Reclamation alters evapotranspiration and its biophysical controls in a meadow grassland on the Mongolian Plateau

• Published in: Journal of environmental management Vol. 370; p. 122528
• Main Authors: Dong, Xiaobing, Dong, Gang, Chen, Jingyan, Legesse, Tsegaye Gemechu, Jiang, Shicheng, Akram, Muhammad Adnan, Qu, Lu-Ping, Wang, Lulu, Deng, Jianming, Shao, Changliang
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2024
• Subjects: Agriculture; Biomass; Central Asia; Crop; cropland; Eddy covariance; environmental management; evapotranspiration; Grassland; irrigation; Land use change; meadows; Mongolia; potatoes; Seasons; Soil; soil water content; tillage; Water; Water cycle; Mongolia; Central Asia; Crop; Grassland; Eddy covariance; Land use change; Water cycle
• ISSN: 0301-4797; 1095-8630; 1095-8630
• DOI: 10.1016/j.jenvman.2024.122528

Global grasslands were constantly being replaced and reclaimed for cropland, and such reclamations may profoundly affect ecological such as water cycles. However, the long-term effects of this conversion on evapotranspiration (ET) processes remain underexplored. To discern changes in ET from grassland to reclaimed cropland and among different crop rotations, a four-year study (2018–2021) was conducted using the eddy covariance system in a Hulunber grassland and a neighboring reclaimed cropland. The ET in reclaimed cropland (248 mm) was 49% higher than the grassland (166 mm) during the growing season (crop growth period), whereas the ET in the grassland (134 mm) exceeded that in the cropland (128 mm) by 6% in the non-growing season. The croplands experienced a 19% increase in precipitation, primarily due to artificial irrigation during the growing season. Meanwhile, the increase in ET in reclaimed cropland might also be influenced by changes in vegetation type and crop growth characteristics, as well as by rational tillage practices that increase the cover of vegetation and biomass. Notably, potato cultivation most closely matched the water balance of grasslands. In addition, irrigation directly increased soil water content (SWC), and that enhancing the sensitivity of ET to SWC. Overall, this study highlighted the importance of understanding ET variations due to grassland conversion to cropland and different crop rotations, emphasizing the role of irrigation and tillage practices. •Evapotranspiration (ET) increased after reclamation from grassland to cropland.•Cropland ET for different types: wheat > rape > potato ≈ grassland.•Grassland ET was mainly influenced by abiotic factors.•Reclamation altered ET sensitivity to soil moisture content.