Drought and Salinity Stress in Agriculture

Water deficit is the most devastating factor. About one-third the world's arable land suffers from chronically inadequate water availability for agriculture, and in virtually all agricultural regions, crop yields are periodically reduced by drought. While currently 80% of the world's useable water resources are consumed by irrigated agriculture, within a few decades, the expanding world population will require more water for domestic, municipal, industrial and environmental needs. This trend is expected to accentuate due to global climatic change and increased aridity. Thus, to meet the projected food demands, more crop per drop is required. Salinity is a major constraint on crop-plant productivity. More than 800 million hectares of land throughout the world are salt affected, which accounts for 6% of the world total land area. In most cases, salinity results from natural causes. In addition, a significant portion of the cultivated agriculture land is becoming saline due to deforestation or excess irrigation and fertilization. Given that a third of the food production comes from irrigated agriculture, salinity is becoming a serious problem for crop-plant productivity.