Assessing the Impact of King Coconut Husk Ash and Biochar, Combined with Chemical Fertilizer Application, on Enhancing Soil Fertility in Coconut Plantations

Sustainable soil fertility management is crucial for enhancing productivity in coconut plantations. This study investigated the synergistic effects of king coconut husk (KCH) ash, biochar, and chemical fertilizers on soil properties in a coconut plantation over a short period (4 months). Six treatments were applied: control, chemical fertilizers alone (F), fertilizers with ash (FA), fertilizers with biochar (FB), fertilizers with both ash and biochar (FAB), and fertilizers with half ash and biochar (FA1/2B). Strongly alkaline KCH ash contained significantly higher total and available potassium content levels than mildly alkaline biochar. Data indicated that KCH ash significantly enhanced soil available potassium, electrical conductivity, and organic carbon content compared to the control and F treatments over a short-term period. Even though biochar application demonstrated initial improvements in soil moisture content, a longer study duration may be required to evaluate its influence on other soil parameters comprehensively. Highlighting the synergistic benefits of KCH ash and biochar, FA1/2B treatment exhibited the highest combined index score based on physical, biological, and chemical soil indicators, suggesting its potential for optimizing agricultural outcomes. It emerged as the most promising approach, underscoring the value of exploring sustainable soil amendments derived from agricultural waste streams to promote soil fertility and sustainable coconut production.