8 
Colorado Agricultural Experiment Station 
good crops without irrigation, will not form seed satisfactorily. Hence 
it is difficult to draw conclusions. But there is ample evidence to show, 
that how, when , and where moisture is supplied has something to do 
with the question as well as the amount of water. 
Plate No. 2, is a view of a dry spot in a field of alfalfa planted 
in rows where irrigation has been withheld for two years to test seed 
production. The soil is a deep sandy loam, sixteen feet to the water 
table, and the alfalfa in this field grew rank with no apparent need of 
irrigation except in some dry spots. Here it seemed 1 possible for one 
to find the proper amount of moisture required to form seed, for some¬ 
where between the dried up center of this spot and the rank growing 
portion of the field there should have been a point that had the pro- 
No. 3.—An alfalfa nursery, each row a different strain, irrigation withheld for over a 
year; in the forground, plants showing need of moisture, distant ends of the rows not need¬ 
ing moisture owing to the capillary moisture in the subsoil; water being applied to the dry 
portion in every other row to test results of light surface irrigations. 
per moisture to set seed. Such was not the case as there was practically 
no difference in the seed yield. The whole field failed to set seed 
satisfactorily. 
A test hole with a soil auger proved that the cause of the dry spots 
was due to a gravel stratum eight feet below the surface which cut 
off capillary moisture. The rest of the field had twelve feet of moist 
soil. 
Plate No. 3, is a view of one of the nursery plats at Rocky Ford 
which has been held without irrigation for over a year. The lower 
