Fu Yue, Tang Xiumei, Sun Tingting, Lin Litao, Wu Lixue, Zhang Tian, Gong Yifei, Li Yuting, Wu Haining, Xiong Jun, Tang Ronghua
College of Agronomy, Guangxi University, Nanning, Guangxi, China.
Key Laboratory of Agro-Environment and Agro-Product Safety, Guangxi University, Nanning, China.
Front Microbiol. 2024 May 30;15:1403338. doi: 10.3389/fmicb.2024.1403338. eCollection 2024.
Microbial carbon (C) and nutrient limitation exert key influences on soil organic carbon (SOC) and nutrient cycling through enzyme production for C and nutrient acquisition. However, the intercropping effects on microbial C and nutrient limitation and its driving factors between rhizosphere and bulk soil are unclear.
Therefore, we conducted a field experiment that covered sugarcane-peanut intercropping with sole sugarcane and peanut as controls and to explore microbial C and nutrient limitation based on the vector analysis of enzyme stoichiometry; in addition, microbial diversity was investigated in the rhizosphere and bulk soil. High throughput sequencing was used to analyze soil bacterial and fungal diversity through the 16S rRNA gene and internal transcribed spacer (ITS) gene at a phylum level.
Our results showed that sugarcane-peanut intercropping alleviated microbial C limitation in all soils, whereas enhanced microbial phosphorus (P) limitation solely in bulk soil. Microbial P limitation was also stronger in the rhizosphere than in bulk soil. These results revealed that sugarcane-peanut intercropping and rhizosphere promoted soil P decomposition and facilitated soil nutrient cycles. The Pearson correlation results showed that microbial C limitation was primarily correlated with fungal diversity and fungal rare taxa (, and ) in rhizosphere soil and was correlated with bacterial diversity and most rare taxa in bulk soil. Microbial P limitation was solely related to rare taxa ( and ) in rhizosphere soil and related to microbial diversity and most rare taxa in bulk soil. The variation partitioning analysis further indicated that microbial C and P limitation was explained by rare taxa (7%-35%) and the interactions of rare and abundant taxa (65%-93%).
This study indicated the different intercropping effects on microbial C and nutrient limitation in the rhizosphere and bulk soil and emphasized the importance of microbial diversity, particularly rare taxa.
微生物碳（C）和养分限制通过产生用于获取碳和养分的酶，对土壤有机碳（SOC）和养分循环施加关键影响。然而，间作对根际土壤和非根际土壤中微生物碳和养分限制及其驱动因素的影响尚不清楚。
因此，我们进行了一项田间试验，该试验涵盖甘蔗-花生间作，并以单作甘蔗和花生作为对照，基于酶化学计量学的向量分析来探究微生物碳和养分限制；此外，还对根际土壤和非根际土壤中的微生物多样性进行了研究。利用高通量测序通过16S rRNA基因和内部转录间隔区（ITS）基因在门水平上分析土壤细菌和真菌多样性。
我们的结果表明，甘蔗-花生间作缓解了所有土壤中的微生物碳限制，而仅在非根际土壤中增强了微生物磷（P）限制。根际土壤中的微生物磷限制也比非根际土壤中更强。这些结果表明，甘蔗-花生间作和根际促进了土壤磷的分解，并促进了土壤养分循环。Pearson相关性结果表明，微生物碳限制主要与根际土壤中的真菌多样性和真菌稀有分类群（，和）相关，与非根际土壤中的细菌多样性和大多数稀有分类群相关。微生物磷限制仅与根际土壤中的稀有分类群（和）相关，与非根际土壤中的微生物多样性和大多数稀有分类群相关。变异分配分析进一步表明，微生物碳和磷限制由稀有分类群（7%-35%）以及稀有和丰富分类群的相互作用（65%-93%）来解释。
本研究表明了间作对根际土壤和非根际土壤中微生物碳和养分限制的不同影响，并强调了微生物多样性，特别是稀有分类群 的重要性。
