170 



from which a crop of stubble cane has just been taken and which ha» 

 been continuously in cane for years without the intervention of a legu- 

 minous crop to restore the nitrogen. Indeed such soils are frequently 

 in an execrable physical condition, which not only precludes the possi- 

 bility of themselves furnishing plant food, but also prevents them from 

 assimilating much of that presented in the form of commercial fertilisers. 

 Hence the unsatisfactory results from manuring succession canes, so 

 often experienced by planters. It is doubtful whether one-half of the 

 plant food applied to succession canes in commercial fertilisers, is re- 

 covered in the canes in the average season. 



Pea vine lands put in plant cane, on account of their excellent phy- 

 sical conditions, not only yield up readily the nitrogen stored up by 

 ihe peas, but can also assimilate large quantities of plant food supplied 

 as fertilisers. Hence such canes usually make large crops. 



Since nitrogen is the chief ingredient taken from the soil by a crop 

 of cane, it follows that with each successive crop of cane grown on the 

 land, without the intervention of a restorative leguminous crop, there 

 arises an increased demand for nitrogen. Hence stubble canes require 

 larger quantities than plant cane, and the older the stubble, the larger 

 its requirements for this element to make a given tonnage. (^). 



EXPLANATION OF THE FORMS OF NITROGEN. 



Sulphate of Ammonia, is a by-product in the manufacture of coal 

 gas of cities. It is the recovered nitrogen stored up in the plants 

 which made the coal ages ago. It is the most concentrated form of 

 nitrogen found on our markets, containing 21 pounds in every 100 

 pounds of salt. It is especially adapted to sugar canes on clayey soils, 

 giving larger returns than any other form. Its high price, however, 

 will always prevent its extensive use. Its present price is from $60.00 

 to §80.00 per ton. It is used, like nitrate of soda, as a top dressing 

 for small and stunted canes, with most excellent results. 



Nitrate of Soda, is a partially refined product from the mines of 

 Chili and Peru, and contains 15 to 16 per cent, of nitrogen. The out- 

 put of the mines is controlled by a syndicate which regulates its price. 

 Hence i's values change but little from year to year, its present price 

 being about §40. 00 to $50.00 per ton. It is the most soluble form of 

 nitrogen and should be used with great care to prevent loss. Small 

 quantities at short intervals applied as a top dressing, are frequently 

 used with excellent results on grass lands. It is believed to be too so- 

 luble, in this climate of heavy rainfall, for the best results. 



The above, sulphate of ammonia and nitrate of soda, are mineral 

 forms of nitrogen. 



Of the vegetable forms of nitrogen available to our planters, cotton 

 •seed meal is by far the most extensively used. Sometimes a ton or 

 two of castor pomace finds its way to Louisiana, but the aggregate 



(3) This is practically the universal experience of sugar growers on all kinds of 

 soil. In most places it is impossible to grow ratoons or stubble canes so as to 

 produce 15 or 20 tons of cane per acre without the use of a fertiliser rich in nitro- 

 gen. Sulphate of ammonia is the nitrogenous fertiliser which most commends 

 itself to West Indian sugar growers. It is a very concentrated manure, easily ap- 

 plied and readily assimilated by the cane plant. — F. W. 



