14 AGRICULTURAL RESEARCH AND THE FARMER : 



and the number of nodules per gram of dry weight. Briefly 

 the results indicate that the marked benefit derived from farm^ 

 yard manure is in part due to an organic constituent of the manure 

 and not merely to the inorganic chemicals which it contains, and 

 further that the advantage is derived from something that is 

 contained in the straw part of the manure. What that some- 

 thing is, further research will, it is hoped, discover, and the results 

 should have a valuable bearing on the question of the cultivation 

 of leguminous crops. 



Artificial Farmyard Manure. 

 The unique value of farmyard manure is undoubted. Some 

 of the older agricultural chemists inclined to the view that 

 artificial fertilisers were the chief source of fertihty, and that Httle 

 more need be done if sufficient amounts of these were added. 

 It is now known that the full action of artificial manures is exerted 

 only when there is an adequate supply of organic matter in the 

 soil. Unfortunately, few farmers are able to obtain sufficient 

 manure for their needs. One method of securing it is, of course, 

 to increase the head of livestock on the farm, but this may often 

 be impracticable. In market-gardening districts around indus- 

 trial centres, which have hitherto depended largely on horse- 

 manure for supplying organic matter to the soil, the gradual 

 substitution of horse by motor transport is being felt acutely. 

 Further, in many parts of the country, particularly in corn- 

 growing districts, large quantities of straw are produced which is 

 not only of no value to the farmer, but he is often in a difficulty 

 as to how to dispose of it. Now straw contains all three essentials 

 to plant growth which are usuaUy supplied in fertilisers, namely^ 

 nitrogen, phosphates and potash. Of itself, however, it is of 

 little value as a fertiliser, quite apart from the difficulty of burying 

 it in the soil. When it is decomposed by the action of animal 

 excrements, however, the mixture, known as farmyard manure,, 

 becomes an invaluable source of fertility. The problem for the 

 scientist to solve, therefore, was how to bring about the decom- 

 position of straw artificially without the use of cattle, and so> 

 provide the farmer with an adequate supply of " artificial "" 

 farmyard manure, and enable the corn-grower to use his straw 

 in this most useful way. The subject has occupied the attention 

 of Rothamsted for some years, and a short description of the 

 progress of the research will enable the readers to judge for them- 

 selves whether the results so far secured have justified the con- 

 siderable amount of labour and abihty involved in their attain- 

 ment. The account will be given in some detail, for it affords 

 an excellent illustration of the value of pure research conducted 



