Forbs differentially affect soil microbial community composition and functions in unfertilized ryegrass-red clover leys. (June 2018)

• Record Type: Journal Article
• Authors: Cong, Wen-Feng; Eriksen, Jørgen
• Is Part Of: Soil biology and biochemistry. Volume 121(2018)
• Page Start: 87
• Page End: 94
• Publication Date: 2018-06
• Subjects: Caraway -- Fertilization -- Forage mixtures -- Nitrogen mineralization -- Plantain -- Soil carbon dynamics; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2018.03.008
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: Increasing plant diversity in agroecosystems is proposed to enhance multiple ecosystem services. Adding selected forbs such as caraway ( Carum carvi L.) and plantain ( Plantago lanceolata L.) to productive grass-clover mixtures can further enhance forage yields, root biomass, uptake of mineral nutrients and improve animal performance. Yet, it remains unclear whether and how adding these forbs to grass-clover mixtures can influence soil microbial communities and associated soil carbon (C) and nitrogen (N) cycling. Based on a three-year grassland experiment varying in species diversity and composition with and without fertilizer application, we determined soil microbial community composition and functions related to C and N cycling under laboratory incubations. Results showed that inclusion of caraway modified soil microbial community composition by enhancing fungal-to-bacterial phospholipid fatty acids of the ryegrass-red clover mixture. Adding plantain to the ryegrass-red clover mixture increased the relative decomposition rate of the labile C pool, but not of the recalcitrant C pool. Yet, β-glucosidase activity and net N mineralization were unchanged due to inclusion of either forb. Moreover, fertilization with cattle slurry generally weakened these forb-induced changes in soil microbial properties. These findings demonstrate that adding selected forbs to unfertilized grass-clover leys can modify soil microbial community composition and associated C and N cycling, implying a potential for promoting long-term soil C sequestration through enhanced fungi-to-bacteria ratio, but a limited role in improving soil N fertility. Highlights: Soil microbial properties of grass-clover mixtures were influenced by adding forbs. Carum carvi L. enhanced fungal-to-bacterial PLFAs of grass-clover mixtures. Plantago lanceolata L. accelerated the decomposition rate of labile soil C pools. These forb-induced effects were mainly driven by the quality of soil C input. Fertilization weakened the forb-induced effects on soil microbial properties.