26 



that sort of phosphate which is most quickly available. The effect 

 on potassic manures is to bring the potash salts into solution, which 

 otherwise would be precipitated and remain unavailable, if no hm 

 were present. 



Many fungoid and insect pests in the soil are destroyed by some 

 forms of lime. 



It should be mentioned here that the hme found in bones, super- 

 phosphate, gypsum, gas hme, &c., is not in a proper state to do away 

 with hming the soil, as it is combined with acids in these manures. 



The following are the commonest forms of hme : — 



Quicklime, obtained by the burning of calcium carbonate, is the 

 commonest kind. On combination with water it becomes slaked 

 lime. If possible, always apply in the form of slaked lime ; if, how- 

 ever, quicklime has to be used, leave it in heaps, and when slaked 

 by the rain it can be spread over the surface, as evenly as possible. 

 It should not be allowed to become too wet and sticky, or it will be very 

 difficult to handle. When it is in a suitable condition it falls into a 

 fine powder. Applications are best made to the bare soil in autumn 

 or winter, as, unless chalk is used, growing roots are greatly injured by 

 lime. It should be applied at the rate of from 8 cwt. to i ton an acre, 

 or 3-8 oz. a square yard. Chalk can be applied at the rate of 2-5 

 tons an acre, or 1-3 lb. a square yard, and should be hoed or forked 

 in, being first broken up well. 



It is better to apply oftener and in smaller quantities than seldom 

 and in large quantities, as in the latter case a bad effect is produced by 

 the delay of nitrification. The price of hme is about 9s. a ton. 



Ground lime is quickhme ground up finely, but is less pure than 

 the latter and costs about i8s. a ton. 



Lime ashes are the waste product of the burning process, and are 

 valuable if fairly clean, and free from cUnkers. 



Gas lime is obtained during the purification of coal gas over freshly 

 slaked lime. It contains several impurities, including sulphur, and 

 makes a very good insecticide if apphed in late autumn to the bare 

 soil, at the rate 'of about 1-2 tons an acre, or 8 oz.-ilb. a square yard. 

 However, any following crop for the next year would probably be a 

 failure. The usual application is 5-10 cwt. an acre, or 2-4 02. a 

 square yard in winter. When old, it can be apphed with safety "to 

 a growing crop. As mentioned before, this material has not an equal 

 effect to that of quicklime, though clay soils are considerably improved 

 by a dressing of it.* 



Gypsum is crystaUized sulphate of hme, and is chiefly valuable in 

 setting free potash and stimulating leguminous crops. It has a 

 preservative effect on ammonia, and is a cheap material to use It 

 should be applied in winter or early spring, at the rate of 3-4 oz per 

 square yard, or 8-10 cwt. per acre. 



Salt is frequently used, but the value lies in hberating potash, not 

 » Owing to improvements in methods of purifyins coal ^as tra^ 1™^ v 

 frequentlylittle insecticidal or fungicidal prop^rties^?fhe prefent lay.^F J c! 



