And college, pusa, for 1914-15. i3 



II. Education. 

 No students have been admitted during the past year. 



III. Meteorology. 



In addition to the usual records for the Meteorological 

 Department, records of (a) soil temperatures, {b) drainage, 

 and (c) pressure by means of a barograph have been main- 

 tained. 



IV. Soil Problems. 



Soil temperatures. The temperature of the soil is well 

 known to have an important influence on the soil, chemi- 

 cally and physically, but perhaps more especially on its 

 biological activity, both with respect to the higher plant 

 and lower organism. Moreover, since plant growth is 

 principally confined to the upper two or three feet of soil, 

 it is the temperature, and the temperature change, occur- 

 ring in this stratum which is of importance. Several re- 

 cords of soil temperature have been maintained by the 

 Meteorological and Survey Departments, but these have 

 related rather to the temperature change of considerable 

 depths than to that of the uppermost soil. For these 

 reasons it was decided in 1910 to maintain such a record 

 at Pusa. The soil being a bad conductor of heat, it is to 

 be expected that the chief diurnal temperature changes will 

 occur within the first few inches. It was then evident that 

 for a record of soil temperature to be of service, it must 

 relate to planes near to the soil surface. The nature of the 

 soil-surface had also to be considered. Commonly this is 

 rough, including lumps of earth varying from one to several 

 inches in diameter with open spaces between them. How 

 would such an irregular surface affect a thermometrical 

 instrument ? A further primary question was what effect 

 would a growing crop have on soil-temperature changes ? 

 It was originally desired to ascertain the temperature 

 changes for exposed soil («) with a plain surface and (b) 

 with a rough one, as well as for land bearing crops, but 

 preliminary work showed that the diurnal variation in the 

 first 3" of soil was so great that an irregularity of 1" caused 



