34 CALIFORNIA VEGETABLES 



soil mass excavated from a depth of seven to ten feet was spread 

 over part of a vegetable garden near by and tomatoes, beans and 

 watermelons were planted on it. The gowth was even better than 

 on the parts of the old surface not covered, which had apparently 

 become somewhat exhausted by years of use. 



Examination has shown that the percentage of humus or vege- 

 table mold is less in the soils of the arid region, but their humus 

 contains more nitrogen. Thus, probably, on the average not only 

 is the aggregate supply of nitrogen in the soils of the arid region 

 approximately equal to that of humid soils, but its absorption by 

 plants is exceptionally favored by climatic conditions. 



As to the minerals which constitute fertility, the soils of the 

 arid region contain nearly fifteen times as much lime, five times as 

 much magnesia, three times as much potash, and about the same 

 amount of phosphoric acid as the soils of the humid regions. 



Significance of These Facts. These leading characteristics of 

 California's horticultural soils are of the highest significance to the 

 vegetable grower because they show that California is rich in soils 

 of ideal excellence for his purposes. They are light soils and there- 

 fore easy of cultivation and not disposed to bake on drying; they 

 are deep, consequently well drained and yet absorptive and retentive 

 enough ; they are exceptionally rich, consequently extremely produc- 

 tive and durable and they can often be given a new fertile surface 

 by deep turning from the fertility of the greater depths. This was 

 the natural endowment which enabled the pioneer vegetable growers 

 to disturb the horticultural peace of the world in 1849-50. The 

 achievements of later years indicate that with rational treatment the 

 superiority of California soils will endure indefinitely into the 

 future. 



The distribution of these desirable soils gives all regions a share 

 in them. Either as residual soils resulting from the decomposition 

 of adjacent rocks, or as transported loams which have been carried 

 greater or less distances by wind, glacial action or other moving 

 force, or as alluvial or sediment soils, deposited by action of flow- 

 ing streams, every California county has its vegetable soils in ample 

 measure. Such is the diversity of soils within narrow areas in 

 California that it may not take a very large farm to enclose several 

 diverse types, and it is the first duty of the settler to learn their spe- 

 cial characters and adaptations and plan his production accordingly. 



Alluvial or Sediment Soils. Though there is marked difference 

 in the origin of our soils which are suitable for vegetable growing, 

 when proper moisture conditions are arranged, it is naturally the 

 alluvial or sediment soils which have hitherto been chiefly used. 

 They have been deposited by recent or ancient water courses and 

 have formerly served as river banks or river and lake bottoms. 

 They have beneath them, generally quite far below, the prevailing 

 soil of the adjacent country. They consist of fine alluvium with 

 seldom any admixture of coarse materials. They are usually very 



