Fertilización nitrogenada en el cultivo de papa: Respuesta fisiológica y eficiencia de uso

The potato is one of the most important crops in terms of human nutrition. In our country it is carried out in two cycles a year, determined by weather conditions. One of the factors with the greatest impact on the length of the cycle is nitrogen fertilization. A high nitrogen supply favors the development of foliage and extends the duration of all crop’s phases. In this trial, different doses of nitrogen were evaluated in two genetic materials. Three complete random blocks were carried out in which the treatments were randomly distributed. They consisted of two genetic materials, Arequita and Red Magic, and four doses of nitrogen: 0, 70, 140 and 210 kilograms per hectare. From the combination of both factors, eight treatments emerge. Four samplings were carried out throughout the crop cycle. Variables related to the growth and development of the plants, and the nitrogen content in the different organs were evaluated. At the end of the cycle, the tuber yield was determined and different efficiency indicators were calculated. Leaf area was strongly conditioned by nutrition, being greater with high doses of the nutrient. However, tuberization was only affected by genetic materials, being higher in Arequita. Nitrogen absorption was conditioned by the nitrogen dose. Arequita demonstrating a very high capacity to absorb large amounts of nitrogen in all conditions. The national cultivar, in addition, presented the highest yields, although the high doses affected the commercial quality of the product, increasing the caliber of the tubers. Red Magic had considerably lower yields and was not able to respond to high fertilization. Although nitrogen affected leaf area, no effect on tuberization was observed. In all cases, a very low accumulation of dry matter was achieved in the tubers. This suggests that there are other imbalances that limit the crop's ability to achieve maximum yield. Arequita proved to be a material capable of adapting to a greater diversity of nutritional environments, achieving great efficiency in treatments without added nutrients and being able to respond to very high doses of fertilization. The behavior of Red Magic suggests that it is a material that requires very tight fertilization management, presenting a limited capacity to absorb nutrients available in the soil and optimal performance with medium doses of fertilization.