- IBiochar (BC) and terra preta substrates (TPS) have recently been promoted as soil amendments suitable for soil stabilization, soil amelioration and long-term carbon sequestration. BC is a carbon-enriched substance produced by thermal decomposition of organic material. TPS is composed of liquid and solid organic matter, including BC, altered by acid-lactic fermentation. Their effect on wettability, soil erodibility and nutrient discharge through overland flfl ow were studied together for the fifi rst time, using laboratory experiments. At water contents between 0 and 100 wettable into a repellent state. The 5 and 10 vol20 volrepellency maxima are shifted to higher water contents with respect to pure sand and are mainly of subcritical nature. The runoff response was dominated by infifi ltration properties of the substrates rather than their wettability. Only the 20 volsandy-loamy soil on a 15 volintensities (45 mm.h1) the 10 volthe 10 volthan in water. Despite the TPS containing more nutrients, nutrient discharge from mixtures was similar to sandy-loamy soils (except for P in TPS and C in BC) regardless of the slope gradient. Increased rainfall intensities (up to 55 mm.h1) led to slight decline in enrichment ratios, while the nutrients concentrations remained comparable in the 10 volapplication of a 1 cm layer onto the soil surface instead of 10 volis not recommended due to high nutrient concentrations in the runoff and the wettability of pure substrates. The usage of 10 vollow frequency and low intensity precipitation and 10 volhigher rainfall intensities appears to be appropriate and commendable according to current results. However, together with reversibility of repellency, it needs to undergo further examination in the fifi eld under different environmental and land use conditions.
