Abstract: The objectives of this research were to determine the effects of moisture and additives on the quality of pepper straw silage and to identify new approaches for feed conservation. Pepper straw was wilted to three different target moisture contents (approx. 75%, 65% and 55%) and treated with (1) formic acid (1.5% FW, FA); (2) propionic acid (1.5% FW, PA); (3) corn flour (100 g/kg DM, CF); (4) potato dregs (30% FW, PD); (5) direct ensiling without additives (CK). After 45 days of ensiling with PE (polyethylene plastic vial, 100 mL), the fermentation quality and nutritional traits were analysed. The results showed that moisture and additives had significantly influenced silage quality (P<0.05). Dry mater and pH increased while lactic acid (LA), acid detergent fiber (ADF) and neutral detergent fiber (NDF) declined with decreasing moisture content. ADF was lowest at 75% moisture content while LA was highest and NH₃-N/TN (total N) lowest. In contrast with CK, FA treatment had significantly increased pH and NH₃-N/TN (P<0.05), lowered LA and water soluble carbohydrate (WSC); PD and CF treatments provided sufficient fermentation substrate; DM and WSC increased (P<0.05). The results indicated that a silage moisture content of 75%+FA produced the best quality silage followed by 65%+PD. In conclusion, the most suitable moisture for pepper straw silage is approximate 75%; adding PD may be advantageous at lower moisture contents.