: Supplementary agriculture of pastoral nomads.]

Though agriculture is regarded with contempt and aversion by pastoral
nomads and is resorted to for a livelihood only when they lose their
herds by a pest or robbery, or find their pasture lands seriously
curtailed, nevertheless nomadism yields such a precarious and monotonous
subsistence that it is not infrequently combined with a primitive,
shifting tillage. The Kalmucks of the Russian steppes employ men to
harvest hay for the winter feeding. The Nogai Tartars practice a little
haphazard tillage on the alluvial hem of the steppe streams.[1116] Certain
Arab tribes living east of the Atbara and Gash Rivers resort with their
herds during the dry season to the fruitful region of Cassala, which is
inundated by the drainage streams from Abyssinia, and there they
cultivate dourra and other grains.[1117] The Bechuana tribes inhabiting
the rich, streamless grassland of the so-called Kalahari Desert rear
small herds of goats and cultivate melons and pumpkins; among the other
Bechuana tribes on the eastern margin of the desert, the men hunt, herd
the cattle and milk the cows, while the women raise dourra, maize,
pumpkins, melons, cucumbers and beans.[1118] [Compare maps pages 105,
487.]

Such supplementary agriculture usually shifts with the nomad group. But
where high mountains border rainless tracts, their piedmont districts
regularly develop permanent cultivation. Here periodic rains or melting
snows on the ranges fill the drainage streams, whose inundation often
converts their alluvial banks into ready-made fields. The reliability of
the water supply anchors here the winter villages of the nomads, which
become centers of a limited agriculture, while the pasture lands beyond
the irrigated strips support his flocks and herds. Where the piedmont of
the Kuen Lun Mountains draws a zone of vegetation around the southern
rim of the Takla Makan Desert, Mongol shepherds raise some wheat, maize
and melons as an adjunct to their cattle and sheep; but their tillage is
often rendered intermittent by the salinity of the irrigating
streams.[1119] Along the base of the Tian Shan Mountains, the felt yurt of
the Gobi nomad gives place to Turki houses with wheat and rice fields,
and orchards of various fruits; so that the whole piedmont highway from
Hami to Yarkand presents an alternation of desert and oasis
settlement.[1120] Even the heart of arid Arabia shows fertile oases under
cultivation