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nitrogen applied in the usual manner. With
the best fertilizer treatment, the yields at the
14 sites ranged from 1.44 to 8.44 ton/ha,
with an average of 5.13 ton/ha. Rainfall during
1969-70 was quite adequate, with only
one location reporting severe damage due to
drought.
Although the analyses of the data obtained
in the other three types of experiments have
not been completed, a few observations may
be made: Maximum grain yields obtained in
variety-fertilizer-density studies under irrigation
at Corrientes and Ascasubi were 9.42 and
11.00 ton/ha, respectively. Deep chiseling apparently
had no effect on yields at any level
of fertilization. The best weed control treatment
was a combination of herbicides and
cultivations.
PRODUCTION
RESEARCH
IN MEXICO
Production factors influencing the yield and
nutrient uptake by different varieties of wheat
and triticale are being studied at the Northwest
Agricultural Research Center near Cd.
Obregon. These studies are cooperative venture~
of the Graduate College at Chapingo;
the Mexican National Agricultural Research
Institute; Dr. S. K. Ries, Michigan State University;
and Drs. Lewis H. Stolzy and S. D.
Van Gundy of the University of California at
Riverside. The fertilization of maize on Andosols
in Western Mexico is also under study.
except maximum yield which was only 4.5
ton/ha. The straw-to-grain ratio of CIANO was
1.43, without nitrogen fertilization, increasing to
a maximum of 2.05 at the 150 kg/ha rate of
fertilization. The straw-to-grain ratio of INIA
varied only from 1.64 to 1.87, as the rate of
fertilization increased from 0 to 400 kg/ha.
Other findings:
Average volume weight of grain of the two
varieties increased from 83.1 kg/hi without
applied nitrogen, to a maximum of 84.7 kg/hi
with 100 kg/ha of nitrogen. These weights
then gradually declined to a minimum of 82.4
kg/hi at the 350 kg/ha rate.
Average grain size increased from 39 mgm,
without applied nitrogen, to a maximum of 46
mgm with the application of 100 or 150 kg/ha
of nitrogen. Grain size then decreased to 43
mgm at the 350 kg/ha rate.
The number of spikelets per head increased
rapidly from 8.3 without applied nitrogen, to
13.1 with the 50 kg/ha rate; then climbed very
slowly to a maximum of 14.3 with the addition
of 250 kg of nitrogen per hectare.
The number of heads per square meter
increased logarithmically from 170, without
applied nitrogen, to a maximum of 470 at the
400 kg/ha rate.
Plant height at maturity was increased from
67 em, without applied nitrogen, to a maximum
of 113 em with 200 kg/ha of nitrogen.
The effect of nitrogen fertilization on the
baking quality of grain from INIA and CIANO
was very similar. The average relationships
between two parameters of quality -protein
content of the flour and loaf volume- and
rate of nitrogen fertilization are shown in Fig. 1.
Fig. 1. The relationships between two baking
quality parameters: protein percentage of the
wheat-flour and loaf volume and the rate of
nitrogen fertilization. Values are averages for the
Inia and Ciano varieties.
14
~
~ 13
;:
o
~ 12
900
Influence of Nitrogen Fertilization on Wheat
The influence of nitrogen fertilization on
wheat development and nutrient uptake was investigated
in a 1968-69 experiment involving
9 levels of applied nitrogen (0 to 400 kg/hal
and two varieties, INIA and CIANO. Grain
yields of INIA were increased in a logarithmic
manner from 0.9 ton/ha, without applied nitrogen,
to a maximum of 5.5 ton/ha with the
addition of 250 kg of nitrogen per hectare. The
response of CIANO to fertilization was similar,
J
'0
& II
l!
I 10
o
50
100
200
300
Amount of applied nl,rooen (kQ/ha)
400
800 u
• E
~
'0 >
700 '0
oJ
~
u
118