ABSTRACT
As noted in Chapter 1, irrigation water may arise from many diverse sources, including groundwater, lakes, ponds, streams, canals, lagoons, reclaimed water, ocean water, and blended combinations. Additionally, irrigation water is sometimes pretreated prior to use, such as acidification to remove excess bicarbonates; also, reclaimed water is sometimes used for irrigation purposes. Depending on the source of water and any treatment prior to irrigation, constituents may remain in the water that could (1) result in accumulation of undesirable chemicals in the soil that may adversely affect plant growth when absorbed by the plants or by hindering water uptake; (2) promote physical or chemical degradation of soil quality; (3) cause direct injury to plant foliage or roots when in contact with the water; (4) potentially cause health or environmental problems in lakes, ponds, or streams receiving the water; (5) result in deterioration of irrigation system components; (6) cause human health concerns on the site where irrigation water is applied; and (7) result in an unappealing water due to odor or color. Thus, assessment of irrigation water quality is an important step in determining potential problems (Rhoades et al., 1992; Ayers and Westcot, 1994; AWA, 2000). There are common or standardized methods to determine various parameters in water (Clesceri et al., 1998; USGS, 2005). Most laboratories that routinely evaluate water for irrigation purposes use highly accurate methods. Because there is no formal “chemical extractant” that is necessary for standard water sample analysis, results from laboratories should be consistent, assuming a good representative turf-exposure sample was collected.
