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tobacco is a; potash-feeder. By adopting a system of rotation of crops, 

 these elements are removed from the soil in turn ; so that while the 

 crop succeeding a nitrogen-feeder is removing ciiefly potash or chiefly 

 phosphorus, the soil has a chance of recouping its available supply o£ 

 nitrogen by allowing i^s dormant supply to be rendered available. 

 In this way the conversion of dormant into active plant food is enabled 

 to keep pace with the removal by the crop of the available matter. 



Though it has been indicated how the land can, by rational and 

 thorouo^h cultivation, be kept fertile and prevented from becoming ex- 

 hausted, it must be admitted that circumstances do arise, which make it 

 necessary that something be added to the land t) increase its fertility. 

 Any substance added for this purpose is a manure 

 Now as the fertility of the land depends not only upon the presence 

 of plant food, but also upon the state in which the pla it food exists, 

 it follows that there aro two ways of increasing the soil's fertility. 

 One, by adding to the store of plant food in the soil, tbe other — an 

 indirect method — by increasing the amount of available plant food 

 by acting upon the dormant. Hence a manure can be placed into one 

 of two classes, according to whether it acts directly or indirectly. Thus, 

 lime is usually regarded as an indirect manure, since it acts upon the 

 dormant potash, causing an increase in the amount of potash at the 

 disposal of the cr ^ps. A direct manure, theref >re, is one which adds 

 plant food to the soil. It may add all the necessary elements re- 

 quired by the plant in which case it is called a general manure ; or it 

 may be a special manure, supplying only one or two of them, as in the 

 case of many of the artificial chemical manures. 



Stable Manure. — The best example of a general manure is that 

 which has long been used under the varying names. Farmyard, Stable 

 and Pen Manure. The name it goes by matters little. Its value as 

 a substance that increases the fertility of the soil, must be appreciated. 

 It is made up of the excrement, solid and liquid, of all the animals 

 kept on a pen or estate, the refuse of livery and other stables, together 

 with trash of some sort used as bedding. On most estates, some, at 

 any rate, of the stock are kept in fenced enclosures, or in stables It 

 is in such cases that there is some accumulation of manure, and that 

 the proprietor has to consider its application to the land. Since this 

 manure is the refuse of plant-consuming animals, the cultivator by its 

 use enriches the land in all the constituents of plant food. For this 

 reason stable manure is par excellence a general manure. No oppor- 

 tunity should be lost, therefore, of using not only all that is produced 

 on the property, but also any that can be obtained at a reasonable 

 cost. In many parts of Jamaica there is certainly a difficulty in ob- 

 taining it ; but in other districts the constabulary and o'her owners of 

 stables are obliged to pay for the removal of their dung, so slight is 

 the value placed upon it. Where stable manure can be procured at a 

 cost very little above that of cartage, its use is certainly to ba advo- 

 cated. 



It has already been shown that some manures have a direct, and 

 others an indirect action in increasing the fertility. This manure acts 

 both directly and indirectly. The latter action is due to the power 

 possessed by stable manure of improving the mechanical condition of 



