CHAPTER XXXIV. 



FERTILIZERS AND FERTILIZING. 



The problems connected with the supplying of the 

 proper food materials to citrus trees are extremely im- 

 portant. Fertilizers in some form must be used sooner 

 or later in all citrus districts, for no soil is inexhausti- 

 ble. In many sections, however, they must be used even, 

 from the planting of the trees. In Florida, where the 

 soils are very deficient in plant food, the kinds, quanti- 

 ties of materials, and the time of their application con- 

 stitutes the great problem of citrus culture. In Califor- 

 nia the most important problems connected with citrus 

 fruit growing are not those which have to do with the 

 use of fertilizers, but with the best methods of irriga- 

 tion and cultivation instead. As pointed out elsewhere, 

 the soils of California and the arid region generally, are 

 extremely rich when compared with those of Florida, 

 and in some places the need of fertilizers has not yet 

 been evidenced. Most growers in the western districts, 

 however, already realize the importance of keeping up 

 the fertility of the land and make regular applications 

 of fertilizers. The fact should be borne in mind that 

 crops of fruit cannot be harvested year after year from 

 a given area without depleting the soil, decreasing the 

 quantity and impairing the quality of the output, unless 

 some return be made to the soil to replace the plant food 

 removed. The elements which enter into the composition 

 of plants are carbon, oxygen, nitrogen, hydrogen, potas- 

 sium, calcium, magnesium, phosphorus, sulphur, iron 

 and sometimes chlorine, but of those obtained from the 



