« AnteriorContinuar »
Q. 10. Work out the cost of a day's labour of a horse, taking into account
food, attendance, and depreciation. Candidates generally showed an improvement in their knowledge of costs.
A small but good set of candidates, possessing a sound general knowledge of Horticulture, and able to express themselves clearly. The questions call for no detailed comment.
SECTION C.- ANIMAL HUSBANDRY. Numbers small, but the work in this section shows improvement; there was more definiteness in the answers, quantities were given and costs realised.
SECTION D.-CHEMISTRY OF PLANT AND SOIL.
A fair set of answers, marred, as in Section E, by the fact that the candidates had often begun to learn Agricultural Chemistry without any training in the pure science. Often an answer would read very correctly until some passage would reveal that the writer had got up the question without any real understanding of the subject, from sheer inability to grasp the meaning of a chemical change. Q. 1. Lime is often said to sink in the soil. What is meant by “lime
in this connection, and how far is the statement justified? What
solvent actions are at work removing “lime” from the soil ? Few candidates knew that a layer of chalk or lime applied to the surface of grass land will be found, after a time, a little distance below the ground level, owing to the action of earthworms. This process is not seen in arable land, and is quite distinct from the removal of calcium carbonate by solution. Teachers might impress upon their students that rain water cannot become charged with carbon dioxide by passing through the air (law of partial pressures); it is only when in contact with the soil gases that the soil water acquires any considerable proportion of carbon dioxide. Q. 4. Have the roots of a plant any solvent action upon the inorganic
materials of the soil ? Describe experiments to illustrate your
answer and discuss the evidence that they afford. Nearly all the candidates ascribed considerable solvent power to the acid root sap, a theory, which is generally discredited nowadays. Few candidates mentioned that the roots do excrete carbon dioxide, and that this is quite capable of etching the marble slab in Sach's well-known experiment. One or two candidates said the acid excreted was acid potassium phosphate, but did not explain why a plant should excrete two of the constituents it is always trying to obtain from the soil. Czapek's observation of the excretion of acid potassium phosphate only referred to germinating seedlings. Q. 6. How is humus formed in the soil, and what does it contain ? Under
what circumstances will the so-called "sweet or "sour” humus
be produced ? Many candidates regarded nitrification as part of the action of making “sweet” humus, denitrification as the corresponding action bringing about sour” humus Q. 3. What are the factors regulating the temperature of the soil ?
Discuss their relative importance and illustrate your reasons by
practical examples. It was not sufficiently recognised that the greater or less evaporation of water is the chief factor in regulating the temperature of the soil.
SECTION E.--CHEMISTRY OF MANURES AND CROPS.
The failures were mostly from one class which had not been taught to the necessary standard. Q. 2. What essential difference in composition is there between the liquid
and the solid portions of an animal's excrement, and which is the more valuable as manure? Which of the two is more subject to
loss and how ? Few candidates appreciated the fact that since the solid excrement represents those portions of the animals' food which have resisted digestion, it will continue to resist the putrefactive bacteria in the soil and decay but slowly. Q. 3. What plant food does the soil obtain from air and rain ? Under
what conditions would this supply be increased or diminished ? Give the amounts received in pounds per acre where this is
possible. Quantities, which are all important in this connection, were rarely given. It is not correct to say that after a thunderstorm there is an increase in the nitrates in the rain water. Q. 7. Name crops specially benefited by nitrate of soda, and others on
which it has generally but little effect. How would its value be affected by very early or very late applications ? Is it generally wise to use nitrate of soda alone ? If not, what else
should be applied to the crop ? Candidates generally were correct in connecting the value of nitrate of soda for wheat with the growth of the latter during the winter, and the small value of the sanie manure for turnips with their growth under conditions rendering nitrification active ; but as regards late applications of nitrate they did not lay enough stress on the fact that a cereal crop almost ceases to take nitrates from the soil after the time of its flowering.
SECTION F.-CHEMISTRY OF ANIMALS AND Foods. The few answers call for no comment.
Details of Successes and Failures in each Stage of each Subject at the Evening Science
XXIII, Physiography, except Stago
1., Section 1.
770 2,027 2,644 5,441 4,917 11,606 6,648 23,171 (9,777 10,429 8,724 28,930
* Passes. † Honours in Subjects X. and XI. and in Subjects Xp. and XIp. are combined.