The relative importance of influence factors to field soil respiration is shifted by straw incorporations: comprehensive analysis of the seasonal variability

• Published in: Journal of soils and sediments Vol. 19; no. 4; pp. 1651 - 1660
• Main Authors: Jiang, Chunming, Yu, Wantai
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2019; Springer Nature B.V
• Subjects: Agricultural management; Agricultural practices; Biodegradation; Biotic factors; Carbon dioxide; Carbon sequestration; Crops; data collection; developmental stages; Dynamics; Earth and Environmental Science; emissions; Environment; Environmental Physics; Growing season; Growth stage; Metabolism; Microbial degradation; Microorganisms; monitoring; Rain; Rainfall; Respiration; Seasonal variation; Seasonal variations; Seasons; Sec 1 • Soil Organic Matter Dynamics and Nutrient Cycling • Research Article; Soil; soil carbon; Soil dynamics; Soil moisture; soil respiration; Soil Science & Conservation; Soil temperature; soil water; Soils; Straw; Temperature; Temperature effects; Seasonal variability; emission; Temperature sensitivity; CO; Straw incorporation
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-018-2211-0

Purpose Understanding the effects of agricultural managements (e.g., straw incorporation) on soil respiration ( R s ) and its temperature sensitivity ( Q 10 ) is crucial for accurate estimation of the soil carbon sequestration potential under an increasing-temperature scenario in the future. However, how the influence drivers regulate R s and whether their relative roles are changed under different agricultural practices remain unexplored. Materials and methods Static chambers were used to monitor field CO 2 flux in one growing season for a straw return experiment, which had been amended with different amounts of straw (CK, no straw return; S 4 , straw amendment at 4000 kg ha −1 ; and S 8 , straw amendment at 8000 kg ha −1 ) for five consecutive years. Results and discussion Our monitoring showed that R s was elevated with intensified use of straw and confirmed soil temperature, soil moisture, and rainfall were important seasonal drivers of R s . Moreover, the lower coefficient of variations (CV) for each series of treatments of R s was detected at the vigorous growth stage of the crop, implying the biotic factor of crop roots might also exert a role simultaneously. Straw addition tended to reduce Q 10 , probably due to the fact that the microbial degradation of SOC in S 4 and S 8 was less sensitive to temperature change. Interestingly, the Q 10 of S 4 but not S 8 was significantly smaller ( P  < 0.05) than that of CK as the reduced magnitude of Q 10 for S 4 was more profound. This result corresponded with more proportional growth of crop root of S 8 than S 4 . By comprehensively analyzing the seasonal variability of our data set, we inferred that for S 8 , the negative impact of straw incorporation on Q 10 would be more offset by upregulated root metabolism. Conclusions Although additional works were needed to corroborate and specify this explanation, present research highlighted the abiotic and biotic factors should both be incorporated to analyze the underlying mechanisms responsible for the seasonal dynamics of soil C emissions under agricultural managements.