680 EXPERIMENT STATION RECORD. 



FERTILIZERS. 



The fertilization of land, E. W. Hilgard {California Sta. Bpt. 

 1895, pp. 123-lri5). — A table shows the draft of different crops ou the 

 fertility of the soil, and the general principles of manuring are discussed 

 with special application to California conditions. 



A study of the soils of California with a view to determining their 

 fertilizer requirements leads to the following general conclusions : 



"(1) Apart from the regions of abundant rainfall in the higher Sierra foothills 

 and in northern California, and a few local exceptions, all the soils of the State con- 

 tain as much lime as is useful in soils. In almost all cases a considerable excess of 

 the carbonate is present, so as to insure the absence of acidity, even in lowlands 

 where it would be expected to occur. 



" (2) The same is almost as generally true as regards potash. The amounts present ' 

 are, in the great majority of cases, so far in excess of the average found in the soils 

 of Europe and of the East that the experience of those countries can not serve as a 

 guide in considering the requirements of our soils. Throughout the valley lands 

 proper of the Great Valley, as well as that in southern California and in the valleys 

 of the Coast Ranges as far north as Mendocino, the soil water carries such large 

 amounts of potash salts (in the alkali lands often as much as 1,000 lbs. per acre) 

 that to add more in fertilization would be sheer folly. While in the uplands adja- 

 cent the drainage toward the valleys prevents such accumulation, the fact that such 

 drainage water carries the same salts is easily verified, and is apparent from exami- 

 nation of the stream waters as well. It is therefore reasonable to conclude that in 

 the great majority of California soils potash will be the last one of the 3 ingredients 

 usually supplied in fertilizers, that need be purchased by the farmer. 



"It should be added that the same rules as regards lime and potash hold good of 

 the greater part of the region lying between the Pacitic and the Rocky Mountains, 

 excepting the humid coast belt of Oregon and Washington ; the cause being the uni- 

 versal one, that in all regions of deficient rainfall the lime and potash that in the 

 rainy countries are currently washed out into the country drainage are partially or 

 wholly retained in the soils. 



"(3) No such rule, however, applies to phosphoric acid, because of its difficult 

 solubility under ordinary soil conditions. Its presence in greater or less amounts 

 depends entirely upon the kind of rocks from which the soil is derived. It happens 

 that in California most of the rocks — aud, therefore, the soils derived from them — 

 are poor in phosphates, contrary to what happens in eastern Washington and Mon- 

 tana. Hence phosphates are among the first ingredients to become deficient in 

 California soils, as has been amply proved by actual experience of farmers in whose 

 hands superphosiihates and phosphatic guanos have become the favorite fertilizers 

 from the first. Exceptions occur in the case of ' black alkali ' soils, in which soluble 

 phosphates frequently circulate just as do the potash salts. 



" (4) As regards nitrogen, the most costly of all the ingredients usually supplied 

 in fertilizers, its average total amount in the soils of the arid or irrigation regions is 

 apparently less than is usually the case in the countries of summer rains. On the 

 other hand, the conditions for rendering it available to plants are much more favor- 

 able, and the chances of Avaste by washing out very much less, save in case of 

 excessive irrigation. So far as our observations go, it is likely to become deficient 

 next in order to phosphoric acid under normal conditions, and should be supplied 

 whenever the superphosphates fail to produce satisfactory results. In alkali soils, 

 however, it occurs so constantly and abundantly in the form of saltpeter as to be in 

 excess at times; in these, therefore, the use of nitrogenous fertilizers will, as a rule, 

 be useless, at least for a number of years. . . . 



