The effect of application of digestate and agro-food industry sludges on Dystric Cambisol porosity

Abstract

The spatial arrangement and pore size distribution play an important role in accumulation and protection of exogenous organic matter (EOM) in the soil, but how different organic materials contribute to modify pore structure is poorly understood. We aimed at exploring possible changes in the complexity of the soil phase during fertilization with different doses of digestate and sludges sourced from the agro-food industry. For this purpose, the shortterm effects-one year, of soil fertilization, were investigated in several sampling periods and within two depths (0-25 cm and 25-40 cm). Changes in the specific surface area (SSA), total pore volume (V MIP), total pore area (S MIP), average pore radius (R MIP) and pore size distribution (PSD) were monitored using N 2 adsorption/desorption (NAD) and mercury porosimetry (MIP) methods. Our results showed that the intensity of observed changes depended on the type and dose of organic material, soil depth and sampling date. Accumulation of EOM increased with soil depth, masking a large proportion of SSA. Deeper soil layer was more susceptible to changes in the pore size distributions due to the formation of new elongated pores. We concluded that this specific structural porosity was related to the decomposition of organic matter during the formation of soil aggregates.

New Insight into Organomineral Interactions in Soils. The Impact of Clay-Size Peat-Derived Organic Species on the Structure and the Strength of Soil Silt Aggregates

“…Surprisingly, for the other aggregates at higher organic substrate loads, the pores become narrower with an increase in pore volume. Our results are somewhat different from those presented by Skic et al [72] and Dlapa et al [73], who reported that a higher carbon content promotes the formation of elongated pores of a higher pore diameter. In the authors opinion, the dependencies between pore parameters could be better understood based on the intrinsic porosity parameters measured below penetration thresholds.…”

Biochar Alters Soil Physical Characteristics, Arbuscular Mycorrhizal Fungi Colonization, and Glomalin Production

“…The shape of hysteresis loops and unrestricted adsorption at high p/p 0 allowed their classification as type H3. This type of hysteresis loop is characteristic for plate-like particles that produce slit-shaped pores [49]. Water sorption of the biochar was much higher than the biochar/soil mixtures (Figure 2).…”