CITRUS CULTURE m £ORTO RICO 



25 



it is left to serve as a mulch. This practice is not advisable where 

 soil moisture is not abundant at all times. The general practice is to 

 plow or to cultivate, or to do both, although in some heavily fertilized 

 groves the soil seems to retain its moisture well under a luxuriant 

 growth of Para grass. Disk plows pulled by tractors are being used 

 successfully, but the area that can be plowed naturally decreases 

 with the spread of tree growth. In the older groves plowing is 

 usually confined to two or three furrows in the spaces between the 

 rows of trees. Disk or cutaway harrows are used almost entirely 

 for cultivation. 



FERTILIZING 



A study of the practice followed locally in fertilizing citrus trees 

 showed a lack of uniformity in the mixtures used, the quantities ap- 

 plied, and the number and times of application. The quantities ap- 

 plied differ greatly in the various groves, but applications are usually 

 made in excess of 50 pounds per tree annually. In some instances 

 60 to 80 pounds are applied and in others 100 pounds annually are 

 applied to each large bearing tree. Such large quantities may not 

 always be necessary for maximum tree growth and fruit production, 

 but the practice has undoubtedly much to recommend it, inasmuch 

 as many growers seem to find it profitable. The number of applica- 

 tions varies from two to three or more a year. Many growers apply 

 half the fertilizer in November or early in December and the other 

 half in June. Some who question the desirability of this practice 

 apply fertilizer three to six times a year. The practice of making 

 four to six applications seems to have nothing to recommend it, but 

 three applications are undoubtedly preferable to two. An applica- 

 tion in December has a tendency to bring on bloom not later than 

 February. However, since the fertility of the soil may not be suffi- 

 cient for the development of the fruit, it may be well to make a 

 second application about March 1 and a third application about 

 June 1. 



For present purposes the question of fertilizing may be summa- 

 rized as follows : With few exceptions the aim is to ship most of the 

 crop before October. This can be done provided the bloom appears 

 in January. Often it does not appear until toward the end of Feb- 

 ruary, in which case the fruit has only six months or slightly more 

 in which to develop. Such fruit is not usually very palatable, even 

 though it may pass the Government maturity test, and can be im- 

 proved in quality by being left on the tree six to eight weeks longer. 

 In other words, the bloom should appear in early January in order 

 that the fruit may have a chance to mature early in September. 



Although no infallible method is known at present for inducing 

 the trees to bloom in early January, the following practice, if con- 

 sistently employed from the time the trees are young, may produce 

 the desired result. Apply fertilizer about December 1 and follow 

 with plowing and cultivation. If a bloom is induced about the latter 

 part of January or the first part of February, apply fertilizers again 

 the latter part of February and continue cultivation until about June 

 1. Then apply fertilizers again and cease cultivation until the first 

 of December. If the trees are far enough apart to permit growing 



