Song et al. (2025) Analysis study on the change of orchard area in Alar reclamation in the past 30 years

Identification

• Journal: Scientific Reports
• Year: 2025
• Date: 2025-11-26
• Authors: Qi Song, Lina Li
• DOI: 10.1038/s41598-025-26156-0

Research Groups

• School of Environment and Resource, Xichang University, Xichang, China

Short Summary

This study analyzed the spatiotemporal changes of orchard area in the Alar Reclamation Area, Xinjiang, from 1990 to 2019 using Landsat imagery and SVM classification. It revealed a significant continuous increase in orchard area from 417.57 km² to 1091.76 km², primarily converted from unused land, which intensifies water-use conflicts and soil salinization.

Objective

• To investigate orchard changes over a continuous 30-year time series, analyzing changes in orchard area, land use type conversions, and spatial dynamics in the Alar Reclamation Area.
• To provide scientific support for ecological governance, land resource planning, and macro-level regulation of orchard areas in the reclamation zone.

Study Configuration

• Spatial Scale: Alar Reclamation Area, Xinjiang Uygur Autonomous Region, China (80°30′ to 81°58′ E, 40°22′ to 40°57′ N), covering a total area of 4,105.92 km².
• Temporal Scale: 30 years, from 1990 to 2019.

Methodology and Data

• Models used: Support Vector Machine (SVM) for supervised classification. Spatial statistical tools in ENVI and GIS software (ArcGIS 10.2) for land use transition matrices and spatial dynamic change maps.
• Data sources:
  • 30 scenes of Landsat remote sensing images (30 m spatial resolution, path/row 146/32, July–November imaging dates, <10% cloud cover) from the United States Geological Survey (USGS) EarthExplorer.
  • Xinjiang Production and Construction Corps Statistical Yearbook (1990–2019) for land use statistics and fruit production data.
  • Field surveys and relevant literature for establishing a classification system and interpretation criteria.

Main Results

• The classification achieved high accuracy, with User Accuracy (UA) and Producer Accuracy (PA) for orchards reaching 95.28% and 97.69% respectively, and an Overall Accuracy (OA) of 87.97%.
• From 1990 to 2019, the orchard area in Alar Reclamation showed a continuous increase, expanding from 417.57 km² (10.17% of total area) in 1990 to 1,091.76 km² (26.59%) in 2019, a net increase of 674.19 km² (16.42%).
• The average annual growth rate of orchards was highest at 6.04% from 1990 to 1995 and lowest at 1.06% from 2015 to 2019.
• Over the 30-year period, 860.38 km² of orchard area was converted out, primarily into cultivated land (832.59 km²), mainly along the Tarim River.
• Conversely, 1,534.58 km² of land was converted into orchards, predominantly from unused land (1,160.44 km²), mainly located in the northwestern part of the reclamation area.
• The continuous expansion of orchard areas has intensified water-use conflicts and exacerbated soil salinization, posing a significant threat to the long-term sustainability of the oasis ecosystem.

Contributions

• Provides a comprehensive, long-term (30-year) continuous time series analysis of orchard area changes, land use type conversions, and spatial dynamics in an arid oasis region, addressing a gap in studies often relying on single-time-point imagery.
• Quantifies the significant expansion of orchard area and its primary sources (unused land) and destinations (cultivated land) in the Alar Reclamation Area.
• Highlights the critical environmental consequences of rapid agricultural expansion in arid regions, specifically intensified water-use conflicts and exacerbated soil salinization.
• Offers scientific evidence to support sustainable land management practices and policy formulation for balancing economic development with ecological conservation in similar vulnerable ecosystems.

Funding

• Project of Xichang University (No. LGLZ202301)

Citation

@article{Song2025Analysis,
  author = {Song, Qi and Li, Lina},
  title = {Analysis study on the change of orchard area in Alar reclamation in the past 30 years},
  journal = {Scientific Reports},
  year = {2025},
  doi = {10.1038/s41598-025-26156-0},
  url = {https://doi.org/10.1038/s41598-025-26156-0}
}