26 The Profitable Culture of Vegetables, 



Taking the average of a large number of analyses of farm- 

 yard manure, it is found that in each ton there are 



15 Ibs. Nitrogen, 7 Ibs. Phosphoric Acid, 11 Ibs. Potash. 

 To obtain the same fertilizing materials in a concentrated 

 form there would be required 



65 Ibs. Sulphate of Ammonia (at 12 per ton) 6 11 



56 !bs. Superphosphates (28% soluble at 52/6 per ton) ... 1 3 

 22 & Ibs. Sulphate of Potash (at 11 per ton) 2 2=10/5 



As farmyard manure can usually be bought at from 5s. to 6s. 

 a ton delivered, it will be seen from the above that the plant 

 foods it contains cost only about half as much as when bought 

 in a concentrated form. But on the other hand some of the 

 constituents of farmyard manure are very slow in action, whilst 

 a large proportion of the nitrogen it contains is never re- 

 covered in the crop at all not more than half of the pro- 

 portion recovered from some of the concentrated nitrogenous 

 fertilizers so that the difference in cost is not so great as at 

 first sight appears. But in addition to its value as a direct 

 feeder of plants, its beneficial effects upon the soil can scarcely 

 be exaggerated. It gives cohesion and water-retaining power 

 to sands and makes clays more open and friable. It provides 

 humus and encourages the multiplication of beneficial bacteria. 

 Its weakness as a complete fertilizer lies in its deficiency in 

 phosphoric acid, and to a lesser degree in its rather small 

 proportion of potash. The best results are therefore obtained 

 when its ingredients are supplemented by concentrated fer- 

 tilizers in the proportions required by the needs of each crop. 



Soils which regularly receive liberal applications of farmyard 

 manure are very responsive to cultivation and^ield early crops, 

 besides being tillable in almost any kind of weather. It must, 

 therefore, be conceded that although many market gardeners 

 use manure rather extravagantly they have some justification. 

 But when land has had heavy and continuous dressings for a 

 number of years it becomes " manure sick' 1 and no longer 

 yields good crops ; the humic and other acids with which it has 

 become overcharged are detrimental to soil bacteria, and as a 

 consequence the decay of organic matter is checked. The 

 remedy is to cease manuring for one season, and to dress the 

 soil with lime instead; this neutralizes the acids, sweetens the 



