Olive pulp and its effluents suitability for soil amendment.

Olive pulp (OP) and its effluents produced after digestion processes were characterised and their suitability as soil amendment materials were investigated. Results showed that OP and its effluent for hydrogen (EH2) and methane production (ECH4) contain high amount of organic matter, remarkable concentration of nutrients and negligible content of heavy metals. Decreasing concentrations of low molecular weight phenols (monomeric phenols) and increasing amount of humic-like materials were found passing from OP to EH2 and ECH4. The effects on both wheat seed germination and seedlings growth were also investigated. Addition of OP at the highest doses delayed both seed germination and seedling growth. These effects decreased when the OP and its effluents were incorporated into the soil. On the contrary an enhancement of seedlings growth was detected by addition of EH2 and ECH4. Enhancement effects also were found out by addition of lower OP concentrations. The phytotoxic effects decreased when the products were incorporated into the soil.

Quantitative estimation of peat, brown coal and lignite humic acids using chemical parameters, 1H-NMR and DTA analyses.

Humic acids extracted from peats (P), brown coals (BC) and lignites (L), were characterized using different (chemical, 1H-nuclear magnetic resonance spectroscopy and differential thermal analysis) techniques. Fourteen variables were obtained from these analyses and only five were selected because uncorrelated in multiple partial correlation. The chosen variables were C concentration, aliphatic and aromatic components and the heat of reaction of the second exothermic peak. The multivariate discriminant analysis was performed on these variables and a discriminant function was obtained which was able to efficiently separate the P, BC and L. This function enables simple predictions on samples of unknown origin. The straightforward method proposed and the results obtained are discussed.

Identification of organic matter from peat, leonardite and lignite fertilisers using humification parameters and electrofocusing.

The organic matter extracted from peats (P), leonardites (Le) and lignites (Li) was characterised by humification parameters and electrofocusing (EF). The degree of humification and the humification index might be used to distinguish P from Le and Li, but not Le from Li because they showed overlapped values, while the humification rate could be used only for the identification of Le and EF profiles of P, Le and Li fertilisers revealed different band patterns: P samples did not show bands in the region with isoelectric point, pI > 4.4; Le samples showed very intense bands in the region with pI > 4.4; Li samples showed a very different band pattern with poorly resolved bands in the region with pI > 3.8. P, Le and Li samples can be distinguished by combining humification parameters and EF.

Evaluation of the transformation of organic matter to humic substances in compost by coupling sec-page.

Humic acids (HAs) from soil and compost at the beginning (S0) and at the end of the stabilization process after 130 days (S130) have been fractionated by coupling size exclusion chromatography (SEC) and polyacrylamide gel electrophoresis (PAGE). Preparative quantities of HA fractions (HAFs) with different molecular sizes (MSs) and exactly defined electrophoretic mobility (EMs) have been obtained from all samples and the HAFs weight content has been studied. A high degree of similarity in HAFs weight content between soil HA and a stabilized compost HAs130 has been observed. Such data seem to be reliable for monitoring the evolution of the compost organic matter to humic substances for their agricultural uses.