H. B. Hutchinson 



97 



A second factor which demanded consideration was the low soil 

 temperature prevailing at the time of these earlier applications, and 

 since other observations had shown the great differences in nitrogen 

 fixation which occur at various temperatures up to 30°, it was decided 

 to make the next application of sugar with a high prevailing soil tempera- 

 ture, that is, in early autumn. 



This change was fully justified by the yields of the 1910 crop, an 

 appreciable increase being shown by the plots which had been treated 

 with sugar and had received an application of phosphatic and potassic 

 manures. A second autumnal application was therefore made in 1910, 

 and the 1911 results were of a still more promising order. (Table I and 

 Fig. 1.) 



Table I. 



The Influence of Carbohydrates on the Fertility of Field Soils. 



Hoos Field Experiments: Crop Barley: Produce per acre. 



* Crop failed completely. 



Two interesting points arise from these results. In the first place, it 

 may be noted that although the total yields of plot 4. 0. are distinctly 

 increased as a result of treatment with sugar, this is due to a great 

 extent to the effect of the treatment on the yield of grain rather than 

 on that of the straw, the mean relative yields of the former being 155 

 per cent, as against 120 for the latter. 



Secondly, it is noteworthy that in both 1910 and 1911 the appHcation 

 of sugar to plot 6. I., which did not receive mineral manures, was quite 

 ineffective in bringing about any crop response. Experience has shown 



Journ. of Agric. Sci. ix 7 



