CONTRIBUTIONS FROM THE WISLEY LABORATORY. 



231 



CONTRIBUTIONS FROM THE WISLEY LABORATORY. 

 IV.— The Inoculation of Leguminous Crops. 

 By F. J. Chittenden, F.L.S. 



For several years past the question whether the inoculation of the soil 

 with the bacteria which are the cause of the formation of the nodules 

 upon the roots of leguminous plants would lead to increased crops, or to 

 crops of greater value, has offered a fascinating field for experiment, and 

 many forms of inoculating material have been placed upon the market 

 and used with variable results, sometimes successfully, often the reverse. 

 The latest material designed for this purpose in this country has been 

 called " Nitro-Bacterine." It has been widely advertised and boomed in 

 the popular Press, surprising results having, in some places, followed its 

 use. It was, therefore, thought well that it should be tried in the Wisley 

 Garden. A brief summary of the scientific investigations which have led 

 up to the expectation that inoculation of the soil would yield increased 

 crops is first given, and then an account of the trial in the Garden of 

 this particular inoculating material. 



Historical Note.* 



It was noticed by many ancient writers that a leguminous crop acted 

 in a beneficial manner upon the s >il, so that the crop succeeding it was 

 much better than where no leguminous crop had been grown. Pliny, for 

 instance, says, " The bean ranks first among the legumes. It fertilizes 

 the ground in which it has been sown as well as any manure " ; and 

 Varro t writes, "Legumes should be sown in light soils: indeed, they 

 are planted not so much for their own crop as for the following crop, 

 since when they are cut and kept upon the ground they make the soil 

 better. Thus the lupine is wont to serve as a manure where the s >il is 

 rather thin and poor." The principle here stated has been rec >gnized in 

 all the most general crop rotations followed by fanners, and many 

 different explanations of this beneficial effect have been given. Among 

 them suggestions were not wanting, although they were not backed up by 

 experimental proof, that the leguminous crop improved the soil by taking 

 nutriment from the air and depositing it in the soil through the roots and 

 stubble.t It was later found that the soil was not only richer in humus 

 after a leguminous crop had been grown up m it, but that it actually 

 contained more nitrogen than was present when the crop was s own. In 

 1854, however, Boussingault § demonstrated the fact that the only source 



* A much longer summary is given in the Bulletin of U.S.A. Dept. Agr., Bureau 

 of Plant Industry, 71, 1905, and in drawing up the brief account here given I have 

 made free use of the material collected there. Those interested should procure this 

 paper. 



t De Be Bustica, i. 23. 



% Thaer, Bationelle Landwirthsch. I. Aufl., Bd. 1. 1809. 

 § Mem. de Chim. Agric. ct de Physiol., Paris. 



