National Key Laboratory of Crop Improvement for Stress Tolerance and Production, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China; Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, Yangling, Shaanxi 712100, China.
Department of Microbiological Sciences, North Dakota State University, Fargo 58102, ND, USA.
Sci Total Environ. 2024 Nov 1;949:174953. doi: 10.1016/j.scitotenv.2024.174953. Epub 2024 Jul 26.
Intercropping can increase soil nutrient availability and provide greater crop yields for intensive agroecosystems. Despite its multiple benefits, how intercropping influences rhizosphere microbiome assemblages, functionality, and complex soil nitrogen cycling is not fully understood. Here, a three-year field experiment was carried out on different cropping system with five fertilization treatments at the main soybean production regions. We found that soybean yields in intercropped systems were on average 17 % greater than in monocropping system, regardless of fertilization treatments. We also found that intercropping systems significant increased network modularity (by 46 %) and functional diversity (by 11 %) than monocropping systems. Metagenomics analyses further indicated intercropping promotes microbiome functional adaptation, particularly enriching core functions related to nitrogen metabolism. Cropping patterns had a stronger influence on the functional genes associated with soil nitrogen cycling (R = 0.499). Monocropping systems increased the abundance of functional genes related to organic nitrogen ammonification, nitrogen fixation, and denitrification, while functional guilds of nitrate assimilation (by 28 %), nitrification (by 31 %), and dissimilatory nitrate reduction (by 10.1 %) genes were enriched in intercropping systems. Furthermore, we found that abiotic factors (i.e. AP, pH, and Moisture) are important drivers in shaping soil microbial community assemblage and nitrogen cycling. The functional genes include hzsB, and nrfA, and nxrA that affected by these biotic and abiotic variables were strongly related to crop yield (R = 0.076 ~ R = 0.249), suggesting a key role for maintaining crop production. We demonstrated that land use conversion from maize monocropping to maize-soybean intercropping diversify rhizosphere microbiome and functionality signatures, and intercropping increased key gene abundance related to soil nitrogen cycling to maintain the advantage of crop yield. The results of this study significantly facilitate our understanding of the complex soil nitrogen cycling processes and lay the foundation for manipulating desired specific functional taxa for improved crop productivity under sustainable intensification.
间作对增加土壤养分供应和提高集约化农业生态系统作物产量具有重要作用。尽管间作具有多种益处，但间作对根际微生物群落组成、功能和复杂土壤氮循环的影响还不完全清楚。在这里，我们在大豆主产区进行了一项为期三年的田间试验，该试验涉及五个施肥处理的不同种植系统。结果表明，无论施肥处理如何，间作系统中的大豆产量平均比单作系统高 17%。我们还发现，与单作系统相比，间作系统显著增加了网络模块性（增加了 46%）和功能多样性（增加了 11%）。宏基因组学分析进一步表明，间作促进了微生物群落功能的适应性，特别是丰富了与氮代谢相关的核心功能。种植模式对与土壤氮循环相关的功能基因有更强的影响（R=0.499）。单作系统增加了与有机氮氨化、固氮和反硝化相关的功能基因的丰度，而硝酸盐同化（增加了 28%）、硝化（增加了 31%）和异化硝酸盐还原（增加了 10.1%）功能类群在间作系统中富集。此外，我们发现，非生物因素（即 AP、pH 和水分）是塑造土壤微生物群落组成和氮循环的重要驱动因素。受这些生物和非生物变量影响的功能基因包括 hzsB、nrfA 和 nxrA，与作物产量密切相关（R=0.076~R=0.249），表明这些基因在维持作物生产方面起着关键作用。我们证明，从玉米单作到玉米-大豆间作的土地利用转化多样化了根际微生物群落和功能特征，并且间作增加了与土壤氮循环相关的关键基因丰度，以维持作物产量的优势。本研究的结果显著促进了我们对复杂土壤氮循环过程的理解，并为在可持续集约化条件下操纵所需的特定功能类群以提高作物生产力奠定了基础。
