2024年全球盐渍土壤状况报告（英）_239页_41mb

Summary of the Global Status of Salt-Affected Soils

Core Content

The Global Status of Salt-Affected Soils report presents a comprehensive overview of the global distribution, causes, and management of salt-affected soils, with a focus on both natural and human-induced salinization. It highlights the growing threat to agricultural productivity and food security, particularly in arid and semi-arid regions, and outlines strategies for sustainable management.

Main Points

1. Definition and Types of Salt-Affected Soils

• Salt-affected soils include both primary (naturally saline) and secondary (human-induced) types.
• These soils are found in diverse environments such as mangroves, marshes, coastal wetlands, inland salt flats, and ancient sea beds.
• They support unique ecosystems that are adapted to high salinity levels, contributing to global biodiversity.

2. Factors Contributing to Soil Salinization and Sodification

• Aridity trends increase the risk of salinization due to reduced water availability.
• Freshwater scarcity exacerbates the problem, especially in regions dependent on irrigation.
• Sea level rise leads to coastal salinization through seawater intrusion.
• Permafrost thaw increases salt availability in permafrost regions.
• Human activities such as deforestation, inappropriate irrigation, overuse of groundwater, canal seepage, and agrochemicals also contribute to secondary salinization.

3. Global Distribution of Salt-Affected Soils

• The report includes a global map showing the extent of salt-affected soils in topsoil (0–30 cm) and subsoil (30–100 cm).
• Salt-affected soils are widespread in Asia, Europe, Latin America, North America, the Near East, and Sub-Saharan Africa, with varying intensities and management approaches.

4. FAO's Role and the INSAS Network

• The FAO has been actively involved in addressing salt-affected soils since the 1970s.
• The International Network of Salt-Affected Soils (INSAS), established in 2019, now includes 743 members from 125 countries.
• The network led to the creation of the Global Map of Salt-Affected Soils (GSASmap) in 2021, which serves as a key resource for understanding and managing these soils.

Key Information

5. Human-Induced Salinization

• Secondary salinization is primarily due to unsustainable land and water management in agriculture.
• Deforestation and land use change lead to reduced water infiltration and increased surface salinization.
• Inappropriate irrigation and drainage practices, such as over-withdrawal of groundwater, contribute to inland and coastal groundwater salinization.
• Canal water seepage and overuse of agrochemicals further worsen the problem.

6. Measurement, Monitoring, and Management

• The report provides regional assessments on the status of salt-affected soils, including:
  • Asia: The lead authors are Sanjay Arora (India) and Jeyanny Vijayanathan (Malaysia).
  • Europe and Eurasia: Lead authors are Katarzyna Negacz (Netherlands) and Bas Bruning (Netherlands).
  • Latin America and the Caribbean: Lead author is Raúl Silvio Lavado (Argentina).
  • Near East and North Africa: Lead author is Ahmad Majar (Syria).
  • North America: Lead author is Ahmad Majar (Syria).
  • The Pacific: Lead authors are Richard J. George (Australia) and Edward G. Barrett-Lennard (Australia).
  • Sub-Saharan Africa: Lead author is Mary Idowu (Nigeria).
• Regional data includes information on salinity measurement methods, soil management practices, irrigation techniques, and demand for services by farmers and extension services.

7. Impact on Food Production

• The report uses GSASmap calculations to assess the impact of salinization on food production.
• It outlines relative potential yield loss due to salinity stress for various crops and countries.
• Salt-affected soils reduce agricultural productivity, especially in cropland, and threaten food security.

8. Sustainable Management Strategies

• Mitigation strategies include:
  • Physical measures: Mulching, interlayers, leaching, drainage, surface scraping, compost incorporation, biochar, low-rank coal, deep tillage, and land shaping.
  • Chemical measures: Use of gypsum and other calcium-containing amendments.
  • Biological measures: Crop rotation, agrobiodiversity, and diversification, agroforestry, and bioremediation.
• Adaptation strategies involve:
  • Breeding salt-tolerant crops (including genetic engineering).
  • Domestication of halophytes and other non-conventional crops.
  • Bioinoculants and halopriming to improve plant resilience.
• Saline agriculture is proposed as an integrated approach to manage salt-affected soils sustainably.

9. Policy and Legal Frameworks

• The report emphasizes the need for national and international legal frameworks to protect natural saline ecosystems.
• It references agreements like the Ramsar Convention as models for policy development.
• Key actions to improve policy include better regulation, monitoring, and community engagement.

Conclusion and Way Forward

• The report concludes that sustainable management of salt-affected soils is essential for food security and environmental conservation.
• It calls for collective action, innovation, and policy support to address the growing threat of salinization.
• The Global Map of Salt-Affected Soils (GSASmap) is a critical tool for understanding and managing these soils on a global scale.
• The legal and policy landscape must evolve to ensure the protection and sustainable use of salt-affected soils, especially in high-risk areas.

Appendices

• Annex 1 outlines the criteria for identifying different classes of salt-affected soils in the GSASmap.
• Annex 2 and Annex 3 provide country-level data on the area of salt-affected soils and their intensity.
• Annex 4 includes estimates of salt-affected areas in countries not covered by the GSASmap.
• Annex 5 summarizes responses to the INSAS survey on soil measurement, monitoring, and management.
• Annex 6 provides relative potential yield loss due to salinity stress for different crops.

Tables and Figures

• The report includes tables detailing regional data, measurement methods, management practices, and yield loss.
• Figures illustrate the global distribution, causes of salinization, and management strategies.

Final Notes

• The report is a collaborative effort by INSAS members and ITPS experts.
• It is a resource for scientists, engineers, decision-makers, and environmental advocates.
• The call to action is to preserve soil health and ensure food security for future generations.