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Teixeira P.E.G.,Institute Ciencias Agrarias UFRA | Fernandes A.R.,Institute Ciencias Agrarias UFRA | Galvao J.R.,Institute Ciencias Agrarias UFRA | Silva V.F.A.,Campi Paraupebas UFRA | Melo N.C.,São Paulo State University
Revista Caatinga | Year: 2014

The establishment of pastures in Amazonia is made to replace the woody vegetation by slash and burn process in chemically poor and low available phosphorus soils. The recovery of degraded areas is required and can contribute to reducing deforestation in the region. This study aimed to evaluate the effects of doses of Arad and NPK combinations in the management of maize in soil with low productive capacity. The experiment was conducted in Santo Antonio do Taua, Pará State, in an area with degraded pasture, in a dystrophic Oxisol. The experimental design was a randomized block split plot design with four replications. The plots were four phosphate: 50, 100, 200 and 300 kg ha-1 of P2O5 as Arad and sub-plots combination with NPK, NK, NK liming, and control (no match). We evaluated the growth characteristics and productivity of corn. Doses of Arad influenced the plant height and number of kernels per row cob. The application of Arad combined with NPK increased grain yield.

de Oliveira F.J.,Programa de Pos graduacao em Agronomia UFRA | Farias P.R.S.,Institute Ciencias Agrarias UFRA | da Silva A.G.,Campus de Paragominas UFRA | Rodrigues K.C.V.,Programa de Pos graduacao em Agronomia UFRA | de Araujo F.C.B.,Programa de Pos graduacao em Agronomia UFRA
Revista Ciencia Agronomica | Year: 2016

This study aimed to evaluate the spatial distribution of citrus leprosis in two orchards in the Eastern state of Pará/ Eastern Amazon citrus region. Two evaluations were performed at monthly intervals between December, 2011 and November, 2012 checking plants with characteristic symptoms of citrus leprosis by recording 1 for presence and 0 for absence. To analyze the disease spatial distribution in the plots, geostatistics was used for semivariogram modeling, and elaboration of kriging maps. The model that better adjusted to the disease spatial distribution was the spherical, the one with the highest coefficient of determination with variations ranging from 18 to 19 meters in area A and 9 to 30 m in area B. The Spatial Dependence Index (SDI) was moderate for all area A evaluations with interval ranging from 0.25 to 0.75, while in area B, except for the months of December 2011, June and September 2012 with a moderate SDI, all the others showed a weak SDI with values below 0.25. Geostatistical analysis has shown itself to be an ideal tool to evaluate Citrus leprosis virus (CiLV) spatial distribution.

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