200 



hindered, or neutralised the value of, the subsequent laboratory work, or 

 prevented its performance, more especially in sparsely populated parts of 

 the country, where, through lack of conveyance, months have at times 

 elapsed before fresh samples could be procured. 



The directions in which investigation was made also show omissions 

 that will be patent on glancing through these pages. Some of these de- 

 fects will, it is hoped, be supplied in the near future; others must of 

 necessity remain defects until contingencies enable one to widen the scope 

 of investigation. Amongst the latter, unfortunately, has to be classed one 

 of the most important studies that pertain to the soil, that is, the soil 

 nitrogen, its exhaustion and replenishment. 



And yet, however beset with difficulties and obstacles the work has 

 hitherto been, the writer thinks that thanks to the assistance of those 

 who have, from time to time, been members of his staff, and whom, first 

 one and then another, he charged with the details of the work these 

 records will show the existence of solid reason for initiating this under- 

 taking, and that the investigation has not been wholly void of fruit must 

 also be apparent. The connection between the composition of the soil 

 and the ravages of bone disease in stock has not been fully traced out, but 

 it is at least remarkable that these diseases find the greatest foothold in 

 just those areas where lime and phosphates are deficient in the soil. In 

 connection herewith the question has been put, why, if the sandstones of 

 the Table Mountain and allied series are so poor in the plant food con- 

 stituents named, " lamziekte " does not make its appearance in the south- 

 west, but is confined to the districts further east? One answer obviously 

 is that, in the more easterly districts, the rocks in which these con- 

 stituents are deficient stretch uninterruptedly over vast extents of country, 

 while in the west they a<re sufficiently diversified by granite and the rocks 

 of the Bokkeveld series. 



The confirmatory testimony given, in many cases, during the course 

 of these investigations, by practical farmers, has shown that, presuming 

 certain necessary data, correct deductions as to the probable fertility of 

 a soil are capable of being made from analytical results. It would be idle 

 to assert that discrepancies do not occur, but in the present state of en- 

 quiry one must needs meet with seeming anomalies : there is a plain neces- 

 city for pushing investigation very much further. The best means of 

 determining the proportions of plant food constituents in the soil have to 

 a certain extent been studied, and the methods finally adopted appear, 

 judging from the confirmatory evidence just spoken of, to be the most 

 suited to the country's circumstances. To transfer hither, unmodified, and 

 without enquiry, European or American methods of treatment, or 

 standards of interpretation, would scarcely have been wise. 



Regarding the irrigation schemes which must continue to bulk largely 

 in the country's future agricultural development, it has been shown how 

 needful it is previously to enquire into the condition of the soil, and here 

 not only the alkali deposits themselves need investigation, but equally so 

 the physical condition of the soil. The important problems of differen- 

 tiating soil types, and of classifying the Colony's soils from a laboratory 

 standpoint an investigation which has proved so useful in America 

 still remain to be grappled, and it is the writer's increasing view that 

 just at this point a thorough study, and, if possible, a mapping out, of the 

 mechanical condition of the soil should go conjointly with, if indeed not 

 actually precede, enquiry into the quantities of plant food present. In 

 connection with a scheme like this an adequate knowledge of the distribu- 

 tion of indigenous plants and of their soil relation is also 

 most necessary. Such a scheme, the writer trusts, will ere long 

 be put into practical operation. How frequently barrenness may 



