Alfalfa Seed Yields 
31 
A close-up view of a dry spot. In the center of the spot conditions were too dry for seed 
production or hay production. Between the center of the spot and the edge, there was 
no zone of seed setting, altho, there was a zone of difference in the moisture content, 
varying quite uniformily from the driest of the center to the wettest of the outer edge. 
changed : 1. With the general practice of irrigation, the water table 
has risen on the old irrigated lands. 2. Soil nitrates have increased 
in the soils to a considerable extent. 
It is now well established that much of the soil in the Arkansas 
Valley is rather overcharged with nitrates. These nitrates are 
evidently developed in some soils and carried to others by irrigation 
waters. This fact has aroused a suspicion that an excess of nitrates 
may be partly responsible for decreased'alfalfa seed yields. In fact, 
there are strong evidences that this is the case. For the past two 
years, alfalfa on the experimental plats has failed to bloom normally. ' 
There was hardly any bloom at all. The soil in these plats is know 
to be strong in nitrates. Alfalfa, in its seed setting traits, seems to 
behave much as plants overfed with nitrates. This suggests that the 
physiological effect of different fertilizers be made a line of future 
investigation. 
SUMMARY 
I. There is a difference in the inherent seed setting tendency of 
different strains of alfalfa. The southern strains seem to be strongest 
