Globally, orchard soils are facing multiple severe health issues. However, different countries and regions have adopted their own soil classification standards, making many studies only useful for improving soil health in local orchards but not widely applicable to other regions. This fragmentation highlights the urgent need for internationally comparable approaches to orchard soil health assessment. Furthermore, there are currently no unified standards for screening orchard soil health indicators or establishing comprehensive evaluation indices. Many proposed orchard soil health assessment frameworks lack practical applicability. This review introduces and compares several soil health assessment methods, critically analyzes their limitations, and explores directions for improvement in their application to orchards. Additionally, it addresses the primary challenges, currently and in the future, facing orchard soil health—climate change and emerging contaminants. This review also evaluates current orchard soil health management practices, focusing on their advantages and limitations. Finally, this paper offers recommendations for data acquisition and analysis in future orchard soil health assessment frameworks and encourages the establishment of a Decision-Making Platform for Soil Health with Cross-Border Cooperation and Feedback, thereby promoting a more globally consistent perspective on orchard soil health.

Long-term continuous deposits and well-preserved thick loess sections are natural archives for the reconstruction of global climate change. However, the loess sections are often discontinuous owing to soil erosions and accumulations. This study aimed at reconstructing long-term continuous paleoclimatic records by integrating the target sections of two typical loess sequences in northeast (NE) China. One section, the Dajiugang (DJG) section, was investigated and sampled, and the Sanbahuo (SBH) section was used as the target for integrating and reconstructing the paleoclimate. Sedimentary, pedogenesis, and luminescence dating analyses were conducted to analyze the potentials for reconstructing the paleoclimate by integrating two typical loess sections. The results indicated that the paleoclimate records derived from the DJG section can be used to reconstruct the continuous paleoclimate of NE China by integrating them with the SBH section. The paleoclimate information inferred from the DJG section could impute paleoclimate data from 71 to 11.7 ka, which were missing in the SBH section. The paleoclimate of NE China generally consisted of three periods from 71 to 11.7 ka: cold and dry from 29 to 11.7 ka, alternately cold and warm from 57 to 29 ka, and warm and wet to cold and dry from 71 to 57 ka. Integrating the target loess sections can contribute to reconstructing regional long-term continuous paleoclimate records where discontinuous loess sequences occurred.

Soil aggregates are crucial for fertility and organic carbon (C) sequestration, with straw decomposition by soil microbes playing a key role in this process. However, the mechanisms of how fertilization and microbes control straw decomposition and the subsequent formation of straw-derived C in soil aggregates are still unclear. Therefore, topsoil samples (0~20 cm) were collected from three fertilization treatments in a long-term (29-year) Mollisol field experiment: (i) no fertilization control, CK; (ii) inorganic fertilizer, IF; and (iii) inorganic fertilizer plus manure, IFM. Thereafter, an in situ micro-plot incubation experiment was conducted without/with ¹³C-labeled straw (abbreviated as CKS, IFS, and IFMS, respectively). Soil aggregates were separated into macro- (>0.25 mm) and microaggregates (<0.25 mm). The aggregate-based changes in straw-derived C content, microbial community composition, co-occurrence network, keystone taxa, and functional characteristics were measured on the 1st, 60th, and 150th day after straw addition. The results showed that straw-derived C content increased averagely by 7 (CKS), 13 (IFS), and 20 times (IFMS) from day 1 to day 150 in the macroaggregates. The straw-derived C content in the microaggregates was the highest in the IFS (0.70%) and IFMS (0.67%) treatments on day 60. After straw addition, the relative abundance of Humicola within the soil macroaggregates significantly decreased from 2.9% (CK) to 1.4% (CKS), and that of Penicillium within the soil microaggregates decreased from 7.5% (IF) to 4.0% (IFS) on day 150. Network analysis revealed greater microbial complexity in microaggregates than in macroaggregates, with fungal keystone taxa responding more strongly to straw than bacterial keystone taxa. The SEM model identified bacterial composition and fertilization as key drivers of straw-derived C formation in macro- and microaggregates, respectively. These findings highlight the distinct roles of bacteria and fungi in various sizes of aggregate and the importance of customized soil management for improving soil fertility and C storage.

Blueberry ( Vaccinium spp.) are one of the most economically important fruit trees globally. However, due to continuous cropping have limited the industry’s ability to produce consistently over the long term, and the mechanism underlying the development of this continuous cropping problem is not yet fully understood. In this study, we applied metagenomic and metabolomic to systematically detect changes in microbial community structure, function and metabolic profiles in rhizosphere and non-rhizosphere soils after different years of continuous blueberry cultivation (0, 2, 4, and 6 years) in Dalian (China). The results showed that continuous cultivation significantly reduced overall microbial diversity and the bacterial and fungal Shannon index, with the decrease being more significant in the rhizosphere soils ( P < 0.05). The β diversity analysis showed that the microbial community structure was distinctly separated between cultivation periods, with the most prominent differences in the rhizosphere soils (PERMANOVA, P < 0.01). The increased cultivation duration led to a decrease in the relative abundance of beneficial functional taxa in the microbial community, while the depletion-tolerant and stress-adapted taxa were gradually enriched. Functional annotation analysis showed that KEGG pathways related to stress response, amino acid degradation, and energy metabolism significantly increased, while functions related to nutrient transformation and plant-microbe interactions were weakened (FDR < 0.05). The metabolomic results further showed that 6 years of continuous cultivation significantly reshaped the rhizosphere metabolite composition. This was evidenced by the accumulation of various secondary metabolites in the rhizosphere soil, including metabolites related to potential self-toxicity (e.g., ferulic acid, 3-hydroxyphenylacetic acid, and 2-hydroxycinnamic acid), mainly involved in the pathways of amino acid metabolism, lipid metabolism, and secondary metabolite synthesis. In conclusion, continuous cultivation of blueberry induced pronounced shifts in rhizosphere microbial community structure, function, and metabolite composition, suggesting that these changes may contribute to the development of continuous cropping obstacles (CCO).