Parcelamento do fósforo na cultura do algodão irrigado em neossolo quartzarênico

• Ano de defesa: 2009
• Autor(a) principal: Aquino, Leonardo Angelo de
• Orientador(a): Berger, Paulo Geraldo
• Banca de defesa: Vieira, Rogério Faria , Rocha, Valterley Soares
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Gossypium hirsutum var. latifolium Hutch; Irrigação; Absorção de nutrientes
• Palavras-chave em Inglês: Gossypium hirsutum var. latifolium Hutch; Irrigation; Nutrient absorption
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA
• Link de acesso: http://locus.ufv.br/handle/123456789/1119

In the soils of cotton cultivation in Brazil, there is predominance in the fraction mineral clay with high capacity to fix the phosphorus in occluded phosphorus forms. Adequate techniques of phosphates fertilizers application are essential for the attainment of satisfactory yields. The objective was to evaluate the parceled application of the fertilizer phosphate in cotton, in comparison to the traditional application in sowing, on the absorption of P, the content of nutrients in the leaf index and the productivity. Three experiments were carried out in a random delineation, with three replicates. The experiments were conducted in soil of arenaceous texture, classified as Quartzanic Neossoil. The cultivar used was the Opal Delta. In the first experiment, treatments had consisted of two doses of P2O5 (50 and 120 kg ha-1) x four ways of parceling application PS, P1, P2 and P3 (100/0; 75/25; 50/50; 25/75 correspondents to the percentage of the dose of P2O5 applied in sowing and to the 35 days after the emergence (DAE), respectively) x two systems of culture (irrigated and dry land) and two additional treatments (not application of P in the culture on the dry land irrigated), totalizing eighteen treatments. In the second experiment, irrigated culture, the treatments consisted of four doses of P2O5 (30, 60, 120 and 180 kg ha-1) x three forms of parceled application. These had been: P1, P2 and P3 (80/20, 60/40, 40/60, correspondents to the percentages of the dose of P2O5 applied in sowing and to the 35 DAE, respectively), and two more treatments with the application of the P in sowing (60 and 120 kg ha-1 of P2O5) and one treatment without P application, totalizing fifteen treatments. The third experiment, irrigated culture, consisted of seven treatments: six forms of parceled application of the dose 60 kg ha-1 of P2O5, plus one treatment, without P. The fertilizer modes of application were: PS (P in sowing); P1, P2 and P3 (80/20; 60/40; 40/60 % of the applied dose of P2O5, respectively in the sowing and to the 35 DAE); besides the P2 treatment with the parcel of P in covering via MAP (P2 - MAP) or via triple superphosphate in powder (P2 - STP). The parcelment applied of P in sowing of all the treatments and that applied during covering in P1, P2 and P3 was via triple superphosphate granulated. In the two first experiments, the only source of P was the granulated triple superphosphate. In all experiments the parcelment of P in covering was applied incorporated in the depth of 10 cm, of 20 cm of plants row. It was evaluated the dry matter production, content and quantity of P in the leaves, branches and reproductive structures in the 35, 50 and 80 DAE; the quantity of nutrients in the fifth leaf completely expanded from the apex to the base (leaf index) on the 80th DAE and, number of bolls per plant, mass of boll and productivity of cotton in boll in the harvest. The parceled application of the phosphate fertilizer, in a general way, did not influence the dry matter accumulation and P content in the aerial part at the 50 and 80 DAE. In the first experiment, there was response to the doses of P on the productivity and absorption of P, only in the irrigated culture. The irrigation increased the number of bolls per plant and the productivity of the cotton in boll. The nutrients quantity in the leaf index was bigger in the dry land culture, except for N and P. In the second experiment, it presented a reduction of productivity of cotton in boll in the parcelment P3 in comparison to the traditional application or to the parcelments P1 and P2. The nutrients quantity, except of P, did not have been affected by the parcel of the phosphate fertilizer. It had responded to the doses of P for the dry mass of aerial part at the 35 and 50 DAE and of dry reproductive structures at the 80 DAE. It had increment on P absorbed and the productivity of cotton in boll, with the increase of the doses of P. The maximum productivity was obtained with the doses of 125, 180 and 180 kg ha-1 of P2O5, in the parcels P1, P2 and P3, respectively. In the third experiment, the nutrients quantity in the leaf index did not have been influenced by the parcelment, except the quantity of P, which was bigger in the treatment P2 - MAP. There was an increment of absorbed P at the 50 DAE with the mode of application P2 - MAP and P3. The P application increased the dry mass of boll, number of bolls per plant and productivity of cotton in boll. The P3 form of application reduced the productivity of cotton in boll. The conclusion is that, in Quartzanic Neossoil, the parcelment of phosphate fertilizer did not modify the nutrients quantity in the leaf index and it did not increase the phosphorus uptake and the productivity of cotton in boll.