Effects of autumn tillage and residue management on soil respiration in a long‐term field experiment in Sweden

Abstract

Several previous field studies in temperate regions have shown decreased soil respiration after conventional tillage compared with reduced or no-tillage treatments. Whether this decrease is due to differences in plant residue distribution or changes in soil structure following tillage remains an open question. This study investigated (1) the effects of residue management and incorporation depth on soil respiration and (2) biological activity in different post-tillage aggregates representing the actual size and distribution of aggregates observed in the tilled layer. The study was conducted within a long-term tillage experiment on a clay soil (Eutric Cambisol) in Uppsala, Sweden. After 38 y, four replicate plots in two long-term treatments (moldboard plowing (MP) and shallow tillage (ST)) were split into three subplots. These were then used for a short-term trial in which crop residues were either removed, left on the surface or incorporated to about 6 cm depth (ST) or at 20 cm depth (MP). Soil respiration, soil temperature, and water content were monitored during a 10-d period after tillage treatment. Respiration from aggregates of different sizes produced by ST and MP was also measured at constant water potential and temperature in the laboratory. The results showed that MP decreased short-term soil respiration compared with ST or no tillage. Small aggregates (< 16 mm) were biologically most active, irrespective of tillage method, but due to their low proportion of total soil mass they contributed < 1.5% to total respiration from the tilled layer. Differences in respiration between tillage treatments were found to be attributable to indirect effects on soil moisture and temperature profiles and the depth distribution of crop residues, rather than to physical disturbance of the soil.

Modelling soil and root respiration in a cotton field using the DNDC model

“…First, this model predicted that soil respiration increased by 16% as the temperature increased from 7.35°C to 13.35°C. This result is consistent with previous studies, which suggested that soil respiration has a significant positive correlation with temperature if soil water content is not a limiting factor ( Zhao et al, 2013; Kainiemi et al, 2015). Second, several publications suggested that the temperature sensitivity of soil respiration decreased with increasing temperature ( Zheng et al, 2009; Zhao et al, 2013).…”

Structural disruption of arable soils under laboratory conditions causes minor respiration increases

“…Our results show that although physical disruption of soils causes SOC losses, the C amounts released are so small that it would take many decades before they could be detected in field trials. This result is supported by previous field studies in Sweden ( Kainiemi et al, 2015), where it was found that the main factor driving soil respiration was management of plant residues and that physical disturbance of the soil structure had no significant effect.…”

“…, Azooz et al., 1997). These reasons also explained higher respiration rates observed in the field when crop residues were left on the soil surface than when incorporated into the soil ( Kainiemi et al, 2015).…”

How does tillage intensity affect soil organic carbon? A systematic review

“…However, changes in soil moisture and temperature and treatment-specific distribution of crop residues have been found to be highly important [e.g. [80][81][82][83]. According to a meta-analysis conducted by Virto et al [32] differences in SOC stocks between NT and inversion tillage were significantly and positively correlated with differences in crop yields.…”