A comprehensive study of the statistical effects of maize harvesting on water quality in ecuadorian soils from 2012 to 2016

The soils of Ventanas Canton (located in the Los Ríos Province, Ecuador) are distinguished for being suitable for grain and cereal agriculture. Agricultural production has required a growing amount of fertilizers and pesticides which have affected the water quality. The objective of this study was to evaluate the water quality in maize crop fields. It was evaluated the following physicochemical parameters: turbidity, potential of Hydrogen, electrical conductivity (EC), total dissolved solids (TDS), temperature, total hardness, nitrites, nitrates, iron, soluble reactive phosphate (SRP), total chlorine and chemical oxygen demand. Water sources in the 6 communities with the highest maize production in Ventanas Canton were selected. The multivariate analysis of variance from analyzing the water's physicochemical parameters from 7 July 2012 to 7 January 2016 showed significant statistical differences during the varying harvesting periods with a 95% confidence level for the studied communities, seasonal variability being present. The highest pollution levels were evidenced during the 01/10/2012, 02/04/2013, 01/10/2013 harvesting cycles, due to lack of crop rotation. The correlation analysis indicated a direct relation between the EC-TDS (r = 0,856, p = 0.0000). Generally, the water contamination levels due to maize crops are on the higher level of the margin allowed by Ecuadorian legislation, having the parameters such as: EC, TDS and SRP far exceeding the maximum permissible limits. In conclusion, this study indicates that efforts must be directed towards sustainable actions for water and soil resources management in order to develop an environmentally friendly maize production in Ecuador.