Sequential effects of spent coffee grounds on soil physical properties

Spent coffee grounds are a bio-residue studied as soil organic amendment and it has been proven that short-term effects on physical properties. However, its sequential the cultivation of clayey soils little studied. Therefore, an in vitro experiment was carried out to evaluate effect increasing doses (1%, 2%, 2.5%, 5%, 7.5%, 10%, 12.5% 15%) spent properties Spanish Mediterranean area which is rich smectites. The addition increased water retention at ?33 ?1500 kPa proportionally added amounts, but increase wilting point much larger than field capacity, decreasing plant available content. A non-linear influence aggregate size demonstrated. It total porosity consequently reduced bulk density. This fact reflected stereomicroscopy images where pores analysed with image analysis observed. Furthermore, SEM corroborate act intensely due interaction between their particles those clay. 5% dose acted threshold from greatest occur. In general, use SCG good sustainable solution because supposes reuse this (15 million tons per year), carbon (SCG contains ? 50% carbon) improvement chemical