e Great Valley the
rivers of the Sierra slope, are the main source of water-supply. On
nearly all lands irrigated some crops will grow in ordinary seasons
without irrigation, but it is this that makes possible selection of
crops; practically indispensable for all field and orchard culture in
the south, save for a few moist coastal areas, it everywhere increases
the yield of all crops and is practised generally all over the state. Of
the acreage devoted to alfalfa in 1899, 76.2% was irrigated; of that
devoted to subtropical fruits, 71.7%. Small fruits, orchard fruits,
hay, garden products and grains are decreasingly dependent on
irrigation; wheat, which was once California's great staple, is (for
good, but not for best results) comparatively independent of it,--hence
its early predominance in Californian agriculture, due to this success
on arid lands since taken over for more remunerative irrigated crops.

_Agriculture._--The spread of irrigation and of intensive cultivation,
and the increase of small farms during the last quarter of the 19th
century, have made California what it is to-day. Agriculture had its
beginning in wheat-raising on great ranches, from 50,000 even to several
hundred thousand acres in extent. A few of these, particularly in the
Great Valley, are still worked, but only a few. The average size of
farms in 1850 (when the large Mexican grants were almost the only farms,
and these unbroken) was 4466 acres; in 1860 it was 466.4, and in 1900
only 397.4 acres. Stock ranches, tobacco plantations, and hay and grain
farms, average from 800 to 530 acres, and counteract the tendency of
dairy farms, beet plantations, orchards, vegetable gardens and nurseries
to lower the size of the farm unit still further. The renting of large
holdings prevails to a greater extent than in any other state except
Texas. From 1880 to 1900 the number of farms above 500 and below 1000
acres doubled; half of the total in 1900 were smaller than 100 acres.
The most remunerative and most characteristic farming to-day is
diversified and intensive and on small holdings. The essential character
of California's economic life has been determined by the successive
predominance of grass, gold, grain and fruits. Omitting the second it
may be truly said that the order of agricultural development has been
mainly one of blind experiment or fortuitous circumstances. Staple
products have changed with increasing knowledge of climatic conditions,
of l