CALIFORNIA FRUITS: HOW TO GROW THEM 



soils and plants which may be described as revolutionary in their 

 relation to older tenets and points of view. There is good reason to 

 believe that the progressive effort which is now being made for fuller 

 understanding of facts and reasonableness of practice will reconcile 

 the conflicts which have so long prevailed both in scientific doctrine 

 and in horticultural experience and point the way to more efficient 

 and profitable recourses in soil restoration and plant feeding. For 

 the purpose of presenting to fruit growers in popular language con- 

 crete conclusions involving the latest results of thought and research 

 on these subjects Dr. C. B. Lipman, Professor of Soil Chemistry and 

 Bacteriology in the University of California, who is a leader in both 

 philosophy and research, has kindly written for this work all which 

 follows in this chapter and merits the gratitude of the reader for this 

 generous service. 



I OLD AND NEW VIEWS OF FERTILIZATION 



The popular conception of a fertilizer, held both by the manu- 

 facturer and consumer, and by many experts, is that it is a substance 

 which contains some chemical element or elements essential to plant 

 growth, and which by application to the soil takes the place of 

 similar material extracted from the soil solution* by plant roots or 

 lost in the leaching of soil by rain or irrigation water. By this 

 conception, fertilization constitutes a method for the so-called main- 

 tenance of a somewhat mysterious something spoken of as "soil 

 fertility." Like most popular conceptions, the foregoing contains 

 a germ of truth, but when taken literally, it is more mischivous than 

 useful and is responsible for much erroneous and unprofitable farm 

 practice, and an endless amount of loose and fallacious thinking, and 

 expensive and wasteful experimentation. -If the purpose of fertil- 

 izers were merely to make good the losses of certain chemical con- 

 stituents in the soil moisture occasioned as above explained, the 

 problem would be indeed a simple one of maintaining the crop- 

 producing power of any soil at a high level ; and the very simplicity 

 of the idea is probably what constitutes its attractiveness, and 

 accounts for the tenactiy with which it is held. Unfortunately 

 for the man on the land, however, the matter is not simple, and 

 recent investigations have shown conclusively that while the task 

 just mentioned may be one of those performed by fertilizers, it 

 is probably only a minor one in most cases where fertilizers are ' 

 used, and in many cases where they are of distinct benefit to plant \ 

 growth, they may not function in that way at all. Thus, this very 

 attractive popular theory of the function and purpose of a fertilizer 

 must be largely discarded. We are not dealing with a simple mat- 

 ter of subtraction and addition of certain chemical elements to soils,- 

 but with a very complicated series of phenomena in the soil and in 

 the plant, which, despite the rapid progress of our knowledge during 

 the last five years, are far from being understood. This is not the 

 place to discuss these important considerations which will form the 



as wVkSow^n" 11 -V he f medi f um , in which Plant roots and soil bacteria grew and, so far 



(nuTrien? a^d 2 SS?M T- l 'K 801 ' [ oiai e> which makes a solution of soil salts 

 nent and is dtr 



(nurien ad M T- 801 oiai e> which makes a solution of s 



nent), and is distributed around and between the soil particles 



