Spatial Variability of Water Electrical Conductivity and Its Implications for Agricultural Planning

Water scarcity is a major problem in terms of human supply and agricultural development, especially in the semiarid region of Brazil. Thus, the aim of this work is to spatialize the flow (Qt) and electrical conductivity (EC) of water from artesian wells located in the municipality of Mossoró, Rio Grande do Norte State, Brazil, and make recommendations for agricultural crop selection according to the salinity levels and water availability in the region. The well flow and electrical conductivity data of artesian wells identified in the study area were based on sampling performed from 2002 to 2003 and obtained from the Secretariat of Environment and Water Resources (SMARH). Spatialization of the Qt and EC in the area was performed using the geostatistical method of ordinary kriging (OK) and fitted using a spherical semivariogram. After spatial analyses, suitable crops for the area were identified according to the EC values, and a map of agricultural capability based on the artesian well Qt and EC was also produced. The average estimated EC was $0.40\mathrm{dS}{\mathrm{m}}^{-1}$, and 38% of the study area was lower than $0.27\mathrm{dS}{\mathrm{m}}^{-1}$. The estimated average Qt was $16.0{\mathrm{m}}^3{\mathrm{h}}^{-1}$, with 64% of the area estimated to have discharge between 10.0 and $25.0{\mathrm{m}}^3{\mathrm{h}}^{-1}$. The southern region of the study area showed the highest Qt values, and the municipality of Mossoró had the lowest water restrictions in the study area. Lettuce, citrus fruit, and melon are the most recommended crops for cultivation throughout the study area. The results of this study demonstrate the importance of agricultural planning for sustainable farming based on factors that can affect production, such as the EC of irrigation water.