122 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



whilst diminishing the apparent amount of nitrification as 

 measured by the nitrate found in the soil, actually increased 

 the amount if it is assumed that the crop takes its nitrogen 

 entirely as nitrate. 



In connection with nitrification studies, further obser- 

 vations were made as to the formation of bacterio-toxins 

 in soils, and a paper on this subject was read at the fifth 

 session of the Indian Science Congress at Lahore. 



Nitrogen fixation, The First Assistant continued his 

 experiments upon the specific nature of various strains of 

 B. radicicola and upon apparent symbiotic fixation of nitro- 

 gen without nodule formation in the case of inoculation 

 with foreign strains. Clear evidence of activation of 

 growth by non-symbiotic nitrogen fixation I>oth by azoto- 

 bacter and nodule organisms was obtained. These obser- 

 vations will form the subject of a paper now in course of 

 preparation. 



Green-manuring. The field trials arranged in colla- 

 boration with the Imperial Agriculturist were continued 

 on the experimental area of the farm ; they are designed to 

 test the field value of the modified method of green-manur- 

 ing described in Bulletin 63, Agric.'Res. Inst., Pusa; the 

 increased returns obtained on- the rabi (winter) crop, 

 although considerable, are not a measure of the practical 

 value of this method which depends largely upon its sus- 

 tained and residual effect. This has been well illustrated 

 in the various crops on the experimental area of this Sec- 

 tion, which have given consistent increases of some 30—60 

 per cent, not only over the unmanured but over plots receiv- 

 ing adequate applications of such manures as nitrate of 

 soda and oilcake, over a period of three seasons including 

 the year of application. The effect on Java indigo in the 

 third year is especially marked. 



Phosphate requirements of soil bacteria. Further 

 work on this subject led to the following general conclu- 

 sions : — 



(1) Increase in available P 2 5 greatly increases the 

 general bacterial activity of a soil, and there- 



