Simultaneous determination of wettability and shrinkage in an organic residue amended loamy topsoil

Abstract

In agricultural land use, organic residues such as compost, digestate, and sewage sludge are discussed as costeffective soil conditioner that may improve the water holding capacity and crop available soil moisture. The objective of this study is to determine the effect of application of digestates with different compositions in maize, sugar beet and winter wheat, compost of shrub debris and sewage sludge on shrinkage behaviour and contact angle of till-derived loamy topsoil of a Haplic Luvisol under agricultural use. Novelty is the simultaneous determination of contact angle and shrinkage of soils amended with digestates composed of different composition in maize, sugar beet and winter wheat, compost of shrub debris and sewage sludge. The results suggest that the application of organic residues impacts the air capacity, while the contact angles remained in the subcritical range between > 0° and < 90°. The relationship between CA values and moisture ratios, ϑ, during proportional shrinkage was positive and linear (r2 of 0.98) and negative during residual- and zero-shrinkage (r2 of 0.93).

Keywords

• luvisol
• organic residues
• contact angle
• wettability
• shrinkage