86 REPORT OF THE AGRICULTURAL RESEARCH INSTITUTE 



bacterial enzymes afforded by the superficial layer of 

 altered material resulting from their first attack. This 

 argument was strengthened by the observation that in 

 nutrient solutions the fall in rate of evolution of carbon 

 dioxide is much less sudden than where solid particles are 

 concerned. The rate of formation of carbon dioxide is 

 materially affected by the size of particles supplied. 

 Partial sterilization of the soil sufficient to eliminate 

 protozoa does not remove this difference. 



Green Manuring. Owing to the difficulty of obtaining 

 even areas of land for field experiments on the farm, it 

 was arranged to take in a comparatively small area of one 

 acre adjoining the outside laboratory of this section; this 

 was divided into 24 plots of equal size and experiments in 

 triplicate laid out for the kharif and rabi crops of 1914-15; 

 the first was merely a crop of sanai (Crotalaria juncea) 

 over the whole area; this was applied as green manure, 

 variations in the method of application and their effect 

 upon the succeeding rabi crops, oats and tobacco, being 

 studied. As was expected, however, unevenness in this 

 area made it impossible to draw definite conclusions from 

 the experiments as a whole although certain deductions 

 could be made from individual cases; these will be dealt 

 with in the current report on green manuring. Some of 

 the more interesting conclusions were drawn from the use 

 of seeth made from sanai {Crotalaria juncea) the utiliza- 

 tion of which had been suggested owing to the difficulty in 

 obtaining indigo seeth consequent upon the reduction of area 

 under this crop. It was found that the seeth water used in 

 making the seeth was roughly equal in manurial value to 

 the seeth itself in the case of the rabi crop (oats), but that in 

 the residual effect on the succeeding kharif crop (maize) 

 the seeth, as was expected, proved greatly superior to the 

 seeth water. In the case of two areas under tobacco, one 

 with normal and the other with comparatively low moisture 

 content in the cold weather the effect of seeth as compared 

 with green manure (sanai) ploughed in, in the ordinary 

 way, was greater in the dry area. The differences produced 



