Sisal (Agave sisalana) is a climate-resilient crop grown on large-scale farms in semi-arid areas. However, further studies are still required to elucidate the impacting mechanisms of stand age‐related effects on soil respiration such as the differences in photosynthesis in rubber plantations. Our results highlight the importance of environmental factors in determining the variation in RS in rubber plantations with different stand age.
The largest Q10 value of RH and RA was found in the old‐growth (49‐y plantation, 2.95) and the mature (32‐y plantation, 8.01) rubber plantations, respectively. The sensitivity of RS to increasing temperature (Q10) was higher in 32‐y and 49‐y than in 12‐y and 24‐y rubber plantations. The contribution of RA to RS was higher in the mature rubber plantation than that in the young (27%) and the old‐growth (20%) rubber plantations. RS was significantly and exponentially related to soil temperature (P < 0.0001) rather than soil water content which led to higher RS in the rainy season than that in the dry season. Our results showed that RS changed significantly among rubber plantations, with the highest RS in the old‐growth rubber plantation (49‐y plantation, 147.30 ± 6.91 mg CO2‐C m‐2 hr‐1) followed by the mature (137.16 ± 7.68 and 108.10 ± 4.83 in 24‐y and 32‐y plantation, respectively) and the young (12‐y plantation, 78.43 ± 3.84 mg CO2‐C m‐2 hr‐1) rubber plantations. A trenching method was used to partition soil respiration (RS) into autotrophic respiration (RA) and heterotrophic respiration (RH) for 3 years in 12, 24, 32, and 49 years‐old rubber plantations. This study aimed to assess the variation of soil respiration and its components in rubber plantations of different stand age. The land use change from tropical forests to rubber plantations has had a great influence on ecosystem‐level carbon (C) exchange and soil C dynamics.
Temperature sensitivity incorporated a combined response of soil respiration to soil temperature, soil water content, soil organic carbon, and fine root biomass and, thus, provided an ecological metric for comparing forest carbon dynamics of these species. davidiana plantations and when the soil water content was below 12.8%. Temperature sensitivity was also significantly higher in P. davidiana plantations, was found to increase with stand age. Temperature sensitivity of soil respiration, which ranged from 1.85–1.99 in P. There was no significant difference in soil respiration between the two plantation species at ages 5 and 10 years (p > 0.05). Soil respiration decreased with stand age for both species. Results showed that mean soil respiration in the 5-, 10-, and 20/30-year-old plantations was 3.37, 3.17, and 2.99 μmol This study investigated soil respiration and its temperature sensitivity at three stand ages (5, 10, and 20 or 30 years) in two plantations of coniferous (Pinus tabulaeformis Carrière) and deciduous (Populus davidiana Dode) species using an automated chamber system in 2013 in the Beijing-Tianjin sandstorm source area. Thus far, however, there is no consensus regarding the variations in soil respiration caused by stand age and forest type. Understanding the effects of stand age and forest type on soil respiration is crucial for predicting the potential of soil carbon sequestration.
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