Effects of Sand Fixation Forest Restoration on Soil Water Infiltration Capacity in Mu Us Sandy Land – Frontiers

Report on Sustainable Afforestation Strategies in the Mu Us Sandy Land

Aligning Land Restoration with Sustainable Development Goals

This report analyzes vegetation strategies for sand fixation in the Mu Us Sandy Land, a region characterized by severe soil erosion and a fragile ecological environment. The research directly addresses key United Nations Sustainable Development Goals (SDGs), primarily focusing on SDG 15 (Life on Land) by seeking methods to combat desertification and restore degraded land. Furthermore, it critically examines the implications for SDG 6 (Clean Water and Sanitation) by evaluating the water consumption of different vegetation types, aiming to ensure the sustainable management of scarce water resources in arid ecosystems.

Research Scope and Methodology

Comparative Analysis of Vegetation Types

The study was conducted to identify the most suitable vegetation for sand fixation that balances ecological restoration with water conservation. Four distinct land cover types were monitored and compared:

• Bare Land (BL) – Unrestored control site
• Natural Grassland (GL)
• Salix cheilophila (SC) sand fixation forest
• Pinus sylvestris (PS) sand fixation forest

Parameters for Evaluation

A comprehensive assessment was performed by measuring key hydrological and soil properties. Fixed-interval monitoring and experiments were conducted to evaluate:

1. Soil moisture content (SWC)
2. Vegetation characteristics and root biomass
3. Soil physical properties
4. Water-holding capacity (WHC)
5. Initial infiltration rate (IIR)

Key Findings: Balancing Land Restoration and Water Sustainability

Water-Holding and Infiltration Dynamics

The analysis of soil hydrological functions revealed critical differences between the vegetation types, impacting their contribution to SDG 15.

• The Pinus sylvestris (PS) forest demonstrated the highest integrated water-holding capacity, measuring 1.25 times that of bare land.
• Water-holding capacity (WHC) was found to have a significant and direct negative effect on both soil water content (SWC) and the initial infiltration rate (IIR).
• The initial infiltration rate (IIR) directly and positively influenced soil water content (SWC).
• While the canopy and litter layers of forests enhance soil moisture replenishment by modifying WHC and IIR, the high water consumption of trees ultimately maintains low overall soil water content.

Soil Moisture and Water Consumption Analysis

Evaluating water consumption is essential for aligning restoration efforts with SDG 6. The study found significant variations in effective soil moisture supply and subsequent water use.

1. Effective Soil-Moisture Supply Depths:
   • Grassland (GL): 40 cm
   • Salix cheilophila (SC): 150 cm
   • Pinus sylvestris (PS): 150 cm
   • Bare Land (BL): 100 cm
2. Water Consumption: Following moisture supply, the Pinus sylvestris (PS) forest exhibited the largest water consumption, depleting soil moisture reserves.
3. Optimal Vegetation for Water Conservation: From the perspective of conserving soil moisture, Natural Grassland (GL) was the most effective vegetation type, followed by the Salix cheilophila (SC) forest.

Conclusions and Recommendations for Sustainable Land Management

Strategic Vegetation Selection for SDG 15.3

To achieve a land degradation-neutral world as targeted by SDG 15.3, vegetation choices must be context-specific. Based on a comprehensive consideration of sand fixation needs and water conservation, Salix cheilophila (SC) is the recommended species for afforestation in this region. It provides a superior balance of effective water holding, infiltration promotion, and moderate water consumption compared to Pinus sylvestris.

Future Directions for Climate-Resilient Restoration (SDG 13)

To build long-term, climate-resilient ecosystems in water-scarce regions, future afforestation projects should prioritize water-efficient models. It is strongly recommended that shrub-grass mixed forests be considered. This approach better mimics natural ecosystems, conserves precious water resources, and ensures the long-term sustainability of land restoration efforts, contributing to both climate action and the protection of life on land.

1. Which SDGs are addressed or connected to the issues highlighted in the article?

SDG 15: Life on Land

• The article directly addresses the core themes of SDG 15 by focusing on the ecological restoration of the Mu Us Sandy Land, an area suffering from “severe soil erosion and a fragile ecological environment.” The primary intervention discussed, the “construction of sand fixation forests,” is a direct action to combat desertification and restore degraded land. The research aims to find the most sustainable methods for this restoration, which aligns with the goal of protecting and restoring terrestrial ecosystems.

SDG 6: Clean Water and Sanitation

• The article highlights a critical challenge in the restoration effort: “water resource scarcity constrains the sustainable development of the ecosystem.” The research investigates the “high soil-water consumption” of different tree species and analyzes soil moisture levels. This focus on water scarcity, efficient water use by different vegetation types, and the overall water balance in a fragile ecosystem connects directly to the sustainable management of water resources as outlined in SDG 6.

2. What specific targets under those SDGs can be identified based on the article’s content?

Targets under SDG 15: Life on Land

• Target 15.3: “By 2030, combat desertification, restore degraded land and soil, including land affected by desertification, drought and floods, and strive to achieve a land degradation-neutral world.”
  • The entire study is centered on this target. The article describes the Mu Us Sandy Land as an area with “severe soil erosion” and the efforts to combat this through “construction of sand fixation forests.” The research comparing different vegetation types aims to optimize these restoration efforts for long-term success.
• Target 15.1: “By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains and drylands.”
  • The article’s investigation into which tree species is “more suitable for construction of sand fixation forests” based on water conservation is a clear example of promoting the sustainable use of a terrestrial ecosystem (drylands). The goal is not just to plant trees, but to do so in a way that does not deplete other critical resources like water, ensuring the long-term sustainability of the ecosystem.

Targets under SDG 6: Clean Water and Sanitation

• Target 6.4: “By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity…”
  • The article’s central conflict is the trade-off between vegetation coverage and “high soil-water consumption.” By evaluating which plant species (e.g., *Salix cheilophila* over *Pinus sylvestris*) performs better in water conservation, the research is effectively seeking to increase the water-use efficiency of the ecosystem restoration project to address the problem of “water resource scarcity.”
• Target 6.6: “By 2020, protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers and lakes.”
  • The study focuses on how sand fixation forests impact the local hydrology, specifically soil moisture, which is a key component of the terrestrial water-related ecosystem. The research on “water-holding capacity” and “infiltration” is about understanding and restoring the natural water regulation functions of the soil ecosystem, which has been degraded by desertification.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Indicators for SDG 15 Targets

• Vegetation Coverage: The article explicitly states that the “construction of sand fixation forests has markedly increased vegetation coverage.” This is a direct indicator for measuring progress in restoring degraded land (Target 15.3).
• Root Biomass: This is mentioned as a keyword. Root biomass is a scientific indicator of plant health, soil stability, and carbon sequestration, all of which are crucial metrics for assessing the success of land restoration and combating desertification.

Indicators for SDG 6 Targets

• Soil Water Content (SWC) / Soil Moisture: The article repeatedly mentions monitoring “soil moisture” and “soil water content (SWC).” These are direct, quantifiable indicators used to assess the impact of different vegetation on water availability and scarcity, relating to Target 6.4.
• Water-Holding Capacity (WHC): The research measures the “integrated water-holding capacity” of different land types. This is a specific indicator of the soil’s ability to retain water, which is fundamental to restoring the hydrological function of a water-related ecosystem (Target 6.6).
• Initial Infiltration Rate (IIR): The study conducts “infiltration experiments” and analyzes the “initial infiltration rate (IIR).” This measures how quickly water enters the soil, serving as a key indicator of soil health and the ecosystem’s ability to capture and store rainfall, which is vital for both water management and ecosystem restoration (Targets 6.4 and 6.6).

4. Create a table with three columns titled ‘SDGs, Targets and Indicators’ to present the findings from analyzing the article.

Source: frontiersin.org