Shrestha Rashmi, Huusko Karoliina, Sietiö Outi-Maaria, Schmid Bernhard, Cappeli Seraina Lisa, Thitz Paula, Gerin Stephanie, Laine Anna-Liisa, Lohila Annalea, Heinonsalo Jussi
Institute for Atmospheric and Earth System Sciences (INAR)/Forest Sciences, 00014 Helsinki, Finland.
Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, 00790 Helsinki, Finland.
FEMS Microbiol Ecol. 2025 Jun 24;101(7). doi: 10.1093/femsec/fiaf068.
Positive relationships between plant diversity, microbial diversity, and ecosystem functioning have widely been observed in experimental grasslands. However, the impact of cover crop (CC) species diversification on soil microbial diversity and function in croplands remains underexplored. This study investigated how increasing the diversity of undersown CCs affected seasonal properties of soil microbiomes and whether these changes resulted in legacy effects on next-year crops. In barley fields undersown with functionally diverse CCs, soil samples were collected throughout the year to assess microbial properties. To evaluate legacy effects on the following year's barley, soil microorganisms were sequenced from spring samples collected before CC termination. Additionally, a pot experiment using flax was conducted to study how CC diversity influenced arbuscular mycorrhizal (AM) fungal colonization in roots. Results showed that vegetation presence and higher CC richness increased microbial biomass carbon and decreased the microbial metabolic quotient. Legumes' presence reduced microbial respiration. Fungal and AM fungal diversity also increased with CC richness, while legumes helped suppress fungal pathogens. In the pot experiment, presence of both vegetation and legumes positively influenced AM fungal root colonization. Overall, undersowing diverse CCs, particularly legumes, can increase soil microbial diversity and soil health, benefiting both the current and next-year crops.
在实验性草地中，植物多样性、微生物多样性和生态系统功能之间的正相关关系已被广泛观察到。然而，覆盖作物（CC）物种多样化对农田土壤微生物多样性和功能的影响仍未得到充分研究。本研究调查了增加间作CC的多样性如何影响土壤微生物群落的季节性特征，以及这些变化是否会对次年作物产生遗留效应。在间作功能多样的CC的大麦田中，全年采集土壤样本以评估微生物特性。为了评估对次年大麦的遗留效应，对CC终止前采集的春季样本中的土壤微生物进行了测序。此外，还进行了一项使用亚麻的盆栽试验，以研究CC多样性如何影响根内丛枝菌根（AM）真菌的定殖。结果表明，植被的存在和较高的CC丰富度增加了微生物生物量碳，并降低了微生物代谢商。豆科植物的存在减少了微生物呼吸。真菌和AM真菌的多样性也随着CC丰富度的增加而增加，而豆科植物有助于抑制真菌病原体。在盆栽试验中，植被和豆科植物的存在都对AM真菌在根中的定殖产生了积极影响。总体而言，间作多样化的CC，特别是豆科植物，可以增加土壤微生物多样性和土壤健康，对当年和次年作物都有益。
