JAMA [OA. 



BULLETIN 



OF THE 



BOTANICAL DEPARTMENT. 



New Series.] MARCH, 1897. T^rS 



MANURES AND ORANGES. 



Fertilisation of the Soil as Affecting the Orange in Health 



wd Disease. 



By H. J. Webber. 



Assistant in Division of Vegetable Pathology, TJ. S. Department of Agri- 

 culture, in Yearbook of the TJ. S. Dept. of Agriculture for 1894.. 



Probably tbe most important question which concerns the orange 

 grower is how to fertilise his trees In Florida, where the orange soils 

 ai*e mostly very sandy and sterile, and require to be fertilised regularly, 

 it is highly important to understand what elements should be used in 

 fertilisation and in what forms it is best to use them. No plant will 

 long withstand improper treatment. In case of slow-growing plants 

 like the orange, where proper treatment prolongs growth and produc- 

 tiveness for centuries, it becomes particularly necessary that correct 

 methods of manuring be used. The condition of tree reflects largely 

 the cumulative treatment of years ; in crops which are replanted each 

 year, however the effect of improper fertilisation is probably less notice- 

 able, especially so far as the devolepment of disease is concerned. 



In growing annual plants one can early notice results and may profit 

 by experience. A few seasons will suffice to determinre about the kind 

 and quantity of fertiliser necessary for them on a particular soil. In 

 the fertilisation of the orange, however, the matter is not so easily 

 determined ; only the observations of a series of years will give results 

 which can be depended upon. An orange grower may fetilise with 

 ~>ne element one year and get good results, but this is no evidence that 

 he same element used the next yea*' or year after year will prove bene- 

 ficial ; it may, indeed, in prolonged treatment, lead to deterioration 

 and disease. It is this difficulty in experimenting and drawing correct 

 conclusions that accounts for the present poor understanding of rational 

 methods of manuring the orange. 



The orange appears to be very sensitive to methods of treatment and 

 fertilisation, and several of the most serious diseases are either caused 

 or aggravated by errors in these. The present paper is based largely 

 on the experiences of intelligent orange growers and upon such obser- 

 vations as the writer has been able to make in the course of investiga- 

 tions of orange diseases. 



