SOILS 
25 
particularly well adapted to lima beans and the industry 
has been extensively developed on these soils. The Pla- 
centia series is used for beans and other vegetables. The 
fine sandy loam of the Sacramento series is valued for 
vegetables and the loam of this area is also used. The 
sandy types of the Salem series are good vegetable soils. 
When irrigated, the San Joaquin series are valuable 
trucking soils, and vegetables are grown to some extent 
on the Stockton series. There are 110,163 acres of muck 
and peat soils of the Pacific Coast valued for the crops 
usually grown on these lands. Puget clay soil and Puget 
fine sandy loam have deficient drainage, but when well 
drained and protected from overflowing, truck crops and 
potatoes are successfully grown. Puget silt loam gives 
promise of becoming a highly prized soil for small fruits 
and vegetables. 
59. Soil texture. — It will be seen from a study of vari- 
ous soil types cited that the value of a soil for trucking 
purposes is determined largely by its texture. The value 
of a soil for very early truck depends mainly upon the 
amount and size of sand. That is, coarse sand is a 
“quick” soil, because it is well drained and dries out and 
consequently warms up very early in the spring, and 
makes early planting possible. Again, the coarse sands 
are warmer during the entire period of growth, thus has- 
tening early maturity. Such soils require a large amount 
of vegetable matter. Liberal fertilizing and irrigation 
are usually a great advantage. The medium sands are not 
quite so early, but are more productive and somewhat 
more retentive of moisture and plant food. The fine 
sands are often our best trucking soils. Although not 
quite so early as the coarse and the medium sands, they 
are usually more productive. The silt and the clay soils 
are often valuable for late crops, and the maintenance of 
fertility is less expensive on the heavier types. 
60. Advantages of sand. — The soils of the most impor- 
