农业食品系统中的可持续氮管理

Sustainablenitrogen managementin agrifood systems Recommended citation The designations employed and the presentation of material in this information product do not imply theexpression of any opinion whatsoever on the part of the Food and Agriculture Organization of the UnitedNations (FAO) concerning the legal or development status of any country, territory, city or area or of itsauthorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies orproducts of manufacturers, whether or not these have been patented, does not imply that these have beenendorsed or recommended by FAO in preference to others of a similar nature that are not mentioned. The views expressed in this information product are those of the author(s) and do not necessarily reflect theviews or policies of FAO. ISBN 978-92-5-139391-8© FAO, 2025 Some rights reserved. This work is made available under the Creative Commons Attribution- 4.0 Internationallicence (CCBY 4.0: https://creativecommons.org/licenses/by/4.0/legalcode.en). Under the terms of this licence, this work may be copied, redistributed and adapted, provided that the workis appropriately cited. In any use of this work, there should be no suggestion that FAO endorses any specificorganization, products or services. The use of the FAO logo is not permitted. If a translation or adaptation ofthis work is created, it must include the following disclaimer along with the required citation: “This translation[or adaptation] was not created by the Food and Agriculture Organization of the United Nations (FAO). FAO isnot responsible for the content or accuracy of this translation [or adaptation]. The original [Language] editionshall be the authoritative edition.” Any dispute arising under this licence that cannot be settled amicably shall be referred to arbitration inaccordance with the Arbitration Rules of the United Nations Commission on International Trade Law(UNCITRAL). The parties shall be bound by any arbitration award rendered as a result of such arbitration as thefinal adjudication of such a dispute. Third-party materials.This Creative Commons licence CC BY 4.0 does not apply to non-FAO copyrightmaterials included in this publication. Users wishing to reuse material from this work that is attributed to a thirdparty, such as tables, figures or images, are responsible for determining whether permission is needed for thatreuse and for obtaining permission from the copyright holder. The risk of claims resulting from infringement ofany third-party-owned component in the work rests solely with the user. FAO photographs.FAO photographs that may appear in this work are not subject to the above-mentioned CreativeCommons licence. Queries for the use of any FAO photographs should be submitted to: photo-library@fao.org. Sales, rights and licensing.FAO information products are available on the FAO website (www.fao.org/publications)and print copies can be purchased through the distributors listed there. For general enquiries about FAO publicationsplease contact: publications@fao.org. Queries regarding rights and licensing of publications should be submitted to:copyright@fao.org. Contents PrefaceviAcknowledgementsviiAbbreviationsviiiExecutive summaryx CHAPTER 1Introduction 1 CHAPTER 2Nitrogen use efficiency in cropping systems3 2.1Introduction32.2Defining nitrogen use efficiency in cropping systems42.3Trends and status of nitrogen use efficiency62.4Improvement options to enhance nitrogen use efficiency122.5Case studies202.6Conclusions and key messages22 Nitrogen use efficiency in livestock systems23 3.1Introduction233.2Quantification of nitrogen use efficiency in livestock systems233.3Factors influencing nitrogen use efficiency in the livestock sector243.4Review of nitrogen use and challenges in different livestock systems 253.5Assessment of nitrogen use efficiency and flows in livestocksupply chains313.6Case studies393.7Conclusion and key messages44 CHAPTER 4Impacts of nitrogen losses on climate and ecosystems45 4.1Introduction454.2Nitrogen in terrestrial and aquatic ecosystems464.3Nitrogen and climate change474.4Effects of nitrogen on terrestrial ecosystems494.5Effects of nitrogen on aquatic ecosystems524.6Approaches for assessing the impacts of the nitrogen challenge554.7Conclusion and key messages57 Transforming agrifood systems through circular bioeconomy59 5.1Introduction595.2Principles to enhance circular bioeconomy in agrifood systems595.3Promising circular bioeconomy solutions in agricultural production 61 5.4Promoting circular bioeconomy approaches in livestock systemsto support better nitrogen management655.5FAO’s work on bioeconomy675.6Circular bioeconomy in the context of food safety685.7Case studies695.8Conclusion and key messages71 CHAPTER 6Policy instruments to promote sustainable nitrogen management73 6.1Nitrogen in crop production policies736.2Nitrogen in livestock development policies766.3Nitrogen in policies relat