Present Scenario of Global Salt Affected Soils, its Management and Importance of Salinity Research

Abstract

Present Scenario of Global Salt Affected Soils, its Management and Importance of Salinity Research 1,2Md. Sanower Hossain 1 Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia 2 Department of Biological Sciences, Sristy College of Tangail, 1900 Tangail, Dhaka, Bangladesh ARTICLE INFORMATION Received: November 29, 2018 Accepted: December 20, 2018 Published: January 31, 2019 Corresponding Author: Md. Sanower Hossain, Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia ABSTRACT Salt-affected soils have gained global concern. The world population is increasing rapidly, while the cultivable land is decreasing gradually 1-2% per year. As a result it is threatening the sustained productivity from the limited land resources to meet food and nutritional demands. Soil degradation due to salinization is considered a major constraint for agricultural productivity. Currently approximately 1125 million hectares of lands are salt-affected, of which approximately 76 million hectares are affected by human-induced salinization and sodification. Therefore, tackling salinity problem is very crucial to achieve food security. Two strategies- fighting salinity and living with salinity are suggested by International Center for Agricultural Research in the Dry Areas (ICARDA) to overcome salinity problems. Conducting researches to find high salt tolerant plant species and remove salts from the affected lands applying bio-techniques are also very important. Minimizing the exposure of cultivable land to salinity and recovering or utilizing salt-affected land for agriculture is crucial to attain future food security. Key words: Abiotic stress, salinity management, salinity stress, salt-affected soils, food security INTRODUCTION Salt-affected soils have gained a major global-regional-national-ecosystem-farm level concern. The worldʼs irrigated land is decreasing by 1-2% every year1 . However, world population is increasing rapidly and will reach 9.6 billion by 20502 . Hence, global food productions will need to be increased 38 and 57% by 2025 and 2050, respectively to maintain current level of food supply3 . Salinity stress is the major abiotic stress that drastically affects plant growth and crop productivity. Soil salinization has been identified as a major cause of land degradation that making the lands unsuitable for cultivation of crops. DISTRIBUTION OF SALT-AFFECTED SOILS The extent and distribution of salt-affected soils yet has not been studied in details worldwide. Current data has shown that worldʼs salinity affected area of land is about 1125 million hectares, of which approximately 76 million hectares are affected by human-induced salinization and sodification4 . Currently, one-fifth of irrigated lands are www.scirange.com 1 Volume 1 | Number 1 | 2019 Int. Res. J. Biol. Sci., 1 (1): 1-3, 2019 Middle East 200 180 160 140 120 100 80 60 40 20 0 Oceania North America Former USSR East Asia South America West Africa USA East Africa South Asia South Africa Canada Southeast Asia Central America East Europe West Europe Japan Salt-affected land (Million hectares) Million/Hectares (a) Fig. 1: Global extents and distributions of salt-affected soils, (a): Different countries and continents4 and (b): Global distribution map4 salt-affected and 1.5 million hectares of lands are becoming unsuitable for agricultural production every year because of high salinity levels. If the salinization of soils continues in such way, 50% of cultivable lands will be lost by 20505 . The countries where significant salt-affected soils exist include but not limited to Australia, Bangladesh, China, Egypt, India, Iran, Iraq, Mexico, Pakistan, the former USSR, Syria, Turkey and the United States. The world distribution of salinity affected land area is shown in Fig. 1. The major causes of soil salinity are natural, such as weathering of parent material, deposition of sea salt carried in wind and rain and inundation of coastal land by tidal water. Human induced causes of soil salinity includes rise of water table due to excessive irrigation using underground water, irrigation with salt containing water and poor drainage. MANAGEMENT OF SALT-AFFECTED SOILS Salinity is a particular problem in irrigated agriculture and tackling of this problem is very crucial for achieving food security. Several control and management strategies such as manage the existing situation, reduce recharge, intercept water in the transmission area, increase water use in the discharge area and strong national policy issues on salinity control and management implementation are essential for tackling salinity problems6 . Scientists at ICARDA follow two main strategies to control and manage the soil salinization. www.scirange.com 2 Volume 1 | Number 1 | 2019 Sodic Saline-Sodic Legend Type and severity levels of salt affected soils Saline Extreme Slight Moderate High Extreme Slight Moderate High Extreme Slight Moderate High (b) Int. Res. J. Biol. Sci., 1 (1): 1-3, 2019 These two strategies are (i) fighting salinity and (ii) living with salinity. Fighting salinity refers to reclaim or install drainage systems that allow salts to be washed out of the soil in combination with better irrigation water management, creating salinity levels acceptable to productive crops. Living with salinity is more pragmatic approach which refers to the ways of adapting crops to more saline conditions. For example, cultivation of increased drought and salinity tolerant varieties (i.e., halophytes) and growing deep rooted perennials are alternative ways of management of saline soils7 . SALINITY RESEARCH Currently salinity is a severe problem and main threat for food security. Conducting salinity researches to find alternative ways to solve salinity problems are very important to meet current and future food demands. A suitable management practices to control salinity problems must be implemented on irrigated fields, in irrigation projects and for geohydrologic systems8 . Generally, development of more salt tolerant varieties of crops by either conventional breeding or genetic modifications that use water more efficiently will be more resilient to salinity stress9 . CONCLUSION A large area of land is salt-affected in the world which needs to be managed for future food security. A strong networking among researchers, farm advisors and farmers could enhance the management of salinity problems. Finding salt tolerant varieties of crops and uses of salt affected lands for other purposes like biomass production would be effective alternative solutions to combat salinity problems. REFERENCES 1. FAO., 2004. World Agricultural Center, FAOSTAT Agricultural statistic Data-Base Gateway. 2. UN News Centre, 2013. World population projected to reach 9.6 billion by 2050 ‒ UN report. [Retrieved on 30 July 2015 from http://www.un.org/en/development/desa/news/ population/2015-report.html]. 3. Wild, A., 2003. Soils, land and food: Managing the land during the twenty-first century. Cambridge, UK: Cambridge University Press, pp: 256. 4. Wicke, B., E. Smeets, V. Dornburg, B. Vashev, T. Gaiser, W. Turkenburg and A. Faaij, 2011. The global technical and economic potential of bioenergy from salt-affected soils. Energy Environ. Sci., 4: 2669-2681. 5. Hasanuzzaman, M., K. Nahar, M.M. Alam, P.C. Bhowmik, M.A. Hossain and M.M. Rahman et al., 2014. Potential use of halophytes to remediate saline soils. BioMed. Res. Int., pp: 1-12. 6. Queensland Government, 2014. Salinity Management Handbook (Chapter 13), pp: 92-97. [Retrieved on 11 Nov 2014 from https://publications.qld.gov.au/dataset/salinitymanagement-handbook]. 7. ICARDA., 2014. Managing soil salinity to boost food security. [Retrieved on 11 Nov 2014 from http://www.icarda.org/ managing-soil-salinity-boost-food-security]. 8. United States Department of Agriculture (USDA), 2005. US Salinity Laboratory. [Retrieved on 11 Nov 2014 from http://www.ars.usda.gov/Aboutus/]. 9. Shinozaki, K. and K. Yamaguchi-Shinozaki, 2007. Gene networks involved in drought stress response and tolerance. J. Exp. Bot., 58: 221-227.