Gao Jiakai, Shi Zhaoyong, Wu Haiming, Lv Jialong
College of Agriculture, Henan University of Science and Technology Luoyang 471023 PR China.
College of Natural Resources and Environment, Northwest A&F University Yangling Shaanxi 712100 PR China
RSC Adv. 2020 Feb 5;10(10):5785-5793. doi: 10.1039/c9ra10279e. eCollection 2020 Feb 4.
Dissolved organic matter (DOM) plays a critical part in many processes of the ecological environment due to its mobility and reactivity in the soil and water interface. In the presented study, excitation-emission matrices (EEM) coupled with parallel factor analyses (PARAFAC) and UV-visible spectroscopy were introduced to investigate the variation of DOM derived from wheat straw biochar produced at different pyrolysis temperatures (300 °C, 500 °C and 700 °C), qualitatively and quantitatively. The dissolved organic matter (DOM) content of 700 °C biochar achieved a maximum of 1.45 g kg, while a minimum of 0.61 g kg was found at 500 °C. Components consisting of protein and tryptophan-like, UVA humic acid-like and UVC humic acid-like substances were extracted from the fluorescence data using PARAFAC. The abundance of fluorescent components predicted that DOM was mainly composed of more aromatic humic materials and litter amino acids with the increase in the pyrolysis temperature. Additionally, a column experiment simulating a paddy field was conducted to evaluate the feasible application of biochar produced at different temperatures, and the results showed that biochar addition enhanced the aromaticity and accelerated the decomposition of DOM released from flooded paddy soil. However, the indices SUVA and SUVA showed increasing tendencies in the soil profile, which may be ascribed to the downward transport of water-soluble DOM during the period of leaching. Briefly, the findings obtained, reinforced by statistical analysis could provide some valuable and distinct optical information of DOM derived from biochar and offer technical guidance when incorporating biochar into paddy soil in agricultural production.
溶解性有机物（DOM）因其在土壤-水界面的流动性和反应活性，在许多生态环境过程中起着关键作用。在本研究中，采用激发-发射矩阵（EEM）结合平行因子分析（PARAFAC）和紫外-可见光谱，对不同热解温度（300℃、500℃和700℃）制备的小麦秸秆生物炭中DOM的变化进行了定性和定量研究。700℃生物炭的溶解性有机物（DOM）含量最高，达到1.45 g/kg，而500℃时最低，为0.61 g/kg。利用PARAFAC从荧光数据中提取了由蛋白质和类色氨酸、UVA类腐殖酸和UVC类腐殖酸物质组成的成分。荧光成分的丰度表明，随着热解温度的升高，DOM主要由更多的芳香族腐殖质和凋落物氨基酸组成。此外，进行了模拟稻田的柱实验，以评估不同温度下制备的生物炭的可行应用，结果表明，添加生物炭增强了芳香性，加速了淹水水稻土中释放的DOM的分解。然而，土壤剖面中SUVA和SUVA指数呈上升趋势，这可能归因于淋溶期间水溶性DOM的向下迁移。简而言之，通过统计分析得到的结果可以提供一些关于生物炭中DOM的有价值且独特的光学信息，并在农业生产中将生物炭纳入稻田土壤时提供技术指导。
