Tillage history and crop residue input enhanced native carbon mineralisation and nutrient supply in contrasting soils under long-term farming systems

Title
Tillage history and crop residue input enhanced native carbon mineralisation and nutrient supply in contrasting soils under long-term farming systems
Publication Date
2019-10
Author(s)
Sarker, Jharna Rani
Singh, Pal Bhupinderpal
Fang, Yunying
Cowie, Annette L
Dougherty, Warwick J
Collins, Damian
Dalal, Ram C
Singh, Brajesh K
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier BV
Place of publication
The Netherlands
DOI
10.1016/j.still.2019.05.027
UNE publication id
une:1959.11/58232
Abstract

Understanding the legacy effect of tillage-based farming systems on soil organic carbon (SOC) mineralisation and nutrient [nitrogen (N), phosphorus (P) and sulphur (S)] supply after crop residue input is critical to appropriately manage plant available nutrients at the farm scale. To enhance this understanding, crop residues [canola (Brassica napus: δ13C 124‰) or wheat (Triticum aestivum: δ13C 461‰)] were added to Luvisol and Vertisol from two long-term (16–46 years) field experiments and incubated under a controlled environment for 126 days. The practices in the Luvisol were conventional tillage (CT) and reduced tillage (RT) under mixed crop-pasture rotation, and no-till (NT) under continuous cereal-cover crop rotation. The practices in the Vertisol were CT and NT under wheat-wheat rotation. The residue input significantly stimulated SOC mineralisation via "positive priming", which was greater (p < 0.05) in the CT than RT/NT in the Luvisol only. The SOC mineralised after 126 days was 3.1–4.2 and 1.6–2.5 times higher in the canola and wheat residue-amended soils, respectively, than the unamended soils. Although the CT or RT versus NT had higher net N availability in the Luvisol only, the residue input did not increase plant available N in both soils, possibly due to stronger residue-induced N immobilisation than mineralisation. The results showed a significant release of available P and S in both residue amended soils (canola > wheat) after 26–50% of residue-C was mineralised over 126 days, and the Vertisol had greater net available P than Luvisol. Our results suggest that considerable quantities of available P and S may release from the soil reserves via SOC priming, and possibly via dissolution/desorption reactions in the soils, in addition to their direct release from the residues. In conclusion, crop residue input to historical farming systems enhanced the supply of available P and S, which varied with tillage, crop residue and soil type.

Link
Citation
Soil and Tillage Research, v.193, p. 71-84
ISSN
0167-1987
Start page
71
End page
84

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