Viability of a macauba palm-Brachiaria grass intercropping system as an alternative to agroforestry production

In intercropping systems, shading is one of the main limiting factors for the development of plants in the understory, especially C-4 plants. However, successful pasture production in silvopastoral systems can be achieved through proper spatial arrangement. This study provides fundamental information that validates the macauba-grass consortium. For 20 months, during two dry seasons and two rainy seasons, microclimatic and physical variables in an Acrocomia aculeata-Brachiaria decumbens intercropping system were monitored. The spacings of the trees were 5 m x 4 m, 6 m x 4 m, 7 m x 4 m, and 8 m x 4 m and were compared to a traditional pasture. The aboveground biomass in the intercropping system was estimated as well as its ability to assimilate atmospheric CO2 and store carbon. Macauba palm presence in the intercropping system had a regulatory effect on the microclimatic conditions of the understory, regardless of tree spacing and season. In spacing, wider, the intercropped forage biomass was satisfactory and similar to that in the monocrop pastures. The spacing 7 m x 4 m and 8 m x 4 m improved the understory microclimatic conditions, allowing efficient forage growth and thus offering livestock food and comfort. These values were equivalent to those of traditional silvopastoral systems that use woody plant species. The estimates of aboveground biomass, carbon stock, and CO2 assimilation in the intercropping system with a spacing of 8 m x 4 m were 1.6 times greater than those of traditional pastures. Therefore, here, we show for the first time that A. aculeata-B. decumbens grass intercropping system is a viable alternative agroforestry practice for tropical regions, since sufficient amounts of fodder are provided alongside beneficial environmental services, such as the efficient sequestration and storage of atmospheric carbon.