Lactuca sativa Growth and Yield as Affected by Cashew Nut Shells Biochar, Cattle Manure and Urea in Northern and Central Benin

Aims: This study aims to identify good combinations of cashew nut shell biochar, cattle manure, and urea for enhancing lettuce (Lactuca sativa L.) growth and yield in the North and Central regions of Benin.

Place and Duration of Study: Two agronomic trials were conducted: one in Tchaourou, Borgou department (2022), and another in Dassa, Colline department (2023).

Methodology: A Fisher experimental design with three replications was used at each site, focusing on fertilization with seven treatments, including four reference treatments (local practices) and three treatments based on the reference treatments with biochar incorporation.

Results: The results demonstrated significant improvements in plant growth parameters and yield, with the application of biochar combined with cattle manure and urea or with cattle manure only. The plants leaves number, height and yields obtained from the application of 10 t ha⁻¹ biochar + 20 t ha-1 cattle manure and 10 t ha-1 biochar + 0.025 t ha-1 urea +10 t ha-1 cattle manure were respectively at least 165 and 318%; 25 and 50%; 42 and 91% higher than those obtained under the producer's mineral fertilization practice at both sites.

Conclusion: The findings showed that integrating cashew nut shell biochar with organic and inorganic fertilizers can significantly enhanced lettuce production, and thus overall vegetable crop yields while reducing the need for mineral fertilizers and dependence of cattle manure. Additionally, studying the best application methods and rates for different soil types and crop systems can help in maximizing the benefits of biochar.