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EFFECT OF SOIL TILLAGE AND COMPACTION ON GREENHOUSE
GAS FLUXES
Lipiec J., Hatano R.
INTRODUCTION
Long term data indicate considerable uncertainty in the evaluation of anthropogenic
greenhouse gas emissions. Recent evaluations imply greater input of greenhouse
gases to the atmosphere from agricultural production than that previously
estimated (Mosier et al., 1998). In this paper we summarize the effects of tillage
practices and compaction with highliting recent literature.
CARBON DIOXIDE
Management practices significantly influence acting of soil as a sink or source
for atmospheric CO 2 and therefore play an important role in sequestering C in soil
(Fortin et al., 1996; Paustian et al., 2000).
Tillage practices
Usually, reduced tillage or no-till vs. conventional tillage results in lower CO 2
emission (e.g. Reicosky et al., 1997; La Scala et al., 2001; Sánchez et al., 2002)
and greater gains of soil organic carbon in soil (Ball et al., 1999; McConkey et al.,
2003). This effect is enhanced by clay content and to a higher extent under subhumid
than semi-arid conditions (McConkey et al., 2003).
Emission of CO 2 is considerably different during and the time since tillage. It was
shown that maximum emission in CO 2 taking place during tillage quickly decline
with time passed after tillage. Comparison of results from different studies revealed
that highest emission at tillage was up to approximately 1.6 g CO 2 -C m -2 h -1 (Wuest
et al. (2003) and 0.5 g CO 2 -C m -2 h -1 after 1 day (Rochette and Angers, 1999) and
0.25g CO 2 -C m -2 h -1 after 15 days (La Scala Jr. et al., 2001). Short-lasting effect of
tillage on CO 2 -C emission was enhanced during the summer seasons (Rochette and
Angers, 1999; Alvarez et al., 2001) when plowing produces in the short-term an
important soil temperature increase and thus more favorable conditions to microbial
activity . The opposite was, however, observed following spring plowing under
cool and wet conditions of Canada (Rochette and Angers, 1999). Figure 1 illustrates
this.
Short-term responses to tillage may be less pronounced in soils with a long history
of cultivation because of a relatively resilient microbial community and/or
because lower initial microbial biomass and nutrient pools preclude a strong response
to disturbance (Calderón et al., 2000). Greater fluxes of CO 2 in tilled soil
went along with enhanced water vapor fluxes and associated soil water losses (Reicosky
et al., 1999; Prior et al., 2000). The relative differences in carbon dixide
emission decreased with time passed after tillage and were related to soil tempera-
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