Carbon stocks in biomass and soils of woody species fodder banks in the dry tropics of Mexico

Understanding carbon (C) dynamics of the silvopastoral systems can help mitigate greenhouse gas emissions. The aim of this study was to evaluate the C concentration and storage in above- and belowground tree biomass as well as in the soils of fodder banks of Leucaena leucocephala (Lam.) de Wit, Guazuma ulmifolia (Lam.) or a combination of the both species. The above- and belowground biomass was quantified by the destructive sampling. We also obtained samples from soil pits, 20-cm deep, and determined bulk density and organic carbon concentration. The mixed species banks produced more foliage dry matter (DM) (6.3 t DM/ha) than the pure fodder banks. The total living biomass stocks ranged from 31.5 to 33.5 t DM/ha and did not differ between fodder bank types. The tissue C concentration was greater in stems (45.1%) and roots (44.9%) compared to the foliage component (43.4%). Total soil carbon (TSC) in the 5–10 cm layer was greater in the fodder banks with legumes alone than in mixed species banks (35.7 vs. 30.8 t C/ha). TSC storage in the 15–20 cm layer was greater in the nonlegume fodder bank than in the legume fodder bank (39.8 vs. 34.5 t C/ha). However, to the 0–20 cm layer, TSC was similar for all fodder banks. Thus, the three types of fodder banks had similar total C storage in plant biomass and soil, but the production of foliage biomass was higher in the mixed species banks.