Long-term compost amendment modulates wheat genotype differences in belowground carbon allocation, microbial rhizosphere recruitment and nitrogen acquisition. (September 2022)

• Record Type: Journal Article
• Authors: Kelly, Courtland; Haddix, Michelle L.; Byrne, Patrick F.; Cotrufo, M. Francesca; Schipanski, Meagan E.; Kallenbach, Cynthia M.; Wallenstein, Matthew D.; Fonte, Steven J.
• Is Part Of: Soil biology and biochemistry. Volume 172(2022)
• Publication Date: 2022-09
• Subjects: Cultivar -- Compost -- Microbial community -- Rhizosphere -- Triticum aestivum; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2022.108768
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: The implementation of soil health-promoting practices, such as cover cropping and compost application, has important implications for nutrient cycling and management in agroecosystems. At the same time, plant belowground carbon (C) allocation patterns can influence nutrient cycling and availability in soil through changes to the microbial community, but the effects may depend on the crop genotype and management practices in place. We evaluated belowground C allocation patterns using 13 C labeling and root architecture in two genotypes of winter wheat ( Triticum aestivum ) with different levels of exudation and belowground allocation strategies in soils with contrasting compost amendment legacy (108.7 Mg ha −1 every 2 years over 10 years vs. no compost). We also measured microbial community structure and function in the rhizosphere and quantified uptake of residue-derived N from 15 N-labelled cover crop residues. We found an interactive effect between soil management and genotype, where in the no-compost soil, the high-exudation genotype (Snowmass) increased exudation by over 4-fold, while the low-exudate genotype (Byrd) increased only 2-fold. While we did not observe genotype differences in rhizosphere enzyme activity or dissolved N pools, residue N uptake was 1.8 times greater for Snowmass in the compost-amended soil. There were more rhizosphere microbial taxa associated with the high-exudate genotype (Snowmass); nine bacterial and seven fungal families were indicative of Snowmass, versus one bacterial and four fungal families for Byrd. Our results suggest that the high-exudation strategy can influence the rhizosphere microbial community, and lead to greater short-term residue N uptake in high SOM soil. By directly linking root architecture, exudation, microbial communities, and N mineralization and uptake dynamics, this work demonstrates that plasticity in root C allocation is genotype-specific and influences microbial communities and nutrient cycling depending on the soil health context. Highlights: We evaluated belowground C in high- and low-exudate winter wheat genotypes with high/no compost amendment history Net root exudation (assessed using 13 C) and root growth were lower in the compost-amended soil. Genotype differences in belowground allocation were greatest in the no-compost soil. The high exudation genotype had greater numbers of specific indicator microbial taxa. Genotype effects on organic N mobilization and uptake depended on soil management.