To clarify the continuous and environmental effects of the amelioration of heavy soda saline soil using desulfurized gypsum

an outdoor pot experiment was conducted to study the growth situation of forage maize

physicochemical properties of the soil

and contents of heavy metals in plants when the soda saline soil was treated with different rates of desulfurized gypsum (0 t/hm2

15 t/hm2

22.5 t/hm2

30 t/hm2). The results showed that the remediation effect of 15 t/hm2 desulfurized gypsum was the best. It could significantly improve seedling emergence rate

plant height

stem diameter

and seedling biomass of forage maize

which was increased by 20.6%

16.8%

8.1% and 10.1% compared to the control

respectively. The pH

EC

and the content of Na+ in the soil were decreased

but the contents of Ca2+ and SO42- in the soil were increased. As the amount of desulfurization gypsum was increased

the effect of desulfurization gypsum became more obvious. The content of As

Hg

and Ni in the soil and forage maize roots increased with increasing amount of desulfurization gypsum. According to the second grade of national environmental quality for the soils (GB 15618—1995)

the contents of heavy metals (As

Hg

Cd

and Ni) in the tested soil were all complied with the Environment Quality Standard. The contents of heavy metals in the forage maize shoots were not significantly correlated with the application rate of desulfurization gypsum

and the heavy metals contents in each treatment did not exceed the standard limits according to Hygienical standards for feeds (GB 13078—2001). The heavy metal contents in stems were less than those in shoot

and the accumulation rate of heavy metals was in the order of Cd＞Hg＞As＞Ni. It can be concluded that the continuous effects of desulfurization gypsum to ameliorate the soda saline soil were good

and did not show adverse impact on the environment.