winter grain (rye or winter wheat), another third to spring grain (oats or spring wheat) and the remainder lay fallow. Other crops (e.g. legumes, vetches) were occasionally grown with the grain and took part in the same cycle. The three-course rotation was an inefficient system, one-third of the land always lying fallow. During the later 19th and earlier 20th centuries a start was made in introducing improved rotations with reduced or eliminated fallow (see `Improving Agriculture' below). Agricultural calendar Common cropping required adherence to an agricultural calendar. There was a latest time for harvesting, and hence for the previous ploughing and sowing. In Russia, with its short growing season, latest times tended also to be earliest, necessitating a fairly tight yearly schedule of tasks. Peasants carried out each field-work job simultaneously. This resulted in a pattern `of parallel columns of men, women and adolescents from the various households working the narrow strips at sowing and harvesttime'. Grain farming occurred in two bursts of activity. Spring, after the melting of the snows, was dedicated to ploughing and sowing the spring field. But the late-summer/early-autumn period was the most intense. Within a six-week period, spring-sown crops had to be harvested and processed and the winter field ploughed and sown — all before the onset of cold inhibited operations. Improving agriculture Improved crop-rotations Improved multi-course crop-rotations began slowly to be introduced on mir arable in the late 19th century. The early experiments were mainly on the non-Black-earth lands, especially the Central-Industrial, West and North-West regions. Flax was the first `new' crop to be introduced into the rotation. But within the three-course system flax exhausted the soil's fertility; peasants learned to replenish it by planting clover. Multi-course systems with sown fodder grasses and clover (travopolye (Травополье), travoseyanie) allowed more cattle and other livestock to be kept, who in turn provided more manure to increase soil fertility. This `fodder-crop revolution' had earlier been central to the 18th-century agricultural revolution in Western Europe. By 1924 multi-crop rotations covered 7.2% of the sown area of the Russian Federation. But these improvements were largely confined to the Central-Industrial, Western and North-Western regions. Moscow province was at the forefront; there the three-field system was almost eliminated by the end of 1926. But, up to the mid-1920s, such progress was largely confined to the Central-Industrial, Western and North-Western regions. The grain-surplus areas had as yet seen little progress. In 1924