Vol. XV. No. 371. 



THE AGRICULTURAL NEWS 



L'-'7 



In regard to manurial experiments with sulphate 

 of ammonia and nitrate of soda, tlie figures show, as usual, 

 that these forms of nitrogen produce important increases of 

 something like 6 tons per acre. 



The mean annual yields during the four crops 1910-13, 

 presumably due to applications of 60R). of nitrogen in each 

 of the manurial applications, were: sulphate of ammonia, 

 94 tons of cane increase per acre; nitrate of lime, 6 7; 

 nitrolim, 5'8; nitrate of soda, iil These increases are from 

 three to six times the probable error, which is indicative of 

 their significance. 



The report then goes on to describe the effect of manuring 

 on the soil. It is of interest to note that the North-east field 

 does not contain any lime in the form of calcium carbonate, 

 and the calcium oxide dissolved by the citric acid used in 

 determining the available constituents must have been derived 

 from calcium phosphate, calcium silicate, or the traces of 

 calcium sulphate in the soil. 



In regard to the significance of physical analyses in 

 which the relative amounts of different particles are determin- 

 ed, the report shows an interesting application of 'probable error' 

 principles. It is stated that it is usual to reduce the probable 

 errors within reasonable limits, say, one-half of I per cent, for 

 each constituent other than clay, on which being determined 

 by difference the cumulative errors fall. For this purpo.se 

 to obtain a reliable sample of the soil of an absolutely fiat, 

 apparently iiniform 5-acre field, the sample must be drawn 

 from at least nine different plots scattered over the field, and 

 preferably from sixteen. From each plot the sample must 

 be drawn, as the samples were in the investigation described 

 in the report, from at least five places, and a sample 

 representative of the soil of the plot prepared by mixing 

 them together. 



In connexion with the importance of nitrogen and 

 humus in the soil, it is stated that the nitrogen of the humus 

 portion of the organic matter does not influence the yield: 

 it appears to be inert The yield of the plots is clearly 

 shown to be due to the proportions of available nitrogen 

 present therein, or rather during the active growth of the 

 crop. It was not possible to trace any relationship in the 

 yields of the plots to their relative contents of either 

 so-called available calcium oxide, potassium oxide or 

 phosphoric anhydride; but the long-continued field trials 

 in British Guiana have shown that soils containing 

 more than •005 per cent, of either potassium oxide 

 or phosphoric anhydride soluble in 1 per cent, citric acid 

 solution do not respond to manuring with these substances, 

 so that the results of the present year are consistent with 

 experience. It is thought, however, that this may not apply 

 to soils in places like Barbados, where the rainfall is less, 

 and the soil lighter in texture. 



During the year it became possible for the first time 

 to compare the sugar content of a considerable number of 

 hybrid varieties of cane with that of their parent cane. The 

 figures given appear to indicate increased variation and vigour 

 in the progeny, often accompanied by improved sugar contents. 

 An interesting piece of work described in the report has 

 reference to an examination of new seedlings of the Bourbon 

 .strain. It has been found that the tendency is for varieties 

 derived from the Bourbon to be relatively low in sucrose, 

 yielding juice having a low (quotient of purity and a high one 

 of non-sugars. Few only of the Bourbon derivatives are 

 characterized by a high or even a medium sugar content. 



With reference to the difi'erent varieties under cultivation 

 in British Guiana, the figures indicate that a large increase 

 occurred in the case of D. 625. The Bourbon cane is rapidly 

 going out of cultivation. 



THE OIL OF THE GROUND NUT. 



In a recent publication issued by the Egyptian 

 Ministiy of Agriculture, the Director General deals 

 ver}' fully with the subject of ground nuts. The follow- 

 ing information in regard to the commercial uses of 

 ground-nut oil is of particular interest, since this side 

 of the subject is not usually discussed at any length ia 

 an agricultural treatment of this crop: — 



The freshness of the nuts used in oil extraction i& 

 indicated by the colour of the oil which results. After 

 keeping the nuts for some time, a colouring matter, which is 

 present in the nut, diffuses itself into the oil cells and 

 renders the oil dark in colour instead of pale straw colour. 

 M. Fieury, in a work on the subject referred to by M. Adams, 

 says that by long exposure to sunlight the oil bleaches com- 

 pletely. Some varieties of ground nuts give an oil of deeper 

 colour than others; those from La Plata, Congo, and Mozam- 

 bique are said to be the palest; those from Spain and Senegal 

 slightly darker; while tho.se from Gambia and Sierra Leone, 

 as well as from India, yield the darkest coloured oil. No 

 comparisons seem to be recorded in this matter with regard 

 to Egyptian groundnut oil. 



M. Fieury mentions that on exposure to the air for 

 some months the oil absorbs a certain amount of oxygen, 

 and becomes slightly resinous. This absorption is acceler- 

 ated by the addition of heat. 



Ground-nut oil contains a little more margarine than 

 olive oil, yet the fluidity of both is the same. It begins to 

 form a quantity of margarine at 8°; at 6° it congeals comr 

 pletely, and at 3° it becomes a solid mass which does not 

 acquire greater consistency The oils from some varieties 

 congeal more rapidly than others. 



As a lubricant, ground-nut oil is slightly inferior to olive 

 oil, but as a luminant it is said to be superior. 



Ground-nut oil of the first expression is often a strong 

 competitor with olive oil as food, and is frequently used 

 for mixing with the latter oil. The most important use, 

 however, is for the manufacture of oleomargarine butter, 

 into which enters about .50 per cent, of milk combined with 

 from 20 to 30 per cent, of oil from Cayor Rufisque 

 (Senegal) nuts, which possess the special flavour required. 



The soaps made from ground-nut oil are excellent, and 

 are largely employed in washing silk and wool. The oil of 

 the third expression is that which is used in the manufacture 

 of soap; those of the two cold expressions being used almost 

 entirely as comestibles. A small quantity of oil is said to 

 have been used for soap making in Egypt at the factory of 

 Arbib, near Zagazig, but this has recently ceased to work 

 (nide Mr. Cartwright). 



The cake is employed both as a cattle food and as. 

 a fertilizer, but the cleaned and decorticated cake is only 

 used for the first named purpo.se. Ground nuts from Southern 

 India are, by reason of their dark colour, less in demand than 

 those from other localities, for which reason they are not 

 skinned before expressing their oil, and the rough cake which 

 is produced from them is employed as manure. The analyses 

 made by M. Fieury, from cake resulting from Rufi.sque nuts,, 

 showed about 8 per cent, of nitrogen, and about \h per cent 

 of phosphoric acid. As a manure, the cake is considered as of 

 great value. 



It is unfortunately not possible at the present time to- 

 give any special analyses of Egyptian ground nuts. 



It may, however, be accepted that the Egyptian product 

 could be used in the same manner as the Gambian or second- 

 quality Senegal qualities. 



