18 BULLETIN 1139, IT. S. DEPARTMENT OF AGRICULTURE. 
1911 plat B was moist to a greater depth than plat A, but in all 
other years when a difference has existed it has favored plat A. 
The margin of difference was greatest in 1912, 1915, and 1916. Plat 
C or D generally, but not always, has been moist to a greater depth 
than the continuously cropped plats. On all the plats the depth 
of feeding has generally been limited by the depth to which moisture 
has been present. However, even when moisture has been present 
in the fifth and sixth feet it has not been entirely used up except in 
extremely dry years. 
At Garden City the character, distribution, and quantity of pre- 
cipitation have had the effect of limiting the penetration of moisture. 
Even the fallow plat has rarely been moist to a depth of 6 feet. In 
plats A and B no available water has been present below the fourth 
foot. The difference between plats A and B in moisture stored dis- 
tinctly favors plat B. The storage of moisture in plat C or D has 
been consistently greater than in plats A and B. All the available 
moisture was removed from all plats except plat C or D in 1920. 
The greater storage of water on plat C or D is reflected in a con- 
sistently higher yield. 
At Dalhart there has been a slight difference between plats A and 
B, favoring plat B both in water storage and in yield. Neither 
plat has fully utilized the storage capacity of the soil at any time, 
and on both plats all of the available moisture in the soil has been 
removed each year by harvest time. Plat C or D has been filled 
with available moisture to a depth of 6 feet each year. Crop require- 
ments for water have been so heavy that each year the wheat has 
suffered for water before harvest. In spite of this all the available 
moisture in the fifth foot section has been removed only twice in 
four years, while the moisture present in the sixth foot has never 
been entirely removed. In three of the four years presented no water 
was removed from the sixth foot by the crop. 
The soil at Amarillo is not easily penetrated by water. In spite of 
the high precipitation at this station, water has never reached a depth 
greater than 4 feet in plat A or 5 feet in plat B. At this station 
there has frequently been a difference between the two in water 
storage, and in every case where a difference has existed it has been 
in favor of plat B. The soil in plat C or D did not become wet to 
a depth of 6 feet until 1915. The crop has never been able to remove 
all of the water added to the sixth foot of soil that year. In nearly 
every year plat C or D has stored water to a depth greater than 
plats A and B, but the difference in most cases has not been large. 
The soil at Amarillo is an example of one that holds very little avail- 
able moisture in the lower depths. It is in many cases very difficult 
to tell whether or not available moisture is present. 
The soil at Tucumcari is sandy in the upper foot sections, and 
moisture is readily taken into it. In the lower depths the soil is of 
a clay texture, and water penetrates it with difficulty. When wet it 
holds only a small quantity of available moisture. The wheat crop 
was able to use all the water to a depth of 6 feet in one year (1915). 
In the year 1914 the highest yields recorded at this station were ob- 
tained on all three plats. In that year no water was used from 
below the fourth foot on any plat, though available water was pres- 
ent in the fifth foot of plat C or D. There has been very little dif- 
