rotations (see below). Flax and potatoes were grown in the west, north-west, Central Industrial Region and the Urals; sugar-beet in northern Ukraine and Central Agricultural region; sunflower in south-eastern Russia and southern Ukraine; cotton in central Asia and Transcaucasia. By 1917 most vegetables and industrial crops were grown by the peasants. By this time sugar-beet was the only culture to be grown mainly on large estates (and this too largely fell into peasant hands as a result of the Revolution). These cultures require much more work than grain (hence called `intensive cultures'). Before the mechanization of agriculture potatoes needed 64 man-days of labour a year per desyatin (1 desyatin is about 1.1 hectare), flax or cotton up to 110 man-days, sugar-beet as much as 180. This compared with only 30 and 23 man-days a year for winter and spring grain respectively. Exports Throughout the 19th century the Russian wheat crop developed into a significant export commodity, with trading and shipping mainly in the hands of members of the Greek Diaspora from the Baltic Sea, Taganrog, and Odessa. Traders and shippers, such as the Vagliano and Ralli Brothers, helped to finance the international trade, with the Baltic Exchange of London developed the market for the Russian wheat crop, while hedging of Russian wheat through futures contracts helped establish the new American futures exchanges, especially during times of uncertainty. By 1910, Russian wheat constituted 36.4% of the total world export of wheat. At the same time, agricultural efficiency was lower in comparison with other developed countries (e.g., grain throughout was 20% lower than in the United States). The growth observed in the beginning of the 20th century was driven mainly by the extensive development of agriculture stimulated by the Stolypin reform, while the mechanization and agrarian culture remained relatively low. Further development was arrested by the dramatic historical events of the period: revolts, World War I and the Russian Revolution. The open fields In most of Slavonic Russia the peasants practised the open field system. The fields lay beyond the village's houses and gardens. Here the peasants grew the extensive cereal cultures and, to a limited but increasing extent, row and industrial crops too. The crops were protected from livestock by temporary fencing. After the harvest the peasants opened the land to let their animals graze on the stubble (which provided manure for the soil as well). (In addition to the arable