Uso sustentável do nitrogênio em pastagens de aveias ou azevém em SIPAS com soja ou arroz no Bioma Pampa

• Ano de defesa: 2026
• Autor(a) principal: Bragança, Lueli Fernandes
• Orientador(a): Castagnara , Deise Dalazen
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Pampa
• Programa de Pós-Graduação: Doutorado em Ciência Animal
• Departamento: Campus Uruguaiana
• País: Brasil
• Palavras-chave em Português: Agricultura regenerativa; Lolium multiflorum; Avena strigosa; bromatology; Eficiência de uso do nitrogênio; Nitrogen use efficiency; Forage production; Bromatologia; Avena strigosa; Avena sativa; Produção de forragem.; Regenerative agriculture;
• Área do conhecimento CNPq: CIENCIAS AGRARIAS
• Link de acesso: https://repositorio.unipampa.edu.br/handle/123456789/11289

Integrated Crop–Livestock Production Systems (ICLPS) contribute to the sustainability of production systems; however, they depend on forage production and the efficiency of use of available resources. Thus, the objective was to study, under field conditions, the effects of rice or soybean rotations with winter pasture and five nitrogen (N) rates (0, 50, 100, 150 kg ha⁻¹) applied to the forage on its productive, nutritional, and N use efficiency parameters. Six experimental trials—two for each forage species (white oat, annual ryegrass, and black oat)—were conducted in a randomized complete block design with split plots and four replications. In each trial, the preceding crop (soybean or rice) was allocated to the main plots and the N rates (0, 50, 100, and 150 kg ha⁻¹) to the subplots. For result presentation, trials were grouped by forage species and repeated annually (2020 and 2021). In the preceding crops, residue inputs and nitrogen-related parameters of crop residues were evaluated. In the pastures, dry matter yield (DMY), forage accumulation rate (FAR), and nutritional value were measured through crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF), dry matter intake as a percentage of live weight (DMILW), total digestible nutrients (TDN), dry matter digestibility (DMD), and relative forage value (RFV), as well as N concentration and N uptake in forage dry matter, in addition to nitrogen use efficiency (NUE), agronomic efficiency (AE), and biological efficiency (BE) of N in the forage. Rice contributed more crop residues than soybean; however, soybean residues had higher N content, a lower C:N ratio, and contributed more N to the system. Increasing N rates increased CP, NDF, and ADF, but reduced DMILW, TDN, DMD, and RFV. N concentration in forage dry matter and N uptake increased with N rates. For white oat, annual ryegrass, and black oat, mean NUE values were 56, 60, and 40%; mean AE values were 28, 24, and 15 kg DM per kg N applied⁻¹; and mean BE values were 44, 41, and 34 kg DM per kg N absorbed⁻¹, respectively. The studied ICLPS allow significant crop residue inputs which, associated with N rates, sustain high forage production, optimize the use of applied N, and enable the validation of environmentally sustainable production models for agricultural exploitation in the Pampa Biome.