Maize-tropical forages intercropping: an evaluation above and below the soil surface

• Autor(a) principal: Souza, Lucas Freitas Nogueira
• Data de Publicação: 2024
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/11/11136/tde-02082024-155304/
• topic: Panicum; Panicum; Urochloa; Urochloa; Zea mays; Zea mays; Consórcio; Intercropping

Tropical soils, which cover 80% of Brazils agricultural land, are susceptible to erosion, leading to biodiversity loss and reduced carbon sequestration, fertility, and organic matter content. The use of plant residues or crop cover, particularly from tropical forage species like Urochloa spp. and Megathyrsus spp., was identified as an effective means of preventing soil erosion. These species, when intercropped with maize, produces residue that degraded slowly, providing longer soil protection. However, managing the competition among intercropped species proved challenging. Factors such as climatic conditions, soil characteristics, nitrogen rate, herbicide management, and intercropping sowing pattern affected the growth and productivity of intercropped maize and forage. This study aimed to perform a meta-analysis of the maize-brachiaria intercropping data, evaluate the performance of the intercropping in an integrated way, and analyze the growth and characteristics of the root system of intercropping and monoculture systems. Intercropping systems, demonstrated superior performance over monocropping in several aspects. Relative to monocropping, intercropping reduced maize grain yield by 5.6% and Brachiaria grass biomass production by 64%. However, under specific conditions such as subtropical climate, early season sowing, and certain fertilization rates, these yield penalties were minimized. Despite the reduction, intercropping systems showed better resource utilization and productivity, with 25% higher total biomass at maize harvest. The land equivalent ratio (LER) of intercropping was consistently higher, indicating optimized resource utilization. Intercropping systems significantly increased root biomass, volume, and length, contributing to soil aggregation, protection against erosion, nutrient cycling, and deep carbon fixation. Intercropping systems boosted profits by an average of 92.1% compared to tropical forages monocropping. In conclusion, intercropping systems offer a robust strategy for simultaneous diversification and intensification of land use, with minor or no trade-off in maize grain yield, highlighting their potential in sustainable agriculture. Despite some production penalties, intercropping systems, with specific management practices and under certain climate conditions, could outperform monocropping in terms of biomass production, root development, resource utilization, profitability, and sustainability.