17 



of them immediately available. 



Since the soils are usually deep, contain a large amount of lime and 

 a fair proportion of water-soluble salts, fertilizers are easily decom- 

 posed and slow acting fertilizers undergo a more rapid decomposition in 

 these soils than in many others. 



Kinds of fertilizers to apply. As most of the soils are alkali and 

 contain sulphates, chlorides and carbonates, care must be taken not to 

 increase them. Chlorides would be increased by the addition of potas- 

 sium chloride. As the sulphates are the least harmful of the three, 

 sulphate of potassium is the best source for potash when potash is 

 imported. Chilli salpetre has a tendency to increase the amount of sol- 

 uble soda. Its use on some soils as a stimulant maybe beneficial; as a 

 fertilizer, it must be used guardedly. Canes that have been injured by 

 insect attacks will sometimes be restored to normal growth by the use of 

 chilli saltpetre. It also helps to prevent tassel ing, and a very little will 

 be beneficial when nitrogen is applied in organic compounds that are 

 not quickly decomposed. Its action on cane is to produce a sudden rank 

 growth, and if used in large quantities acts very much as an alkali. It 

 has a tendency to make the juice gummy, and so might interfere with 

 the elaboration. The time to use it is when the cane needs a 

 stimulant. Every estate should keep it in stock. 



Dried blood, tankage, the meals, etc. are good sources of nitrogen 

 for these soils as they are slow in their action. The Peruvian guano 

 approaches as nearly a perfect fertilizer as any outside of those chem- 

 ically prepared, since it contains both nitrogen and phosphoric acid, 

 soluble and insoluble, and a little potash. It acts as a stimulant to the 

 young cane and is a source of reserved plant food. The phosphoric acid 

 added in the guano may not all be used by the cane, but comparative- 

 ly little is lost and its addition to the soil is not injurious. While the 

 natural guano may not be in the proportions of a high grade fertilizer, 

 it is excellent and cheap, and for these soils, if mixed with potassium, 

 sulphate would make an almost perfect fertilizer. 



Quantity of fertilizer to apply. This depends on the kind of soil and 

 the class of cane desired. Some soils need building up as well as plant 

 food, and it may be better to add fertilizer in large quantities for a 

 few years with the aim of getting the soil into healthy shape; after 

 that, the fertilizer may be added pretty nearly in the proportion that 

 the cane would remove it from the soil. There will always be some 

 loss of fertilizer in the irrigating water. The highest development in 

 the art of fertilizing would be to know how to add the least amount 



