Resposta do cafeeiro arábica em produção à adubação fosfatada

• Ano de defesa: 2012
• Autor(a) principal: Saraiva, Edson Santana
• Orientador(a): Martinez, Hermínia Emília Prieto
• Banca de defesa: Guimarães, Paulo Tácito Gontijo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Teores foliares; Fósforo; Coffea arábica; Extratores
• Palavras-chave em Inglês: Foliar contents; Phosphorus; Coffea arabica; Extractors
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4568

In recent years appeared a group of researchers that indicate high doses of phosphorus (P) aiming to improve the coffee productivity, and thus avoid the biennial cycle of production this crop. According this statement, become necessary to evaluate in different conditions of this crop the response of phosphorus doses when applied in the soil. This study aimed to evaluate the influence of application rates and sources of P2O5 on the coffee yield, content of labile P in the soil, as well as the levels of P and other nutrients in the leaves, flowers, bark and coffee grains. For this, two experiments were conducted in field conditions. The first assay was carried out in the period 2007 to 2010 at the experimental field of the UFV in an area with the Oeiras cultivar aged of 4 years old, with spacing of 2 x 1 m. Doses of 33, 83, 166, 333 and 666 kg of P2O5 per ha, applied as mono-potassium phosphate, represented the main factor studied. The treatments were applied in four randomized blocks being arranged five homogeneous plants per plot. Phosphorus fertilization was applied in two times during the rainy season. In the treatments with lower doses of P2O5, the potassium (K) was added as KCl, so as to provide the same amount of K for all treatments. The quantity of 400 kg ha-1 of nitrogen (N) per ha was provided as urea applied on three times as well as micronutrients through foliar spray. The second assay was conducted from October 2009 to April 2011 in a crop of coffee located in the country of Porto Firme, MG. In that experiment it was used the cultivar Paraíso aged two years old, spaced 3.0 x 0.6 m. The experimental design used was of randomized blocks with three replications in a factorial scheme (4 x 2) + 1 comprising four sources of phosphate as following: reactive natural phosphate (RNP), simple superphosphate (SS), triple superphosphate (TS), and potassium dihydrogen phosphate (PDP) in two doses (80 and 320 kg/ha of P2O5). The additional treatment consisted of the absence of phosphorus. Each plot was consisted of two rows of 5m, being the two central plants of each line adopted as useful area. Phosphorus fertlization was performed only once on the soil, on the canopy projection of the plants. In the treatments with sources of P2O5 and without K as well as treatment with lower doses of P2O5 (PDP), the K was supplemented with KCl, so as to provide the same amount of K in all treatments. Thus, in the first parcel of fertilization, all treatments received 209 kg ha-1 of K2O. In addition, were made two additional fertilization with 95.5 kg ha-1 of K2O per ha in all treatments, using KCl. The quantity 400 kg ha-1 of nitrogen (N) divided in three portions was provided as urea and applied on three times as well as micronutrients through foliar spray. It was evaluated the yield, plant height (PH), production of plagiotropic branches (PPB), number of internodes per plagiotropic branch (NIPB), content of macro and micro nutrients in the leaves, bark and fruits, as well as soil chemical characteristics at 0-20 and 20-40 of depth. There was no significant effect of the different doses of P tested in relation to the variables PH, PPB, EIPB in both assays. Soil analyses indicated significant increase in concentrations of P in the soil extracted by both the extractors: Mehlinch-1 and exchange resin of cations and anions. In experiment 1, it was observed that the productivity in the first year showed no significant difference between the P doses, but in the last two seasons it was observed significant difference for this parameter, reaching 90% of maximum yield with the dose of 113 kg ha-1 of P2O5. However, 90% of the maximum economic efficiency was obtained with doses of 322.7 kg ha-1 of P2O5 in 2009 and with 341.66 kg ha-1 of P2O5 in 2010. In experiment 2, there was no effeect interaction between sources and doses of phosphorus on the productivity in the two evaluated production seasons. Comparing the treatments that received P with the untreated plots, it was verified that this last treatment had significantly lower productivity. The sources PDP, TS and SS showed yields statistically similar, but these yields were statistically superior that observed with RNP. These results show the importance of fertilization with soluble phosphorus to achieve adequately the nutritional requirements of the coffee plants and get desired yields. Higher P levels in soil were obtained by applying greater doses of P2O5 and the average values extracted by the cations and anions exchange resin were higher than those obtaine by the Mehlich 1 extractor.