干旱区生态环境知识资源中心

The rapid population growth in many municipalities in the arid and semiarid of the world continues to place increasing demands on limited fresh water supplies. Many cities and districts are struggling to balance water use among municipal, industrial, agricultural, and recreational users. The population increase has not only increased the fresh water demand but also increased the volume of wastewater generated. Treated or recycled wastewater appears to be the only water resource that is increasing as other sources are dwindling. Use of recycled wastewater for irrigating landscapes is often viewed as one of the approaches to maximize the existing water resources and stretch current urban water supplies. Irrigation plays a vital role in increasing crop yields and stabilizing production. In arid and semi-arid regions, irrigation is essential for economically viable agriculture, while in semi-humid and humid areas, it is often required on a supplementary basis. One of the applications of wastewater is its reuse as irrigation water in agriculture. In arid and semi-arid regions, wastewater is considered a valuable source of irrigation water and a fertilizing materia1. Although wastewater reuse in irrigation is a common practice in these regions, there is a widespread and growing concern about its adverse environmental impact on the environment and health hazards. Use of wastewater can be successfully used to irrigate and enhance growth of forage crops. High yields of forage crops such as corn and vetch can be obtained by wastewater irrigation. Moreover, wastewater provided factors other than N and P for improving crop production such as improving soil fertility and soil organic matter that were measured and reported in other articles. Continuous application of wastewater may lead to accumulation of plant nutrients and heavy metals to undesirable high levels in the crops and thereby reducing their quality and nutritional value as forage crops for animal feeding. Therefore, crop selection and rate of application should be carefully managed to minimize any possible adverse effect on crop quality. A periodic monitoring of crop quality parameters is required when using wastewater for irrigation.