8 
The Colorado Experiment Station 
trouble, as the salts remain in the soil after the water has^ evapo¬ 
rated. If proper drainage is provided, the salts, to a large ex¬ 
tent, will be carried off in the waters thru the subsoil and into the 
drainage. 
The nitre trouble is only one of the problems which confront 
the land owners; another and equally important one is seepage. 
Cheap and abundant irrigation water have led to over-irrigation. 
This, togeher with the natural seepage from canals and laterals 
has filled up the subsoil with water and brought the alkaline salts 
to the surface. In many instances the water table is within 4 feet 
of the surface, and on some of the lower land the water reaches 
the surface. Where these conditions exist, drainage is the only 
remedy. The occurrence of nitre in the soils of the Grand Valley 
and other sections of the State, has little or no relation to drain¬ 
age but is a distinct and separate problem. 
While the apple tree roots, in most cases, do not extend 
deeper than 4 or 5 feet, (practically all the feeding roots are con¬ 
fined to the upper 3 feet of soil), capillary action carries the water 
too close to the feeding roots and interferes with the proper drain¬ 
age and aeration of the soil in the feeding zone. Further, the 
high water table usually occurs during the growing season, and 
thus directly affects the growth of the trees. A high water table 
is less harmful during the winter months when the trees are dor¬ 
mant. 
The importance of good drainage and the use of cover crops 
in connection with orchard operations should be known by every 
fruit grower in the Valley. 
A CKNO WEED GHENT 
The author wishes to acknowledge the help of Professor R. 
A. McGinty for photographic work, and for aid in looking after 
the field work during one season; also to Dr. Headden and Pro¬ 
fessor Sackett for suggestions and aid in preparing this bulletin. 
