1752 MANXTRES AXD MANURING 



obtained whether iron or ahmiiniuni filings were employed confirmed the 

 deduction that the citrophosphate group was intimatelj^ connected with 

 the iron or akrminium. 



It has been shown previously that all the secondary products contained 

 in basic slag are dissolved by 2 per cent citric acid to an extent which va- 

 ries with the nature of the slag. The writer found that by using a solution 

 of saccharose to remove the lime the solubilit}^ of the phosphoric acid was 

 increased, like\\ise that of all the other constituents. The secondary com- 

 pounds of slag can therefore be classified into two groups: i) those which 

 hinder the solubility of phosphoric acid (lime, silica, silicates and manga- 

 nese), and 2,) those vv^hich assist it (sulphates, iron and ahmiinium). Amongst 

 the latter group the sulphates maj^ be neglected as thej^ are only present 

 in minute quantities but the presence of the two metals not only counter- 

 balances the effects of the first group of substances, but actually exerts 

 a definite solvent action on the phosphoric acid. 



Conclusions. — Basic slag like the mineral phosphates contains phos- 

 phoric acid in the form of tricalcic phosphate. Their relatively high degree 

 of solubility in citric acid as compared with mineral phosphates is attri- 

 buted to the presence of iron and aluminium in the slag. The difference 

 in the solubilit}^ of slags may be due to any or all of the following three 

 causes : i) a variation in content of iron and aluminium ; 2) the percentage 

 of soluble phosphoric acid present ; 3) the presence of other bodies which 

 exert a retarding effect on solution. 



1264 - Nitrate of Soda and Ammonium Sulphate on Sugar Cane in Java. — 



Geerts J. INI., in Medcdedingcn van hcl Pyocfstaiion voor dc J ava-Siiikcrindustrie, Vol. VI, 



No. 9, pp. 223-305. Soerabaia, 1916. 

 Experiments have been carried out in Java during the last few years 

 to compare the manurial value of sodium nitrate and ammonium sulphate 

 for sugar cane (i). These have shown that ammonium sulphate gives the 

 best results on sandy soils and sodium nitrate on heaw land. 



Where nitrate was used no deleterious action on the structure of the 

 soil was observed, nor is there any likelihood of this occuring in Java as 

 the nitrate is not applied ever>^ 3^ear and further the land is irrigated. 

 Owing to its extreme solubility nitrate is speciall}- adapted to regions of 

 low rainfall and gave the best results when applied in two or three dressings. 

 It did not retard the ripening of the crop. 



In Java ammonium svilphate is the more suitable manure in the major- 

 ity of cases, and, unless supplies fail or the price of nitrate falls, it will 

 continue to be the more popular fertiliser. 



1265 - Manurial Trials in Java. ^ — de Jong a. W. K., in Mededeelingen van het Agricul- 

 tur-Chcmisch Labor at or mm. No. XII, pp. 1-27. Buiterzorg, 191 6. 



A report is given of manurial trials in Java during the year 191 5. 

 With manioc, sodium nitrate had an excellent effect especially when 



(i) See R. June iqifi, No. 647. 



