Soil nutrient transformation and the microbial metabolism are primarily regulated by soil microorganisms, including fungi and bacteria, which exhibit distinct growth patterns, energy substrate utilization, and survival strategies. Despite their significance, our understanding of the key microorganisms governing the soil microbial metabolism and multifunctionality in subtropical woodlands remains limited. To address this knowledge gap, we conducted a large-scale investigation and assessment of the soil microbial metabolic limitation and soil multifunctionality in Camellia oleifera Abel and Pinus massoniana Lamb. woodlands in subtropical China. Our results reveal that the microbial phosphorus limitation was more severe in C. oleifera compared to P. massoniana woodlands. Nonetheless, the pattern of carbon metabolic limitation for microbes and soil multifunctionality was similar in both types of woodland. Specifically, the microbial carbon limitation was positively associated with both bacterial and fungal richness, while the microbial phosphorus limitation was significantly correlated with fungi including the richness and community structure in the P. massoniana woodland. By contrast, we did not observe significant correlations between microbial metabolic limitation indices and microbial parameters in C. oleifera woodlands. Regarding soil multifunctionality, the results reveal a strong positive correlation between the soil multifunctionality and fungal community in both P. massoniana and C. oleifera woodlands. Furthermore, our structural equation modeling revealed that the soil fungal community, rather than the bacterial community, had a significant effect on the microbial metabolic limitation and soil multifunctionality. Overall, our study provides profound insights into the relative importance of bacterial and fungal communities in shaping the soil microbial metabolic limitation and soil multifunctionality in subtropical woodlands. The findings of our study have important implications for the management and conservation of subtropical woodlands.

Ratoon rice, the cultivation of a second crop from the stubble after the main harvest, is recognized as an eco-friendly and resource-saving method for rice production. Here, a field experiment was carried out in the Yangtze River region to investigate the impact of varying stubble heights on the grain quality of ratoon rice, as well as to compare the grain quality between the main and ratoon season. This study, which focused on 12 commonly cultivated rice varieties, conducted a comprehensive analysis assessing milling characteristics, appearance, and cooking quality. The results show that ratoon rice crops exhibited a higher milled rice rate and head rice rate compared to the main rice crops. Conversely, chalky rice percentage, chalkiness degree, and amylose content were lower in ratoon rice crops. Principal component analysis grouped eight relevant quality indicators of rice quality which were concentrated into three categories, with amylose content identified as the key indicator of rice quality for distinguishing between different stubble heights. Random forest results reveal a robust and significant correlation between appearance quality index and amylose content. Subordinate function analysis indicated that a stubble height of 30 cm resulted in optimal rice quality, with Lingliangyou 211 exhibiting the highest quality and Xiangzao Xian 32 the lowest. Overall, our study suggests that ratoon rice crops generally outperform main rice crops in terms of quality, with the optimal measurement at a stubble height of 30 cm. This study holds substantial importance for selecting appropriate stubble heights for ratoon rice crops and enhancing overall rice quality.

Developing high phosphorus (P) efficient rice varieties is essential for sustainable phosphate resource conservation. This study evaluated 16 rice cultivars from four breeding eras: ancient (<1940), early conventional (1940–2000), modern conventional (2000–2020), and hybrid rice (2000–2020). Using pot experiments in low-P soil, we examined two P treatments: P0 (no P application, simulating low-P stress) and P50 (50 kg hm⁻¹ P application, normal P input). We systematically compared agronomic traits, P distribution patterns, and P uptake efficiency across breeding generations. The result showed that modern breeding significantly increased root biomass, shoot biomass, and grain yield while reducing plant height. Low-P stress (P0) had minimal impact on growth traits but negatively affected P uptake, particularly plant P content and accumulation patterns. Under P0 treatment, modern conventional varieties maintained a higher stem P concentration (0.47–0.65 g·kg⁻¹ vs. 0.27–0.49 g·kg⁻¹ in hybrid varieties; 0.47–0.65 g·kg⁻¹ vs. 0.18–0.28 g·kg⁻¹ in ancient varieties, p < 0.05). P allocation strategies varied significantly across breeding eras. Root P accumulation ratios decreased from ancient to modern varieties, while modern conventional rice had the highest stem P storage (24.1–30.5%), and hybrid rice allocated the largest partition of 76.4–78.1% P to grains. Additionally, P uptake efficiency and P fertilizer productivity increased by 131.09% and 91.21% (p < 0.01) from ancient to modern conventional rice, with hybrids exhibiting the highest values for both parameters. Principal component analysis (PCA) revealed distinct trait clusters separating ancient, conventional, and hybrid rice based on the agronomic traits, P uptake, and rhizosphere soil parameters. Random forest analysis identified that, under low-P conditions, root P content was the strongest predictor of grain yield, whereas under normal P conditions, rhizosphere pH had the highest relationship to grain yield. These findings demonstrate that modern breeding has enhanced P adaptation through optimized root architecture and organ-specific P allocation strategies, which providing valuable insights for developing future P-efficient rice varieties.