Structure alteration of a sandy-clay soil by biochar amendments
- 879 Downloads
The aim of the present study was to investigate structure alterations of a sandy-clay soil upon addition of different amounts of biochar (f bc ).
Materials and methods
All the f bc samples were analyzed by high energy moisture characteristic (HEMC) technique and 1H nuclear magnetic resonance (NMR) relaxometry. HEMC was applied in order to evaluate aggregate stability of biochar-amended soil samples. 1H NMR relaxometry experiments were conducted for the evaluation of the pore distributions through the investigation of water dynamics of the same samples.
Results and discussion
The HEMC technique revealed improvement in aggregate stability through measurements of the amount of drainable pores and the stability ratio. The latter increased as the amount of biochar was raised up. The 1H NMR relaxometry revealed a unimodal T 1 distribution for both the sole sandy-clay soil and the biochar. Conversely, a bimodal T 1 distribution was acquired for all the different f bc samples.
Improvement in aggregate stability was obtained as biochar was progressively added to the sandy-clay soil. A dual mechanism of water retention has been hypothesized. In particular, intra-aggregate porosity was indicated as the main responsible for molecular water diffusion when f bc comprised between 0 and 0.33. Conversely, inter-aggregate porosity resulted predominant, through swelling processes, when f bc overcame 0.33.
KeywordsBiochar Biochar amended soils High energy moisture characteristics NMR relaxometry
- Conte P, Alonzo G (2013) Environmental NMR: fast-field-cycling relaxometry. eMagRes 2:389–398Google Scholar
- Crescimanno G, Baiamonte G (1999) Hydraulic characterization of swelling/shrinking soils by a combination of laboratory and optimization techniques. In: Int. Workshop European-Society-of-Agricultural-Engineers, Field of Interest on Soil and Water on “Modelling of transport processes in soils at various scale in time and space”, Leuven, Belgium, 24–26 November 1999Google Scholar
- Eswaran H, Rice T, Ahrens R, Stewart BA (2002) Soil classification—a global desk reference. CRC Press Boca Radon FL (USA)Google Scholar
- Hillel D (2004) Introduction to environmental soil physics. Elsevier Science, London UKGoogle Scholar
- Kishimoto S, Sugiura G (1985) Charcoal as a soil conditioner. Int Achieve Future 5:12–23Google Scholar
- Ouyang L, Wang F, Tang J, Yu L, Zhang R (2013) Effects of biochar amendment on soil aggregates and hydraulic properties. J Soil Sci Plant Nutr 13(4):991–1002Google Scholar
- Pusceddu E, Criscuoli I, Miglietta F (2013) Morphological investigation and physical characterization of ancient fragments of pyrogenic carbon. J Phys: Conf Ser 470:012003Google Scholar
- Stolte J, Veerman G (1991) Manual of soil physical measurements. Version 2.0 Winand Staring Centre (ed) Wageningen, the NetherlandsGoogle Scholar
- van Genuchten MT, ThLeij FJ, Yates SR (1991) The RETC code for quantifying the hydraulic functions of unsaturated soils. U.S. Salinity Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Riverside, CaliforniaGoogle Scholar
- White RE (2006) Principles and practice of soil science, 4th edn. Blackwell Publishing, MA, USAGoogle Scholar