Land-use intensification and dairy effluent effects on soil water repellency and soil carbon of a silt loam topsoil

ABSTRACT

In Canterbury, New Zealand, there has been widespread conversion of dryland sheep grazing to more intensive irrigated dairying. We determined the effects of these land uses on soil carbon on a centre-pivot sprinkler-irrigated dairy farm site, a dryland sheep site, and a non-grazed control site. The dairy site had significantly greater carbon density and carbon storage at 10–20 cm and 0–30 cm depths than the sheep farm site. The dairy farm site had significantly greater carbon stock (equivalent soil mass method) than the sheep farm site at 10–20 cm depth. The dairy farm site intensification did not adversely affect soil carbon, including carbon stock by the equivalent soil mass method. The effects of dairy effluent application on soil water repellency and water movement were investigated. The dairy site had significantly greater subcritical repellency index than the sheep site and a dairy effluent site. Further research is required across more farms and soils to confirm these results in these land uses and under other management and climate conditions.

KEYWORDS:

• Soil carbon
• repellency
• soil quality
• soil health
• intensification

Acknowledgements

The authors would like to thank the Lincoln University Dairy Farm and other farm staff; Neil Smith, Roger Cresswell, Leanne Hassall, Vicki Zhang at Lincoln University; John Dando of the Manaaki Whenua – Landcare Research soil physics laboratory; Paul Mudge for ESM advice; Dave Saville of Saville Statistical Consulting Ltd for the statistical analyses; Anne Austin for editing; and anonymous reviewers that helped improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding was provided by Lincoln University, with assistance from Alexanders Chartered Accountants to support N. Mesman. Funding was also provided by the Manaaki Whenua – Landcare Research and Plant & Food Research-led research programme ‘Maximising the Value of Irrigation’, and the Next Generation S-Map programme, funded by the New Zealand Ministry of Business, Innovation and Employment (contracts C09X1309 and CX09X162).