Cashew Clones Water Productivity and Production Responses to Different Biochar Levels

The cashew peduncle, the so-called cashew apple, is frequently considered as waste generated by the cashew nut industries. It needs production quality improvements to achieve a more noble use. The objective of this research was to evaluate the application of biochar over irrigation water productivity, yield, and cashew apple quality of two clones (‘BRS 226’ and ‘CCP 76’) of an irrigated cashew orchard. This field experiment tested four treatments of biochar from tree pruning mixed hardwood as source material, corresponding to 0, 10, 20, and 40 g per kg of soil, equivalent to the amounts of 0.0, 1.0, 2.0, and 4.0 kg per plant, respectively. The evaluated production variables were irrigation water productivity in terms of cashew nuts and peduncles per cubic meter of irrigation water applied, cashew nuts, and apples’ individual mean weight and yield. Cashew apple quality was also evaluated by soluble solids (SS), titratable acidity (TA), soluble solids/titratable acidity ratio (SS/TA), and firmness. The use of biochar had positive effects on the nut and cashew apple irrigation water productivity, on mean individual cashew apple weight only for ‘BRS 226′ Clone and soluble solids for both clones (‘BRS 226’ and ‘CCP 76’). The soluble solids/titratable acidity ratio also improved only for the BRS 226 cashew clone. There was no statistically significant positive effect of applied biochar in cashew nut and cashew apple yield and firmness. The optimal doses were 1.70 kg, 1.90 kg, 4.00 kg, 2.10 kg, and 2.25 kg per plant of biochar, respectively.