Fly ash influence on near-surface temperature of a clay loam soil

Abstract

. 1998. Fly ash influence on near-surface temperature of a clay loam soil. Can. J. Soil Sci. 78: [345][346][347][348][349][350]. It has been suggested that fly ash, when applied as a soil amendment, would increase soil temperature. However, no quantitative data have been provided to support this hypothesis. This hypothesis was tested on four fly ash treatments (0, 100, 200, and 400 t ha -1 ) applied to clay loam soil in a randomized block design. Bi-hourly soil temperatures were measured on 3 summer days over 2 yr, and afternoon temperatures were measured on randomly selected spring days at 5-, 10-, and 20-cm depths in the four fly ash treatments. Temperatures were measured in conjunction with surface bulk density, water content, and particle size distribution which were also used to calculate thermal heat capacity. Fly ash decreased percent clay, soil water content, and soil heat capacity. Contrary to previously expected trends, fly ash amendment did not significantly increase mean daily soil temperature under dry conditions. Generalizations in the literature regarding the influence of fly ash on soil temperature, bulk density, and water-holding capacity must be considered carefully since they generally relate only to coarse to medium textured soils.Key words: Soil amendments, bulk density, reclamation, heat capacity, thermal diffusivity, thermal conductivity, volumetric water content, particle size distribution On mesurait aussi la température d'après-midi (14-16 h) à certains jours de printemps choisis au hasard. En même temps que la température du sol, on mesurait la densité apparente, la teneur en eau et la répartition granulométrique du sol de surface, ce qui a servi également à calculer la capacité calorifique totale. La présence de cendres volantes abaissait le pourcentage d'argile, la teneur en eau du sol et sa capacité calorifique. Contrairement aux tendances attendues, l'apport de cendres volantes n'accroissaient pas significativement la température moyenne journalière du sol en conditions arides. Les tentatives de généralisation publiées au sujet de l'influence des cendres volantes sur la température, la densité apparente et la capacité de rétention d'eau du sol doivent donc être abordé avec prudence puisqu'elles ne portent que sur des sols de texture grossière à moyenne.Mots clés: Amendements du sol, densité apparente, remise en valeur, capacité calorifique, diffusivité thermique, conductivité thermique, teneur volumétrique en eau, répartition granulométrique

Soil science at the University of Alberta: a century of service to science and society

“…Sale et al (1996Sale et al ( , 1997 showed potential of fly ash as a soil amendment as it decreased bulk density and influenced barley growth. Lussier and Chanasyk (1992) found fly ash improved soil tilth, and Hammermeister et al (1998aHammermeister et al ( , 1998b found it altered soil temperature regimes and posed potential boron toxicity issues. Studies on organic amendments showed enhanced soil water retention (Moskal et al 2001); deep ripping with or without additions of peat and manure improved subsoil drainage, alleviated compaction, and improved soil tilth ).…”