Vol. XII. Xo. 281. 



THE AGKICULTURAL NEWS. 



41 



to above have conducted wider enquiries into the 

 cause i)f chlorosis as manifested in lime soils Efenerally. 



Vicia narhonensis was grown successfully in water 

 cultures containing all the essential elements for 

 proper nutrition. The solution contained no carbonates. 

 When, however, calcium carbonate was added to the 

 culture solution at the rate of 2 per thousand, the 

 plants became regularly chlorotic after producing 

 half a dozen normal leaves. Drops of a solution of 

 ferric nitrate at 0'2 per thousand deposited on the 

 discoloured leaves caused the appearance of chlorophyll 

 after three days. Magnesium sulphate does not e.xert 

 any action on this chlorosis. It is therefore the 

 calcium carbonate that has produced the chlorosis by 

 the withdrawal of iron. 



The explanation of these facts is as follows. In the 

 solution supplied with the calcium carbonate, the iron 

 is made entirely insoluble. Certain plants like maize 

 possess the property of absorbing it by means of the 

 acid secretion of their roots (malic acid in maize). 

 Other plants like lupin or V. mirhonensis are inca- 

 pable of utilizing the unavailable iron and hence 

 become chlorotic. A similar incapacity on the part of 

 the sugar-cane may possibly explain the presence of 

 unproductive patches in cultivated fields, such as those 

 in Antigua (where they are called 'gall patches'), par- 

 ticularly since these affected areas are, in the special 

 instance mentioned, confined to the limestone districts 

 of the island. 



The Improvement of a Useful Grass. 



The Report of the American Breeders' Association, 

 Vol. V^l, 1911, contains an article by L. A. Moorhouse 

 on the selection of Devil's grass {Cynodon Dactylon), 

 called in the United States Bermuda grass. In West 

 Indian agriculture, Devil's grass is one of the most nox- 

 ious weeds of arable land, but it is of value as a pasture 

 grass and indispensable as a grass for lawns. It is also 

 useful for covering banks of sand and similar situations 

 where excessive erosion or washing is likely to occur. 

 From these points of view much benefit can be derived 

 from careful selection. 



For pastures a type should be selected which pro- 

 duces a dense growth of upright stems; for the preven- 

 tion of washing, plants with a vigorous underground 

 system should be selected; whilst a type which forms 

 an exceedingly close turf is best suited for growing 

 on lawns. 



The initial step towards obtaining improved 

 strains is to select a hundred, or even more, plants 

 which ajjpear to possess the desired characteristics; it 

 will be well to obtain these mother plants from different 

 localities, noting the i-ainfall and kind of soil of each 

 situation. The cuttings from these plants should be 

 planted in good, but not heavily .nanured soil, at 

 a distance of 2 feet by 4 feet. The cuttings from one 

 individual plant should be confined to one row, and 

 a nursery number given to each plant. 



After one or two seasons, those plants which 

 correspond in a measure to the desired ideal, can be 

 transplanted by cuttings into larger plots. From this 

 area material will be available for general field planting. 



Barbados Education Gazette. 



The first number of this publication was issued on 

 January 1-"), 1912, under the authority of the Barbados 

 Education Boai'd. It contains sixteen pages of printed 

 matter arranged in a useful and suggestive manner, 

 such that the magazine possesses an educational value 

 quite apart from its function as a medium for the 

 announcement of purely ofificial information. 



The matter relating to nature study, psychology 

 and moral instruction is to be commended, for along 

 these lines lie the main problems of West Indian 

 education. It is apparently the aim of the Education 

 Gazette to keep these problems in view, and there can 

 be no doubt that, in time, this policy will engender 

 a wider appreciation as to what education really iueans. 



The Student's Corner and other sections dealing 

 with scholastic matters are likely to serve a useful 

 purpose, but it would possibly be better to publish the 

 answers to questions given in the Student's Corner, 

 not in the same, but in the following issue of the 

 publication. 



The magazine is well edited, and except for one or 

 two printer's errors (pp. 2 and 11) and the absence of 

 a reference to page 1.3 in the table of contents, the 

 publication is free from mistakes. 



Rhizobia in the Soil. 



In the Experiment Station Record, Vol. XXVI, 

 No. 9, reference is made to investigations by R. Greiw- 

 Smith, in New South Wales, on soil fertility. It is 

 stated that the most numerous nitrogen- fixing organism 

 in the soil is Rhizobium, which occurs to the extent of 

 3 to -i millions per gram, and that the number present 

 affords an indication of the comparative fertility of the 

 soil. The effect of cultivation is to increase greatly the 

 number of these organisms in a given soil. 



These facts regarding the nitrogen-fixing power of 

 Rhizobium require attention when consideration is 

 given to the similar effect of the Azotobacter organisms 

 — an effect which, it will be remembered, is increased 

 temporarily by the partial sterilization of the soil by 

 antiseptic substances like ether, toluene and carbon 

 bisulphide. 



— ^ 



Science Instruction in British Guiana. 



The Report of the Local Examinations and 

 Lectures Syndicate of the University of Cambridge on 

 science instruction in Queen's College, British Guiana, 

 receives attention in a Report from that Colony' on the 

 examinations of Queen's CollCj^e in July 1912. 



The part of the report dealing with science 

 subjects shows that in chemi.siry the work sent in was 

 good, though some weakness appeared in the matter 

 of illustrating answers by clear diagrams. The results 

 obtained in the practical examinations were also satis- 

 factory. In botany good answers were sent up, and 

 very good accounts were written of the specimens set 

 for description. 



On the whole, the science work is said to show 

 evidence of proper teaching from the beginning, and 

 the boys have reached a satisfactory standard. 



