Escarificação e gessagem na descompactação do solo sob sistema plantio direto
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2017-02-21
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Universidade Federal de Goiás
Resumo
In areas under no-tillage system in Brazil’s Cerrado, compaction is becoming
increasingly frequent. It is noticeable because there are changes in soil physical properties
and in the root system as well as reduction in crop yields. The practices of scarification and
gypsum application are alternatives to mitigate compaction. In this sense, the objective of
this work was to evaluate the effects and length of scarification and gypsum application on
soil physical and chemical properties and on soybean yield under a no-tillage system
deployed 15 years ago. The study was divided into two steps. The first step consisted of the
diagnosis of soil compaction in an area of 315 ha divided into a 63-point sampling grid,
where each point represented five hectares in Joviânia, GO. In this area, moisture samples
were collected and a penetrometer was used at each point of the mesh, in the 0.0-0.20 m
and 0.20-0.40 m layers, in three periods: 1) prior to the scarification; 2) at 60 days after soil
scarification; and 3) at 390 days after scarification. Based on the results found in the first
step, one of the points of this area was selected to perform the second step of the work,
which consisted in setting up 24 plots, divided into six randomized blocks, composed of
four treatments: (C) = Control, (S) = Scarification, (G) = Gypsum application, (G+S) =
Gypsum application and scarification. The following properties were determined: soil
fertility (MOS, pH, H+Al, P, K, Ca and Mg), gravimetric moisture and physical indicators
in four soil layers, in addition to soybean yield. The data were submitted to analysis of
variance and when they were significant, Dunnet’s test was applied for comparison of
treatments at the level of probability of 5% of error (p<0.05). These results show that
scarification offered short-lasting benefits, because although there was a reduction in
resistance to penetration at 60 days after scarification, these values already showed a
significant increase in resistance to penetration at 390 days after scarification. Scarification
affected macroporosity and total porosity positively in the 0-0,10 m layer. Macroporosity is
a physical indicator of great influence in determining soybean yield under a no-tillage
system. The use of agricultural gypsum resulted in increased root volume and deeper root
systems.
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BARROS, L. R. Escarificação e gessagem na descompactação do solo sob sistema plantio direto. 2017. 62 f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Goiás, Goiânia, 2017.