Irrigation districted in low-lying areas of Ningxia

where drawing water from Yellow River

suffering from salinization and poor ecosystem problems. Aiming to construct vegetation rapidly in these areas

experiments of water and salt management that chose poplar (Populus) as target plant included five drip irrigation treatments

in which controlled soil matric potential (SMP) higher than -5 kPa

-10 kPa

-15 kPa

-20 kPa and -25 kPa respectively. Results showed low salinity zone

which enlarged as the irrigation water amount increased

appeared irregular oval. At the enhanced leaching stage that before the soil matric potential treatments was conducted

the salt leached rapidly with a decrease of 70.87% compared with the initial values and the water consumption per ECe unit (dS·m) decrease was 41.7 mm. As the soil matric potential (SMP) treatments conducted

the ECe and SAR from 0 to 40 cm depth soils had significant difference while significant difference was not showed in the whole depth soils. The ECe and SAR increased linearly as the soil matric potential controlled decreased. Principal component analysis of poplar’s growth factors，including height

crown width

stem diameter

diameter at breast height (DBH)

and growth rate of treetop

showed the treatments of both -15 kPa and -5 kPa got scores higher than average value while others got lower scores than average value. Based on principle of efficient water use and the effect of salt leaching

the -15 kPa could be used as a controlled SMP value to instruct the poplar ecology forestry construction in this area.