29 



spring drought, which is so frequently injurious to the orange 

 tree, and sometimes fatal to the fruit crop. Growers not sup- 

 plied with facilities for irrigation would, undoubtedly, find it 

 profitable to consider carefully points of this nature in fertilisa- 

 tion. The noticeable effects of potash on the oran^-e treo 

 appears to be its aid in completing and maturing the wood. 

 Apparently an insufficient amount of potash is shown by an 

 excessive growth of weak, immature wood, which does not 

 harden up as winter approaches and is liable to be injured by 

 frost. An abundance of potash, in the form of sulphate of 

 potash, or tobacco stems, is said by many growers to produce- 

 excessively sour fruit. That potash is necessary in fruit pro- 

 duction is shown by the fact that the fruit contains a large 

 percentage of this element. An average of fifteen analyses of 

 different varieties of Florida oranges shows 52'05 per cent, to 

 be about the usual amount of potash in the ash of the orange 

 fruit. The ash in these fifteen analyses averaged 0"916 per 

 cent., or less than 1 per cent., of the total weight of the fruit. 



Phosphoric Acid. 



Phosphoric acid, which is a very necessary element of ferti- 

 lisation on Florida orange lands, is mostly used in the form of 

 dissolved bone-black, acidulated bone or phosphate rock, soft 

 phosphate, raw bone, guano, etc. The immediate effect of phos- 

 phoric acid on the orange tree and fruit is little understood. 

 Several intelligent growers claim to be able to recognise the 

 effect of phosphorous starvation by the appearance of the new 

 growth of leaves. If these when they first push out, or while 

 they are still young and tender, present a slightly variegated 

 appearance, mottled with light and dark green, it is claimed 

 that they are suffering from lack of phosphorus, and that if a 

 liberal application of some soluble phosphate is applied, this 

 appearance may be checked. If this can be shown to be true 

 it will prove a valuable index to the available quantity of phos- 

 phoric acid in the soil. A similar appearance may, however, 

 appear in light cases of the so-called " trenching," a disease, or 

 more probably a symptom of disease, which is not uncommon. 

 Phosphorous starvation, it is true, may have some effect in 

 inducing this disease. 



Lime. 



Lime, it is usually supposed, is present in sufficient quantities 

 in most of our soils. It may be questioned, however, whether 

 the common high pine land and scrub land, and indeed much 

 of the flat woods and hummock of the interior of Florida, might 

 not be benefitted by dtessings of lime. From the supei'iority of 

 oranges grown on soils which are known to be rich in lime it 

 would seeni that this is probably a very desirable and necessary 



