Ntonta S., Zengeni R., Muchaonyerwa P., Chaplot Vincent
Source
Rhizosphere, 2024,
29, p. 100850 [10 p.]
Crop residue decomposability in soils is of major importance for maintaining soil carbon (C) stocks and nitrogen (N) mineralization, which are vital for soil fertility and climate change mitigation. The impact of biochemical quality on decomposition and N mineralization of sorghum cultivars and/or crop residue parts is not well documented. In the present study, field and laboratory experiments spanning 168 and 120 days, respectively, were used to assess the rate of decomposition and N mineralization in soils from five sorghum cultivars and to relate the results with residue quality (i.e. lignin: N ratio) over time. High-quality cultivars (i.e., Mamolokwane and OS-Potch) exhibit rapid decomposition (>50% DM loss) and elevated carbon dioxide emissions in shoots, attributed to a low lignin-to-nitrogen ratio. Low-quality residues (i.e., AS8 and KZ5246) initially undergo net nitrogen immobilization, transitioning to mineralization at later stages. Notably, shoots consistently release more nitrogen than roots, with distinct NO3 -N mineralization values ranging from 22.7 to 11.5 mg N/kg for OS-Potch and KZ5246 shoots and 20.6 to 9.3 mg N/kg for their root residues. Results suggest that low-quality sorghum residues, particularly KZ5246 and AS8 roots, release carbon and nitrogen at a slower rate, providing potential for carbon storage and limited nitrogen availability compared to high-quality residues like OS-Potch shoots.
Plan de classement
Sciences du milieu [021]
;
Pédologie [068]
;
Sciences du monde végétal [076]
