Species and Genotype Effects of Bioenergy Crops on Root Production, Carbon and Nitrogen in Temperate Agricultural Soil

• Published in: Bioenergy research Vol. 11; no. 2; pp. 382 - 397
• Main Authors: Gregory, Andrew S., Dungait, Jennifer A. J., Shield, Ian F., Macalpine, William J., Cunniff, Jennifer, Durenkamp, Mark, White, Rodger P., Joynes, Adrian, Richter, Goetz M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2018; Springer; Springer Nature B.V
• Subjects: Agricultural industry; Agricultural land; Agricultural management; Analysis; Arable land; Biomass; Biomass energy; Biomedical and Life Sciences; Carbon; Clay loam; Cores; Crops; Energy crops; Experiments; Genotypes; Hypotheses; Land use; Life Sciences; Miscanthus; Nitrogen; Organic soils; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Renewable energy; Root matching; Soil dynamics; Stable isotopes; Sustainable agriculture; Willow; Wood Science & Technology; Perennial bioenergy crop; Carbon-13 isotope; Carbon sequestration; Land use change
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-018-9903-6

Bioenergy crops have a secondary benefit if they increase soil organic C (SOC) stocks through capture and allocation below-ground. The effects of four genotypes of short-rotation coppice willow ( Salix spp., ‘Terra Nova’ and ‘Tora’) and Miscanthus ( M.  ×  giganteus (‘Giganteus’) and M. sinensis (‘Sinensis’)) on roots, SOC and total nitrogen (TN) were quantified to test whether below-ground biomass controls SOC and TN dynamics. Soil cores were collected under (‘ plant ’) and between plants (‘ gap ’) in a field experiment on a temperate agricultural silty clay loam after 4 and 6 years’ management. Root density was greater under Miscanthus for plant (up to 15.5 kg m −3 ) compared with gap (up to 2.7 kg m −3 ), whereas willow had lower densities (up to 3.7 kg m −3 ). Over 2 years, SOC increased below 0.2 m depth from 7.1 to 8.5 kg m −3 and was greatest under Sinensis at 0–0.1 m depth (24.8 kg m −3 ). Miscanthus -derived SOC, based on stable isotope analysis, was greater under plant (11.6 kg m −3 ) than gap (3.1 kg m −3 ) for Sinensis. Estimated SOC stock change rates over the 2-year period to 1-m depth were 6.4 for Terra Nova, 7.4 for Tora, 3.1 for Giganteus and 8.8 Mg ha −1  year −1 for Sinensis. Rates of change of TN were much less. That SOC matched root mass down the profile, particularly under Miscanthus , indicated that perennial root systems are an important contributor. Willow and Miscanthus offer both biomass production and C sequestration when planted in arable soil.