Water stress and vegetable crops

Environmental sustainability is a current issue in global agenda as it includes, among other issues, the efficient use of water. Drought, high soil salinity, and flooding are the most severe global problems for contemporary agriculture. Water logging occurs when the water is present in the soil in amounts exceeding its optimum requirement and drought stress occurs when the accessible water in the soil is concentrated and atmospheric circumstances cause permanent loss of water by evaporation or transpiration. Supplies of good quality irrigation water are expected to reduce in the future because the extension of new water supplies will not keep pace with growing water needs. Therefore, irrigated agriculture faces the challenge of using less water, in many instances of poorer quality, to produce and supply food for an expanding population. Some of these future water requirements can be met by more efficient utilization of available water supplies, but perhaps it will turn out to be necessary to make enhanced use of municipal wastewaters and irrigation drainage waters. While the exploitation of these waters may demand only minor modifications of existing irrigation and agronomic strategies in most cases, there will be some situations that will need basic changes in crop cultivation, the method of water application, and the use of soil amendments. Lack of water affects crop growth in many ways. The effect is determined by the severity, duration, and period of stress in relation to the stage of development. The great diversity of vegetable crops also complicates management. Within a single plant, water stress during the vegetation season causes reduced growth, leaf area, stem height, chlorophyll content, and root development. Plants also respond to abiotic stresses by modulating the expression of many of their genes. Therefore, the development of plants with improved survival rates and growth during water stress is a major objective in crop breeding. There are also used other treatments and approaches. Many studies indicate that inoculation of vegetable with vesicular-arbuscular mycorrhizal fungi before planting into saline soils alleviates water deficit effects on growth and yield. Also, addition of phosphorus to salinized soil reduced the water stress consequences. Awareness of the growing influence of environmental stress has led to worldwide efforts in adapting agricultural vegetable production to adverse environmental conditions, focusing on alleviating quantitative yield losses. Numerous experiments demonstrate that it is possible to minimize water use in agricultural practice without significant losses in yields. Moreover, increased levels of health-promoting and quality-related nutrients and postharvest protection effects are apparent in response to adverse environmental factors. The use of controlled stress (water deficit, water excess, high soil salinity, heat, cold) is an effective strategy to increase accumulation of bioactive compounds in food.