15G ACTIOX OF SOIL OX FOOD OF PLANTS IX MANURE. 



all the conditioiis of healthy growth from the surface soil, 

 which is restored to its original state of productiveness 

 by the manure applied. 



But from our acquaintance with tlie properties peculiar 

 to arable soil, Ave know that a layer 6 to 10 inches 

 deep will retain all the ammonia potash and phosphoric 

 acid contained in the largest quantity of manure usually 

 apphed by farmers ; and this, too, so firmly that, except 

 for some accidentally favourable circumstances, hardly a 

 particle will ever reach the subsoil. 



If a field is sown with plants wliich require deep 

 ploughing, so that a sufficient portion of the rich surface 

 is mixed with the exhausted subsoil, it is easy to under- 

 stand that the latter may gradually become again fruitful 

 for peas. The time in which this is effected depends of 

 course upon the accidental selection of the plants grown 

 in succession on the field. 



In this view of the matter, the agriculturist has it in his 

 power, by right management of his field, to shorten the 

 time, and make the land again fit for successive crops of 

 peas. 



It is a fact, that many fields in the vicinity of towns 

 will bear year after year, or every two years, abundant 

 crops of peas, without ever becoming ' pea-sick ; ' and we 

 know that the gardener, to achieve this result, has re- 

 course to no extraordinary appliances, but merely tills his 

 land deep and very carefully, using much more manure 

 than the farmer can afford to do. 



The frequent failure of peas is therefore not so very 

 unaccountable ; and there seems no reason why the far- 

 mer should despair of cultivating peas as often as serves 

 his purpose, if he employ the right means to enrich his 

 field in tlie proper spots with the elements of food which 

 peas requfre. 



