Impact of compost and biochar amendment on date (Phoenix dactylifera) production at different phenological stages.

Abstract The date palm is the pivot of the oasis system. This work focuses on improving date production by using amendments based on date palm waste. The main objective is to study the effect of compost and biochar on date production. The trial was carried out at the ITDAS “El-Hadjeb” station on 36 palm trees of the “Deglet Nour” cultivar over 10 years old. For field fertilization, several combinations were tested, including biochar combined with manure and chemical fertilizers, as well as biochar combined with compost and fertilizers, or biochar alone with manure or compost. Biometric parameters measured included date length, width, and weight, as well as yield (kg/palm) at different maturity stages (Loulou, Khalal, and Tamar). Biochemical parameters measured included moisture and acidity at the Tamar stage. The main results indicate that the biochar-manure combination treatment was more effective than other treatments in improving biometric parameters at different stages of maturity, increasing yield by around 92 kg/palm. For biochemical parameters, the lowest average titratable acidity was recorded with the biochar-manure-fertilizer and biochar manure combinations, at 0.06 meq/100g and 0.0625 meq/100g respectively. On the other hand, the highest average was observed for the control with 0.287 meq/100g. The lowest water content was recorded in the mineral fertilizer treatment with an average of 9.5%. However, the highest average was observed in the biochar-manure treatment with a value of 15%. Biochar can help retain water and nutrients in the soil, creating a favorable environment for date growth. This can enable plants to benefit rapidly from available nutrients.