In the state of Yucatán, studies focused on the distribution of groundwater quality from an agricultural perspective are scarce. Furthermore, spatial analyses of these resources have not yet been conducted although this could lead to a better use of water and to a decrease of soil degradation hazard.

In order to foresee and achieve the modernization process of agricultural activities in the state of Yucatán, which would necessarily involve an irrigation alternative, it is essential to evaluate the current state of water quality. Seasonal agriculture is characterized by a very low productivity and in several regions it barely provides enough produce for subsistence. The evaluation of water quality is a fundamental requirement for implementation of rural developments projects at state level (some of which are already beginning to develope). The present study considers chemical parameters related to variations in water salinity and hardness because both conditions are important limiting factors for commonly grown crops in the region, such as maize, beans, grasslands, fruit trees (mainly citruses) and other produce for human consumption.

The main purpose is to identify and characterize zones in the state of Yucatán by distinctive groundwater qualities as regards agricultural use, based on the geostatistical validation of agricultural parameters.

Water samples were collected at 113 supply wells. The concentrations of Ca2+, Mg2+, Na+, K+, HCO3, SO42-, NO3, Cland the electric conductivity (EC) were determined. Sodium adsorption ratio (SAR), potential salinity (PS) and effective salinity (ES) were also calculated. A geostatistical analysis by kriging interpolation was performed. ES, PS and SAR as well as Na+, EC, Cl, SO42-, and Ca2+ were selected to make maps, in accordance with the values of semivariogram and values of cross validation. The map of the ES was taken as the base to make the map of zones of agricultural quality groundwater.

The quality of karstic groundwater in the state of Yucatán cannot be recommended for agriculture in Zones I (EC and ES), II (EC, Chlorides, PS and ES) and III (EC, sulfates and ES); in Zones IV and V the water is of medium quality and in the Zone VI, water is considered good for agricultural use.

Zonas

In Zone VI, the water quality was classified as good quality due to low values of chlorides, PS and ES. Zone VI covers 1056.8 km2 and corresponds to 28.7% of the state of Yucatán.

The water in this zone is classified as good for agricultural uses. However, soil salinity monitoring is recommended.

Zone VI has the best agricultural groundwater but it is also the zone with most urban population, industrial development and pig farming, so it is the zone with greater pollution with lead, chromium, cadmium, arsenic, copper, zinc, nitrates, pesticides and fecal pathogens that hazard human health.

This information will be relevant in decision-making for government’s agricultural and environmental planning.

Now we have a software for the evaluation of agricultural irrigation water quality (Agriwater), with this software analysis time is less and increases the efficiency of the evaluation. https://www.actswithscience.com/agriaqua/

The paper reference is: Delgado C. C., Pacheco A. J., Cabrera S. A., Batllori S. E., Orellana R. and Bautista F. 2010. Quality of groundwater for irrigation in tropical karst environment: the case of Yucatán, México. Agricultural water management. 97, 1423-1433. Factor de impacto 2.016. SCI. http://www.sciencedirect.com/science/journal/03783774