Irrigated Agricue,ture in the San Luis VaeeEy 
21 
early planting is that peas is a cold weather crop; that is, the plants 
grow and make their best development in the cool spring weather. 
When planted late they are blossoming and developing seed at the 
most heated period of the season. As a consequence there is a ten¬ 
dency with late planting to a heavy production of vines and a 
light production of seed. 
In order to plant early and properly it is necessary to plow in 
the fall or exceedingly early in the spring. The seed bed should 
be worked down until it is fairly compacted. The peas should be 
drilled in. The amount of seed per acre to give the best results 
will vary widely in different localities. On new lands, especially, 
more seed is required than on land that has grown peas for a num¬ 
ber of years. This is due partly to soil fertility and is partly a 
question of inoculation. On new lands the soil is not inoculated 
for peas. When peas has been grown on the land for several years 
there is plenty of inoculating material present so that a smaller 
amount of seed will produce a larger number of plants. 
Probably sixty pounds of seed peas per acre will be sufficient 
unless the crop is to be raised on new lands, where it may be ad¬ 
visable to plant as much as ninety pounds per acre. On many ol 
the richer old lands which have been growing peas for a number 
of years, as low as thirty-five pounds per acre is amply sufficient. 
Varieties .—^There is an exceedingly large number of varieties 
of field peas, but despite this only a comparatively few have received 
very wide distribution. The two varieties most widely grown are 
the so-called San Luis Valley Stock Pea or “Mexican,” and the 
White Marrow Fat, or Colorado White. The so-called Mexican 
pea is not a pure variety, but consists of a large number of mixed 
sorts, and for adverse conditions, is probably the best one to plant. 
Where conditions are good for pea growth, the White Marrow Fat 
will make heavier yields. 
Numerous other varieties have been tried, some of which give 
considerable promise, but there is a large opportunity for improve¬ 
ment by seed selection. Considerable work has been done by indi¬ 
vidual farmers and a little work by the Experiment Station. This 
has not yet resulted in many new sorts, but it has been carried far 
enough to show that there is possibility of heavy increases thru 
selection breeding. The** Warshauer-McClure Sheep Company of 
Antonio has been hand-selecting a variety. They have obtained a 
large white pea which matures at least two weeks earlier than the 
common peas. It does not make as heavy a vine growth, but pods 
very heavily. Farmers who have hand selected their peas claim that 
they have obtained heavy increases in yield over those not hand 
selected. The selection of high yielding individual plants to become 
