126 BOARD OF AGRICULTURE. [Pub. Doc. 



economically and with profit the very useful materials that 

 are now upon the market in concentrated forms. Soils poor 

 in respect to total plant food and j^hysical character very 

 frequently need lime, and an abundance of it, even if the 

 soils are derived from the decomposition of limestone. Clay 

 soils that are dense and compact need lime in order to floc- 

 culate the fine particles, making them more open and porous, 

 and the loose sandy soils need lime, both to provide the 

 plants with this element, as well as to make them more 

 absorptive and retentive of water and plant food. They 

 should also be supplied more generously with vegetable mat- 

 ter which has a tendency to decay, and which encourages 

 those activities, bacteriological, chemical and physical, which 

 permit not only the easy and more ready distribution of the 

 fertilizer elements, but their rapid change into available 

 forms. 



Another matter of very great importance in a way (yet 

 I am satisfied too much importance has been given to one 

 phase of the question and not enough to another) is the 

 fact that different plants require different kinds and forms 

 of plant food. This has given rise to the manufacture of 

 different brands of fertilizers suitable for different crops. 

 That is, plants have been classified into groups, — nitrogen- 

 loving, or those that require a relatively greater abundance 

 of nitrogen ; the phosj^hatic groups, which do not make rapid 

 growth and mature properly without an abundance of phos- 

 phoric acid ; and the potash-consuming plants which luxuriate 

 in an abundance of this mineral. That is, a crop belonging 

 to the first class must have nitrogen in excess of the other 

 elements; plants belonging to the phosphatic group must 

 have phosphoric acid in excess ; and the same is true of the 

 potash group. The difficulty with this reasoning is that 

 plants whose composition shows an abundance of any one of 

 these elements are not an evidence that a larger supply of 

 available food is required, but that because of their habits, 

 their root systems and their time of growth, certain plants 

 are able to acquire a larger proportion than others to use in 

 their construction and development. 



On the average, it is not so much a question of proportion 



