II28 



THE BOOK OF GARDENING. 



clearly to the slow action of the dung, and showing that it rarely 

 produces much effect in the first year of its application. 



Further, it was found that when 2oolb. of nitrogen was applied 

 to the Potato crop in the form of farmyard manure, which also 

 contributed a very large amount of mineral constituents, in no 

 case was the increased yield of the crop so great as was obtained 

 by an artificial mixture of minerals and nitrogenous manure sup- 

 plying only 861b. of nitrogen, but in a more readily available 

 condition. Nor was the increased assimilation of any one of the 

 individual constituents so great under the influence of farmyard 

 manure as when these were applied in the rapidly available 

 condition, as in the artificial mixtures. 



In the case of several other crops it has also been found that 

 only a small proportion of the nitrogen of farmyard manure was 

 taken up in the first year of the application. 



In ordinary garden practice farmyard and stable manure are 

 not only largely relied upon for the growth of most crops, but 

 are applied in considerable quantities. It is probable, therefore, 

 that independently of the liberal supply of all necessary con- 

 stituents of plant-food, the beneficial effects of this manure are in 

 a considerable degree due to its influence on the mechanical 

 condition of the soil, rendering it more porous and easily 

 permeable to the surface-roots, upon the development of which 

 the success of so many garden plants greatly depends, Then, 

 again, something may be due to an increased temperature of 

 the surface-soil, engendered by the decomposition of so large an 

 amount of organic matter within it ; whilst the carbonic acid 

 evolved in the decomposition will, with the aid of moisture, serve 

 to render the mineral resources of the soil more soluble. 



There are several practical considerations which count in favour 

 of using well-rotted manures, especially when not used in con- 

 junction with an artificial fertiliser. It is especially worthy of 

 observation that, whilst the insoluble organic matter of dung 

 is much reduced in quantity during the fermentation, the 

 insoluble organic matter which remains is richer in nitrogen 

 than an equal quantity of the same substance from fresh dung. 

 Therefore, weight for weight, well-rotted farmyard manure is- 

 richer in soluble fertilising constituents than fresh dung, and 

 contains especially more readily available nitrogen, and hence 

 produces a more immediate and powerful effect on vegetation. 

 Many practical gardeners have urged that fresh manure, even 

 if it does not actually injure the crop to which it is applied, may 

 still tend to the production of stems and leaves rather than of 

 seeds and fruits. The rankness, however, of fresh dung and 

 urine could be controlled and utilised by applying the manure 

 in small quantities, and supplementing it with artificial fertilisers 

 of kinds appropriate to the crops or individual plants that are 

 to be grown. 



