332 HORTUS GRAMINEUS WOBURNENSIS. 



are devoured by insects at the roots, and seldom repay the 

 expense of labour. 



The comparative disadvantages which attend the ordinary 

 mode of converting thin sandy pastures into tillage by ploughing 

 only, are found by experience to be far greater than those which 

 result to the soil by the process of burning. Sir Humphry Davy 

 says, that " the process of burning renders the soil less compact, 

 less tenacious, and retentive of moisture ;" burning, therefore, 

 increases the natural defects of sandy soils, and lessens the 

 quantity of soluble vegetable matter they contain. It seems 

 probable, however, that the process of burning may be conducted 

 in such a manner as to prevent any diminution of the original 

 quantity of soluble vegetable matters contained in the soil. For 

 when the parings or turfs are submitted to the lire, they should 

 only be burnt till the ashes are black, and will then contain 

 carbonaceous matter, which will be found to afford more soluble 

 vegetable matter than the soil originally contained. But when 

 the parings are burnt till the ashes are red or white, the carbona- 

 ceous matter is destroyed, and the ashes that remain will be found 

 to consist of oxides and saline matters of little value to such 

 soils. With respect to tenacious clayey soils, the case is directly 

 the reverse : these cannot be too much burnt, by the ordinary 

 process of burning, as the object here is not so much to destroy 

 insects and the seeds of noxious plants, as to correct the texture 

 of the soil, by rendering it more friable, and less tenacious or 

 retentive of moisture. 



It is evident that the application of clay or marl, and vegetable 

 manure, even in small quantities, will compensate the soil for the 

 greater division of its parts and loss of decomposing vegetable 

 matter, let the process of burning be conducted in what manner 

 it may ; but there are no remedies at present known, for the 

 prevention or even palliation of the ravages of the wire-worm, 

 grubs, and other voracious insects with which these soils generally 

 abound, except that of burning, which, when properly effected, 

 experience has proved to be effectual to their destruction. 



In Scotland and in England I have witnessed the practice of 

 converting rough pastures, containing heath, furze, and coarse 

 grasses, by first burning the plants on the surface while growing, 

 and then ploughing the land for a course of crops. By this, it 

 invariably happened that the land soon became stocked with 

 its original unprofitable plants, as their seeds and roots were 



