282 The Profitable Culture of Vegetables. 



by experiment that excellent crops of good sound Potatoes can 

 be grown in thoroughly decayed manure alone, it would seem 

 that such advice is misleading. Well-decayed farmyard manure 

 is the best practical means known for supplying to the soil the 

 physical condition and the plant foods necessary to the produc- 

 tion of an abundant crop of Potatoes, but it is not a perfect 

 manure because it contains, proportionately, an insufficient 

 quantity of phosphoric acid and potash, and these ingredients 

 need supplementing, according to the nature of the soil, with 

 suitable artificials. The mischief which sometimes arises in con- 

 nection with its application to Potatoes is not from the quantity, 

 but rather from the crude, rank condition in which it is given, 

 often combined with overcrowding and with badly-drained land. 

 Excessive moisture at the roots causes unhealthy growth, and 

 when this is coupled with a damp and stagnant atmosphere in 

 and around the foliage, the conditions are such as to foster the 

 incubation and cause a rapid spread of the disease. Therefore, 

 the primary conditions for heavy crops of sound Potatoes are 

 (1) deeply worked and well drained soil, (2) ample space between 

 rows and sets, and (3) liberal dressings of well-rotted farmyard 

 manure. If the manure is not well decayed it must be turned 

 under in the autumn ; the nearer to the time of planting, the 

 more thoroughly decayed it must be. Good crops can be grown 

 without any manure on newly-broken old pasture land or on 

 any other soil which contains an accumulated store of fertility, 

 or on most ordinary soils with the aid of concentrated fertilizers 

 only, but consideration will make it apparent that such a pro- 

 cedure is a temporary expedient, and that crops so obtained 

 draw upon and reduce that store of fertility in the soil which it 

 ought to be the aim and ambition of every "thorough" gardener 

 continually to increase by every means in his power. 



The average yield of Potatoes per acre throughout the whole 

 of Great Britain is between 5 and 6 tons, but this, of course, 

 includes the results from poor land and insufficient manuring. 

 On better soil with more liberal treatment the yield often runs 

 as high as 10 or 12 tons per acre over a large area. Under 

 special conditions from 15 to 20 and more tons per acre have 

 frequently been grown, but such yields are always the result 

 of a thorough working of the soil accompanied by generous 



