82 BOARD OF AGRICULTURE. [Pub. Doc. 



ammonia ; while under ordinary conditions they hold very 

 tenaciously both phosphoric acid and potash, whatever the 

 forms in which they may be applied. This important differ- 

 ence must be kept in mind in deciding to how great an 

 extent it is desirable to endeavor to increase the store of 

 food in the soil. It is evident that we may safely direct our 

 practice toward this end, in so far as phosphoric acid and pot- 

 ash are concerned, for the bank which holds these is " solid," 

 and a working capital is desirable ; but with nitrogen we 

 must clearly pursue a diflerent plan. Solul)le nitrogen fertil- 

 izers applied one season in excess of the requirements of the 

 crop are likely to be lost in the drainage waters of the soil 

 before another crop is planted. To endeavor to accumulate 

 a working nitrogen capital by the application of soluble 

 materials such as nitrate of soda is folly ; but such capital is 

 desirable, and its accumulation in the various organic sub- 

 stances, such as manures, stubble and roots of grass and 

 clover, green crops to be ploughed under, etc., is sound 



practice . 



Green Manuring. 



What part, if any, green manuring should occupy in farm 

 practice, is a question which many are now asking ; and, as 

 it is a question of chief importance in its relations to the 

 soil nitrogen, it may well be briefly noticed in this connec- 

 tion. It should be understood, first, that green manuring 

 cannot increase the total of either phosphoric acid or potash 

 in the soil. Whatever of these elements the plant grown as 

 a green manure may contain was taken from the soil ; it can 

 come from no other source, and it is simply returned thereto. 

 Neither is the growth of a green crop of any great import- 

 ance in preventing loss of phosphoric acid or potash by 

 drainage ; for, as I have pointed out, the soil has the 

 capacity to retain these. Must we then conclude that green 

 manuring is of no benefit in so far as the elements under 

 consideration are concerned? My answer is, no. The 

 feeding roots of all plants are provided with an acid which 

 enables them to exert a powerful solvent action upon the 

 particles of the soil with which they come in contact. The 

 crops suited for green manuring are all especially vigorous 

 growers. Their myriad roots ramify throughout the soil, 



