In this case study, the evaluation of different managements in coffee plantations will be presented as an example of a sustainable crop system. Soto and coworkers (2005) conducted an experiment of organic and conventional agroforestry systems of coffee (Coffea Arabiga variety Caturra) in Turrialba, Costa Rica.  They measure the contribution of biomass and the recycling of nutrients on three different arboreal shade treatments, two leguminous (Erythrina poeppigiana & Chloroleucon eurycyclum) and a timber species (Terminalia amazonia) (Soto et al. 2005). In addition, Soto et al. (2005) evaluated three different management levels: (1) high conventional, (2) moderate conventional and (3) high organic.

The results of this experiment showed that shade treatments with leguminous trees had the higher contribution of biomass and better recycling of nutrients compared with the treatment of timber tree shadow (14,335 kg/ha vs. 9,034 kg/ha) (Soto et al. 2005). The total average of nutrients recycled inside the organic systems was enough to maintain the nutritional demands of coffee plantations (see Figure 15) (Soto et al. 2005). Additionally, the quantity of recycled nutrients in the organic system was greater than the quantities applied via chemical fertilization in conventional systems (Soto et al. 2005). These results show that organic practices associated with leguminous trees could better sustain the productivity of this crop (Lyngbaek et al. 2005, Soto et al. 2005). In addition, the average production of the organic systems was higher than the production of the conventional systems (6.9 vs. 6.5 Fresh-fruit Tons/ha) (Soto et al. 2005). Finally, the organic management in a coffee plantation is an example of a sustainable model with higher productivity than the conventional systems.  

Figure 15. N balance in an organic shadow coffee system (Soto et al. 2005)