Navegando por Autor "Ferreira, Letícia Aparecida Ronqui"

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    Manejo da fertilização nitrogenada e do inibidor de urease NBPT na cultura do trigo
    (Universidade Estadual do Norte do Paraná, 2021-03-30) Ferreira, Letícia Aparecida Ronqui; Kölln, Oriel Tiago; https://orcid.org/0000-0002-8507-9808; http://lattes.cnpq.br/8041626078120100; Silva, Sérgio Ricardo; https://orcid.org/0000-0001-6951-8324; http://lattes.cnpq.br/8067599760812752; Silva, Sérgio Ricardo; https://orcid.org/0000-0001-6951-8324; http://lattes.cnpq.br/8067599760812752; Otto, Rafael; https://orcid.org/0000-0003-1472-298X; http://lattes.cnpq.br/3650975021682224; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449
    The suitable choice of the source, rate and timing of application of nitrogen (N) fertilizer helps to minimize N losses. In addition, there are chemical additives capable of reducing ammonia volatilization, such as the urease inhibitor N-(n-butyl) triamide thiophosphate (NBPT). The objective of this work was to evaluate different agronomic management techniques for urea and ammonium nitrate fertilizers, as well as the use of NBPT to increase urea efficiency, aiming to improve wheat N nutrition and grain yield, considering three environmental conditions. Two different experiments were carried out in field situation in two locations in Paraná State (Londrina and Ponta Grossa). In Londrina, rainfed (Lrainfed) and irrigation (Lirrig) conditions were used, while in Ponta Grossa wheat was grown only in rainfed (PGrainfed). The first experiment was carried out in a randomized block design in a factorial arrangement (2 × 2 × 2) + 1, with two rates of N (40 and 80 kg ha⁻¹), two sources of N (ammonium nitrate and urea), two timings for N fertilization (during crop sowing or at the beginning of plant tillering), and an additional treatment with no N fertilization (control). Agronomic characteristics evaluated: grain yield, hectolitric weight, thousand grain weight, plant height and lodging, apparent harvest index, density of fertile plants, shoot dry matter (SDM), N concentration and accumulation in the SDM, and N utilization efficiency for grain yield (NUEGY) and for SDM production (NUESDM). Nitrogen fertilization reduced harvest index in Lrainfed and NUEGY in both water conditions in Londrina; however, it increased NUESDM in all environmental conditions. Urea and ammonium nitrate showed equivalent efficiency in terms of wheat grain yield, regardless of rate or timing of fertilization. In Lirrig and Lrainfed the rate and the timing of N application did not influence grain yield. However, in a colder climate (PGseq), the use of a higher N rate at sowing provided greater grain yield, thousand grain weight, and density of fertile plants. Therefore, the N rate can be reduced in environmental conditions that favor the mineralization of soil organic matter and the decomposition of soybean straw. The option for urea or ammonium nitrate can be based on economic criteria in environments with low water deficit and low potential for NH₃ volatilization. Nitrogen fertilization carried out exclusively at sowing may be suitable to supply N crop requirements. The second experiment was carried out in a randomized block design in a factorial arrangement (2 × 4 × 2) + 1, consisting of two rates of N (40 and 80 kg ha⁻¹), urea treated with four rates of NBPT (0, 250, 500, and 2000 mg kg⁻¹), two timings for N fertilization (during crop sowing or at the beginning of plant tillering), and an additional treatment with no N fertilization (control). The same agronomic characteristics of the first experiment were evaluated. Environmental conditions set the effectiveness of N fertilization and NBPT, influencing NUE and grain yield. NBPT did not influence grain yield in environments with acidic soils and high water availability. Nitrogen fertilization carried out exclusively at sowing was enough to supply wheat N requirement. We conclude that N fertilization and NBPT management should consider environmental features (such as soil pH, temperature and humidity) during the wheat-growing season.