Effects of irrigation on soil physical properties in predominantly pastoral farming systems: a review

ABSTRACT

This paper reviews the effects of irrigation on soil physical properties, particularly soil water movement and storage, under predominantly pastoral systems. Few studies address how irrigation impacts these in temperate climates, with very few studies under modern spray irrigation and intensive pastoral farming. Irrigation generally means intensive land use will occur. It is difficult to uncouple factors affecting physical conditions such nutrient cycling, land use, stock class, grazing management and animal treading. Irrigation (with associated increased land use intensity) tends to alter soil physical properties, changing them to be like soils formed under higher rainfall particularly in arid and semi-arid climates. Changes in physical properties under irrigation in temperate and sub-humid climates were more variable. Some studies showed increased available water capacity, while others showed no change. Knowledge gaps include effects of irrigation intensification on soil physical properties under modern farm systems to improve process, management, spatial and temporal information.

KEYWORDS:

• Irrigation
• soil
• compaction
• land use
• soil quality
• pasture
• agriculture

Acknowledgements

The authors would like to thank Carolyn Hedley and Andre Eger for feedback on earlier paper drafts, Anne Austin for editing, Nicolette Faville for assistance with the diagram, and two anonymous reviewers who improved the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Funding was provided by the Ministry for Primary Industries Sustainable Farming Fund [project 405305], supported by Federated Farmers of New Zealand Inc, Foundation for Arable Research, Amuri Irrigation Company Ltd, Rangitata Diversion Race Management Ltd, Waimakariri Irrigation Ltd, Central Plains Water Ltd, Manaaki Whenua-Landcare Research, Barrhill Chertsey Irrigation Ltd, Opuha Irrigation Ltd, Morven Glenavy Ikawai Irrigation Company Ltd, Irrigation New Zealand, Environment Canterbury Regional Council, Beef and Lamb New Zealand Ltd, and DairyNZ Ltd. Funding was also provided by the Manaaki Whenua – Landcare Research and Plant and Food Research led research programmes, Maximising the Value of Irrigation and Next Generation S-Map, funded by the New Zealand Ministry of Business, Innovation and Employment [contracts C09X1309 and CX09X162].