Physiological response of ‘Castillo el Tambo’ coffee plants to biochar and chemical fertilization applications

The fertilizers costs are currently elevated, and it is necessary to evaluate complementary agronomic strategies. Biochar (BC) offers several potential benefits at a relatively low cost. The research aimed was to study the effect of the application of four different doses of biochar (BC) (0, 4, 8, and 16 t ha-1) and four fertilization levels (FL) (0%, 33%, 66% and 100% of the nutritional requirements). We obtained the BC from coffee (Coffea arabica L.) pulp. The selected response variables were: Stomatal conductance (gs), water use efficiency (WUE), root hydraulic conductivity (K), leaf photosynthetic pigments (Chl), and total dry weight (TDW) of coffee ‘Castillo el Tambo’. The experiment was conducted under greenhouse conditions. The results showed that plants with 0 t ha-1 and 0% FL registered low values in the physiological parameters evaluated (gs = 60.5 mmol m-2 s-1; WUE = 3.03 g DM L-1 H2O; Chl = 59.4 atLEAF readings; Kr = 9.7×10-6 kg s-1 MPa-1; TDW = 9.7 g). On the other hand, we recorded a positive effect when ‘Castillo el Tambo’ coffee plants received 8 t ha-1 BC (Kr = 11.8×10-6 kg s-1 MPa-1), especially at fertilization levels of 66% and 100% (gs = 146.7 and 167.5 mmol m-2 s-1; Chl = 72.8 and 66.6 Chl content; WUE = 4.3 and 5.0 g DM L-1 H2O; TDW = 13.6 and 16.0 g, respectively). In conclusion, the use of BC manufactured with coffee pulp, mainly at a dose of 8 t ha-1, can be an alternative to complement the chemical nutrition of coffee plants.