Catch crop diversity increases rhizosphere carbon input and soil microbial biomass
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ORIGINAL PAPER
Catch crop diversity increases rhizosphere carbon input and soil microbial biomass Norman Gentsch 1 & Jens Boy 1 & Juan Daniel Kennedy Batalla 1 & Diana Heuermann 2 & Nicolaus von Wirén 2 & Dörte Schweneker 3 & Ulf Feuerstein 3 & Jonas Groß 4 & Bernhard Bauer 4 & Barbara Reinhold-Hurek 5 & Thomas Hurek 5 & Fabricio Camacho Céspedes 6 & Georg Guggenberger 1 Received: 5 February 2020 / Revised: 29 April 2020 / Accepted: 3 May 2020 # The Author(s) 2020
Abstract Catch crops increase plant species richness in crop rotations, but are most often grown as pure stands. Here, we investigate the impacts of increasing plant diversity in catch crop rotations on rhizosphere C input and microbial utilization. Mustard (Sinapis alba L.) planted as a single cultivar was compared to diversified catch crop mixtures of four (Mix4) or 12 species (Mix12). We traced the C transfer from shoots to roots towards the soil microbial community and the soil respiration in a 13C pulse labelling field experiment. Net CO2-C uptake from the atmosphere increased by two times in mix 4 and more than three times in mix 12. Higher net ecosystem C production was linked to increasing catch crop diversity and increased belowground transfer rates of recently fixed photoassimilates. The higher rhizosphere C input stimulated the growth and activity of the soil microbiome, which was investigated by phospholipid fatty acid (PLFA) analyses. Total microbial biomass increased from 14 to 22 g m−2 as compared to the fallow and was 18 and 8% higher for mix 12 and mix 4 as compared to mustard. In particular, the fungal and actinobacterial communities profited the most from the higher belowground C input and their biomass increased by 3.4 and 1.3 times as compared to the fallow. The residence time of the 13C pulse, traced in the CO2 flux from the soil environment, increased with plant diversity by up to 1.8 times. The results of this study suggest positive impacts of plant diversity on C cycling by higher atmospheric C uptake, higher transport rates towards the rhizosphere, higher microbial incorporation and prolonged residence time in the soil environment. We conclude that diversified catch crop mixtures improve the efficiency of C cycling in cropping systems and provide a promising tool for sustainable soil management. Keywords Catch crops . Cover crops . Agrobiodiversity . 13C pulse labelling . Rhizosphere C-transfer . Soil microbiome
Introduction Sustainable agriculture poses the challenge of developing innovative farming solutions to maintain or even increase
productivity without negatively affecting the ecosystem services provided by agricultural landscapes. Catch cropping was identified as an economical and suitable tool for the ecological intensification of cropping systems (Kaye and Quemada
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00374-020-01475-8) contains supplementary material, which is available to authorized users. * Norman Gentsch [email protected] 1
Institute of Soil S
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