Sugarcane cultivation altered soil nitrogen cycling microbial processes and decreased nitrogen bioavailability in tropical Australia
Journal Publication ResearchOnline@JCUAbstract
Purpose: Land use conversion of natural ecosystems to intensive agriculture can alter soil biogeochemical processes and nutrient cycling, while increasing potential for land degradation. The disturbance of soil microbial community, due to land use conversion, may also lead to detrimental effects on soil ecosystem processes and services. Therefore, the objective of this study was to examine how sugarcane cultivation alters soil nitrogen (N) bioavailability and associated microbial processes in tropical Australia. Methods: Two adjacent paired sites (native forest vs sugarcane cultivation for 78 years; pasture vs sugarcane cultivation for 78 years) were selected and five composite surface soils (0–10 cm) were collected from each site. Results: Sugarcane cultivations decreased total organic carbon (OC; 45–48%), total N (51–54%), and total phosphorus (P; 26–37%) pools compared with native forest and pasture. Total mineral N (NH4+-N + NO3−-N), dissolved organic C and N contents and cumulative aerobic respiration were also lower in sugarcane than native forest and pasture lands. Reduction in soil microbial biomass (60%) following long-term conversion to sugarcane has resulted in higher metabolic quotient (qCO2) and lower C use efficiency, indicating higher level of environmental stresses in sugarcane sites. Among N cycling-associated genes, only narG showed significantly higher abundance in sugarcane than pasture land use, while narG, nosZ, nirK and nirS genes had significantly lower copy numbers in sugarcane compared with native forest. Conclusion: Sugarcane cultivation decreased soil health and biochemical quality, N bioavailability, and N cycling processes in tropical climate of this study.
Journal
Journal of Soils and Sediments
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Volume
24
ISBN/ISSN
1614-7480
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Pages Count
10
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Publisher
Springer
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DOI
10.1007/s11368-023-03704-7