Answer to the fertilization sulfurated
in exploratory fringes
Source:
Fernando Martínez and Graciela Cordone
The UEEA INTA Casilda
has obtained excellent answer to the sulfurated fertilization of the cultivations of the
region, especially in those of summery cycle. One has worked looking for alternative of
fertilization with sulfur that they don't modify the usual handling that he/she carries
out the producing of the Center-south of the Pcia substantially. of Santa Faith and of the
Southeast of that of Córdoba. This is a region of continuous agricultural use, with
predominance of the cultivated surface with soya and, in some areas, with erosion
problems. Usually, the producing siembra the corn in the best lots, and it dedicates those
more degraded to sorghum granífero or soya of first. The fertilization of the corn with
N+P is a practice that is frequently carried out. For this regional approach, he/she
intended to the producer to add a fertilizer source sulfurated to the usual treatment that
he applies. The objective of this work was to explore the answer from the corn to the
attaché of sulfur in the great cultivation, in different atmospheres of the region, and
with the technology of the producer, to evaluate its result about the yield of the
cultivation and its economic viability.
Materials and
Methods
7 atmospheres of good
productivity were selected, located on the floor series in Peyrano, Hansen, Chabás and
Baldissera, without erosion. In the qualification of an atmosphere such aspects are
included as the state of degradation of the floor, the technology of floor handling and
cultivation, sequence of cultivations, level of previous yields, etc.
They settled fringes
matched up with two fertilization treatments:
Technology of current
use (TUA): MAP or DAP (23 to 36 kg/ha of P2O5) + 100 to 150 kg/ha of granulated Urea;
2) New technological
alternative (NAT): Idem 1) + 10.5 to 14 kg/ha of S-SO4 = + 12 to 26 kg/ha of N.
The size of the
fringes was of 25 x 300 meters. The sources of used S were ammonium sulfo-nitrate (SNA)
and sulfate of granulated ammonium (INC). These products S and N contain; the
concentration of nutritious of the SNA is of 14% of S and 26% of N, and that of INC is of
24% of S and 21% of N. This means that the effect on the yield will be atribuído to the S
and the N additional attaché together with the S.
The hybrid ones used
they were Dekalb 696 (half cycle) and Dekalb 757 (complete cycle). For both hybrid ones
and in all the lots, 78.000 semillas/ha was sowed. The suitable places as 1, 5, 6 and 7
were implanted in direct siembra; the lots 2, 3 and 4 were laboreados with chisel and
escardillo. The control of overgrowths was carried out with residual herbicides in all the
cases. The siembra and the crop were carried out with the machinery of the producer, and
the yield was determined weighing that harvested in each fringe with scales of 4 plates.
The P was applied
laterally to the siembra line in all the fringes. The urea was incorporate to the floor in
4ta to 6ta leaf of the cultivation in both treatments. In the town Chabás, the producer
didn't apply the dose of urea because it considered that the state of the cultivation was
excellent in that moment, anyway the obtained result is presented. In all the cases, the
sulfurated source was applied to the siembra, incorporate laterally, alone or in mixture
with the P to facilitate the handling of the producer. Therefore, in the treatment with S
the additional dose of N was available to the siembra.
Results and
Discussion
The yield average of
the TUA in the 7 rehearsed atmospheres was 8.993 kg/ha (+ / - 814), superior value to the
yield average of the region. According to the data of the Address of Economy Agricultural
Agrarian-estimates (SAGPyA), the yield average of corn for the campaign 1998/99, of the
Homemade Departments, San Lorenzo, Constitution, Iriondo and Belgrano of Santa Faith; and
Union and Marcos Juárez from Córdoba, was 6.762 kg/ha. The comparison of the two values
average confirms that this work was carried out in atmospheres of productivity media/alta.
The NAT had a yield
average of 10.160 (+/-139) kg/ha. it is observed that the standard deviation is smaller
for the treatments with attaché of S that for those only fertilized with P+N. Possibly,
when improving the atmosphere through a more complete fertilization, the yield of the
different places and hybrid it becomes more uniform.
The obtained results
showed an increment of yield average of 1167 kg/ha for the NAT with the attaché of a
combined source of S and N. it is observed that in the atmospheres of Italian Colony,
where the yields of the TUA were very high, the answer for the attaché of S was of scarce
magnitude; while in Sanford, where the yield of the TUA was the lowest, the answer to S it
was the highest. Considering that the 2 places of Italian Colony could be of "non
answer", the increment average of the 5 towns "with answer" it was of 1.536
(+ / - 748) kg/ha.
When comparing the
contributed nutrients and required, it is observed that in most of the cases it was
applied between 20 and 30% of the requirement of N, with ends of 6,45 and 43%; and
approximately, between 35 and 50% of the required S when the source of S. was applied
therefore, the production level that is reached in the considered lots continues being
made to expense of the mineralización of the organic matter of the floor. On the other
hand, assuming that the contained nutrients in the grain are those that leave the system
and that the contents in the stubble are recycled in the floor, the level of nutrients
neither added compensates the quantity exported with the grains for the 3 considered
nutrients. The calculated reinstatement level of the exported nutrients reached values
average of 57% for N and 45% for P, while with the proposed dose of S he/she recovered 82%
I average of the quantity exported in the grain.
If the difference is
compared among the calculated requirement of nutritious of both alternatives to the yield
increase and the dose of applied S, it arises that this it would only have been used in an
average of 28%, with range from 8 to 60%. however, the additional requirement of N is
similar or it overcomes to the added additional dose of this nutrient. This can be an
indicator of a bigger efficiency of use of the N in presence of S, and also that the level
of N would have been insufficient for the achievement of more yields, limiting the use of
the added S.
Also, the economic
result of the rehearsed fertilization alternatives allowed to see that the additional
entrance taken place by the attaché of a source of sulfurated fertilizer overcame to the
alternative of the producer in 6 cases, while the net result was negative in only 1 case.
Conclusions
In 6 of the 7
evaluated situations it was feasible to increase the yields of corn through adding a dose
of S combined with N to the usual alternative of fertilization used by the producer.
In those 6 situations,
the additional entrance overcame at the additional cost of applying the new fertilization
alternative.
The added doses of N,
P and S only compensated an average of 57%, 45% and 82%, respectively, of the export of
the same ones in the grain. This demonstrates that those production levels are reaching to
expense of the decrease of the stock of nutritious of the floor.
According to the
calculations of requirements of nutritious, the dose of applied S would have been used in
low proportion. This suggests that the levels of N and P should be increased to take
advantage of the answer to the S through a balanced fertilization.
When a source of
sulfurated fertilizer, the productive yield was added it was more uniform for the
different atmospheres and for the 2 hybrid used.