REPEATED TRENCHING. 145 



A new trenching of the ground once in eight or 

 ten years, in respect of giving newness and fresh- ( 

 ness to the soil, is equal to an eight or ten years' 

 fallow a mode of renovation which would be death 

 to man; whereas trenching both renovates the soil 

 and continues the supplies of human wants. There 

 can be no doubt that some advantage is gained also 

 by burying the larvae of countless insects; for whilst 

 the leaves of plants in other parts of the garden are 

 eaten and decayed, every blade on the newly trenched 

 ground is green and entire. Trenching furnishes an 

 exclusive system of production, leaving nothing on / 

 the surface but what the cultivator designs. An- 

 nual weeds are scarcely to be noticed as an exception, / 

 they are so easily destroyed, and all bad and deeply 

 established roots are sent to a lower region, there to 

 rot at their leisure. Worms, snails, grubs, and the 

 like, share the same fate; and for a length of time 

 show no families on the earth, which to them has 

 suffered a ruinous convulsion. In this, your new ' 

 empire, every thing favourable to production conies 

 into your service, and every thing hostile is expelled. 

 Animal bodies, formerly destructive, now minister 

 to fertility by their decomposition: the earth, heav- 

 ing and porous, like a fermenting substance, seems 

 to borrow warmth from the very rains which chill and 

 check the vegetation of the neighbouring grounds, 

 and the intense heat which elsewhere burns upon 

 a sickly growth seems here to cool, by drawing up 

 a copious vapour, nourishing the roots and spreading 



a broad dark leaf as a cover from the sun. 



K 



