NEW YO 

 BOTANIC 



IMPERIAL DEPARTMENT OF AGRICULTURE FOR THE WEST INDIES. o^««b' 



A FORTNIGHTLY REVIEW 



OP THK 



Vol. XI. No. 273. 



BARBADOS, OCTORER 12, 1912. 



Pkiok id. 



CONTENTS. 



The Practical Value of Soil Analysis. 



iHEN soil analysis is mentioned, it is 

 'usually understood that an investigation and 

 I statement of the chemical and physical con- 

 stitution of the soil are intended. In the part of the 

 statement relating to the chemical investigation, first 

 attention is paid to the content of the soil in more or 

 less available compounds containing nitrogen, potash 

 ind phosphorus; while the information relating to the 

 physical condition of the soil is concerned chiefly with 

 the proportions that it contains of particles of different 

 sizes, and with the quantities of these that, speaking 



broadly, are of a sandy or clayey nature. If all this 

 information is properly understood and applied with 

 a correct regard to its limitations, it is of the greatest 

 use to the agriculturist. If it is thought to provide an 

 absolute indication of the degree of fertility of the soil, 

 and to show necessarily the plant food constituents 

 that the soil lacks, its provision may be of little avail, 

 and actually harmful. 



A recent discussion*, of the correctness of the 

 view that the analysis of a soil gives a ready means of 

 obtaining an indication of its fertility, and of deter- 

 mining its manuriai requirements, deserves notice 

 here in the light of conditions and experience in the 

 West Indies. First attention may be directed to the 

 question — 'to what extent does an analysis of a soil 

 give an indication of that soil's fertility?' 



The fertility of a soil is measured by its power to 

 grow crops, and this power is most obviously limited 

 by its ability to supply the plant food requirements 

 mentioned already. It is not sufficient, nevertheless, 

 for the soil merely to contain these bodies in adequate 

 amounts. One matter of the greatest importance 

 is that there shall be an ample provision of water 

 to be taken up by the roots, and there are other 

 essentialsf, such as proper aeration of the soil. 

 It is not the purpose of this article to disauss 

 these: it is only expedient to point out that 

 insufficiency in any one of them prevents the proper 

 use by the plant of all the others. Their useful pro- 

 vision depends, in turn, on such factors as climate, 

 exposure and depth of soil, and drainage. The chief 



* The Journal of the Board of Agriculture,Septemher 1912, 

 p. 479. 



+ Agricultural Netvs, Vol. IX, p. 257. 



