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Pathways of different forms of nitrogen and role of ammonia‐oxidizing bacteria in alkaline residue sand from bauxite processing
Author(s) -
Goloran J. B.,
Chen C. R.,
Phillips I. R.,
Liu X.
Publication year - 2015
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12274
Subject(s) - chemistry , nitrification , leaching (pedology) , fertilizer , mineralization (soil science) , ammonium , ammonia volatilization from urea , environmental chemistry , nitrogen cycle , nitrogen , ammonia , denitrifying bacteria , nitrate , agronomy , denitrification , soil water , ecology , biology , biochemistry , organic chemistry
Summary Nitrogen ( N ) dynamics and associated processes are often overlooked in the rehabilitation protocols of disturbed landscapes. This study reports on the transformations of N fertilizers and the microbial community, and plant growth responses in rehabilitated strongly alkaline residue sand from bauxite processing ( BRS ). Ryegrass was grown in specifically designed growth chambers in a two‐factorial completely randomized design. Different forms of N fertilizer, such as ammonium sulphate ( AS ), potassium nitrate ( KN ) and glycine ( GL ), were applied at two rates. Nitrogen uptake by plants, residual inorganic N and N losses through leaching and volatilization were determined and quantified throughout the growing period. The abundance of both ammonia‐oxidizing archaea ( AOA ) and bacteria ( AOB ) was determined by quantitative polymerase chain reaction. The results showed that N uptake was greater with KN fertilizer (31.3–56.4%) than with AS (23.4–47.8%) and GL (16.4–38.1%), in spite of the substantial leaching loss of NO 3 − . Combined N losses by volatilization and leaching with GL (39–53%) and AS (40–60%) fertilizers indicated both physico‐chemical and biological transformations of N by mineralization and nitrification. Ammonia‐oxidizing bacteria, rather than AOA , were the dominant nitrifiers that colonized the freshly rehabilitated BRS growth media. The gene copy number of AOB correlated with both soil extractable NO 3 − ‐ N ( r = 0.92, P < 0.001) and ryegrass leaf biomass N ( r = 0.89, P < 0.001). We concluded that AOB play a pivotal role in the cycling of N in BRS , whereas NO 3 − ‐ N is critical for plant N nutrition and rehabilitation in the alkaline BRS disposal areas.