THE DIVERSIFIED FARM. 



169 



rated and again condensed in the sur- 

 rounding air is sufficient to raise the tem- 

 perature ten degrees throughout a space 

 eighty feet square and deep. 



FERTILIZING ORANGE ORCHARDS. 



BY W. 0. FITZSIMMONS. 



IN no department of soil tillage does a 

 knowledge of "book farming" pay 

 better than in the production of fruits of 

 various kinds. The question of fertilizing 

 the soil in order to reach the best results 

 in fruit production is one which few un- 

 derstand fully, and none can wholly com- 

 prehend without study and thought along 

 the lines which science has traced as a 

 guide to the intelligent horticulturist. 

 Chemical analysis alone can properly de- 

 termine the composition of fruits or other 

 products of the soil, and it is by a study 

 of results reached in the laboratory, that 

 the orchardist is enabled to apply to his 

 soil the proper ingredients in right pro- 

 portions to produce a crop. The chief 

 and most expensive substances entering 

 into the necessary food for fruit crops of 

 nearly all kinds are nitrogen, phosphoric 

 acid and potash. Without definite amounts 

 of these substances to feed upon, a full 

 crop of perfectly formed fruit is impossi- 

 ble. It should be understood by all 

 orchardists that Nature is inexorable in 

 her demands, and when she asks for bread 

 she will not be satisfied with a stone. In 

 other words, her call for nitrogen, phos- 

 phoric acid and potash must be heeded, or 

 no crop. There is no appeal from this, 

 and no orchardist should delude himself 

 with the hope of deceiving her by substi- 

 tuting carbon, soda and magnesia or any 

 other combination of ingredients, how- 

 ever captivating the name or small the 

 cost. 



Take an orange grove for example: At 

 twenty four feet apart the trees would 

 stand at the rate of about seventy -five to 

 the acre. At ten or twelve years of age 

 many trees will yield, say, seven boxes of 

 fruit per tree, weighing about 500 pounds. 

 Let us see then the amount and cost of 

 the chemical ingredients which must enter 

 into that 500 pounds of fruit, and without 

 which it will be impossible to produce that 

 amount on one tree. The principal chem- 

 ical substances to be found in the orange 

 and derived from the soil are: Nitrogen, 

 potash, phosphoric acid, soda, lime, mag- 



nesia, and oxides of iron, alumina and man- 

 ganese, also sulphuric acid, silica and 

 chlorine. All save the three at the head 

 of the list may generally be disregarded, 

 since repeated analyses have shown most 

 soils in which orange trees are planted in 

 the United States to be fully supplied 

 with the small amounts required save per- 

 haps lime. But lime is abundant almost 

 everywhere and cheap, hence we shall con- 

 fine this discussion to the three chief sub- 

 stances required. According to analysis 

 made at the laboratory of the California 

 Experiment Station, 500 pounds of seed- 

 less oranges contain 1.6 pounds of potash, 

 .27 pound phosphoric acid and .92 pound 

 nitrogen. With the prices of 5 cents a 

 pound for potash, 6 cents for phosphoric 

 acid and 15 cents for nitrogen these in- 

 gredients entering into 500 pounds of 

 seedless oranges (presumably the product 

 of one tree) would cost 23.6 cents; or, if 

 lime be required, say 25. cents per tree. 

 At the prices given, the absolute require- 

 ments of the fruit in the way of plant 

 food would cost at the rate of $18.75 per 

 acre. If the soil already contains all or 

 any part of these substances, it would, of 

 course, lessen the cost of the annual fer- 

 tilization. And right here is where many 

 orchardists in fact most of them neg- 

 lect an opportunity if not a duty. They 

 should have their soils analyzed for the 

 chief ingredients here mentioned, and 

 thus learn what they lack or how long the 

 present supply will last. In fact, without 

 some such guide, the orchardist is at a 

 great disadvantage and must in a certain 

 sense grope his way in the dark to reach 

 results. But this is the requirement of 

 the seedless fruit only, and takes no ac- 

 count of the growth of the tree itself and 

 of the perfecting of the seed growth. For 

 these purposes a further supply of each 

 of the ingredients would be required, 

 bringing the probable cost to 15 cents 

 more for a tree large enough to bear 500 

 pounds of fruit* It is probable, therefore, 

 that an orange tree producing as above 

 stated uses each year some 40 cents' 

 worth of fertilizing material. This must 

 be already in the soil or must be put there 

 by artificial means, else a crop to meet 

 reasonable expectations cannot be pro- 

 duced. It is useless to attempt to replace 

 one of these essential ingredients with 

 some other substance. That is, the lack 

 of potash cannot be supplied by an excess. 



