Important energy exchanges at soil surface
regulate the thermal environment within top soil layer and
the boundary layer above it. By this reason, the application
of mulches or the modelling of micro relief by soil tillage are
common practises to modify the thermal regime of a soil.
The aim of this study is to compare the effect on thermal
behaviour of a Luvisol resulting of soil tillage and the
application of stubble mulch and, different amounts of straw
mulch. For this purpose, experiments were performed from
January to May 2007 in a field sowed with winter wheat.
Temperatures were measured with copper-constantan (Type
T) thermocouples placed over straw and over stubble, at soil
surface and at 2, 4 and 8 cm depth. Temperatures above
canopy were also recorded.
Daily mean temperatures and temperature amplitudes
in the top soil layer covered by straw mulch were smaller
than those verified either by stubble mulch or with soil
tillage. Daily minimum temperatures in mobilized plots or
covered by stubble mulch were smaller than those verified in
plots covered by straw mulch, therefore being the former
treatments more susceptible to frost than the later ones.
Thermal differences between the four plots decreased
significantly with wheat growth. Implications of these
techniques of soil temperature control for crop growth are
also discussed
