42 REPORT OF THE AGRICULTURAL RESEARCH 



to another series at Pusa, determinations of the amount of 

 water present in the soil having been made monthly 

 throughout the dry season 1907-08. The latter season 

 was unusually dry at Pusa, so that the soil here was desic- 

 cated to a greater extent than generally happens. After 

 reviewing the data of the two seasons, it was found that 

 too much weight had been placed on the effect of atmo- 

 spheric humidity in the first method of calculating the rate 

 of loss, and that the latter can be accounted for by the effect 

 of temperature in addition to the special characteristics 

 of the soil. The calculated values agree very closely with 

 those found. The data for the Cawnpore soil show it to 

 possess a marked difference from the Pusa soil in the 

 amount of water present at the conclusion of the monsoon, 

 for this quantity is only about 161b per cubic foot, where- 

 as the Pusa soil contains about 25tb. Moreover, during 

 the season it lost water only to a depth of three feet as 

 against seven feet at Pusa. 



The soil at Bhatowlia was selected, because it is a 

 coarse sand for more than 10 feet. This soil only con- 

 tained about 5tb water per cubic foot at the conclusion 

 of the monsoon. 



8. Water Required by Plants. — An investigation of the 

 amount of water transpired by plants, was commenced in 

 1907 by the pot-culture method. In the following cold 

 weather one field experiment was made in conjunction with 

 the latter, and it was found to yield data in close corre- 

 spondence with those obtained from the pot-cultures. Dur- 

 ing the last year the pot-culture investigation was extend- 

 ed so as to include (a) a larger variety of crops and (b) a 

 number of essentially different soils, and in conjunction 

 with this a series of field experiments with various crops 

 was carried out. The data which have been obtained have 

 been put together in a memoir which will shortly be 

 published under the title of " The Water Requirements 

 of Crops in India." 



9. Available Plant Food in Soils. — This investigation 

 continues to occupy a part of the time of the section, but 



