PREPARING SEED BEFORE SOWING. 



199 



in cases of prolonged drouth, in the several inches of 

 soil through which the ascending sprout has passed, 

 there will be found sufficient moisture for the 

 requirement. 



Many of these difficulties are overcome by a 

 thorough working of soils intended for beets. The 

 ambient temperature has a great influence on the 

 amount of moisture a soil retains ; while the actual tem- 

 perature beneath the surface is lower than in the air, 

 the difference is not as great as might be imagined. 

 However, experiments have been made in this direc- 

 tion and we can conclude that during, twenty-four 

 hours at 73.5 degrees F., the surface will have lost one- 

 fourth of its total moisture; after the second day, the 

 drying process will have extended to a depth of one- 

 tenth of an inch. Consequently, if seed be placed in 

 the ground at a depth of one to two inches, depending 

 upon the texture of the soil, during an unusual dry 

 spell, it would not penetrate to the strata where is 

 lodged the seed during the first ten days after sowing. 

 Briem's experiments on moisture of soils are 

 important. He used two kinds of seed, one dried in 

 the air and the other steeped in water; his results were 

 as follows: 



From these experiments it is concluded that if the 

 soil contains 22 per cent, of water, germination is not 

 possible; from 19 to 20 per cent., very slowly; from 7 to 

 17 per cent, of moisture, the soil appears to be in the 

 best condition. Below 5 per cent., germination is 

 impossible, unless the seed has beeri previously pre- 



