A FORTNIGHTLY REVIEW 



OF THE 



IMPERIAL DEPARTMENT OF AGRICULTURE FOR THE WEST INDIES. 



LIBRA 

 NEW Y< 

 BOTaNIi 



QaRDE 



Vol. YIII. Xo. l.-<i. 



BARBADOS, MAY 15, 1909. 



Price Id^ 



CONTENTS. 



Soil Inoculation. 



W^^ GPJCULTURAL literature has of late 



(''y-^^pt'^ years included numbers of papers and 



4e*ar^35§ reports on the subject of ' soil inoculation.' 



O^ This term is applied to the various attempts that have 



O": been made to increase the crop-yielding power of soils 



I by the introduction of bacteria which are known to be 



oo the cause of the nodules frequently observed on the 



^ roots of leguminous plants, and which are capable of 



— , assimilating free nitrogen from the atmosphere, that 



can be utilized as food by the plants in whose roots 

 tlie bacteria live. 



Practical agriculturists have for generations past 

 been well aware of the f;tct that the growth of 

 a legmninous crop such as peas, beans, alfalfa, etc., 

 results ill an increase in the crop-yielding capacity of 

 the lai.d cultivated, although it is only within com- 

 paratively recent years that a satisfactory explanation' 

 of the mutter was brought forward. One of the early 

 (ibser\e's in respect to this subject was a Frenchman, 

 Boussiiiganlt, who, as the result of weighing and 

 analy.sing the crops grown on his own farm throughout 

 si.\' separate courses of rotation, was able to state 

 definitely that from one-third to one-half more nitrogen 

 was renioved in the produce than was supplied in the 

 manure. He observed, too, that the gain of nitrogen 

 was particularly large when clover or other crops of 

 the same family were grown. 



Investigation work in relation to the manner in 

 which leguminous plants i obtained the supply' of 

 nitrogen was undertaken by a number r)f experimentors, 

 but the credit of carrying out the researches which 

 ultimately cleared up the whole matter belongs to two- 

 German scientists, Messrs. Hellriegel and Wilfarth, 

 who published their results in 1886. These results, 

 demonstrated conclusively, that leguminous plants were- 

 capable, under certain conditions, of obtaining and. 

 utilizing nitrogen from the atmosphere. It was further 

 shown that this nitrogen assimilation was dependent 

 upon the production of nodules on the roots of the 

 plants. In later research work it was found that the 

 root nodules were full of bacteria, which were the 

 evident agents by which the free nitrogen was appro- 

 priated, and to these the name PsftuJoniiinas rmhi-icola 

 was given. Other observers have since confirmed the 



