16 Nebraska Agricultural Exp. Station, Research Bui. 6. 
these water requirements were reduced 28.9 per cent, 17.1 per 
cent, and 8.1 per cent, respectively. However, the total water 
requirement per plant was increased by an application of manure 
to infertile, intermediate, and fertile soil respectively 106.7 
per cent, 42.6 per cent, and 28.7 per cent. From these figures 
it is apparent that increasing the fertility does not reduce but 
rather greatly increases the total amount of water necessary per 
plant. This is due to increased plant growth. The reduction in 
water requirement per pound of dry matter is due, not to some 
effect of a denser soil solution upon the need for a rapid transpira- 
tion rate, but rather, simply to a more thrifty and vigorous growth 
of the plant, resulting from a more favorable supply of food 
materials. It appears to be more a matter of nutrition than of 
transpiration. 
23. The average water requirement per pound of dry matter 
of two varieties of corn which had been grown for many years 
under the humid conditions of New York was approximately the 
same as the average for two varieties which have been grown 
continuously under the relatively dry conditions of western 
Nebraska. 
24. The extreme variation in the water requirement of 11 
different corns was 230 pounds and 296 pounds per pound of 
dry matter, which suggests that varieties may differ markedly 
in their water requirement. Most varieties, however, were rather 
uniform in this regard. 
25. Several corns with alleged special drouth resistance pos- 
sessed practically the same water requirements per pound of 
dry matter as the average for all 11 corns tested. 
26. The water requirement for milo was the same as the 
average for 11 corn varieties, while it was considerably higher 
for Black Amber sorghum. It appears that the drouth-resistant 
qualities of certain crops must lie elsewhere than in a low water 
requirement per pound of dry matter. 
27. Wild sunflowers possessed a water requirement per pound 
of dry matter approximately double that of corn, and a total 
water use somewhat greater than that of three corn plants. 
28. A study was made of the intake of soil solutes as 
measured in terms of ash content in the crop harvested. Data 
were obtained concerning the relation between transpiration and 
ash content as affected by (1) atmospheric humidity, (2) seasonal 
climatic differences, (3) soil fertility, (4) soil moisture, (5) kind 
of crop and variety, and (6) limitation of the amount of soil thru 
the size of the potometer. 
An increase in atmospheric humidity under greenhouse con- 
trol, which lowered the free water evaporation 47 per cent, re- 
