CHAPTER XIV 



FERTILIZERS FOR TREES AND VINES 



It was a popular doctrine among early Californians that Cali- 

 fornia soils would never need fertilization, and that there is some- 

 thing in our soil and climate which would release us forever from 

 repaying anything to the ground for the wealth of produce which 

 we take from it. Such a view was, of course, without foundation, 

 and yet it is not difficult to see how it arose. Early attempts to 

 enrich the soil by the turning under of coarse stable manure, as is 

 done in other countries, was undertaken here on light soil in a region 

 rather short of rainfall. The manure did not decompose, and its 

 coarse materials made a soil, already too light to retain moisture 

 well, so open and porous that its moisture was quickly carried away 

 by evaporation, and crops did not grow so well as upon adjacent 

 land which had not been manured. So the fiat went forth against 

 manure. The corrals became undisturbed guano deposits, and ma- 

 nure piles were fired in dry weather to get the "soil poison" out of 

 the way. Innumerable tons of bones were gathered and ground in 

 San Francisco and shipped away to countries which need fertilizers ! 

 Nature did much to foster the popular delusion, for field crops were 

 gloriously large, and trees and vines grew rampantly and bore fruit 

 the weight of which they were unable to sustain. How could there 

 be more conclusive evidence that manure was a detriment to Cali- 

 fornia soils? 



A few decades of experience have swept away such fallacies and 

 now California growers, especially those handling citrus fruits, are 

 not only freely investing in commercial fertilizers, but are buying 

 and shipping considerable distances all available animal manures, 

 having cleaned up all available accumulations during the pioneer 

 period of non-fertilization. They are also untiring students of the 

 art of fertilization and the sciences underlying it. It was in re- 

 sponse to that demand that the California Legislature in 1903 passed 

 a fertilizer control law. All dealers are required to register and 

 submit samples of their brands and there is constant inspection to 

 detect departures. Semi-annual reports are published for public in- 

 formation and these, with special instructions for taking samples 

 when purchasers desire analyses on their own account, can be had 

 by application to the State Department of Agriculture at Sacra- 

 mento. The total amount of sales reported under the law for the 

 year ending June 30, 1920, was 58,636 tons. 



During the last few years the University Experiment Station 

 chemists and bacteriologists have continued studies of California 

 soils and their relation to fertilization and have conducted prolonged 

 experimentation toward the establishment of fundamental facts and 

 the interpretation of their practical significance. In the course of 

 this work they have made notable contributions to the science of 



