Evaluación de la fertilización y el riego en la Lixiviación de nitratos en suelos agrícolas del Cantón Píllaro

Abstract

The aim of this research was the fertilization and irrigation evaluation on nitrate leaching in the agricultural soils of Píllaro County, principally in San Andrés Rural Parish. 20 one-kilogram soil samples were collected in the most representative areas of the sector, then the conditioned soil samples were added to the leaching columns, which consisted of a PVC tube with one of its ends covered by a fine mesh and connected to a collection system. Fifty grams of "granulated Blau Korn 12-8-16" fertilizer was used as well as 480 ml of distilled water for each irrigation event. In addition, pH, EC and TDS parameters were analyzed in the leached solution, nitrates were determined by means of a chemical test based on the reduction of nitrates in presence of cadmium by colorimetry. The data from the leaching columns were exposed to environmental modeling using QGIS as well as the soil & water assessment tool (SWAT), obtaining 176 hydrological response units (HRUs), 17 Subbasins, 22 Aquifers and 4 main outflows. Cardosanto, Rumipungo, Chaupiloma, La lindera, Huapante Grande, Huapante Chico and Chinintahua columns concentrated the highest amount of nitrates per hectare 120.0 (kg/ha). Finally, it was necessary to emphasize the risk caused by poor agricultural practices in the contamination phenomena, as well as the appropriate type of planting which is the crop rotation with the sprinkler or drip irrigation method. In addition, the dosage of chemical fertilizers or the use of organic amendments should be based on the nutritional requirements of the plant. It is always recommended to calibrate the SWAT model and include a greater number of physical and environmental variables to corroborate the results obtained.