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BACKGROUND: Despite the optimal characteristics of peat, more environmental‐friendly materials are needed in the nursery sector, although these must guarantee specific quantitative and qualitative commercial standards. In the present study, we evaluated the influence of biochar and compost as peat surrogates on yield and essential oil profile of two different varieties of basil (Ocimum basilicum var. Italiano and Ocimum basilicum var. minimum). In two 50‐day pot experiments, we checked the performances of biochar from pruning of urban trees and composted kitchen scraps, both mixed in different proportions with commercial peat (first experiment), and under different nitrogen (N) fertilization regimes (second experiment), in terms of plant growth and volatile compounds profile of basil. RESULTS: Total or high substitution of peat with biochar (100% and 50% v.v.) or compost (100%) resulted in seedling death a few days from transplantation, probably because the pH and electrical conductivity of the growing media were too high. Substrates with lower substitution rates (10–20%) were underperforming in terms of plant growth and color compared to pure commercial peat during the first experiment, whereas better performances were obtained by the nitrogen‐fertilized mixed substrates in the second experiment, at least for one variety. We identified a total of 12 and 16 aroma compounds of basil (mainly terpenes) in the two experiments. Partial replacement of peat did not affect basil volatile organic compounds content and composition, whereas N fertilization overall decreased the concentration of these compounds. CONCLUSION: Our results support a moderate use of charred or composted materials as peat surrogates. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Land use change is one of the anthropogenic interventions that may induce substantial modifications to both the quantity and quality of soil organic matter (SOM). Soils from three cultivated areas (two types of rainfed upland and one irrigated lowland) and two forests (subtropical managed and temperate unmanaged) in a midhill watershed of Nepal were studied to assess the effect of land use change on SOM quality. Bulk SOM was analyzed using solid-state [sup.13]C nuclear magnetic resonance (NMR) and fractionated by acid hydrolysis into pools with different chemical composition and, thus, different tendencies to decomposition. The NMR analysis showed a clear prevalence of O-alkyl C over alkyl C and aromatic C, with major differences between both soils and two depth intervals of the same soil (0-20 and 20-40 cm). Acid hydrolysis revealed that the labile C pool is larger in the 0- to 20-than the 20- to 40-cm soil depth of each land use. Labile C was larger in the temperate unmanaged forest and the irrigated cultivated land than in the other soils at both soil depths. Of the cultivated rainfed soils, the recently reclaimed soil contained less labile C than the historically cultivated soil, while the labile C in the irrigated soil exceeded that in both rainfed soils. The results suggest that changes in land use from forest to cultivation and the irrigation of the cultivated land may significantly affect not only the quantity but also the quality of the SOM and, more importantly, its chemical recalcitrance to degradation. As a consequence, any future decisions regarding land management in the fragile mountain areas of Nepal should be carefully considered with respect to the nature of the SOM. Abbreviations: Bari 1, anciently reclaimed rainfed cropland; Bari 2, recently reclaimed rain fed cropland; CEC, cation exchange capacity; CP, crossed polarization; Khet, irrigated rice field; LP, labile pool; MAS, magic angle spinning; NMR, nuclear magnetic resonance; SC, temperate forest of Schima wallichii and Castanopsis indica; SOC, soil organic carbon; SOM, soil organic matter; St, managed dense forest of Shorea robusta.

The brittleness of fragipans is generally ascribed to the close-packing fabric arrangement acquired at the initial step of pedogenesis thanks to physical processes. However, there is an on-going debate over the agent causing soil densification. In this work, we tested the plausibility that ice segregation or liquefaction could have been the cause of the compaction of four fragipans. Two of them are located in nonseismic areas that have experienced periglacial conditions; one is from a strongly seismic area not affected by periglacial conditions, while the fourth site underwent moderate seismic activity and slight periglacial conditions. After disaggregetion in the laboratory, soil specimens were submitted to freeze--thaw cycles and vibrations at different amplitude and duration, either dry or water-saturated. Analyses of aggregate stability, bulk density, porosity, and pore-size distribution were made on natural and treated specimens. Results indicated that the compactness arose mainly from the close-packing arrangement of particles. The freeze-thaw cycles were able to reproduce only some of the features in the water-saturated specimens, independent of whether they came from periglacial or seismic areas, while those from seismic areas successfully acquired the original arrangement after vibrations-induced liquefaction. This different behavior could be partly explained by the fact that consolidation after liquefaction occurs only if a material with proper particle-size distribution and mineralogical assemblage is saturated by solutions able to disperse phyllosilicates and promote their face-to-face arrangement. Our findings support the hypothesis that liquefaction of soil material due to earthquakes could indeed provide a dense parent material in which the fragipan may develop through pedogenesis.

Humans act at worldwide scale as a growing geomorphic agent since mid‐Holocene (8,200–4,200 y BP) through the pervasive impacts of domestication, deforestation, agriculture, urbanization, and mining. The concept of Anthropocene has been introduced exactly to indicate the timespan in which humans have joined with other natural forces in impacting the outermost shell of the planet and the biosphere. Soils, which are the Earth's skin, are sensitive archives of any major human‐induced local to global change. Especially when buried, soils can permanently preserve the primordial traces of a significant impact of man on the environment, which occurred at different times and rates in different areas. As a result, we assert that the oldest "anthropogenic" soils from all around the world collectively are an appropriate marker for the diachronous dawn of an early Anthropocene. [ABSTRACT FROM AUTHOR]