Water quality for agricultural irrigation in the Calera aquifer region in Zacatecas, Mexico

Abstract

In the region that includes the Calera, Zacatecas aquifer, the intensive production of chili (Capsicum ssp.) is of great economic importance, and depends entirely on groundwater. Being an overexploited aquifer in a karst and semi-arid zone, water availability becomes more limited and water quality is relevant. The objective of the research was to evaluate the impact on the chemical quality of the water and determine its aptitude for agricultural use through the criteria of salinity, sodicity and toxicity. For two consecutive cycles, a sampling was performed according to NOM-014-SSA1-1993 to wells that are frequently used for irrigation of chili. Five strata were designed whose depth ranges from 50 to 280 m above the static level. For the three criteria the water quality parameters were determined, their classification was shown on a Richards diagram and their hydrogeochemistry using a Piper diagram. A statistical analysis of main components, a randomized complete block analysis and a cluster analysis were performed to identify the parameters that have a significant impact on water quality. The results showed that the cultivation of chili has not impacted the quality of the aquifer water and that the depth of the wells does not influence it, rather it depends on the region where each well is located, recharge processes, geology of the region , speed of underground currents and infiltration by the action of faults and geological fractures.