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

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.

Leaching efficiency and plant growth response in an integrated use of saline water for coastal saline soil reclamation

“…It is interesting to note that 'Worcester Gold' had a lower survival rate than both herbaceous (Zhang et al, 2019) and trees cultivated in the same experimental site. The same underperforming of shrubs was also observed in the same experimental site with a different soil texture (Li, 2019). We attributed the underperforming to the fact that herbaceous, shrubs, and trees have different growing and root characteristics so that the shallow-rooted herbaceous with the death of aboveground part during dormancy period were favorable to suffer less salt stress than deep-rooted woody plants, and the trees benefit from dilution of the salt into the relatively large existing biomass than the shrubs.…”

“…Relate to this, 15 landscaping species, including herbaceous, shrub, and tree species were tested on two coastal saline soils with different textures around Bohai Bay in China, integrated using slightly saline to saline water, drip irrigation scheduled by matric potential, and gravel‐sand layer as subsurface drainage. It was reported in previous papers that feasible reclamation of saline soil and acceptable maintaining of plants was achieved and impacted by both soil texture and plant life forms (Li, 2019; Li et al, 2016; Li, Kang, Wan, Chen, & Chu, 2015; Zhang et al, 2019).…”

Modeling the effect of wastewater irrigation on soil salinity using a SALT‐DNDC model

“…The optimization of irrigation water quantity and quality are critical for maintaining soil health and plant growth. Furthermore, because different crops have different salt tolerance thresholds (Li, 2019), optimal ranges of soil salinity based on irrigation water could be examined using the SALT-DNDC model.…”