828 Journal of the Department of Agriculture. 



5. Retentiveness. — Any water remaining" above the soil column at 

 tlie conclusion of the above described percolation experiment is 

 removed and the covered cylinder allowed to drain for twenty-four 

 hours. By weighing before and after, and by taking into account the 

 moisture contents of tlie air-dried soil, one calculates the percentage 

 water retained by 100 grns. of oven-dry soil. 



Neither the figures for permeability nor for retentiveness are to 

 be regarded in any way as accurate. They have been found, however, 

 to furnish very useful comparative data. 



{Succeeding articles of this series iciJJ deal iritii the Agriculture 

 and Soils of the Elliot District.) 



Sterilization of Grain. 



An article in the August, 1919, issue of the '' Monthly Bulletin " 

 of the California Department of Agriculture tells of difficulties 

 encountered by the American Government in guarding against the 

 accidental introduction of new plant diseases in connection with 

 emergency importations of cereals during the war. Maize from 

 Asiatic countries, it is stated, was permitted to enter after steriliza- 

 tion by heat. A temperature of 212° F. was applied for a net period 

 of three minutes and found to destroy disease spores and improve 

 the quality of the maize. "This treatment," the article continues, 

 " applied to barley, oats, or rye, does not interfere with the value of 

 the cereal for stock feed. It does, however, kill the germ of the seed, 

 making it useless for planting. Experiments completed and in i)ro- 

 gress show that the value of wheat for flour and bread making is 

 also seriously impaired. Heating wheat with dry heat to 140° F. 

 destroys all insects, but injury to the quality of the flour for baking 

 begins at 160° F., and is completely ruinous to good break-making at 

 212° F. The loaf decreases in volume as the heat is increased, wliile 

 at the same time the colour becomes more yellow and the texture 

 more brittle. The effect of live steam is even more pronounced. Live 

 steam at 212° F. applied for three minutes reduces the loaf volume 

 one-half, and otherwise renders it unfit. No application of heat which 

 does not seriously injure the flour for bread-making will destroy the 

 fungous spores, and, conversely, all applications of heat which destroy 

 the spores completely ruin the flour for bj-ead-making." 



