Notes on the Society's Work in 1897-1918. xxxiii. 



The latter varieties are unsuited to cultivation on very heavy clay 

 soils under conditions of oft-repeated ratooning. 



One ton of nitrate of soda under favourable conditions produces one- 

 fifth less sugar than does a ton of sulphate of ammonia, but in practice it 

 is safer to assume it will produce a third less. When used on land long- 

 manured with sulphate of ammonia a change to nitrate of soda may 

 prove to be beneficial and the yield of sugar may approach or even exceed 

 that normal to the nitrate of soda when used under favourable conditions 



It is probable that during this year the colony will be about 4,500 

 tons short of sulphate of ammonia or of its equivalents which means that 

 its crops will be probably 20,000 to 25,000 tons of sugar less than they 

 would be under normal conditions. This position should be strongly 

 represented to the Government of Canada. If that country cannot supply 

 us with sulphate of ammonia or its equivalent we shall be unable to supply 

 it with sugar. 



During the many year manurial experiments with the sugar-cane 

 have been in progress in British Guiana practically every available com- 

 mercial substitute for sulphate of ammonia has been under trial. The 

 only ones which have not been tried are cotton-seed meal and castor- 

 seed meal. The average efficiencies as compared with sulphate of 

 ammonia taken as 100 of equivalent quantities of nitrogen in the 

 various manures we have tried are shown in the following statement : — 



Dissolved Peruvian guano ... ... 103 



Sulphate of Ammonia .. ... 100 



Nitiolim ... .. ... 97 



Nitrate of Potash... .. ... 94 



Nitrate of Soda ... .. ... 92 



Dried Blood ... ... ... 90 



Raw Chinchas guano ... ... 88 



Lofoten Fish Guano ... ... 85 



Nitrate of Lime ... ... ... 80 



Animal Products Manure ... ... 60 



Stable Manure ... ... ... 35 



Our planters and farmers will do well to turn their attention towards 

 substitutes other than purely nitrogenous products for sulphate of 

 ammonia. The practical ones are : 



(a) The use of slaked lime in dressings of not less than 2 tons p9r 

 acre. 



(b) The utilisation of the colony's vast production of rice-straw. 



(c) The use of legumes or pulses as cover-crops. 



(a) On new land or on land long-rested from cultivation in sugar-cane, 

 dressings of from 2 to 3 tons of Barbados " white-lime," or better, if 

 procurable, of from 1 to 1£ tons of Trinidad quick-lime allowed to become 

 air-slaked before application to the soil, should largely increase the yield 



