Effect of crop residue addition on soil organic carbon priming as influenced by temperature and soil properties

Abstract

Priming of soil organic carbon (SOC) is a crucial factor in ecosystem carbon balance. Despite its increasing importance in the changing global climate, the extent of influence of temperature and soil properties on the priming effect remains unclear. Here, soil priming was investigated using 13 C labeled wheat residues in two cultivated subtropical soils of Australia (Vertisol and Luvisol) at four incubation temperatures (13, 23, 33 and 43°C). The priming effect was computed from respired CO2 and associated δ 13 C, which were measured periodically over the 52-day incubation period. Wheat residue addition resulted in greater priming effect in the Luvisol (1.17 to 2.37% of SOC) than the Vertisol (0.02 to 1.56 % of SOC). The priming of SOC was the highest at 23°C in the Luvisol, and at 43°C in the Vertsiol, which indicates a variable positive priming effect of temperature in different soil types. Wheat residue addition significantly increased the temperature sensitivity (Q10) of SOC mineralization in the Vertisol at temperature ranges below 33°C (i.e., 13-23 and 23-33°C) and had no significant effect in the Luvisol. A negative correlation was observed between temperature and the Q10 values. Across soils, the Q10 of residue C was lower than SOC suggesting that soil C is more vulnerable to climatic warming. This work demonstrates that the magnitude of SOC priming by wheat residue and Q10 of SOC mineralization varied significantly with soil type (Luvsiol > Vertisol) and incubation conditions (temperature and time). Given the current trend towards increasing atmospheric temperatures, future studies should evaluate temperature effects on the priming of different pools of SOC induced by crop residue in different agro-ecosystems.

Impact of tillage practices on soil aggregation and humic substances under double‐cropping paddy field

“…In the present study, there was a significant difference in size class of soil aggregates under different soil tillage treatments, where each size class of soil aggregates under the CT, RT, and NT treatments were higher (P < .05) than that under the RTO treatment in both years, as was also reported by Zhang et al (2018). The reason for this could be due to the different mechanisms of effects (soil microbial activities, soil particles, and soil moisture content) on soil aggregation of crop residues and soil tillage practices (Lenka et al, 2019). Furthermore, the soil physical structure was also affected by the CT, RT, and NT tillage practices in Chinese milk vetch and double-cropping rice systems, the soil aggregate stability was increased, and the aggregate-binding materials produced by plant roots and rhizosphere played a synergistic role during the crop growth stages (Jensen et al, 2019).…”

“…(). The reason for this could be due to the different mechanisms of effects (soil microbial activities, soil particles, and soil moisture content) on soil aggregation of crop residues and soil tillage practices (Lenka et al., ). Furthermore, the soil physical structure was also affected by the CT, RT, and NT tillage practices in Chinese milk vetch and double‐cropping rice systems, the soil aggregate stability was increased, and the aggregate‐binding materials produced by plant roots and rhizosphere played a synergistic role during the crop growth stages (Jensen et al., ).…”

“…Soil organic carbon (SOC) plays an important role in sustaining soil fertility and quality, and the role of SOC in agriculture and ecosystem sustainability has been identified by many researchers (Lenka et al., ; Tang et al., ). Some field management practices, such as soil tillage, organic manures, and the use of crop residues were recommended to help sequester carbon (Saikia, Sharma, Thind, Sidhu, & Yadvinder, ).…”

“…Some field management practices, such as soil tillage, organic manures, and the use of crop residues were recommended to help sequester carbon (Saikia, Sharma, Thind, Sidhu, & Yadvinder, ). Therefore, the SOC content and soil properties are affected by different soil tillage and crop residues practices (Gupta Choudhury et al., ; Kumar et al., ; Lenka et al., ). In general, the SOC content and stocks increased in the upper soil layer under no‐tillage (Xu et al., ), but the SOC content and stocks decreased in the subsoil layer when compared with plow tillage (Hu, Shi, Wang, Gu, & Zhu, ).…”

“…Soil organic carbon (SOC) plays an important role in sustaining soil fertility and quality, and the role of SOC in agriculture and ecosystem sustainability has been identified by many researchers (Lenka et al, 2019;Tang et al, 2019). Some field management practices, such as soil tillage, organic manures, and the use of crop residues were recommended to help sequester carbon (Saikia, Sharma, Thind, Sidhu, & Abbreviations: C-FAF, soil fulvic acid; C-HAF, soil humic acid; C-HUM, soil humin; CT, conventional tillage with crop residue incorporation; NT, no tillage with crop residue incorporation; RT, rotary tillage with crop residue incorporation; RTO, rotary tillage without crop residue incorporation; SOC, soil organic carbon.…”