THE NEW SOIL SCIENCE. 



81 



THE NEW SOIL SCIENCE. 



By W. Dyke, F.E.H.S. 



Do we require a new soil science ? may be a question reasonably asked. 

 Undoubtedly we do, and must have it, before the multitude of practical 

 gardeners can be convinced that there is truth in our teaching. 



That a plant lives, grows, and requires food are facts recognised by every 

 grower ; but that there is something wrong with the theories put forward 

 by scientists to explain the condition in which the soil food is absorbed 

 Ty crops, is evident to all who know by heart their text-book, and have 

 to grow plants either for pleasure or profit. From a practical standpoint 

 the whole subject seems to be a mass of contradictions; consequently the 

 very men that should benefit by a knowledge of soil science have no 

 faith in it. 



I say this in no cavilling spirit, for no one could have been more 

 impressed than myself by a book knowledge of soils, manures, and plant 

 food, and it was not until many years had been spent in experimenting 

 with every kind of manure in commerce, that I saw how little was 

 known regarding this very important subject. 



My object in writing this paper is of a twofold nature, first, to try 

 and show where the theory is weak, and secondly, to point out the way 

 to remedy the weakness. 



Before proceeding to discuss the main question it would be well to 

 see in what direction our present knowledge of manures and manuring 

 leads us. Nitrogen in a combined state is a soil constituent necessary 

 for the life and development of all crops. More money is paid for a 

 pound of it than for any other constituent of plant food, or, to be precise, 

 it costs from (yd. to Is. a lb., according to the form in which it is 

 bought. 



The top foot of an acre of ploughed land contains 3,500 lb. of nitrogen, 

 a good garden soil twice or thrice as much. Supposing in field cultiva- 

 tion we wish to grow a crop of Potatos, we should find it advisable to 

 apply about twenty tons of farmyard manure per acre. The twenty tons 

 of dung would contain 200 lb. of nitrogen. A fairly good yield of Potatos 

 would be six tons to the acre, and to this must be added 4,274 lb. of 

 haulm. 



The six tons of Potatos and 4,272 lb. of haulm take from the 

 soil but 67 lb. of nitrogen, and yet a soil containing 3,500 lb. of nitrogen 

 is incapable of supplying this small amount, and we even have to give, 

 in addition to it, three times as much as the Potatos require in the form 

 of manure to get a satisfactory return. 



Pat in other words, it amounts to this, we have a balance at our 

 bankers' of £3,500, and wishing to withdraw £67 the manager says we 

 may if before doing so we pay into our banking account £'200. The whole 

 of this vast mass of soil-nitrogen seems useless or nearly so, and the 



