Vegetation establishment in coastal salt‐affected wasteland using drip‐irrigation with saline water

by Xiaobin Li

Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101 PR China

https://doi.org/10.1002/ldr.3324

https://onlinelibrary.wiley.com/doi/abs/10.1002/ldr.3324

Abstract

Saline water has been successfully used for irrigation in arid, semiarid, and coastal regions, and drip‐irrigation is widely regarded as the most promising system to deliver such water, particularly for reclaiming saline soils, because drip‐irrigation saves water and leaches salts efficiently. As coastal regions continue to be urbanized rapidly, vegetation establishment in coastal salt‐affected wastelands becomes increasingly urgent, but information on plants suitable for the purpose is scanty. The effects of drip‐irrigation with saline water (EC 0.8–7.8 dS/m) on the leaching of salts and on the performance of 15 plants suitable for landscaping were evaluated. The field experiment comprises trees, herbs, and shrubs, and irrigation was scheduled on the basis of soil matric potential threshold set at −5 kPa in 2013, −10 kPa in 2014, −15 kPa in 2015, and −20 kPa in 2016. As a result of irrigation controlled thus, soil that was severely saline initially became mildly saline or even nonsaline in its profile up to a depth of 1 m irrespective of the salinity of irrigation water. However, the survival rates of plants differed with the salinity and SMP threshold: Survival was more than 80% in four herb species and three tree species when irrigated with saline water at 7.8 dS/m for 4 years but decreased, especially in shrubs, as the SMP threshold was lowered. The thresholds of ECiw(electrical conductivity of irrigation water) and SMP were set based on the response of plants to salinity, and some plants are recommended for the ecological environment establishment. A combination of controlled irrigation with saline water and the right mix of plant species are helpful in reclamation of saline coastal areas.

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Author: Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.