136 STATE HORTICULTURAL SOCIETY. 



the soil cannot be very different from the decomposition in the laboratory 

 for there is present in the soil the very agencies which affect the de- 

 composition under laboratory conditions. I refer to the countless num- 

 ber of microscopic organisms: bacteria, molds, yeasts and fungi. You 

 are all familiar with the work of these organisms on various materials 

 above ground and I need only to call to you minds a few examples, 

 as for instance, the souring of milk by bacteria, the destruction of 

 grain by molds when stored in a warm, damp place, the transforma- 

 tion of sugar in apple juice into alcohol and vinegar by yeasts and the 

 brown rot of grapes by fungi. Changes in the organic matter of the 

 soil, of a like nature to these, are going on continually in the soil, when 

 the temperature conditions are favorable, and the result must be the 

 production of a great many compounds in the soil of which, as yet, we 

 know very little. 



Some of these compounds contain nitrogen and some contain phos- 

 phorus and a great many of the compounds already isolated contain 

 neither one of the so-called plant food elements and I now come to the 

 most interesting and perhaps most important phase of the subject. 



It has usually been considered that nitrate is the best form of nitro- 

 gen for plants and that it could not be used by plants in any other 

 form. Now we do not find nitrogen in plants in the form of nitrates 

 (with the exception of a few cases) but on the contrary it is in the 

 form of very complex protein compounds. It is very evident then, that if 

 the plant gets all of its nitrogen as nitrate it must expend an enormous 

 amount of energy in building up these complex compounds. Now, as 

 has already been indicated, when these protein compounds are decom- 

 posed by bacteria or other agencies, they are split up into simpler but 

 still complex compounds, which are again acted upon by the same or 

 other agencies with the production of more simple compounds. This 

 action may be carried on until a part of the nitrogen, originally present 

 in the protein compounds has been changed into nitrate or ammonia. 

 Now, since the plant must transform its food material into these very 

 complex materials what is more plausible than that it may make use 

 of some of these simpler decomposition products before they have been 

 reduced to nitrate. 



While I realize that this is decidedly contrary to the time honored 

 theory that plants can only take their food material in the simplest 

 forms but, why not change our views on this subject if the evidence is 

 sufficient? We are now experiencing a similar change in regard to the 

 theory of animal feeding. For a long time it has been supposed that 

 a ration balanced with respect to protein, carbohydrates and fats had 

 solved the problem of cattle feeding, but recent researches have disclosed 

 the fact that there is a great difference in the feeding value of the vari- 

 ous protein compounds and indicate that in order to obtain the greatest 

 efficiency we must take into consideration the decomposition products 

 of the protein materials we feed. We must therefore, take into con- 

 sideration the possibility of the plant making use of these soil decom- 

 position products as plant-food just as they can use the more simple 

 forms of nitrogen, phosphoric acid and potash. 



It has in fact already been demonstrated that plants will use some 

 of these soil decomposition products and even when it has access to the 



