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CORN AND WHEAT
PRODUCTION RESEARCH
IN ARGENTINA
The National Institute of Agricultural Technology
of Argentina (INTA), the Ford Foundation,
and CIMMYT continued their cooperative
program to accelerate corn and wheat production
in Argentina. A field study of wheat
production was carried out in 1969 at locations
distributed throughout most of the wheat region,
from La Banda and Reconquista in the
north, to Balcarce and Bordenave in the south.
Experiments to measure the response of wheat
to several rates of nitrogen and phosphorus
were conducted at 32 locations. The yielding
abilities of six wheat varieties were compared
at three levels of fertilization at eight sites.
Fertilizer rate studies were conducted on
farmers' fields under natural rainfall conditions,
except for one irrigated trial at La
Banda. Recommended varieties and rates of
seeding (usually 90 kg/ha) were employed.
Weeds were controlled chemically in about 40
percent of the experiments and insecticides
were used to combat the green aphid at 25
percent of the sites. Information was obtained
at most locations on soil moisture conditions,
rainfall, soil characteristics, previous cropping
history, management practices, and the effects
of insects, diseases, birds, rodents, etc.
Data are available on the results obtained
in 27 of the rate studies. Moderate to severe
drought damage was observed at 14 locations.
Damage due to green aphids, weeds, frost, or
hail was reported in one or more of the trials.
Three experiments were lost due to a combination
of severe drought and green aphid
damage.
The yield of unfertilized wheat in the 24
harvested experiments ranged from 0.6 to 2.9
ton/ha with an average of 1.8 ton/ha. There
was a response to fertilization in 16 of the
experiments, with 12 experiments showing response
to nitrogen and 14 showing response
to phosphorus. Increases in yield due to fertilization
varied from 0.2 to 1.~, ton/ha with
an average of 0.7 ton/ha.
All of the variety-fertilizer studies were conducted
at experiment stations (two experiments
received one or more irrigations). Yields
ranged from 1.5 to 4.3 ton/ha. A response to
fertilization was observed at four locations.
Experimental wheat varieties showed greater
yields than commercial varieties in 6 of the
trials.
The corn production research program coordinated
by the staff at the Pergamino Experiment
Station in 1969-70 was considerably
broader in scope than that of the previous
year. Most of the experiments were located
near the Pergamino Station, but other trials
were conducted at experiment stations in
areas of Argentina where corn production is
important, or potentially so.
Four types of experiments were conducted:
Type I was a fertilizer rate study with
eight combinations of four levels of nitrogen
and two of phosphorus, pius two additional
treatments to measure the effect of a "popup"
fertilizer application (in contact with the
seed).
Type II consisted of three varieties, four
fertilizer treatments, and three population densities.
Type III compared deep chiseling of soil
versus no chiseling, at 4 levels of fertilization.
Type IV consisted of 12 treatments in
which herbicides and cultivations were compared
separately and in combinations.
The number of experiments of types I, II,
III and IV were 14, 12, 8, and 6, respectively.
Grain yields, without fertilization, in the 14
fertilizer rate studies varied from 0.85 to 6.41
ton/ha with an average of 3.95 ton/ha. There
was a positive response to nitrogen at nine of
the locations. The increases in yield from
the application of 50 kg of nitrogen per hectare
in the nine experiments varied from 0.20 to
2.35 ton/ha, with increases of more than one
ton per hectare at four sites. Within the 14 experiments,
the average increase in yield from
the application of 50 kg of nitrogen per hectare
was 0.62 ton/ha. At one location with a
heavy weed infestation, yields were reduced
by the application of nitrogen.
The addition of 50 kg of P 2 0 5 per hectare
as started fertilizer increased yields by 0.45
and 0.66 ton/ha at two locations. At these
locations, a "pop-up" application of 10 kg of
nitrogen plus 25 kg of P205 per hectare was
as effective as the starter application of 50
kg/ha of P 2 0 5 • At the 12 sites not responding
to phosphorus, the "pop-up" application
had about the same effect as 10 kg/ha of
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