Tomato is one of the most important crops in the world and its cultivation is usually based on a great use of inorganic fertilizers applied as broadcast fertilization and with several fertigations. For a more sustainable agriculture authors studied the synergistic effects of the application of two different composts, combined with an inorganic fertilizer, on the main chemical-physical soil properties and on the yield and qualitative parameters of a plum tomato variety. Two composts, obtained mixing sewage sludge or the organic fraction of the municipal solid wastes with pruning residues, grape marc, and exhausted olive pomace, were tested at 2 or 4.5 t ha −1 in a field experiment, replacing a part of the inorganic fertilization and respecting the N crop requirement.From an environmental point of view, the addition of composts to the soil caused an increase in the total and available heavy metals content, even if no soil pollution has been recorded. The yield of tomatoes resulted higher with the combined application of amendments and inorganic fertilizer with respect to the sole inorganic fertilization. The quality of tomatoes was apparently not affected by the fertilization and, although certain heavy metals tend to increase their tomato concentration with the application of composts, their concentrations did not exceed the legal thresholds.

The changes in soil organic matter composition induced by anthropogenic factors is a topic of great interest for the soil scientists. The objective of this work was to identify possible structural changes in humic molecules caused by a 2-year rotation of durum wheat with faba bean, lasted for a decade, and conducted with different agricultural practices in a Mediterranean soil. Humic acids (HA) were extracted at three depths (0–30, 30–60 and 60–90 cm) from a Mediterranean soil subjected to different tillage (no tillage, minimum tillage and conventional tillage), crops (faba bean and wheat), and fertilization. The changes in HA quality were assessed by several chemical (ash, yield and elemental analysis) and spectroscopic techniques (solid-state 13C nuclear magnetic resonance, Fourier transform infrared and fluorescence). The results suggest that the different agronomic practices strongly affected the quality of HA. Smaller but more aromatic molecules were observed with depth, while the fertilization induced the formation of simpler and less aromatic molecules due to the enhanced decomposition processes. Under no tillage, more stable humic molecules were observed due to the less soil aeration, while under conventional tillage larger and more aromatic molecules were obtained. Compared to wheat, more aromatic and more oxidized but less complex molecules were observed after faba bean crop. The inorganic fertilization accelerates the decomposition of organic substances rather than their stabilization. At the end of each crop cycle, humic matter of different quality was isolated and this confirms the importance of the rotation practice to guarantee a diversification of the soil organic matter with time. Finally, no tillage induces the formation of more stable humic matter.

Four hundred hectares of the inland and hilly part of Apulia Region (Southern Italy) were contaminated by using low-quality composts for many years. That territory now belongs to a national park and needs a sustainable soil restoration. Therefore, a greenhouse experiment was carried out to test the phytoremediation potential of the frugal Helichrysum italicum (Roth) Don, alone and mycorrhized by Septoglomus viscosum. The aims of the research were (a) to test if the H. italicum can reduce the soil content of Cd, Co, Cr, Cu, Ni, Pb, and Zn; (b) to identify in which part of the plant those metals are mainly accumulated; (c) to check the role of S. viscosum in promoting the plant growth and the soil phytoremediation. The results showed better plant growth in contaminated soils in comparison to control soils, regardless of the presence of mycorrhiza, probably due to the better soil fertility parameters in contaminated soils. In addition, nonmycorrhized plants from contaminated soil accumulated greater amounts of heavy metals, especially Cr, Cu, Pb, and Zn, in their root system. According to the translocation and bioconcentration factors, the mechanism by which H. italicum incorporated heavy metals was ascribable to a phytostabilization process. In contrast, the application of mycorrhiza in the contaminated soil reduced the uptake of heavy metals by the roots, possibly through an exclusion mechanism, reducing the phytoremediation potential of H. italicum. KEYWORDSheavy metals bioconcentration, heavy metals translocation, mycorrhizal fungus, phytostabilization, soil metals contaminationLand degradation includes many processes affecting natural resources (including soil), which reduce their capacity to carry out their ecological functions and, therefore, cause degradation (Sacristán, Peñarroya, & Recatalá, 2015). Among these processes, the heavy metals contamination has assumed considerable relevance in recent decades because of the increasing human activities that release these inorganic pollutants.In fact, they impact negatively on the soil microbial community due to their toxicity (Khan, Hesham, Qiao, Rehman, & He, 2010) and, especially Hg, Cd, Pb, As, Cu, Zn, Sn, and Cr, can accumulate in the tissues of living organisms (Wright, 2007). of Pb in roots (Cao, Cappai, Carucci, & Muntoni, 2004). It grows in dry places, well exposed to sun, and often in sandy and in uncultivated soils, and it is able to colonize rocky and marginal areas, contributing with its root system to the consolidation of soils. This frugal plant can be used Each site was sampled using a hand auger, collecting several soil subsamples from the top 20 cm and following an X scheme in an area of about 100 m 2 . The weight of each composite sample was about 150 kg, and an aliquot was air dried, crushed, and passed through a 2-mm sieve. | Greenhouse experiments

The excessive use of fertilisers and frequent and deep tillage are not considered good agricultural practices because they increase production costs and reduce soil fertility. Water extractable organic matter (WEOM) is the fraction of soil organic matter responsible for nutrient transport and bioavailability. The aim of this work was to investigate the effect of a 2-year rotation of faba bean–wheat, cultivated for a decade, and the agricultural practices (conventional vs no tillage, and fertilisation vs no fertilisation) on selected soil parameters and WEOM quality. Results showed that the soil organic carbon (SOC) and the total nitrogen (TN) content increased after the wheat and faba bean, respectively. Plots managed with conventional tillage showed WEOM with higher OC content with respect to no-tillage plots. A higher WEOM OC content was observed also in the fertilised plots. The WEOM of fertilised and faba bean plots was derived from decomposition of native SOC, but the microbial community decomposition was the main origin of WEOM after wheat.

The interaction of organic matter with the finest soil fractions (<20 μm) represents a good way for its stabilization. This study investigates the effects of conventional (CT), minimum (MT), and no (NT) tillage, fertilization, and non-fertilization, and soil depth (0–30, 30–60, and 60–90 cm) on the amount of organic carbon (OC) in four soil fractions. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) was performed to obtain information about the OC quality and the mineralogical composition of these fractions. The CT shows the highest amount of the finest fraction while the fertilization enhances the microbial community with the increase of soil micro-aggregates (250–53 μm). The coarse fraction (>250 μm) is highest in the upper soil layer, while the finest fraction is in the deepest one. The greatest OC content is observed in the topsoil layer and in the finest soil fraction. DRIFT analysis suggests that organic components are more present in the finest fraction, calcite is mainly localized in the coarse fraction, quartz is in micro-aggregates and 53–20 μm fraction, and clay minerals are in the finest fraction.

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