ABSTRACT
In our epoch world agriculture tends to occupy moderate and subtropical areas. But in 1931 great Russian scientist N.I. Vavilov noticed that 73.7% of the cultivated land worldwide belonged to a strip located between 55 and 23°30′ of north [1]. To the beginning of XXI century only 1/17 part of all arable land of the Earth located on northern areas above 55°.
