Boron Enriched Biogeochemical Food Webs in Arid Ecosystems

In arid conditions a soil content of boron 30 ppm leads to boron toxicity for plants and animals. We can consider this value as the maximum permissible concentration (standard). Physiological and morphological alterations of plant growth are typical forms of boron toxicity. The animal toxicity is related to the decrease 

As an example of a boron biogeochemical snb-region and corresponding B enriched provinces, we can consider the Central Asian arid steppes and deserts in neighboring areas of Kazakhstan and Uzbekistan. 

The predominant landscapes are dry steppe, semi-desert and desert, mainly calcium-sodium, gypsum and salt-enriched types. The well expressed forms ofmeso-and micro-relief, such as saucer-like and outstretched depressions, temporary water channels, and micro-hills, as typical plain relief and the shallow ground water level are accompanied with the contrast moisture redistribution, distinguish differentiation of soil and vegetation types. This is finally accompanied with an extensive accumulation of boron in salty depressions due to the transpiration biogeochemical barrier. 

Now we will consider the content of boron in various links of biogeochemical 

The soil forming rocks in this region are soft Tertiary and Quaternary sedimentary rocks, very often salty, with carbonate, and predominantly heavy granulometric composition (clay and loam-mergel depositions). The micas are responsible for the main part of boron in clay, sandstone and sand and the boron minerals represent the minor part (Table 12). 

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