﻿18 BULLETIN 1139, U. S. DEPARTMENT OF AGRICULTURE. 



1911 plat 13 was moist to a greater depth than plat A, but in all 



other years when a difference has existed it has favored plal A. 

 The margin of difference was greatest in 1912, 1915, and 1916. Plal 

 C or D generally, but not always, lias 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 moist ure. 

 Even the fallow plat has rarely been moist to a depth of G 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 onty 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- 



