Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.05.027 Byline: Takashi Kume (a), Chieko Umetsu (a), K. Palanisami (b) Abstract: The tsunami of 26 December 2004 struck the Nagapattinam District, Tamil Nadu, India. Sea water inundation from the tsunami caused salinization problems for soil and groundwater in coastal areas of the district, and also induced salt injuries in crops. To document the recovery of the agricultural environment from the tsunami, we conducted observations of the soil, groundwater, and vegetation. Soil electrical conductivity increased sharply after the tsunami, but returned to pre-tsunami levels the following year. Groundwater salinity returned to pre-tsunami levels by 2006. These rapid rates of recovery were due to the monsoon rainfall leaching salt from the highly permeable soils in the area. MODIS NDVI values measured before and after the tsunami showed that vegetation damaged by the tsunami recovered to its pre-tsunami state by the next rice cropping season, called samba, which starts from August to February. From these results, we conclude that the agricultural environment of the district has now fully recovered from the tsunami. Based on the results, we have also identified important management implications for soil, groundwater, and vegetation as follows: 1) due to the heavy monsoon rainfall and the high permeability of soils in this region, anthropogenic inputs like fertilizers should be applied carefully to minimize pollution, and the use of green manure is recommended; 2) areas that were contaminated by sea water extended up to 1000m from the sea shore and over pumping of groundwater should be carefully avoided to prevent inducing sea water intrusion; and 3) data from a moderate resolution sensor of 250m, such as MODIS, can be applied to impact assessment in widespread paddy field areas like the Nagapattinam District. Author Affiliation: (a) Research Institute for Humanity and Nature, 457-4 Kamigamo-Motoyama, Kita-ku, Kyoto, 603-8047, Japan (b) IWMI-TATA Policy Research Program, International Water Management Institute (IWMI), South Asia Regional Office, ICRISAT campus, Patancheru 502 324, Andhra Pradesh, India Article History: Received 29 August 2008; Revised 20 April 2009; Accepted 16 May 2009

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1477-8947.2009.01217.x Byline: Manzoor Qadir (1), Andrew D. Noble (2), Asad S. Qureshi (3), Raj K. Gupta (4), Tulkun Yuldashev (4), Akmal Karimov (3) Keywords: Soil salinity; Waterlogging; Salt-affected soils; Water quality; Magnesium-affected soils; Saline water; Central Asia Abstract: Abstract Expansion of irrigated agriculture in the Aral Sea Basin in the second half of the twentieth century led to the conversion of vast tracks of virgin land into productive agricultural systems resulting in significant increases in employment opportunities and income generation. The positive effects of the development of irrigated agriculture were replete with serious environmental implications. Excessive use of irrigation water coupled with inadequate drainage systems has caused large-scale land degradation and water quality deterioration in downstream parts of the basin, which is fed by two main rivers, the Amu-Darya and Syr-Darya. Recent estimates suggest that more than 50% of irrigated soils are salt-affected and/or waterlogged in Central Asia. Considering the availability of natural and human resources in the Aral Sea Basin as well as the recent research addressing soil and water management, there is cause for cautious optimism. Research-based interventions that have shown significant promise in addressing this impasse include: (1) rehabilitation of abandoned salt-affected lands through halophytic plant species; (2) introduction of 35-day-old early maturing rice varieties to withstand ambient soil and irrigation water salinity; (3) productivity enhancement of high-magnesium soils and water resources through calcium-based soil amendments; (4) use of certain tree species as biological pumps to lower elevated groundwater levels in waterlogged areas; (5) optimal use of fertilizers, particularly those supplying nitrogen, to mitigate the adverse effects of soil and irrigation water salinity; (6) mulching of furrows under saline conditions to reduce evaporation and salinity buildup in the root zone; and (7) establishment of multipurpose tree and shrub species for biomass and renewable energy production. Because of water withdrawals for agriculture from two main transboundary rivers in the Aral Sea Basin, there would be a need for policy level interventions conducive for enhancing interstate cooperation to transform salt-affected soil and saline water resources from an environmental and productivity constraint into an economic asset. Author Affiliation: (1)International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria and the International Water Management Institute (IWMI), Colombo, Sri Lanka (2)IWMI Southeast Asia, Vientiane, Lao PDR (3)IWMI, Central Asia Sub-regional Office, Tashkent, Uzbekistan (4)ICARDA, Central Asia and Caucasus Regional Office, Tashkent, Uzbekistan Article note: Manzoor Qadir is with the International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria and the International Water Management Institute (IWMI), Colombo, Sri Lanka. e-mail: m.qadir@cgiar.org.