Alfalfa Sefd Production 
7 
, inherent forage producing tendency in alfalfa has much the same rela¬ 
tion to seed yields as an exceptionally favorable growing condition. 
Thus it is thought that the best types of alfalfa should be developed by 
systematic selection and breeding. Then, the seed for commercial seed¬ 
ing should be produced where the conditions of growth can be regulated 
to some extent, either by .natural conditions favoring the production 
of seed, or by artificial methods of controlling the growth of the forage. 
Moisture Requirements for Seed Production .—The amount of 
moisture in the soil best suited to seed yields has not been determined 
in unit terms of any kind. In fact the results of observations on this 
point are rather conflicting. 
No. 2.—A dry spot in an alfalfa field where irrigation was witheheld two seasons, to 
test seed production. The dry spot was caused by a gravel layer eight feet below the 
surface; balance of field growing rank with the subsoil moisture. 
It is usually conceded that a heavy, dashing rain when the alfalfa 
is in full bloom is injurious to the seed prospects, as the flowers that 
are out at the time usually fail to form seed. Yet there are numerous 
experiences which seem to indicate that a light irrigation when the 
field is just passing out of full bloom is often beneficial to the seed 
crop. Again it has been noted that alfalfa on ditch banks, where 
there is a continual supply of moisture, has some times set well with 
seed; while in fields that have plenty of subsoil moisture, growing 
