RESPECTIVE VALUES OF ORGANIC AND INORGANIC MANURES. 21 7 



THE RESPECTIVE VALUES OF ORGANIC AND 

 INORGANIC MANURES. 



By H. E. P. Hodsoll, F.C.S., M.S.E.A.C. 



[Read August 31, 1915 ; Dr. F. Keeble, F.R.S., in the Chair.] 



One of the results of the great increase in the use of artificial 

 manures in recent years is that their variety has grown with the 

 demand, and the question of their comparative values and peculiar 

 properties has become one of some complexity and at the same time 

 of great importance to all interested in hoiticulture. 



With the increase of motor traffic and mechanical transport the 

 horse is fast disappearing from our streets. While this is a fact 

 on which the general public may undoubtedly congratulate itself, 

 bringing as it does quicker and more efficient transport and cleaner 

 and healthier streets, yet to one class of the community — the market 

 grower — the change is a serious matter. This is particularly so 

 in the districts round London and the big towns where for genera- 

 tions stable manure — with perhaps, latterly, a little nitrate of soda — 

 has been almost the only fertilizer used ; consequently its increasing 

 scarcity is producing something akin to dismay in the mind of the 

 grower, who is faced with the necessity of finding some other means 

 of enriching his soil in order that he may maintain the standard 

 of his production. 



I want to show that the pith of the matter is the vexed 

 question of the respective values of these two classes of manures, and 

 that if we understood their action in the soil and on the plant it 

 would greatly assist us in deciding what artificial to use for the pur- 

 pose we had in view. 



Unfortunately, although this question has long been the subject 

 of controversy among scientists, it has received little practical 

 attention at the hands of scientific investigators or the authorities 

 in charge of our Experimental Stations and any evidence that we 

 can obtain from the latter is therefore necessarily indirect and 

 circumstantial. 



First let us see what is meant by organic and inorganic manures. 

 The former are those having an organic or living origin : that is, they 

 are obtained from some living thing either animal or vegetable. 

 Under this heading, therefore, we have farmyard manure and such 

 artificials as crushed hoof, meat meals, bone stuffs, shoddy, feathers, 

 &c, from an animal source, and rape meal, castor meal, and green 

 manures from the vegetable kingdom. 



Inorganic manures are those having an inanimate or mineral 



