Optimizing grassland productivity and sustainability: effects of a legume or N fertiliser application on N cycling Article Swipe

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Cycling Grassland Productivity Sustainability Agroforestry Legume Environmental science Natural resource economics Agronomy Agricultural economics Business Agricultural engineering Economics Geography Forestry Ecology Engineering Biology Economic growth

João Guedes Borré , Israel Ramalho , Rafael Monteiro , Wesley Canedo de Souza , Stallone Soares , Lígia Souza , Bruno José Rodrígues Alves , Daniel Rume Casagrande , Bruno Grossi Costa Homem , Robert M. Boddey , R. Macedo , Segundo Urquiaga ·

YOU? · · 2024 · Open Access · · DOI: https://doi.org/10.21203/rs.3.rs-4602562/v1 · OA: W4400378327

<title>Abstract</title> The absence of grazing management, coupled with limited N replacement, significantly promotes grassland degradation. Nitrogen input via fertiliser or biological fixation is critical for achieving productive and sustainable grassland systems. This two-year study assessed the N cycling of three pasture types (PTs): 1) mixed Marandu palisadegrass (<italic>Urochloa brizantha</italic>) and perennial horse gram (<italic>Macrotyloma axillare</italic>) without N fertiliser (Mixed); 2) monoculture Marandu palisadegrass fertilised with 138 kg N ha− 1 yr− 1 (N-fertilised); and 3) monoculture Marandu palisadegrass without N fertiliser (Unfertilised). Litter responses, forage and N intake, N livestock excretion and N cycling were measured. There were no differences between PTs for the existing litter (an average of 3,485 kg ha− 1; <italic>P =</italic> 0.204). More N was cycled via litter in the Mixed pasture than N-fertilised and Unfertilised pastures (95.7 vs. 63.6 and 51.8 kg N ha− 1 season− 1; <italic>P <</italic> 0.001). There was no difference between PTs for the total N excretion per animal (an average of 79.5 g animal d− 1; <italic>P =</italic> 0.727). However, per hectare, total N excretion in the N-fertilised pasture increased 20.4 and 22.5% than Mixed and Unfertilised pastures, respectively (<italic>P =</italic> 0.010). In the N-fertilised and Mixed pastures, there was a positive overall change of N in the soil-plant-animal system of 83.5 and 28 kg N ha− 1 year− 1, respectively. In the Unfertilised pasture, there was an overall negative change of N in the soil-plant-animal system of -27 kg N ha− 1 year− 1. Nitrogen application or perennial horse gram integration in a grass pasture increased the conservation of soil N reserves.