Above-ground biomass models for coffee bushes (Coffea arabica L.) in Libano, Tolima, Colombia

Biomass models are practical and useful tools to estimate biomass of perennial wood plants in land use systems that mitigate climate changes, such as coffee plantations. In Colombia, biomass models for coffee (Coffea arabica L.) have not been developed. These models have been built through destructive sampling of 40 individuals of Caturra and Castillo cultivars that grow in the most dominant coffee production systems in the municipality of Libano, Tolima, Colombia: (1) monoculture; (2) agroforestry systems (AFS) with plantain (Musa AAB); (3) AFS with Spanish elm (Cordia alliodora (Ruiz & Pavon) Oken)); and (4) organic. The bushes were measured (trunk diameter at 15 cm high, D (15), and total height, ht), cut at ground level, and their biomass was estimated gravimetrically by component (trunks, branches, leaves and fruits). Correlation analysis between dependent and independent variables were carried out, and generic models with linear and transformed variables were tested. Biomass models by component, and total, with R-2 of 0.62-0.88, including D (15) and ht as an independent variable were found. However, for practical purposes, a total above-ground biomass model was developed exclusively based on D (15) [B = 0.36 - 0.18 * D (15) + 0.08 * D (2)(15); R-2 = 0.82; where B: total above-ground biomass (kg/plant)]. These models represent practical tools in carbon fixation studies and nutrient cycling.