Effects of elevated CO.sub.2 and nitrogen addition on organic carbon and aggregates in soil planted with different rice cultivars

• Published in: Plant and soil Vol. 432; no. 1-2; p. 245
• Main Authors: Wu, Qicong, Zhang, Congzhi, Yu, Zhenghong, Zhang, Jiabao, Zhu, Chunwu, Zhao, Zhanhui, Xiong, Jiananran
• Format: Journal Article
• Language: English
• Published: Springer 01.11.2018
• Subjects: Carbon dioxide; Environmental aspects; Health aspects; Plant-soil relationships; Rice; Soil carbon
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-018-3801-8

Background and aims Elevated CO.sub.2 and nitrogen addition can increase rice yield and stimulate rice to absorb more nutrients from the soil. The aim of this study was to investigate how soil organic carbon and aggregates change under such high-output conditions. Methods Rice cultivars IIY 084 and WYJ 21 (strong and weak response to elevated CO.sub.2, respectively) were planted in free-air CO.sub.2 enrichment (FACE) platforms. Treatments included: 1) elevated CO.sub.2 without nitrogen addition (EC); 2) nitrogen addition and ambient CO.sub.2 (EN); 3) combined elevated CO.sub.2 and nitrogen addition (ECEN); and 4): ambient CO.sub.2 without N addition (CK). Soil organic carbon (SOC), readily-oxidizable organic carbon (ROC) and soil aggregate components were measured. Results Treatment EC increased SOC and ROC, while EN decreased SOC and ROC compared to CK in soil under either rice cultivar. EC and EN decreased the percentage of large macroaggregates (LM) and the mean weight diameter (MWD) of aggregates compared to CK in 'WYJ 21' soil, while they increased LM and MWD in 'IIY 084' soil. ECEN increased LM and MWD compared to CK in soil under either rice cultivar. Conclusions High productivity of 'IIY 084' through long-term cultivation under current N fertilization in future climatic conditions of elevated CO.sub.2 could be achieved due to increased soil aggregate stability and SOC.