Evaluation of Coconut Wastes as an Amendment to Acidic Soils in Low-Input Agricultural System

Abstract

The effectiveness of plantation wastes along with locally available organic materials in ameliorating acidic soil was studied by conducting an experiment with coconut husk, poultry manure, vermicompost, and compared with limestone. Application of organic amendments significantly increased the soil pH, and it was greatest in poultry manure–amended soils followed by vermicompost and coconut husk + poultry manure treatments. The relative liming efficiency was greatest for poultry manure through out the observation period of 180 days. The coconut husk alone showed the least liming effect and its liming efficiency had increased when applied in combination with poultry manure and or vermicompost. This increase in soil pH was mirrored by significant reductions in exchange acidity, exchangeable aluminum (Al³⁺), diethylenetriaminepentaacetic acid (DTPA)–extractable iron (Fe²⁺), and manganese (Mn²⁺) and increases in cation exchange capacity, exchangeable bases, especially calcium (Ca), and Olsen-extractable phosphorus (P) by addition of organic amendments and lime. This study indicated the potential of using coconut husk along with poultry manure for managing acidic soils in low-input agricultural systems, especially in tropical islands.

Keywords:

• Available phosphorus
• exchangeable cations
• exchange acidity
• organic amendments
• relative liming efficiency
• soil acidity