The effects of rice (Oryza sativa L. ssp. japonica) husk biochar on nitrogen dynamics during the decomposition of hairy vetch in two soils under high-soil moisture condition. Issue 2 (4th March 2017)

• Record Type: Journal Article
• Authors: Shimotsuma, Moe; Uchida, Yoshitaka; Nakajima, Yasuhiro; Akiyama, Hiroko
• Is Part Of: Soil science and plant nutrition. Volume 63:Issue 2(2017)
• Page Start: 178
• Page End: 184
• Publication Date: 2017-03-04
• Subjects: N2O -- N2 -- andosol -- fluvisol -- soil type; Soil science -- Periodicals; Plants -- Nutrition -- Periodicals; 631.4
• DOI: 10.1080/00380768.2017.1290498
• Languages: English
• ISSNs: 0038-0768

Abstract

ABSTRACT: Legumes, including hairy vetch ( Vicia villosa Roth), are widely used as green manures. They fix nitrogen (N) and provide the N to other crops when they decompose, and thus are considered alternatives for chemical N fertilizers. However, N-rich plant residues, including hairy vetch, are also sources of soil nitrous oxide (N2 O) emissions, a greenhouse gas. On one hand, rice ( Oryza sativa L. ssp. japonica) husk biochar is widely used as a soil conditioner in Japan and has been reported as a tool to mitigate soil N2 O emissions. We conducted a soil core incubation experiment (1.5 months) to compare the N2 O emissions during the decomposition of surface-applied hairy vetch (0.8 kg dried hairy vetch m −2 soil) under semi-saturated soil moisture conditions (~100% water-filled pore space (WFPS)), using two soil types, namely Andosol and Fluvisol. Throughout the incubation period, the use of biochar suppressed soil NH4 + -N concentrations in Andosol, whereas the effect of biochar on NH4 + -N was not clear in Fluvisol. Biochar increased the nitrate (NO3 − -N) levels both in Andosol and Fluvisol, suggesting a negative influence on denitrification and/or a positive influence on nitrification. Biochar application did not influence the cumulative N2 O emissions. Our study suggests that rice husk biochar is not a good option to mitigate N2 O emissions during the decomposition of surface-applied hairy vetch, although this study was performed under laboratory conditions without plants. However, the trends of the inorganic-N concentration changes followed by the addition of hairy vetch and biochar were markedly different between the two soil types. Thus, factors behind the differences need to be further studied.