Abstract
Soil degradation is a crucial problem, particularly in tropical and subtropical areas. Prevention or reduction of soil erosion requires strategies based on thorough rapid vegetation cover (VC) and favorable soil quality in subtropical and tropical areas. This study applied wood biochar (WB) and rice husk biochar (RHB) in a mudstone soil, which is widely distributed in Southern Taiwan, to investigate the effects of biochar application on soil erosion and vegetation restoration. The standard erosion unit plots (22.13 m in length and 9% in slope gradient) were set up to determine the relationship among soil losses, VC, and natural rainfall characteristics with and without biochar application. The results indicated that biochar application increased the growth rate (identified by cover ratio) of Bahia grass (Paspalum notatum Flüggé) by 2−2.6 times within 40 days compared with control (without biochar application) and increased VC by 20% after 120 days of treatment. The biochar application could effectively reduce soil losses by 60% at least in the mudstone soil. A well-predicted regression function of soil loss with VC and rainfall kinetic energy was established (amount of soil lost = −0.435 × ln VC + 0.54 × RKE, r = 0.89, p < 0.01).