50 



FERTILISING FOR GROWTH AND FRUIT. 



Primarily the orange grower desires t > know how to fertilise so as to 

 stimulate either growth or fruit production. With oranges, as with 

 many other agricultural plants, one may fertilise in such a manner that 

 excessive growth is stimulated at the expense of fruit production. A 

 strong nitrogenous fertiliser results usually in much growth and little 

 fruit. This seems to be particularly true if the ammonia is added in an 

 organic form. While trees are young it is probably well to favour the 

 growth of wood principally, but at an age of seven or eight years from 

 the bud, the tree, if it has grown properly, will have attained sufficient 

 size to begin to produce a fair quantity of fruit. It should then be given 

 a slightly modified fertiliser, containing more potash and 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 fertilisation. As oranges are 

 purchased very largely on their appearance and quality, this becomes 

 an important consideration in manuring. Many intelligent growers 

 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 lack- 

 ing, and not using, as the majority do, a complete fertiliser, in definite 

 proportions, regardless of whether all the elements ane 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 

 w y to fertilise. 



It seems reasonable to suppose that by careful study pathological 

 characters induced by starvation might be found, which would serve 

 to indicate clearly the lack of any particular element, ^ome 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. JSome of these characters will be men- 

 tioned below under the consideration of the different elements used 



EFFECT ON SOIL MOISTURE. 



In fertilisation 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 injurious effects 

 during the spring drought, if the trees are on high and dry land On 

 the other hand, such soils might be ameliorated 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 kaini't, would tend to draw up the subsoil moisture and 

 probably aid largely in supplying the necessary moisture during this 

 trying season. The use of organic manures, on the contrary, would only 

 exaggerate the damage produced by drought. If groves are on very 

 moist land, as is frequently the case in Florida, where the necessity is 

 to lessen the moisture rather than to increase it, some form of organic 

 manure, as muck or blood and bone, might be found of benefit. 



