Kravchenko Ekaterina, Wang Yu Chen, Dela Cruz Trishia Liezl, Ng Charles Wang Wai
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
Sci Total Environ. 2023 Oct 10;894:164922. doi: 10.1016/j.scitotenv.2023.164922. Epub 2023 Jun 17.
As a primary source of greenhouse gas emissions and a carbon sink, soil plays a key role in climate regulation. The development of cracks in soil strongly influences CO emissions, and soil amendment with biochar has been shown to reduce cracking. However, the impact of biochar on CO emissions during soil cracking is not well understood. This study investigates the release of CO flux during the cracking of peanut shell biochar-amended soil. The biochar-amended soil was incubated at a constant temperature of 35 °C for 160 h with periodic photography and analysis of CO concentration and soil moisture. To achieve continuous monitoring of incubation soil, a new coupled sensor was specially designed to measure CO concentration and soil moisture, based on the Arduino microcontroller. Measured results reveal that peanut shell biochar reduced the evaporation rate by 29 % compared to unamended soil, resulting in slower soil cracking caused by water loss. The biochar also decreased the shrinkage crack length by 20 % compared to unamended soil. In addition, the crack volume fraction was reduced by 16 % after the peanut shell biochar amendment. Due to the reduction of the soil crack channel openings during drying shrinkage when biochar was applied to the soil, cumulative CO fluxes were also reduced by 5 % compared to unamended soil. The presence of biochar induced more stable and larger compounds with the soil particles, which blocked the crack propagation path and inhibited further development of the crack.
作为温室气体排放的主要来源和碳汇，土壤在气候调节中起着关键作用。土壤裂缝的发展强烈影响二氧化碳排放，并且已表明用生物炭改良土壤可减少裂缝。然而，生物炭对土壤开裂过程中二氧化碳排放的影响尚不清楚。本研究调查了花生壳生物炭改良土壤开裂过程中二氧化碳通量的释放情况。将生物炭改良土壤在35℃恒温下培养160小时，定期拍照并分析二氧化碳浓度和土壤湿度。为了实现对培养土壤的连续监测，基于Arduino微控制器专门设计了一种新型耦合传感器来测量二氧化碳浓度和土壤湿度。测量结果表明，与未改良土壤相比，花生壳生物炭使蒸发速率降低了29%，从而减缓了因水分流失导致的土壤开裂。与未改良土壤相比，生物炭还使收缩裂缝长度减少了20%。此外，花生壳生物炭改良后，裂缝体积分数降低了16%。由于在土壤干燥收缩过程中，当生物炭施用于土壤时土壤裂缝通道开口减少，与未改良土壤相比，累积二氧化碳通量也降低了5%。生物炭的存在使土壤颗粒形成更稳定、更大的化合物，从而阻塞了裂缝扩展路径并抑制了裂缝的进一步发展。
