EXTENT, IMPACT, AND RESPONSE TO SOIL AND WATER SALINITY IN ARID AND SEMIARID REGIONS

Sustainable management of land and water resources in arid and semi-arid regions is of concern as a result of increased population pressure and the need for more food and fiber. Soil and water salinity is widespread across the arid and semi-arid regions of South Asia, Central Asia, Arabian Peninsula, and North Africa and affected agricultural productivity and livelihood of rural population. While natural processes (primary) and anthropogenic activities (secondary) cause salinity, the latter contributed more to agricultural productivity losses in these regions. Recent estimates suggest that up to 50% of irrigated land has become saline in these regions. However, there is cautious optimism for managing salt-affected soils and saline waters for crop and animal production and protection of soil and water resources through research-based interventions using integrated soil-water-plant management practices. The successful use of salt-affected soils and saline water takes the pressure off using freshwater for irrigation. Significant promises for addressing soil and water salinity through an integrated approach include: (1) the use of salt-tolerant crops, forages, and halophytes for human and animal consumption and bio-fuel production, (2) development of agro-forestry through planting forage crops within the interspaces of salt-tolerant trees that co-exist with forage crops and salt-tolerant shrubs, (3) development of appropriate surface and subsurface drainage systems to remove excess water and salt from the soil, (4) alternate and/or blended use of saline and fresh water to minimize salt accumulation in the soil, and (5) maintenance of proper irrigation scheduling to ensure that adequate water is available for crop growth and at the same time removal of excess salt from crop-rooting zone. Monitoring the effectiveness of the above mentioned technologies is important for maximizing the benefits. Finally, appropriate policy and institutional interventions that encourage the general community to accept the technology are required. Isotopic and nuclear techniques play a key role in developing and monitoring the technology for the sustainable use of salt-affected soils and saline waters and protect land and water resources.