英文摘要: |
Soil salinization and freshwater shortage are important factors restricting urban and peri-urban landscaping in coastal regions of China, where rapid industrialization and urbanization have expanded. This study explores saline water resources and soil matric potential control as a part of functional irrigation management to cope with the landscaping on salt-affected soils. A 4-year field experiment was carried out in coastal saline soil of North China, to establish four ornamental tree species (Fraxinus pennsylvanica, Crataegus cuneata, Broussonetia papyrifera, and Diospyros kaki) using saline water with five salinity levels (ECi of 0.8, 3.1, 4.7, 6.3, and 7.8 dS.m(-1)) by drip irrigation scheduled by yearly-lowered soil matric potential thresholds. Periodic monitoring results show that the survival rates of 100% were observed in the first post-transplant year for all ECi treatments and tree species, but survival rates decreased both as ECi increased and as matric potential thresholds decreased. The DBH, height, and canopy diameter of the surviving trees deteriorated as ECi increased and simultaneously increased each year. The initial soil salinity (ECe > 27 dS.m(-1)) at the 0-1 m depth decreased to 2.6, 2.1, 2.1, 3.4, and 6.3 dS.m(-1) for five ECi treatments, respectively. Severe saline soil was reclaimed to non-saline and mildly saline soils. A performance indicator (PI) combining survival and growth rates was developed and applied to quantitatively assess performance of trees. According to the linear relationship between PI and ECi and the acceptable reduction of PI, F. pennsylvanica, C. cuneata, and B. papyrifera are recommended for landscaping with saline water, with threshold ECi of 6.1, 4.1, and 2.5 dS.m(-1), respectively. The sustainability and implications for landscaping of irrigation management are discussed. |