Vol. XII. No. 297. 



THE AGRICULTURAL XEWS. 



301 



STUDENTS' CORNER. 



.SEl'TEiMBKR. 



Secoxb Period. 



Seasonal Notes. 



THE M1\IN<. UV KEIITILIZEKS. 



The student who has not had a great deal of practical 

 experience in the a[ii>lication of mineral manures will often 

 feel uncertain in regard to the mixing of the various forms. 

 It is possible, too, that mistakes in this respect are sometimes 

 made by those who might be expected to know better. 

 ■With a view to assisting the memory, the diagram given 

 below ha.^ been reproduced from a recent publication.* The 

 manures joined by a heavy black line should never be mixed 

 together; t'aose connected by a double line must only be 

 mixed immediately before use; and those joined by a thin 

 single line may be safely mixed together at any time. 



The student should endeavour to explain the reasons 

 for theec rules in regard to mixing. Thus nitrate of 

 soda must not be mixed with superphosphate because the 

 free sulphuric acid in the latter has a very great affinity for 

 soda and will set free the nitric acid in the form of poisonous 

 fumes (nitric anhydride N.^ O,), whereby the nitrogen is 

 lo<t. It would really have been safer to have connected 

 these two substances in the diagram by a black line rather 

 than by a double one, but the figure has been reproduced 

 without modification 



(.Questions, for instance, on structural botany can only be 

 properly answered with the aid of scale drawings. Similarly, 

 descriptions of experiments .should be supplemented by simple 

 illustrations. ^ 



With reference to answering questions on practical work 

 in general, the student should endeavour to assume the 

 mental attitude of the teacher, as it were. Little details 

 which give cause for worry at the first attempt at an 

 operation should be remarked upon. They may seem very 

 small and unimportant when the operator is familiar with his 

 task, but to the novice they frequently make all the difference 

 between success and failure. 



Questions for Candidates. 

 PEELniiNAr.Y Questions. 



(1) Discuss the following fruits in regard to their 

 value as food: banana, mango, pine-apple, tamarind, and papaw. 



Can you explain why most tropical fruits have a thick 

 skin! 



(2) Describe an arrangement for destroying the larvae 

 of the small moth borer of the sugar-cane without injury to 

 the natural enemies of this pest. 



Inteemedi.^te Questions. 



(1) Describe the effect of manganese on the growth of 

 pine-apples. 



(2) How v7ould you find the area of a triangular piece 

 of land? 



Final Questions. 



(1) Draw up an account sales form in connexion with 

 the shipment of citrate of lime. 



(2) Describe in a practical, but general manner, how 

 you would proceed to plant 100 acres in coco-nuts. 



Fn;. 24. 1, Sdperphosph.vte and Dissolved Guano; 

 2, Basic Slai;; 3, Barn Yai;d Manure, Guano, and 

 Dried Blood; 4, Kainit; 5, Nitrate ok Soda; 6, Potas- 

 sium Sulphate; 7, Sulph.^te of -Ammonia; 8, Lime, 

 Nitrolim, Ashes, Nitrate of Limk. 



Again, slag phosphate contains a strong alkali in the 

 form of caustic lime, and if sulphate of ammonia is mixed 

 with it, the ammonia is displaced by the lime and dissipated 

 into the air. Or, again, if superphosphate and bones or 

 slag are mixed, the soluble phosphate will take up some 

 base and become reverted, or reduced, phosphate. 



the AN.SWERINi: OF iHE-STIONS. 



The simple illustrations which are given occasionally in 

 the Students" Corner have for their object not only to present 

 information in a concise way but also to call the students' 

 attention to the fact that the diagrams actually do this. The 

 annual examinations conducted by this Department will 

 Boon engage special attention and in answering many types 

 of questions, diagrammatic representation is frequently of 

 the greatest assistance, both to the candidate and 

 to the examiner. Drawing should be included where 

 possible in answers to questions relating to practical work. 



*Que(nsland Agrieuliuial Jonrmd ['•t July 1913. 



POLLINATION AND CROSS-FERTILIZ- 

 ATION OF RICE. 



In view of the necessit}' of having information 

 concerning the extent of natural crossing for purposes 

 of ensuring a pure seed .supply, investigations in regard 

 to the natural fertilization of rice have been carried 

 out in Lower Bengal and the following are the main 

 conclusions arrived at: — 



1. That in Lower F>engal under favourable conditions 

 cross-fertilization may take place in rice to an extent which 

 may be provisionally estimated at about 4 per cent. 



2. That this cross-fertilization takes place wholly 

 through the agency of the wind and would seem to be 

 effective only between flowers of adjacent plants to a radius 

 of a few feet. 



3. That as regards certain characters at least, e.g., 

 grain colour, segregation along Mendelian lines appears to 

 take place. 



4. That ,so long as seed of a variety is kept free from 

 accidental mixture, there is no risk of contamination from 

 cross-fertilization, but that if seed gets mixed, cross- 

 fertilization will undoubtedly take place between adjacent 

 plants in a plot and to an extent suflicient in a few years' 

 time to reduce a variety to a number of splitting types. 

 Hence the imperative necessity of taking every precaution 

 to keep seed of varieties free from accidental mixtures. 



The paper from which these connclusions have been 

 taken appeared in tlie ^['rlnoirs of the Department of 

 Aoricidti'.re in India (June 1918). The author i.s 

 G. P. Hector, M.A., B. .So, Economic Botanist, Bengal. 



