A review of the cost-effectiveness and suitability of mitigation strategies to prevent Phosphorus loss from dairy farms in New Zealand and Australia
The loss of phosphorus (P) from land to water is detrimental to surface water quality in many parts of New Zealand and Australia. Farming, especially pasture-based dairying, can be a source of P loss, but preventing it requires a range of fully costed strategies because little or no subsidies are available and the effectiveness of mitigation strategies varies with different farm management systems, topography, stream density, and climate. This paper reviews the cost-effectiveness of mitigation strategies for New Zealand and Australian dairy farms, grouping strategies into (i) management (e.g., decreasing soil test P, fencing streams off from stock, or applying low-water-soluble P fertilizers), (ii) amendments (e.g., alum or red mud [Bauxite residue]), and (iii) edge-of-field mitigations (e.g., natural or constructed wetlands). In general, on farm management strategies were the most cost-effective way of mitigating P exports (cost range, $0 to $200 per kg P conserved). Amendments, added to tile drains or directly to surface soil, were often constrained by supply or were labor intensive. Of the amendments examined, red mud was cost effective where cost was off set by improved soil physical properties. Edge-of-field strategies, which remove P from runoff (i.e., wetlands) or prevent runoff (i.e., irrigation runoff recycling systems), were generally the least cost effective, but their benefits in terms of improved overall resource efficiency, especially in times of drought, or their effect on other contaminants like N need to be considered. By presenting a wide range of fully costed strategies, and understanding their mechanisms, a farmer or farm advisor is able to choose those that suit their farm and maintain profitability. Further work should examine the potential for targeting strategies to areas that lose the most P in time and space to maximize the cost-effectiveness of mitigation strategies, quantify the benefits of multiple strategies, and identify changes to land use that optimize overall dairy production, but minimize catchment scale, as versus farm scale, nutrient exports.... [Show full abstract]
Keywordsphosphorus; phosphorus loss; mitigation; dairy farm; New Zealand; Australia; fertilizer; soil; stream; irrigation; grazing; effluent; drain; pasture; crop; wetland; Agronomy & Agriculture; Animals; Cattle; Water Pollutants, Chemical; Dairying; Cost-Benefit Analysis
Fields of Research0703 Crop and Pasture Production; 079902 Fertilisers and Agrochemicals (incl. Application); 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.); 040608 Surfacewater Hydrology; 0503 Soil Sciences; 04 Earth Sciences; 05 Environmental Sciences; 06 Biological Sciences
- Metadata-only (no full-text) 
Copyright © 2012 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.