It is now necessary that a detailed classification be undertaken in the various sections of the sugar belt. Ten factories now show a loss in the filter cake of less than one per cent, of the sucrose in the cane.
APPENDIX
Decrease in purity Crusher to syrup Increase in purity mixed juice to syrup Reduces the sugar ratio of mixed juice. Sucrose in mixed juice % Sucrose in sugarcane Reduced extraction (based on 1 2 . 5% fiber) Primary juice loss.
COMPARATIVE RESULTS FOR RECENT YEARS
Purity of first crusher Purity of mixed juice Purity of last roller juice Purity of syrup. Total for the North Coast between the Umgeni and Tugela Rivers Total for Natal south of the Tugela (excluding Zululand).
GENERAL REPORT ON WEATHER CONDITIONS FOR THE YEAR 1940
For the total of the 35 rainfall stations reporting to us, the average for the year is 44.80 inches, which is 3.88 percent. July was, as usual, the coolest month of the year with an average temperature of 62.8°, or 1.2° above normal for the month. However, for the sixth consecutive year there was no night frost; the lowest value of the grass thermometer was 38° on July 6.
The average grass thermometer reading for the year was 57.5°, which is the highest recorded here, the annual normal being 55.2°. The mean maximum solar radiation thermometer (vacuum bulb) reading for the year was.
A PROGRESS REPORT OF THE FILTRATION COMMITTEE ON THE WORKING OF THE OLIVER FILTER, S94I OFF-SEASON
FILTRATION COMMITTEE PROGRESS REPORT ON OLIVER FILTER WORK, S94I OFF-SEASON. This report has already briefly mentioned the maintenance and upkeep aspect of the Oliver filter. With the Oliver filter, cake washing was direct, but with the old system, intensive dilution was required.
Further investigation into the operation of the Oliver filters was necessary and should be undertaken. He still considers the recovery of sucrose due to the installation of the Oliver filter a moot point.
NATAL SUGAR HILL RESULTS
EXAMINED IN THE LIGHT OF NOEL DEERR FORMULÆ
Tables I and II show the annual weighted average of the results of these thirteen factories. Tables V I I and VIII provide a cross analysis of the effect of 1° purity change on the virtual molasses coefficient. A reasonable interpretation of the results would be: —. i) The proof that changes in the variations of fiber and purity cause a change in the corresponding coefficient of unit loss. ii).
The finite sum of the variations from the mean was taken in each case over 169 pairs of associated variables, giving a gross correlation across 169 items. S T E I N explained that there was no time factor in these calculations when the t a t a of the same year was used.
THE MOBREY JUICE LEVEL CONTROL
The motorized valve is placed in the fluid supply line on the delivery side of the fluid pump. In operation, the float rises or falls with the liquid level in the pre-evaporator. When the fluid level drops, the float allows the valve to open, releasing oil pressure against the piston.
It was mentioned in the paper that a centrifugal pump was used to deliver the juice to the evaporator, but would it not be possible, if necessary, to have an elevated tank for the duty. Macbeth that it would be much more satisfying to have an elevated tank for the juice.
SOME OBSERVATIONS ON BAGASSE BOILING
After cooling, the weight of the contents was determined and the extract was polarized, using a 400 mm. This he attributed to weaker circulation in the Hawaiian method due to the reduction of the extraction water in relation to the bagasse. However, circulation is also greatly increased by boiling, and while the contents of the digester in the Queensland method never actually boil, in ours, as in the Khainovsky method, vigorous boiling takes place during the extraction period, thus freeing circulation of the liquid through the bagasse, and better extraction of the sucrose therein.
The above results therefore indicate the necessity of keeping the bagasse below the surface of the liquid and of ensuring that a state of ebullition is maintained. DU TOIT said that despite the paper's modest title, it was very interesting.
ORGANIC MANURES, COMPOSTS AND ARTIFICIAL FERTILIZERS
Despite the above negative criticisms, it is not intended to discourage composting. But the plain truth is that tillage destroys organic matter – not the growth of a crop. Humus is added to the soil as a by-product of growing cane and costs nothing to the grower.
Numerous root hairs trap soil particles and protect the soil from erosion. The loss of organic m a t e r came from, de-composition, i.e., slow burning of the cane manure in the pile.
NOTES ON THE PRESENT SUGARCANE VARIETY POSITION IN SOUTH AFRICA, 1941
Tons of cane per acre Sucrose per cent, cane Tons of sucrose per acre Per cent, of Co.281 Purity of juice. Following this is the percentage superiority of Co.281 over Uba in the yield of sucrose per acre at each successive cutting. It is this trait of cold resistance that makes Co.281 of particular value in Louisiana as a windrow cane.
Co.281 has so far proved highly resistant to sugarcane diseases now present in this country. Co.290 shows relatively little difference, and since it is most important that this variety should be cut.
LIST OF SUGARCANE VARIETIES IN THE COLLECTION, AND SEEDLINGS RAISED LOCALLY, AT THE EXPERIMENT STATION, MOUNT EDGECOMBE, AND OF VARIETIES INTRODUCED
INTO THE QUARANTINE GLASSHOUSE IN DURBAN
Further propagation was also carried out on a selected number of Indian seedlings of the cross Co.421 x Co. He was particularly interested in Co.331 and N.Co.67 and asked Mr. Dodds when these rods will be available to planters. Booth said he had already applied for the release of Co.331, but did not yet expect its release.
It was found that Co.290 did not do well in the South Coast hills, and the red rot which attacked this variety caused much trouble in the factories. In Co.301 they spread to the neighboring node, while in Co.290 the entire stem was affected.
BUD SPORTS OF SUGARCANE IN NATAL
The shape of the leaf, the habit and other characteristics can also change. Of the newer varieties, the one in which the most bud variation was found is Co.281. Other specimens were found in which the stripe was accompanied by changes in other characteristics of the variety.
A few years ago a stand of this variety was observed by the writer in which most of the plant was normal, but a few canes had drooping instead of erect leaves. Mutations thus involve changes in the color of the stem, habit of the leaf and other organs, and vigor of growth.
SEVENTH PROGRESS REPORT ON EXPERIMENTS AT UMFOLOZl
Total sucrose value per acre £5.71 per ton ..£23 Gain over Uba for this crop. GARLAND said that, in his experience, red rot appeared after Co.301 settled, and that he did not see how the sucrose of such cane could be improved by leaving it in the field for a few months. There were cases, however, when the number of dead canes was considerable, and under those conditions he doubted whether the sucrose per acre would improve, and it might be better to cut down such badly damaged canes as soon as possible.
Co.301 and Co.281 grew well together and did not adversely affect each other, and Co.281 prevented Co.301 from inhabiting. GARLAND suggested that the Experiment Station conduct some determinations of sucrose from a large field of Co.301 introduced cane.
INSECTS AND SUGARCANE
Coccids : Pseudococcus sacchari, Ckll., the sugarcane whitefly, is the most commonly found of these insects and is in fact probably the commonest insect on sugarcane in Natal. Nomadacris septemfasciata, Serv., the red locust, has hitherto been the most serious pest of sugarcane in Natal. Noctuidas : Sesamia calamistis, Hmpsn., the larva of which is a common borer in maize, sorghum, reeds, and a number of the larger grasses, is quite often found boring in sugar-cane.
Cirphis leucostricha, Hmpsn., the sugarcane worm, sometimes causes noticeable damage, especially to fresh cane in cut and felled fields. Outbreaks occur suddenly and the leaves can be so severely damaged that cane growth is adversely affected.
ESTIMATION OF THE AVAILABILITY OF PHOSPHORIC ACID, POTASH AND NITROGEN, IN SOILS BY A
NEW RAPID TECHNIQUE
From the table above, it can be concluded that when the pH value of the extract remains above 1.7, the extraction of available phosphoric acid is not complete. In this way a full contact of the alcohol with the contents is made, a most important stage in the test. Preparation of Standards.—The turbid solutions developed above are either compared with standard color charts, as in the Spurway method, or, as is more usual, superimposed on sets of lines of varying intensity to be observed when a set is made of lines. Invisible.
Comparison with other methods.—A number of soils were analyzed by the present method and two other known methods—the 1 per cent. citric ammonium chloride in 1 liter of water, then 2 ml. Phosphoric acid was determined colorimetrically on the citric acid extracts, using the author's technique.1 Potash was determined by the well-known sodium cobalt-nitrite method as standardized by Milne,9 with a modified procedure recommended by the author in 1934.2 The following is the results:—. filter cake, which is responsible for the unusually high potash content:—. Here again a rough agreement of results is obtained.
NOTES ON SOME FERTILITY INVESTIGATIONS
Many researchers have shown that phosphate fertilizer moves little in the soil, although there is evidence to the contrary. Note.—The above experiments are illustrative of the many experiments which have been made on the principal types of soil found on the property. The response to potash is significant at the B level in the plant crop and at the A and B levels in the ratoon crop.
A nitrogen trial appears to be necessary to determine the soil nitrogen content corresponding to optimum nitrogen use. He did not agree that the new canes, which produce a higher yield, necessarily take more plant food from the soil.
INSTRUCTIONS TO AUTHORS
