Adequacy of contrasting sampling methods for root mass quantification in a slash-and-burn agroecosystem in the eastern periphery of Amazonia

• Published in: Biology and fertility of soils 2010-10, Vol.46 (8), p.851-859
• Main Authors: Rodrigues de Sousa, João Thiago, Gehring, Christoph
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agricultural production; Agriculture; Biomass; Biomedical and Life Sciences; Coarse roots; Cultivation; Fine roots; Land use; Life Sciences; Monolith; Original Paper; Regrowth; Root auger; Root biomass; Sampling methods; Sampling scheme; Sampling techniques; Shifting cultivation; Slash and burn; Soil depth; Soil profiles; Soil Science & Conservation; Soil sciences; Terrestrial ecosystems; variability
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-010-0490-8

Root research needs to optimize sampling schemes to address different scales and dimensions of variability within a framework of feasible effort and, in some cases, acceptable soil perturbation. Both large and small sample volumes are utilized in root research, and this study is designed to help field researchers in optimizing root sampling. We evaluate the performance of three contrasting sampling strategies—large monoliths (LM, 25 dm⁻³), small monoliths (SM, 3 × 1 dm⁻³), and root auger (RA, 5 × 196.3 cm⁻³). We compare root biomass estimates obtained in a shifting cultivation agroecosystem in eastern Amazonia. We sampled a slash-and-burn field at 1/2 and 1 1/2 years of cultivation, and a paired 3-year-old spontaneous secondary forest regrowth down to 1 m soil depth, and we distinguish roots by diameter class and taxonomic origin (palm vs. non-palm roots). LMs are the only reliable quantification method for coarse roots. Both SM and RA methods are inadequate due to high variability and the frequent failure to detect the presence of coarse roots in the sampled soil. The SM method is acceptable for mid-sized (2-5 mm) roots, and both methods are adequate for fine root (