Water Used by Plants 31 



of water, although it was unquestionably less than it would have 

 been had the plants not been affected by the blight. As it was, 

 the plants received an average of 24.6 inches, which is three times 

 the amount of rainfall during their season of growth. 



It should be said further, in regard to the amount of water 

 used this season, that the whole of the watering was from the 

 bottom, so that the surface of the ground was kept dry throughout 

 the time. In order to introduce the water at the bottom, a layer 

 of sand was first placed in each cylinder before the soil was filled 

 in, and then a column of 3 -inch drain tile was set up against one 

 side, reaching from the bottom to the top of the cylinders, and in 

 adding the water it was poured into these tiles. 



In the case of the cylinders of oats which were grown in 1894, 

 they were watered in the same manner, so that in these cases 

 nearly all of the water used did actually pass through the plants. 



The results with the oats are given below: 



No. 1 No. 2 No. 3 No. 4 



LBS. LBS. LBS. LBS. 



Amount of water used 282.8 280.2 283.3 285.6 



" dry matter produced .. .5232 .5165 .4198 .4663 



water per Ib. of dry 



matter 540.6 542.7 674.9 614.7 



Vl " dry matter per acre... 12,900 12,730 10,350 11,500 



IN. IN. IN. IN. 



Total water used, in inches 30.77 30.48 30.82 31.18 



If reference is made to the yields of 1891 and 1892, which have 

 been given on a preceding page, it will be seen that the yields for 

 1894 have been decidedly larger than they were in the former 

 cases, but so were the amounts of water used by the plants. The 

 mean of the three earlier trials gives a yield of 8,525 pounds of dry 

 matter per acre, using 19.345 inches of water to produce it; but 

 in these last cases the mean yield of dry matter was 11,870 pounds 

 per acre, and the water used to produce it was 31.08 inches. The 

 yields of 1894 average 1.39 times the earlier ones, and the amount 

 of water used in producing this greater yield was 1.06 times the 

 amount required for the smaller. 



