274 HORTICULTURE, FORESTRY, FLORICULTURE 



results from the quantity and kind of fertilizers used ; but it must 

 be constantly remembered that fertilizing is but one of the links in 

 the chain of good culture and will be quite useless if tillage, 

 moisture supply, and other essentials be neglected. 



No prescription can be given for fertilizing which will fit all 

 cases, but a few guiding principles may be stated. As in the case 

 of all fruits, the same proportions of fertilizing ingredients should 

 not be used on bearing trees as on young orchards which have not 

 yet begun to produce fruit. Trees which should be growing rapidly 

 but have not arrived at the bearing age require relatively large 

 amounts of nitrogen and much less potash than those producing 

 heavy crops. The latter require a higher percentage of both potash 

 and phosphoric acid in the mixture. In Florida the following pro- 

 portions have proved popular: For young trees; Phosphoric acid, 

 6 per cent; potash, 8 per cent; nitrogen, 4 per cent. For produc- 

 ing trees: Phosphoric acid, 8 per cent; potash, 12 per cent; nitro- 

 gen, 3^ per cent. A ton of such a fertilizer might be constituted 

 as follows: 



oMakeweight is material which has no fertilizing value, but which must neces- 

 sarily be used If certain proportions such as the above are to be maintained in the 

 mixed fertilizer. 



An abundant supply of nitrogen will be indicated by a good 

 growth and dark-green foliage. An excess of nitrogen, accom- 

 panied by a lack of potash, is manifested by rank growth and com- 

 parative barrenness, and, in the fruit, a thick rind and abundant 

 rag (the tough, fibrous part of the interior of the fruit). Liberal 

 supplies of potash tend to greater fruitfulness, thinness of rind, less 

 rag, and better keeping qualities. 



The fertilizing ingredients may be bought unmixed or they 

 may be mixed to order at the factory. Sulphate of potash is usually 

 preferred to muriate. Acid phosphate is a good source of phos- 



fhoric acid. As to the best source of nitrogen, experiences differ, 

 n California, organic sources, such as dried blood, tankage and 

 stable manure, have proved satisfactory, as well as the chemicals 

 nitrate of soda and sulphate of ammonia. In Florida, on the other 

 hand, the use of organic nitrogen has proved a prolific source of 

 die-back and other troubles and is being abandoned. Leguminous 

 cover crops may, however, often be used as a cheap and very satis- 

 factory source of nitrogen. These do not seem to have produced the 

 disastrous results in Florida which have followed the use of other 

 organic fertilizers. 



