NITROGEN COMPOUNDS IN WATER FROM THE SAN PEDRO RIVER AND THE MAIN WATER CANAL IN IRRIGATION DISTRICT 005 OF CHIHUAHUA, MEXICO

The use of fertilizers and the proximity of communities to sources of water negatively impact on health, increase soil salinity and damage the entire ecosystem. The objective of this research was to evaluate the nitrogen composition in the San Pedro River and in the main water canal of Irrigation District 005 (ID 005) in Chihuahua, Mexico. Six water samples were obtained from the San Pedro River and six from the canal in spring 2011, summer 2011 and winter 2012, for a total of 36 water samples. A CHEMets Nitrate Kit K-6904 was used for in situ nitrate quantification. As well, the parameters of pH and total dissolved solids (TDS) were quantified in situ using a Hanna potentiometer and the Kjeldahl methodology was used to detect organic and ammonia nitrogen. The statistical analysis of data considered a factorial treatment design and, in addition, a multivariate technique was applied. Significant interactions were found between source-site and source-season (P<0.10), as well as the effect of the season on ammonia nitrogen levels and the effect of source on organic nitrogen levels (P<0.10). The results showed that the river is more disturbed than the irrigation canal at the most distant sites from the dam. Ammonia nitrogen levels clearly varied between spring and winter due to farming activities of planting and applying fertilizers. The organic nitrogen levels may be related to the influence of the nearby communities of Rosales, Meoqui and Delicias. Nitrate levels, as well as other parameters, were more evident in the feeder river.