Tea is an economic shrubby plant in tropical and subtropical regions of the world. To obtain high yield in tea cultivation, chemical fertilizer application rates have generally been used. However, a large quantity of chemical fertilizer application in a long-term continuously ratooned and monoculture tea orchard can inevitably lead to soil acidification and a decline in fertility. Therefore, the restoration of soil fertility and the sustainable development of tea planting by organic ways are critical for the tea industry. In this study, field trials were conducted in the tea orchard that was continuously ratooned and mono-cultured for 20 years. Nitrogen fertilizer (NF), Laredo soybeans green manure (LF), and goat manure (GM) treatments were applied to restore optimum acidity, soil fertility, microbial activity, and the community structure of a long-term continuously monoculture tea orchard. This paper investigated that the pH value was increased from 4.23 to 4.32 in GM and LF, respectively. Similarly, the content of exchangeable acidity (EA) was decreased by 1.21 and 1.46 cmol·kg⁻¹ in GM and LF, respectively. Available nutrient results indicated that the content of NH₄⁺-N was increased by 3.96, 4.38, NO₃⁻-N by 1.07, 2.16, AP by 3.46, 6.86, AK by 0.26, 0.3 mg kg⁻¹ in GM and LF treatments, respectively. Enzyme analysis revealed that the activity of urease and sucrase was promoted by 7.98 mg·g⁻¹·24 h⁻¹ and 6.77 mg·g⁻¹·24 h⁻¹, respectively, in LF treatment. Likewise, the activity of acid phosphatase and polyphenol oxidase was sharply increased by 2.3 mg·g⁻¹ h⁻¹ and 63.07 mg·g⁻¹ h⁻¹ in LF treatments. Additionally, the activity of urease, sucrase, acidic phosphatase, polyphenol oxidase, and peroxidase were also significantly increased by applying GM treatments. Meanwhile, LF and GM treatments significantly improved soil microbial biomass as well as low weight organic acid content in degraded tea rhizosphere. Furthermore, high throughput sequence results illustrated that the relative abundance of Rhizobiaceae and Bradyrhizobiaceae families increased in LF and GM treatments, respectively, which are mostly a kind of nitrogen fixer and plant growth promoting bacteria. Taken together, the physiological traits of the new sprouts and the biochemical components of new tea leaves were also significantly improved by GM and LF treatments. From this study, it is concluded that LF and GM are good agriculture management practices, which promote plant growth, yield, and nutrient availability by maintaining and improving pH, enhancing available nutrients status, improving the secretion of low molecular weight organic acids, and balancing the microbial community structure in the long-term mono-cultured tea orchard.

Crop perennialization has garnered global attention recently due to its role in sustainable agriculture. However, there is still a lack of detailed information regarding perennial rice’s regenerative characteristics and physiological mechanisms in crop ratooning systems with different rice stubble heights. In addition, the response of phytohormones to varying stubble heights and how this response influences the regenerative characteristics of ratoon rice remains poorly documented. Here, we explored the regenerative characteristics and physiological mechanisms of an annual hybrid rice, AR2640, and a perennial rice, PR25, subjected to different stubble heights (5, 10, and 15 cm). The response of phytohormones to varying stubble heights and how this response influences the regenerative characteristics of ratoon rice were also investigated. The results show that PR25 overwintered successfully and produced the highest yield, especially in the second ratoon season, mainly due to its extended growth duration, higher number of mother stems, tillers at the basal nodes, higher number of effective panicles, and heavier grain weight when subjected to lower stubble heights. Further analysis revealed that PR25 exhibited a higher regeneration rate from the lower-position nodes in the stem with lower stubble heights. this was primarily due to the higher contents of phytohormones, especially auxin (IAA) and gibberellin (GA₃) at an early stage and abscisic acid (ABA) at a later stage after harvesting of the main crop. Our findings reveal how ratoon rice enhances performance based on different stubble heights, which provides valuable insights and serves as crucial references for delving deeper into cultivating high-yielding perennial rice.

The effects of soil acidification on the phoD-harboring microbial community and the fractions of soil phosphorus in tea plantation soils are still unclear. In this study, tea plantations with different soil pH were used as the research object to analyze changes in soil phosphorus fractions, phoD gene abundance, phoD-harboring microbial community composition, and their relationship with tea yield and quality. The results showed that the content of tea polyphenols, caffeine, free amino acids, theanine, and tea yield decreased significantly after acidification. Moreover, the content of total phosphorus in the acidified soil also decreased significantly. Further analysis of soil phosphorus fractions showed that the acidification of the tea plantation soil resulted in a significant decrease in the content of different types of labile and moderately labile phosphorus, whereas the content of non-labile phosphorus exhibited the opposite trend. As the content of soil NaHCO₃-Po, NaOH-Po, Resin-Pi, NaHCO₃-Pi, NaOH-Pi, and HCl-Pi decreased significantly after acidification, its organic and inorganic phosphorus content also decreased significantly. Its phosphorus activation capacity decreased by 4.75% after soil acidification. Soil acidification significantly reduced the diversity of phoD-harboring microbial communities by 61.89%. Analysis of the phoD-harboring microbial community composition suggested that the microbial abundance of Acidobacteria and Proteobacteria showed a decreasing trend in acidified soils, while for Nitrospirae, Verrucomicrobia, Actinobacteria, and Planctomycetes, it showed an increasing trend. Correlation analysis showed that microorganisms with significantly decreasing abundance in tea plantation soils were significantly and positively correlated with soil pH, labile phosphorus, moderately labile phosphorus, phosphorus activation coefficients, and tea yield and quality after soil acidification. It is evident that soil acidification inhibited soil phosphorus availability by shifting phoD-harboring microbial community composition in tea plantation soils, thus affecting the yield and quality of above-ground tea leaves.

In response to the severe continuous cropping obstacles encountered during the cultivation of passion fruit, which leads to significant declines in yield and quality, as well as rampant pests and diseases, it is particularly important to explore strategies for mitigating these obstacles. The present study used the rhizosphere soil samples from one-year-old (FY, first-year cropping) and two-year-old (SY, second-year cropping) “Golden Passion Fruit” plants, along with soil from uncropped land (CK) as a control and the techniques such as high-throughput sequencing, qRT-PCR, and HPLC-MS to analyze the main physicochemical properties, phenolic acid content, and microbial community changes in the rhizosphere soil of passion fruit under different continuous cropping durations, the results indicated that the contents of total nitrogen, total phosphorus, available nitrogen, available phosphorus, available potassium, and organic matter in FY soil were significantly higher than those in SY soil, and the pH value of the FY soil was also significantly higher than that of SY soil. Additionally, compared with FY soil, the activities of polyphenol oxidase, peroxidase, urease, and invertase in SY soil were significantly reduced by 18.0%, 43.6%, 19.8%, and 45.5%, respectively. HPLC analysis revealed that the concentrations of syringic acid, vanillin, benzoic acid, and ferulic acid in the SY soil were significantly increased by 18.0%, 21.9%, 24.4%, and 21.1%, respectively, compared to those in the FY soil. qRT-PCR analysis showed that as the duration of continuous cropping increased, the total number of bacteria in the rhizosphere soil of passion fruit decreased by 9.37%, while the total number of fungi increased by 57.8%. High-throughput sequencing results demonstrated that at the genus level, the relative abundances of Acidothermus, Acidibacter, Bacillus, and Acidobacterium were significantly increased by38.0%, 56.3%, 34.3%, 77.3%. whereas the relative abundances of Rhizomicrobium, Nitrospira, Burkholderia, Sphingomonas, Gemmatimonas, Streptomyces, and Nocardioides were significantly lower 45.2%,59.3%,50.6%,89.1%,74.5%,82.7% in the SY soil, relative to those in the FY soil. In summary, as the duration of continuous cropping increases, the soil fertility, enzyme activity, pH value, and beneficial microbial content in the rhizosphere of passion fruit decrease significantly, while the contents of phenolic acids and pathogenic microorganisms increase significantly. The findings of this study provide a theoretical basis for further elucidating the formation mechanism and mitigation strategies of continuous cropping obstacles in passion fruit.

To clarify the yield benefits of biochar application in maize and soybean intercropping and its effects on rhizosphere microbial functions, a two-year field experiment was conducted in Putian, Fujian Province, China, from 2025 to 2026. The experiment included three cropping systems, namely maize monocropping (MM), soybean monocropping (MS), and maize and soybean intercropping (SM), combined with two fertilization regimes: conventional chemical fertilization (CF) and biochar combined with chemical fertilizer (BF). We evaluated crop yield, rhizosphere soil physicochemical properties, enzyme activities, and microbial carbon-source utilization. The land equivalent ratio (LER) of maize and soybean intercropping remained above 1 in both years, indicating a stable land-use advantage. Compared with the corresponding monocropping treatments under conventional fertilization (MM-CF and MS-CF), SM-BF significantly increased maize and soybean yields by 29.40% and 34.78%, respectively. In the maize rhizosphere, SM-BF increased polyphenol oxidase, peroxidase, urease, and sucrase activities by 29.63%, 17.89%, 17.98%, and 35.03%, respectively, whereas the corresponding increases in the soybean rhizosphere were 27.96%, 17.89%, 26.10%, and 35.03%. These enzyme activities were the highest among all treatments. SM-BF also maintained relatively high levels of available N and available P in the maize rhizosphere and total N, available N, available P, and available K in the soybean rhizosphere. Biolog analysis showed that SM-BF generally resulted in the highest average well color development (AWCD) and microbial utilization of amino acids, polymers, carboxylic acids, and carbohydrates. Principal component analysis further showed that the cropping system contributed substantially to variation in rhizosphere microbial carbon-source utilization, while fertilization also had a detectable effect. Overall, maize and soybean intercropping showed a stable land-use advantage. Under biochar combined with reduced chemical fertilizer, the intercropping system maintained relatively high rhizosphere nutrient levels, enzyme activities, and microbial carbon-source utilization. These results suggest that interspecific interactions and fertilization management may jointly regulate the rhizosphere environment and microbial functional characteristics, which may be associated with the yield advantage of intercropping. This study provides a theoretical basis for efficient nutrient management and reduced chemical fertilizer input in maize and soybean intercropping systems.

Silicon deficiency is widespread in soils of Southeastern China and may constrain nitrogen (N)-use efficiency and yield formation in oilseed rape; therefore, this study aimed to identify an N-reduction window enabled by silicon (Si) fertilization and to clarify the underlying mechanisms. Field experiments were conducted in Putian, Fujian Province (2023–2025), with five treatments: conventional N (T1, 300 kg·N·ha⁻¹), conventional N plus Si (T1+Si, 150 kg·Si·ha⁻¹), and three N rates (120%, 80%, and 60% of conventional N; T2+Si, T3+Si, and T4+Si) under a fixed Si input. Yield, N-use efficiency, plant physiological traits, soil quality index (SQI), and nitrogen-cycle ecosystem multifunctionality were assessed. Compared with T1, T1+Si and T3+Si increased yield by 6.55% and 6.06%, respectively, accompanied by higher dry matter translocation (27.20% and 34.60%) and improved N-use efficiency (28.86% and 39.66%). SQI increased by 31.42% (T1+Si) and 33.03% (T3+Si), while nitrogen-cycle multifunctionality increased by 32.42% and 58.42%, respectively. Correlation and path analyses indicated that Si promoted yield formation by simultaneously alleviating soil constraints (lower exchangeable acidity and Al³⁺; higher cation exchange capacity) and enhancing plant assimilation and allocation processes, thereby reducing potential N losses and strengthening N cycling. Overall, applying 150 kg·Si·ha⁻¹ combined with a 20% reduction in N (240 kg·N·ha⁻¹) achieved stable yield gains and coordinated improvements in soil quality, providing an operational fertilization window for Si-enabled N management in regional oilseed rape systems.