Five-year vegetation conversion from pasture to C3 and C4 plants affects dynamics of SOC and TN and their natural stable C and N isotopes via mediating C input and N leaching

• Published in: The Science of the total environment 2024-02, Vol.912, p.169481-169481, Article 169481
• Main Authors: Hosogoe, Yuka, Nguyen-Sy, Toan, Tang, Shuirong, Bimantara, Putu Oki, Sekikawa, Yuka, Kautsar, Valensi, Kimani, Samuel Munyaka, Xu, Xingkai, Tawaraya, Keitaro, Cheng, Weiguo
• Format: Article
• Language: English
• Subjects: Climate change; cold; dissolved organic carbon; environment; Eulalia; Japan; land use change; leachates; Lysimeter experiment; lysimeters; nitrates; nitrogen; pastures; soil; soil organic carbon; Soil organic matter; sustainable agriculture; total nitrogen; Vegetation conversion; vegetation types; δ13C; δ15N
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.169481

Understanding the effects of land-use change on stock and composition of soil organic carbon (SOC) and nitrogen (N) is pivotal for sustainable agriculture and climate change adaption. However, previous studies have often overlooked the specific vegetation type in land-use changes. Therefore, a five-year lysimeter block experiment was conducted, involving non-vegetation, eulalia (C4 plant), and clover (C3 plant) to investigate the impacts of vegetation conversion from pasture on SOC and N dynamics and their natural stable isotopes. Non-vegetation caused 26.21 % and 25.88 % decreases in SOC and total N (TN) contents. Five-year eulalia and clover cultivation maintained stable SOC content, with clover exhibiting higher soil TN content. Eulalia-derived soil C was 1.64–7.58 g C kg−1 and SOC loss in eulalia treatment was 1.86–7.90 g C kg−1. Soil δ13C in eulalia increased at a rate of 0.90 ‰ year−1, significantly surpassing clover and non-vegetation treatments. Conversely, soil δ15N decreased over time, showing insignificant difference among all treatments. Eulalia exhibited significantly higher dry weight and δ13C but lower TN content compared with clover. However, no significant differences were observed in total C and δ15N between the two vegetation treatments. Non-vegetation exhibited higher dissolved organic C concentration than two vegetation treatments in 2017, decreasing over time. Dissolved TN and nitrate concentrations in leachate followed the order clover> non-vegetation> eulalia, with nitrate being the predominant form of N leaching from leachate. Our findings reveal that vegetation conversion affects soil C and N contents, and alters their natural isotopes as well as the leaching of labile soluble nutrients. Notably, non-vegetation consistently reduced SOC and TN contents, whereas eulalia cultivation maintained SOC content, improved C/N ratio and δ13C, and reduced N leaching compared with clover cultivation. These results highlight the potential of eulalia as a candidate plant for enhancing C sequestration and reducing N leaching in cold regions of Japan. [Display omitted] •A 5-year vegetation change from pasture to eulalia and clover was conducted in Japan.•Non-vegetation decreased SOC and TN contents by 26.21 % and by 25.88 %, respectively.•Eulalia had higher soil δ13C but the decreased soil δ15N was similar in all treatments.•Eulalia-derived C and SOC loss in eulalia was 1.64–7.58 g kg−1 and 1.86–7.90 g kg−1.•Eulalia did not alter SOC but improved