Weed control in urban and peri-urban orange orchards is challenging due to operational and legislative restrictions. Tillage, besides from negatively affecting soil fertility and microorganisms, is demanding for humans. On the other hand, herbicides are advised against due to the possibility to reach waterbodies from the soil surface. Therefore, in urban and peri-urban areas, instead of tillage and herbicides, mulching with black plastic geotextile fabric is often used. This study aimed at assessing the impact of long-term soil mulching with black plastic geotextile fabric on soil fertility, microbial community and yield of an orange orchard in comparison to conventional tillage. To this aim, four soil management systems were set up: rotary tillage for the last 15 years, mulching with black plastic geotextiles for the last 15 years, rotary tillage for 7 years followed by mulching for the last 8 years, mulching for 7 years followed by rotary tillage for the last 8 years. Soil samples were analyzed to determine the chemical and biochemical parameters related to soil fertility. In addition, the abundances of the main microbial groups were investigated. Mulching increased soil total organic C at least by 65%. The greater soil organic C in mulched soil in turn contributed to increase the cation exchange capacity (+62% on average) and microbial biomass C (+120% on average). Additionally, the microbial quotient exhibited higher values in mulched soils compared to tilled ones, suggesting a greater soil organic matter accessibility by soil microorganisms. Moreover, mulching favored fungi over bacteria, and Gram-positive bacteria over Gram-negative bacteria, thus contributing to the establishment of a microbial community more efficient in utilizing C sources. The latter result was confirmed by the lower values of the metabolic quotient in mulched soil compared to tilled one. Overall, the black plastic geotextile fabric improved chemical and biochemical soil fertility that, in turn, lead to a higher orange yield in mulched soil.

The citrus industry produces a large number of sludges as a consequence of citrus wastewater treatment. The correct disposal of citrus sewage sludges (CSSs) has been attempted using anaerobic digestion, aerobic digestion, and lime stabilization. However, since CSSs hold nitrogen, phosphorus, and other macronutrients required by crops, in line with the circular economy principles, they could be utilized for agricultural purposes, such as organic fertilizer. The aim of this study was to assess the effect of CSSs supplied at different doses on soil fertility and lettuce performance. To this end, a pot experiment was established. The soil was amended with CSSs at three different concentrations (2.5, 5, 10 t ha⁻¹). After 46 days of lettuce growth, the experiment was stopped, and soils and plants were analyzed. Soil amended with CSSs showed an increase in total organic C ranging from 7% to 11%. Additionally, available P increased but only at the highest CSS dose. The addition of CSSs affected the biochemical properties of soil, but a univocal trend related to the number of CSSs applied was not found. Microbial biomass C increased only with the highest dose of CSS applied, while the metabolic quotient (qCO₂) decreased. Such a positive effect on soil fertility and soil microorganisms, in turn, lead to an increase in lettuce biomass. Moreover, results indicated that following CSS addition, lettuce crops adsorbed more N in leaves than in roots, whereas P, Ca, Mg, K, and Na showed an opposite pattern and increased more consistently in roots. In conclusion, amendment with CSSs enhances soil fertility by increasing, regardless of CSS dose, total organic C, and, at the highest dose, P availability and microbial biomass C. Such improvement in soil fertility, in turn, increases lettuce biomass production without affecting its quality, i.e., alteration of the (K + Na)/(Ca + Mg) ratio.

Cover crop management in vineyards under a semiarid Mediterranean environment needs strategies that enhance soil C and N status and microbial functioning without increasing disturbance. This study compared cover crops biomass incorporation (harrowing, HR; rotary tillage; RT) and non-incorporation (NI, residues left on the topsoil) into the soil in a 12-year Grecanico dorato vineyard. Traditional vineyard soil management (continuously tilled for weeds control) was also used as a control. Soil samples from 0 to 20 and 20 to 40 cm were analyzed for total organic carbon (TOC), total nitrogen (TN), microbial biomass carbon (MBC) and nitrogen (MBN), and enzyme activities. NI and HR raised TOC and TN in the topsoil versus TR, with NI frequently maintaining advantages at depth. NI also maximized MBC/MBN and reduced the metabolic quotient (qCO₂), indicating improved microbial C-use efficiency; RT showed intermediate chemistry but depressed subsoil MBC and altered MBC/MBN. Enzyme profiles reflected contrasting mechanisms: RT boosted β-glucosidase in the topsoil, TR peaked for urease and arylsulfatase but alongside lower biomass and higher specific enzyme activities, while NI supported greater overall functioning via larger biomass and lower per-C enzyme demand. The calculated geometric mean enzyme (GMea) index emphasized transient TR flush versus steadier conservation functioning. Strong vertical stratification occurred for all indices, yet NI transmitted some benefits to 20–40 cm. We conclude that residue retention or moderate incorporation promotes larger, more efficient microbial population and more balanced nutrient cycling, whereas repeated rotary tillage risks subsoil inefficiencies. In semi-arid Mediterranean vineyards, low-disturbance cover-crop incorporation (HR) or, preferably, residue retention at the topsoil (NI) offer a simple, scalable route to sustain soil quality and long-term fertility.

Italy is the third largest producer of Opuntia fruits in the world after Mexico and the United States, and 97.72% of these fruits produced by Italy are grown in Sicily. The use of prickly pear fruits or juice leads to a high production of by-products. In this study, ensiling was chosen to preserve prickly pear peels (PPPs) and “pastazzo” (PPS) mixed with 12% wheat bran. PPP silage presented a lower DM than PPS silage (20.03 vs. 41.37%; p < 0.01), as well as aNDFom (25.31 vs. 66.66% DM; p < 0.01), but had the best protein content (12.02 vs. 9.55% DM; p < 0.01). For both by-products, fermentation proceeded rapidly with increasing temperature, with the temperature for PPS (38 °C) being higher than that for the PPP (30 °C). Mesophilic LAB (lactic acid bacteria) were detected at higher levels than thermophilic LAB, and rod counts were higher than cocci counts. The detected organic acids and silage pH indicate an optimal fermentation process for these by-products. PPP silage had a higher polyphenol content than PPS silage (30.24 vs. 24.22 mg GAE/g DM; p < 0.01) and, consequently, also higher antioxidant activity. The results of this study on the mineral composition and macro- and micro-nutrients in silage highlight that these by-products are sources of minerals, with high levels of potassium, calcium, and magnesium.

Background: Soils under organic farming systems exhibit better quality and higher biological activity than conventional systems. Manure addition, especially coupled with reduced or no tillage, significantly enhances microbial biomass and activity by improving soil physical properties and providing carbon (C) and nitrogen (N) sources. While several studies have examined the effects of transitioning from conventional to organic farming on soil chemistry and biochemistry, limited research has explored the influence of land use variations on soil fertility within long‐term organic farming systems.Aims: Therefore, the aim of this study was to assess how three different land uses—pasture, vegetable crops, and orchard—affected soil fertility under a long‐term organic farming system.Methods: Soil samples were collected from the 0 to 15 cm layer of plots used for pasture, vegetable crops and orchard, being the latter cover cropped with legumes, and analyzed to determine chemical and biochemical soil parameters.Results: Contrary to expectations, high land use intensity (vegetable crops and orchard soils) resulted in increased soil organic C and total N, compared to low intensity (pasture). Such an increase was ascribed to farmyard manure addition that counteracted the negative impact of tillage. Consequently, microbial biomass C and activity also increased. The greatest availability of organic substrates favored bacteria, particularly gram‐positive strains, shaping the microbial community. However, despite changes of microbial biomass and of the main microbial groups, microbial activity was only slightly affected, suggesting high functional redundancy of microorganisms in long‐term organic farming soil.Conclusions: Results suggested that if land use intensification provides for organic supply, its negative impact on soil fertility may be mitigated.