— 156 -A majority of tlu' problems encountered originate in customs and tradition upon which any modern superstructure must necessarily be founded. Innovations must stand the test of the experience of centuries, and a thorough understanding of the reasons underlying existing practice is essential to a sympathetic handling of an intensely conservative and suspicious population. The situation is further complicated by varying standards of agricultural skill and education, each class of land, if not every district, calling for individual examination and treatment. A brief examination of the principal local systems of cultivation will consequently serve to define the limits of the present undertaking.

Classification of Agricultural Areas.—Cultivated areas in the Northern Sudan have been classified with relation to the river flood, which determines the method of irrigation and incidentally the choice of crops and their treatment.

" Gezireh " land embraces alluvial areas which are entirely submerged at high Nile, and includes mud flats, sand banks and the lower shelves of the bank proper. In consistency they vary from sands to clay loam, and annually receive a deposit of silt and sand in varying proportions. Sowing takes place after the river falls and as soon as the surface is firm enough to bear the weight of the cultivator. A considerable vairiety of crops are cultivated, and particularly wheat, bulrush millet, pigeon-pea, cowpea, safilower, cucumbers, gourds, pumpkins, melons, tomatoes, lentils, lupines and roselle. The most primitive methods are followed ; ploughing is unpractical, as the crop is dependent upon a rapidly-falling water-table for its moisture requirements, while the deposit of alluvium discounts the value of manuring or any regular rotation of crops.

" Garf " land lies just above the average flood level in the neighbourhood of the river bank. It is completely covered by the Nile in years of exceptionally high flood only. As a general rule the water necessary to garf cultivation is derived from lateral seepage. The breadth of the strip of garf depends upon the conformation of the river bank and the consistency of the soil. Garf land is invariably a light and friable alluvial deposit of recent development, and absorbs and retains a large amount of moisture. The crops generally grown and the methods employed are very similar to those found on gezireh lands, though cotton of the native type, and in' the last few years American varieties in certain districts, have been also successfully cultivated.

" Maya," or basin, lands are periodically flooded at high Nile. They are connected with the river by natural or artificial channels, through which the flood reaches the b'asin and later drains back into the river as the water-level falls. The value of the flood depends upon the amount of water reaching the basin, the quantity of silt deposited, the period during which the water remains on the land and the rapidity with which it drains off when the river falls. If the land is not thoroughly flooded the crop will suffer from or succimib to drought before harvesting. Should the water remain for too long a period water-logging