A four-year field experiment was carried out to evaluate an integrated
use of saline water for the saline soil reclamation in Hebei Province of
North China. A landscape shrub (Caryopteris × clandonensis ‘Worcester
Gold’) was cultivated using drip irrigation scheduled by rootzone soil
matric potential control at five levels of water salinity (ECi): 0.8,
3.1, 4.7, 6.3, and 7.8 dS·m−1. Soil matric potential control was applied
using a threshold of −5, −10, −15, and −20 kPa in the first, second,
third, and fourth year, respectively. After four growing seasons, the
saline soil (initial ECe value of 27.8 dS·m−1) was reclaimed to slightly
saline soil for 0–1 m depth (4.1–7.2 dS·m−1) under drip irrigation
with saline water of ECi < 7.8 dS·m−1. The salt leaching
efficiency of root zone soil was highest in the first year and lowered
year-by-year. The plants strongly responded to the different soil water
and salinity regime. Significant decreases in survival rate, plant
growth, and shoot dry weight in response to increasing ECi were found.
To achieve a relative survival rate of >50%, the threshold
salinity of irrigation water for ‘Worcester Gold’ cultivation was 7.8,
7.0, 5.6, and 5.3 dS·m–1, for the first, second, third, and fourth
growing season, respectively. It is recommended to use an inter-seasonal
evolving matric potential threshold of −10 kPa for dry season of the
third year, −15 kPa for rainy season of the third year and dry season of
the fourth year, and −20 kPa for rainy season of the fourth year.
Salt leaching of heavy coastal saline silty soil by controlling the soil matric potential
