Two types of biochars: one made from sugarcane bagasse, other one produced from paper fiber sludge and grain husks and their effects on water retention of a clay, a loamy soil and a silica sand.

Biochar (BC) is used as a soil amendment to enhance plant growth by improving mainly soil chemical and hydrophysical properties. In this work the effects of two types of BCs on soil water retention properties were analysed. The first type of BC was made from sugarcane bagasse. It was added to a clay "Shimajiri Maji" soil at an application rate of 3 w%. The second type of BC was made from paper fiber sludge and grain husks. It was added into a loam soil at rates of 3.6, and 7.3 w%. It was assumed that the effect of BC amendment will be more pronounced in coarse-grained soil than in fine-grained one. Therefore, the second type of BC was applied additionally in the silica sand, in a textured contrast material compared with the loam soil. The BC amendment caused statistically significant increase of water content in the transmission pores of the clay soil, in the storage pores of the loam soil, and in the macropores and the storage pores in the silica sand. Despite of the positive effect on soil water retention, statistically significant increase of available water capacity (AWC) was identified only in the loam soil with the larger BC amendment rate. Possible reasons are discussed. [ABSTRACT FROM AUTHOR]