare were evaluated at eight, ten and twelve months after planting. The root number per plant was infuenced (p <0.05) by the varieties, and was higher for the variety Seda; number and weight of commercial root which did not vary (p> 0.05) depending on the varieties and harvest intervals. The root weight per plant does not present significant differences (p> 0.05) between varieties and harvest intervals. Commercial root weight and root yield were significantly (p <0.05) higher in harvest intervals performed 12 months after sowing, where the Tacuara variety showed the highest yield. Variety of table or sweet manioc Tacuara presents superior performance at 12 months after sowing. Cassava varieties tested have acceptable production parameters, and the knowledge of them as well as cutting interval may allow better use mainly by small farmers. It is recommended to evaluate the influence of planting density on the varieties and cutting interval.