干旱区生态环境知识资源中心

Degraded land area is increasing in many arid and semi arid countries (UNEP, 2010). Additionally, fresh water resources are becoming limited and routine irrigation practices in conventional agriculture are causing a steady increase in soil salinity. This will lead to further desertification of affected areas in the future with concomitant reduction in the yield of crops known for human and animal consumption. Consequently it has become imperative to search for suitable alternatives and develop ecologically sustainable and economically sound biological systems that can use low quality water and drought affected saline lands to produce plants of economic importance. A large number of halophytes could be used as animal forage/fodder without encroaching upon arable lands and irrigation water. This paper emphasizes the agricultural importance of these salt tolerant plants in a world where most of the water is saline at any given moment. However, the economic use should be in accordance with the ecological demands suited to particular biomes. Pakistan for example, is spread over an area of 800,000 square kilometers with varied climatic conditions ranging from temperate to sub-tropical desert, eventually displaying a high biodiversity in local flora including halophytes. About 16% of the world halophytic flora is distributed in Pakistan with more than 410 species and among them >100 have potential economic usages as cattle feed. A number of these species are also distributed in the regions between the Atlantic coasts of Africa to western India. The Sindh/Balochistan coast of Pakistan extending from Seer Creek to Jiwani and from coast to mountains including Indus basin are rich sanctuaries for many of these plants. There is a need to conduct systematic survey of this flora, ascertain their chemical characteristics for nutritive value and subsequently identify the species suited to particular conditions through animal feeding trials. Some of these trials have already indicated a promise for ecologically sustainable use of perennial grasses such as Panicum antidotale, formerly identified as Panicum turgidum and Desmostachya bipinnata that may be taken to commercial scale. The system that was developed in Pakistan may serve as a model to other semi-arid subtropical countries of the region.