SOIL TEMPERATURE REGIME IN TOP SOIL LAYER WITH BIOCHAR AMENDMENT

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-05-8 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 32, 523-530 pp, DOI: DOI: 10.5593/sgem2017/32/S13.068

ABSTRACT

Biochar is a porous, carbon-rich material produced by heating of organic matter to temperatures between 300 °C and 1000 °C in an environment with limited or no oxygen. During the past decade, numerous articles focusing on the use of biochar have been published, but have shown inconsistent results. Reactions in the soil after the addition of biochar depend on the characteristics of biochar, soil, climate and soil-inhabiting organisms. However, due to high variability in the quality of biochar, its effects on soils and plants are likely to differ. Pyrolysis temperature has also large effect on biochar characteristics.
Little is known about the effects of biochar amendment on soil thermal properties and soil temperature, especially in field conditions. The objective of this study was to evaluate an effect of biochar amendment and actual water content on soil temperature at experimental field in Nitra-Malanta area (Slovakia). The biochar was applied at rate of 0, 10 and 20 t/ha-1 to a depth 0-15 cm of soil profile in year 2014. We focused on an analysis of treatment without biochar amendment (Control) and treatment with biochar applied at rate of 20 t/ha-1 (B20). Soil temperature and soil water content (SWC) were measured in depth of 5 cm in year 2015 using 5TM sensors by Decagon Devices. Measurements were conducted in the period from August to October in 5 minute interval. The field was sown with maize (Zea mays L.). Results showed no significant difference in average daily soil temperature at 5 cm depth of soil profile among studied treatments. There was dependence between SWC and soil temperature. With increasing SWC, the volume of air in pores was decreasing, i.e. higher content of soil water as a better heat conductor increased the thermal conductivity of soil.

Keywords: biochar, soil temperature, soil moisture, field measurements