pools and percent clay as a potential abiotic factors, and
(3) estimated N and P inputs via organic and mineral fertilizers
as a management factor regulating on-farm nutrient loss. In
June–August of 2008, 100 m2 plots were established in each farm.
We randomly selected ten coffee stems and recorded their diameter
at 15 cm as well as plant height. Similarly, diameter at breast height
(dbh) was measured for all shade trees in the plot. Individuals of
all species were counted, and shade tree and coffee density were
extrapolated to a hectare. Aboveground biomass was estimated
using allometric equations derived for Coffea (Segura et al., 2006);
Erythrina (Frank and Eduardo, 2003), and Musa (Hairiah et al., 2001;
Tully and Lawrence, 2011). Pruning affects tree biomass, and the
equation used to calculate Erythrina biomass included a term for
the level of pruning (Tully and Lawrence, 2011). Pruning intensity
was categorized into two levels: partial (all but 3–5 of the tallest
branches removed); and total (all branches removed – leaf biomass
estimated to be 65% lower than for partial; biomass values are presented