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Cuiabá, Brazil

Cabral C.E.A.,FAMEV UFMT | Bonfim-Silva E.M.,ICAT UFMT | Bonelli E.A.,FAMEV UFMT | da Silva T.J.A.,ICAT UFMT | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012

The primary macronutrients have an important role in the forage fertilization, depending on their contribution to the production cost. This paper aimed to evaluate the effects of soil compaction on the concentration of primary macronutrients present in diagnostic leaves of Piatã and Mombaça grasses. The experiment was conducted in a greenhouse with a randomized statistical design, consisting of eight treatments and three replications in 2 × 4, factorial scheme, with two grases (Piatã grass and Mombaça) and four soil densities (1.0, 1.2, 1.4 and 1.6 Mg m-3). Two harvest of shoots were made, the first 42 days after the plant thinning, and the second 46 days after the first cutting. In the first growing period, the soil compaction interfere with the absorption of nitrogen and phosphorus, while in the second growing period there is a limitation in the absorption of nitrogen and potassium. Nitrogen is the primary macronutrient most limited by soil compaction.

Almeida C.O.S.,SIG | Amorim R.S.S.,DSER UFMT | Eltz F.L.F.,Brazilian National Council for Scientific and Technological Development | Couto E.G.,DSER UFMT | Jordani S.A.,Engineering Florestal da UFMT
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012

The rainfall erosivity constitutes an indispensable factor for prediction of soil losses by water erosion. In this way, the present study was carried out with the objectives to model the relationship among the erosivity index (EI30) monthly values, obtained from rainfall chart data with the precipitation and monthly rainfall coefficient for four municipal districts (Canarana, São José of Rio Claro, Poxoréo and Vera) of Mato Grosso State; to determine the erosivity factor (R) obtained from rainfall data for the four municipalities, as well as its return period and its occurrence probability; and to study the EI30 annual, seasonal and monthly distribution in these four municipalities. The potential relationship between the rainfall erosivity index and the rainfall coefficient make possible to evaluate the monthly and annual rainfall erosivity with good reliability (ERM ≤ 7%) for the municipalities of Canarana, Vera and São José of Rio Claro. However, for Poxoréo this good reliability is verified only for the annual erosivity. In the four municipalities the spring and summer seasons correspond to the period of larger erosivity, being responsible, except for Poxoréo, for 94% or more of the annual total erosivity.

Almeida C.O.S.,SIG | Amorim R.S.S.,DSER UFMT | Couto E.G.,DSER UFMT | Eltz F.L.F.,Federal University of Santa Maria | Borges L.E.C.,Graduanda em Engineering Florestal da UFMT
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2011

The objectives of this study were: (a) to determine the erosivity factor (R) for the city of Cuiabá, as well as its return period and probability of occurrence, (b) to study the annual distribution, seasonal and monthly index erosivity (EI30), (c) to define the period of return for the indices of annual erosivity and maximum most erosive monthly values, and (d) to correlate the EI30 monthly average with rainfall coefficient and monthly precipitation. A set of 889 erosive individual rains was studied in the period 1972 to 1975, 1977 to 1985 and 1995 to 1999, which were digitized and subsequently analyzed to obtain the EI30. The R factor for the Cuiabá city was 8.810 MJ mm ha-1 h-1 year-1, classified as high, with probability of 42.92%, being matched or exceeded at least once every 2.33 years. The period from October to April concentrated 87% of total annual erosivity, indicating that it is the period of greatest erosion probability. The potential model showed a better fit between the monthly EI30 with the rainfall coefficient.

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