AMELIORATION OF LAND 91 



thickness, has been left over the surface of 

 the ground. Should this process be repeated 

 during some months or, it may be, a year or 

 more, the level of the ground may be raised 

 several feet. The material so deposited is rich 

 in plant food and, although rather impervious 

 and difficult to work, it is very suitable for 

 the growth of certain kinds of crops, notably 

 wheat and potatoes. In the course of time, 

 the improved conditions thus effected tend 

 to disappear, when the operation must be 

 repeated. 



An ameliorative process which has had a 

 great vogue in the past, and which is still 

 fairly extensively practised throughout the 

 country, is Liming. Lime is an essential 

 element of plant food, and where the per- 

 centage of lime in soil is very low it is possible 

 that artificial dressings may have a directly 

 beneficial effect upon crops. But it is not for 

 the purpose of supplying plant food that lime 

 is usually applied, and therefore the applica- 

 tion of lime must be classed as an ameliorative 

 rather than as a manurial process. 



Lime may be applied in various forms, but 

 for the most part it is used in the condition 

 of burned lime, which is either ground into 

 powder and distributed while in the unslaked 

 condition, or is allowed to absorb moisture 



