**4. Irrigation impacts and risks: fixing the environmental limits**

According to the Organization for Economic Co-operation and Development (OECD), a key challenge for the agriculture sector is to feed an increasing global population, while at the same time reducing the environmental impact and preserving natural resources for future generations. Agriculture can have significant impacts on the environment [30]. While negative impacts are serious and can include pollution and degradation of soil, water, and air [31], agriculture can also positively affect the environment, for instance by trapping GHG within crops and soils [32], or mitigating flood risks through the adoption of certain farming practices [33]. In recent years, there have been some encouraging signs that the agriculture sector and irrigation activities are capable of meeting its environmental challenges. In particular, farmers have made improvements in the use and management of nutrients [34], pesticides [35], energy [36], and water [37], using less of these inputs per unit of land and adopting more environmentally beneficial practices, such as conservation tillage [38] or soil nutrient testing [39]. Taking into account the urgent challenge of matching demand for food for a larger population using the same land footprint, the Global Water Forum (an initiative of the UNESCO Chair in Water Economics and Transboundary Water Governance) discussed the expansion of irrigated areas and their affection to agroecosystems and sustainability [40]. To mitigate that risk while responding to increased global water needs, agricultural management options could include blending different qualities of water sources [41], matching irrigation methods or promoting deficit irrigation [42], and selecting salt tolerant crops [43]. Whatever methods and strategies are used to increase food production, they must also preserve soil ecological functionality and minimize environmental risks.
