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The formation and stability of soil aggregates affect plant growth, carbon sequestration, and many other physiological and biogeochemical processes. Aggregates may be destabilized by nitrogen (N) deposition due to decreased inputs of binding materials; however, the legacy effects of which are unknown. An increase in labile carbon (C) input could mitigate the negative impacts of N addition on soil aggregate stability through the improvement of soil physical, chemical and biological conditions. Using a field experiment with the addition of NH4NO3 at multiple levels in a meadow steppe, we terminated the addition of N at the sixth year and shifted to applying labile C in the form of sucrose at three levels (C-0, C-200, and C-2000 g C m−2 y−1) to soil for two years. Then we examined the aggregate size distribution and the associated soil properties. The high historical N addition rates decreased the proportion of macroaggregates (>2000 μm) and increased microaggregates (

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Root–soil interactions in the rhizosphere are central to resource acquisition and crop production in agricultural systems. However, apart from studies in idealized experimental systems, rhizosphere processes in real agricultural soils in situ are largely uncharacterized. This limits the contribution of rhizosphere science to agriculture and the ongoing Green Revolution. Here, we argue that understanding plant responses to soil heterogeneity is key to understanding rhizosphere processes. We highlight rhizosphere sensing and root-induced soil modification in the context of heterogeneous soil structure, resource distribution, and root–soil interactions. A deeper understanding of the integrated and dynamic root–soil interactions in the heterogeneously structured rhizosphere could increase crop production and resource use efficiency towards sustainable agriculture. Root–soil interactions, involving rhizosphere sensing, root architecture and function, as well as root-induced rhizosphere processes, are crucial for soil health, sustainable food security, and resource use efficiency. Heterogeneity is an important feature of the rhizosphere and this poses a challenge to a thorough understanding of root–soil processes. Uneven distribution of soil particles and resources shapes root activities and the consequent root-induced modification of the rhizosphere. Understanding and integrating root biology with soil processes in the context of the heterogeneous physical structure and resource distribution in soil will help close the application gap between rhizosphere research and agricultural practice, thereby contributing to sustainable crop production. [ABSTRACT FROM AUTHOR]

Purpose: Successive mineral fertilization might have side effects on soil environmental quality, such as aggregate structure, contamination, and enzyme activity. To gain a more comprehensive understanding of the influences of mineral fertilization on biotic and abiotic properties of forest soils, we investigated the effects of successive nitrogen and phosphorus fertilization on physical structures, contaminant contents, and microbial communities of forest soils with different sampling depths. Materials and methods: Mineral nitrogen (N) and phosphorus (P) were applied, alone or together, at different rates to provide nutrients to economic tree species (Chinese fir) in a forest plantation since 2011. Surface soil samples were taken at different sampling depths, and soil aggregate, contaminant content, and microbial properties were determined and comprehensively linked. Results and discussion: Our results showed that successive fertilization, sampling depths, and their interactions had negligible impacts on soil aggregate ratios and cadmium (Cd) and arsenic (As) contents. Contrastingly, soil β-glucosidase, phosphate, and fungal and actinomycetal biomass were significantly affected by the mineral fertilization, and sampling depth was a key factor determining the responses of microbial communities to the mineral fertilization. Conclusions: In the surface (0–20 cm) soils, abiotic properties had resistance to different fertilization and sampling depths, but biotic properties were markedly or significantly affected by the mineral fertilization or sampling depths. Simultaneously, sampling depths should be considered to reveal the impacts of managements on microbial properties in the surface forest soils. [ABSTRACT FROM AUTHOR]

Biological soil crust (BSC) as a nature-based strategy has a great potential to restore soil and water in arid and semi-arid natural ecosystems. Yet, little is known about its effects on soil fertility and productivity as affected by the BSC inoculation in agroecosystems. We hypothesis that BSC inoculation can improve soil quality, while increasing crop productivity and economic benefits in semiarid rainfed region. To address this issue, we carried out field experiment using forage maize (Zea mays L.) from 2018 to 2019, with four treatments as follows: 1) conventional flat planting (control, CK), 2) flat planting with the inoculation of BSC (BSC), 3) ridge-furrow planting (RF), and 4) sectional ridge-furrow planting (SRF). The results showed that BSC inoculation significantly enhanced maize shoot and root biomass by 53–63 % and 30–67 % accordingly (P < 0.05), compared with CK in two growing seasons.Also, BSC treatment slightly increased soil water content and soil temperature, while significantly decreasing soil pH and soil bulk density, relative to CK, RF and SRF (P < 0.05). Compared with CK, the BSC inoculation markedly improved soil microbial biomass carbon by 54 % and nitrogen by 52%, soil organic carbon by 21 %, and total nitrogen by 30% respectively (P < 0.05) Critically, the contents of above four parameters were 42 %, 32 %, 19 % and 32 % greater in BSC than RF and SRF, respectively (P < 0.05). Simultaneously, the BSC significantly decreased soil C/N ratio by 7 %, while SRF and RF slightly decreased C/N ratio by 0.2 % and 2 % only, in comparison with CK. Interestingly, soil C&N mineralization efficiency were significantly greater in the BSC treatment than CK, RF and SRF (P < 0.05). In addition, the economic benefit under BSC was the highest relative to other three planting systems In conclusion, BSC can be used as a nature-based strategy (NbS) to improve soil properties, promote microbial C&N uptake and utilization via enhancing C&N mineralization and lowering C-N ratio. In conclusion, BSC can act as a green solution to achieve high productivity and promote soil fertility in semiarid agricultural ecosystem. • Biological soil crust (BSC) as nature-based strategy was tested in forage maize field. • BSC significantly enhanced forage maize biomass than flat planting (control). • BSC significantly enhanced carbon & nitrogen mineralization than control. • BSC also showed similar ecological advantages over natural ridge-furrow planting strategies. • BSC is a promising nature-based strategy to restore the functionality of semiarid ecosystem. [ABSTRACT FROM AUTHOR]