﻿WATER UTILIZATION BY SPRING WHEAT. 17 



fleeted in the yield. All available water has been removed from 

 all foot sections of soil in all years under study. 



The soil at Scottsbluff is sandy in character. It is easily penetrated 

 by water in the upper depths, but evidently becomes increasingly 

 difficult of penetration in the lower depths. Plat B has never had 

 available water present below a depth of 4 feet, and plat A only 

 once. The maximum depth of penetration of plat C or D has been 

 6 feet, and this depth has been reached but once. On this soil all 

 available water has been removed from all plats each year. Plats 

 A and B have exhibited only minor differences in the extent to 

 which they have utilized the storage capacity of the soil. Plat C 

 or D has been superior to the others in water stored and in yield. 

 The soil is evidently porous enough to allow root development suffi- 

 cient to remove all moisture penetrating into it under ordinary con- 

 ditions. 



The soil at North Platte is probably the most uniform of any at 

 these stations on the Plains. It is open and porous and offers a 

 maximum opportunity for penetration of water and roots. The 

 precipitation at this station has been high enough at different times 

 to wet the soil thoroughly to a depth greater than 6 feet. Determi^ 

 nations of soil moisture to a~ depth of 15 feet have been made at 

 this station, but spring wheat has shown no evidence of feeding to 

 a depth greater than 6 feet. The station record comprises about 

 an equal number of good and poor years. The fact that roots will 

 not penetrate a dry layer of soil to obtain water in moist lower 

 depths is illustrated by plat A in 1908 and by plat B in 1908, 1909, 

 1911, 1917, and 1919. These two plats exhibit some differences in their 

 moisture relations in individual years, but on an average they show 

 about the same water storage and water utilization. Plat C or D 

 has stored much more moisture than plats A and B. In all years 

 except 1914 it has carried available moisture to a depth of 6 feet, 

 and there is evidence that on several occasions water has penetrated 

 beyond the sixth foot. This water has been lost to the wheat crop, 

 as the roots of wheat do not penetrate the seventh foot section, even 

 in this favorable soil. The season of 1915 at North Platte was one 

 of the wettest on record at any station. All three of the plats con- 

 tained as much moisture in the first foot at harvest as they had at 

 any time during the growing season, and all foot sections of soil 

 on all plats had available water at harvest. The use of water in the 

 fifth and sixth foot sections of soil has been usual on plat C or D, 

 but only on one occasion has all of the available water been used 

 from these units. Plat C or D in 1911 shows the result of severe 

 climatic conditions in limiting the depth of feeding. In that year 

 the weather was so hot and dry and the demands of the crop for 

 moisture so excessive that the crop died before it was able to extend 

 its roots to the available water in the fourth, fifth, and sixth foot 

 sections. 



Under natural conditions and under some conditions of cultivation 

 there is considerable run-off from the soil at Akron. After water 

 penetrates the surface the character of the soil does not definitely 

 limit further penetration or development of the roots. Plat A has 

 shown on an average a deeper water penetration than plat B. In 



