146 STATE BOARD OF HORTICULTURE. 



phosphoric acid and less nitrogen, to "stimulate fruit production 

 as much as possible. The so-called chemical manures appear 

 to be much more active in stimulating fruit production than 

 organic manures. 



Effect on Quality of Fruit. The experience of many orange- 

 growers indicates that the quality of the fruit may be largely 

 controlled by fertilization. As oranges are purchased very 

 largely on their appearance and quality, this becomes an 

 important consideration in manuring. Many intelligent grow- 

 ers are coming to believe that the best results can be obtained 

 by giving the trees an application of that element only which 

 seems to be lacking, and not using, as a majority do, a com- 

 plete fertilizer, in definite proportions, regardless of whether 

 all the elements are needed by the plant or not. If it can be 

 determined by the appearance of the tree and fruit what 

 element is lacking, this would seem to be the most rational 

 way to fertilize. 



It seems reasonable to suppose that by careful study patho- 

 logical characters induced by starvation might be found, which 

 would serve to indicate clearly the lack of any particular 

 element. Some growers claim to be able to recognize these 

 characters now, and are fertilizing largely on this modified plan, 

 taking advantage of what we might call the sign language of 

 the tree. Some of these characters will be mentioned below 

 under the consideration of the different elements used. 



Effect on Soil Moisture. In fertilization at least two .factors 

 must usually be considered: the element of plant-food supplied, 

 and the effect of this upon the soil as aiding it in supplying 

 the plant with moisture. The heavy application, in late fall 

 or early spring, of an organic manure, like blood and bone, 

 which is extensively used in Florida, is liable to lead to injuri- 

 ous effects during the spring drought, if the trees are on high 

 and dry land. On the other hand, such soils might be ameli- 

 orated by using substances which attract water and increase 

 the surface tension of soil moisture. Nitrogen, for instance, 

 used in the form of nitrate of soda, and potash, in the form of 

 kainit, would tend to draw up the subsoil moisture and prob- 

 ably aid largely in supplying the necessary moisture during 

 this trying season. The use of organic manures, on the con- 

 trary, would only exaggerate the damage produced by drought. 



