ToL. VIII. No. 193. 



THE AGRICULTUEAL NEWS. 



31)1 



STUDENTS' CORNER. 



SEPTEMBER. 



Second Period. 

 Seasonal Notes. 



By tliis time the sugar-cane will have reached a stage at 

 which its growth will give indications of the soil conditions 

 beneath it. The first of these is always that which has rela- 

 tion to the supply of water, as plants are more quickly and 

 seriously affected by a lack of this than of any of the other 

 substances which they take in. If the weather has been 

 .-somewhat dry, a good opportunity will be afforded to take 

 note of the difference between canes wliicli have been mulched 

 either with a dust mulch or with vegetable matter (trash) 

 and those growing in soil which has not been mulched at all. 

 Why is it that water does not rise through a nuilch to any 

 great extent '! What effects on soils, beside that of assisting to 

 conserve water in them, are due to tlie presence of a vegetable 

 mulch ? Where some fields of cane have been green dressed 

 with leguminous plants, while others have had a dressing 

 which is Don-leguminous, note if there is any difference in 

 the appearance of the plants in the two cases. If there is, 

 to what may the difference be due ( 



Under the wet conditions of this time of the year, fungi 

 will be prone to increase, especially on those plants which are 

 most susceptible to their attacks, that is cultivated plants. 

 A consideration of tlie question why plants which are raised 

 in any quantity, and with a view to obtaining a product 

 which is superior to the forms of it found in nature, are 

 most likely to be damaged by pests should lead to some use- 

 ful conclusions. Itead the editorial in the present issue of 

 the AyricuJtuuil Xen's, and look up tlie references there 

 cited, as far as possible. Although it deals more particu- 

 larly with cotton blights, much that is said in it is of 

 general application. Itemember that the control of fungus and 

 bacterial pests (as well as of many insect pests) is far more 

 a matter of prevention than of remedies after the disease has 

 appeared to a .dangerous extent. This is important, for 

 there are generally several measures whicli will help greatly 

 in the matter of prevention, while there are only one or two 

 remedies (which are none the less inqjortant when disease 

 has been allowed to break out severely) that can be applied 

 econoniicall)', and even then, not always with perfect confi- 

 dence in their effectiveness. In relation to preventive 

 measures we may consider separately the soil and the plant. 

 With regard to the former, good cultural operations will 

 make it of less use in harbouring jjests until a host plant is 

 provided, and will produce a condition which will lead to the 

 growth in it of good, healthy plants that are well able to 

 resist disease : while rotation of crops will starve such pests 

 out. As far as the plant is concerned, it will be greatly 

 aided by the provision of good, healthy propagating material 

 (such as seeds and cuttings), which has been raised if po.ssible 

 from disease-resistant varieties. Care in this respect is 

 especially necessary if the material is being introduced from 

 another island, as the bringing of a pest to a (ilace where its 

 natural parasites are either absent or in partial abeyance is 

 ■bound, in the end, to lead to serious damage. 



Questions for Candidates. 



PEELIJIIX.iEY QUESTIONS. 



(1) What are the benefits to be derived by the soil 

 from (a) surface cultivation, (b) thorough cultivation? 

 When should these processes be performed i 



(2) AVhat is the function of Jlje root-hairs of plants, and 

 the conne.xion between them and the 'film-water ' of the soil % 



- (3) What are the chief .systems' of bones in the legs hi 

 a horse I , The metacarpus of draft horse.s has a carrying 

 strength that is more than 31 per cent, greater than that of 

 the same bone in carriage horses. Why is this ? 



INTERMEDIATE QUESTION.S. 



( 1 ) What is a fungus i Give a general account of the 

 characters and life-history of a fungus. 



(2) Give general information in regard to soil and 

 cultivation in the case of maize. 



(3) Briefly discu.ss the ett'ects of soil on climate, and of 

 climate on plants. 



Tlie Effect of Moisture on Stored Sugar. 



The following information regardincr the deteriora- 

 tion of sugars is given in Bulletin 9, Division of 

 Physiology and Plant Pathology, Hawaii : — 



In a bulletin published by the Division of Agriculture 

 and Chemistry about a year ago on the deterioration of 

 sugars on storage, an experiment was described w-hich was 

 undertaken ' to determine the percentage of water which it 

 is safe to leave in sugars '. Separajte portions of a sample of 

 moist sugar containing fermenting organisms were dried in 

 a vacuum so as to contain decreasing amounts of moisture 

 from rS6 to 0'29 per cent. 



The samples were polarized and put into tightly 

 stoppered bottles. At the end of one and two months they 

 were polarized again, and it was found that, in those samples 

 containing more than 1 per cent, of moisture, the polarizations 

 were lower than originally. 



These sanqiles have been recently polarized again after 

 standing twelve months, and the results further confirm the 

 original conclusion that raw sugars containing 1 per cent, 

 or more moisture are liable to deteriorate on storage. The 

 original table with the further polarizations added is given 

 below : — 



Polarization. 



Xotwithstanding tliat the bottles were closed with 

 rubber stoppers, the sugar was so hygroscopic that the 

 samples had nearly all increased slightly in moisture during 

 the year, which accounts for the lower iiolarizations of thoKe 

 containing less than 1 \>>it cent, of moisture. 



