594 Summary of Agricultural Experiments, [oct., 



with the production of nitric and. sulphuric acids, and in order 

 that its action may not be harmful by rendering the soil sour these 

 acids must be neutralised as produced. This paper describes some 

 further experiments on the subject. It was pointed out that when 

 dilute solutions of ammonium salts are distilled, ammonia is given off, 

 and that consequently the ammonia given off in estimating the amount 

 of lime available as a base in basic slag might not be due to the basic 

 slag. By distillations of ammonium sulphate without basic slag 

 Mr. Hendrick found that ammonia was given off, but only in an 

 amount which, when stated as its equivalent in lime, would amount 

 to a very small percentage of the slag. He concludes that the results 

 in the former paper are not materially affected by the fact that 

 ammonia is volatilised when a dilute solution of ammonium sulphate 

 is boiled, but that these further experiments support the conclusion 

 that there is in basic slag a considerable proportion of lime capable of 

 acting as a base in the soil, and that a part of this lime is readily 

 liberated. Distillation with a solution of ammonium chloride provides, 

 however, a better method of determining the available base in slag 

 than distillation with ammonium sulphate. 



Finally, the glass of the vessels used for distillation in experiments 

 on ammonium salts may have a very appreciable influence, especially 

 if alkaline solutions have previously been boiled in the glass. 



Effect of Heavy Nitrogenous Manuring on the Quality of the Sugar 

 Beet (Osterr.-Ungar. Zeitschr. fur Ziickerindustrie und Landw., 6 Heft, 

 (1909). — The application of large quantities of nitrogenous manures alone, 

 e.g., nitrate of soda, sulphate of ammonia, and calcium nitrate, was 

 shown in these experiments to increase the weight of the leaves, both 

 fresh and dry, to a much greater extent than the weight of the roots. 

 The leaves being of small value compared with the roots, such manuring 

 will generally be unprofitable. The percentage sugar-content of the roots 

 was found to be lowered, and the quality suffered since the amount of' 

 nitrogenous compounds in the roots which are detrimental in the 

 manufacture of sugar was increased, together with the content of the 

 roots in non-sugar substances, as a result of the increased application 

 of nitrogenous manures. In addition, heavy nitrogenous manuring 

 alone was found to reduce the manurial capital of the soil, especially 

 phosphoric acid. 



Continuous Growing of Crops (Rothamsted Expt. Station, Annual 

 Report, 1910). — The season of 19 10 proved very unfavourable for the crops 

 at Rothamsted. The wheat, which has been grown on Broadbalk 

 Field since 1843, produced on the unmanured plot only 7*5 bushels per 

 acre ; only on three occasions during the 67 years has it been lower. 

 The yields all round were low, the highest being 28 bushels per acre 

 on the dunged plot. On the plot without manure, but fallowed in 

 alternate years, the yield was little more than 9 bushels, not much 

 better than on the unmanured plot with wheat every year, a result 

 which would be expected from the wet character of the winter. 



The yield of barley was also poor. The most noticeable feature 

 was the striking results produced by superphosphate, the crop on the 

 plots without phosphoric acid being very small. This prevails generally 

 in the experiments; phosphoric acid has its greatest effect in wet and 

 cold seasons. 



