72 PREPARATION OF LAND FOR TILLAGE. 



to soils purely siliceous, for these can receive no modification 

 from the action of fire. 



When the soil is in a wild, uncultivated state, and its vege- 

 tative powers in a great measure dormant and inactive, they 

 cannot be called into full action without some stimulus. In 

 that case, the ashes produced by sod-burning, with the aid of 

 lime, are generally necessary and always effectual. 



When land covered with thick-tufted coarse grass is broken 

 up and sown, the old rubbish carries most of the moisture from 

 the seed, and proves a harbour for grubs, slugs, and other ver- 

 min; whereas when the turf is burnt, these enemies to culti- 

 vation are destroyed, the causes of sterility are removed, and 

 in its stead a fertilizing power is created, which, without the 

 aid of this process, could not probably have been obtained. 



The turf being cut an inch or more in thickness, is set up 

 on edge to dry; and after having remained in this state a suffi- 

 cient length of time to render it dry enough to burn, it is either 

 set on fire as it stands, or is collected into heaps. 



The heaps are set on fire and left to burn, being so covered 

 as that they shall burn with a smothered heat. By this slow 

 combustion the whole heap is equally consumed. The greatest 

 care is necessary in keeping the heap well covered, to prevent 

 the fire bursting out. 



But there is often difficulty in getting the heaps to burn, in 

 which case it is necessary to employ straw, light wood, and 

 other substances to maintain the combustion. When the heaps 

 are burned, the ashes are spread upon the surface of the ground, 

 and as quickly as possible covered by a shallow ploughing. 



The process of paring and burning cannot be strongly re- 

 commended in this country; the cases in which it is advisable 

 rarely exist; and it is difficult to believe, notwithstanding the 

 high English authority by which it is sustained, that paring 

 and burning are good as a regular system. But while injurious 

 where indiscriminately practiced, there is no reason why we 

 should not avail ourselves of so powerful an instrument of 

 improvement when it can be beneficially employed, as it un- 

 doubtedly may be under various circumstances. 



The cases in which it may be safely used seem to be 

 1. In the case of poor cold clays, marls, and calcareous soils, 

 when broken up for the first time. 2. In the case of swamps, 

 where there is a considerable stratum of peat, and which are 

 broken up for the first time. 3. In the case of deep peaty 

 soils, where there is an excess of undecomposed vegetable 

 fibre. 



