We expected N (but not P) fluxes to be elevated in the conventional
farms, as the conventional agroforests received 2.5 times as
much N in the form of fertilizer annually than organic agroforests.
However, N fluxes at 15 cm and 100 cm were not significantly different
among agroforest despite differences in fertilizer quantities
(Fig. 1). Both conventional and organic agroforests received similar amounts of P. As expected, P fluxes were similar between conventional
and organic agroforests.
Nitrogen fluxes at 100 cm were 127 and 111 kg N ha−1 yr−1 in
organic and conventional agroforests, respectively (Fig. 1a). Phosphorus
fluxes at 100 cm were 1.5 kg P ha−1 yr−1 in both organic
and conventional agroforests (Fig. 1d). Nitrogen fluxes were significantly
reduced at depth, and were 68% lower at 100 cm than at
15 cm in the conventional agroforests and 47% lower in the organic
agroforests (P = 0.002). Phosphorus fluxes were also reduced at
depth in agroforests (by 10%), but not significantly so. While N
losses were not significantly related to the quantity of N added in
fertilizer, P losses at 100 cm increased significantly with increased
fertilizer inputs