Pioneer Hybrid Maturity 
0 Pioneer hybrids recommended for the 
North Central section and the Southern half 
of Iowa are classified under three groups: 
(1) early maturing, (2) medium maturing, and 
(3) late maturing. These groupings are made 
to meet: first, climatic conditions; second, 
various soil types and conditions peculiar to 
the North Central section and the Southern 
half of Iowa; third, date of planting; and, 
fourth, personal demands of the farmers. 
NORTH CENTRAL IOWA 
O In North Central Iowa, the early maturing Pio¬ 
neer Hybrids 357 and 352 should be used for late 
plantings; for slow soils if planted around May 15th- 
25th; and for locations where the first freeze occurs 
unusually early in the fall. Under these conditions, 
with normal weather, the early maturing hybrids will 
ripen and produce good, sound corn. 
Under average North Central Iowa climate and 
average soil fertility, any hybrid in the medium ma¬ 
turing group. Pioneer Hybrids 322, 324, 335, 349, and 
315, will mature ahead of the average first freeze 
if planted by the middle of May. None of these 
hybrids should be planted too late on slow or poor 
soils. 
The late maturing group. Pioneer Hybrids 330, 314, 
311, and 311-A, is recommended for very rich or 
fast soils; for quite early planting on soils of average 
to high fertility; and for silage or fodder corn. None 
of these hybrids should be planted late on slow or 
poor soils. 
SOUTHERN HALF OF IOWA 
9 In the Southern half of Iowa, the early maturing 
group. Pioneer Hybrids 322, 324, 330, 314, 311, and 
311-A, should be used for late plantings; for slow 
soils if planted around May 15th-25th; and for loca¬ 
tions where early freezes are common. 
Under normal climate and average soil fertility in 
the Southern half of Iowa, the medium maturing 
group. Pioneer Hybrids 307, 317, 331, and 318A, will 
take full advantage of the entire growing season and 
mature properly before the average first freeze if 
planted by the middle of May. 
The late maturing group. Pioneer 313 and 332, is 
recommended for rich or fast soils; for early planting 
on soils of average to high fertility; and for silage 
or fodder com. 
The above recommendations are based on aver¬ 
age temperature and rainfall for the North Central 
section and the Southern half of Iowa. These two 
factors, in abnormal seasons, vary the maturity of 
corn considerably. 
REFER TO PAGE 9 FOR MAP OF IOWA SHOWING THE NORTH CENTRAL AND SOUTHERN SECTIONS 
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