Effects Of Soil Amendments On Coastal Saline-alkali Soil And Rice Growth

This study improved the saline-alkali soil in the eastern coastal areas of Zhejiang Province,15 kinds of improved treatments were established by using five common saline-alkali soil ameliorants such as gypsum,superphosphate,cinder,biochar and polymaleic anhydride in indoor soil column leaching experiment and field experiment.And this study systematically combined soil properties,growth characteristics and yield changes of rice to evaluate the effects of 15 improved treatments.In the end,the study revealed the improved effect mechanism of different improvement measures on coastal saline-alkali soil and the best improved measures.The main findings are as follows:(1)The five amendments had significant effects on the salinity indexes and physicochemical properties of saline-alkali soil.Cinder,superphosphate and polymaleic anhydride had significant effects on reducing soil pH and sodium adsorption ratio.biochar had the most significant improvement effect on soil conductivity(EC)and salt content.2%biochar,2%superphosphate and 2%polymaleic anhydride had the best effect on improving the nutrient content of saline soil.(2)The leaching effect of different modifiers on the accumulation of salt-based cations gradually increased and then stabilized.1.5%gypsum had a significant effect on reducing HCO3-;1%,1.5%superphosphate could significantly reduce K+,Ca2+,Mg2+;1%cinder had the best effect on leaching Na+and K+;1.5%,2%biochar had the best effect on leaching Na+,Mg2+,HCO3-,Cl-;1%,2%polymaleic anhydride significantly reduced Na+,Ca2+,Mg2+.(3)The effects of different treatments on soil urease activity,invertase activity,catalase activity,and phosphatase activity were significantly different.The effect of 2%gypsum on urease activity and invertase activity was significantly higher than other treatments;2%polymaleic anhydride had the greatest effect on sucrase activity;1.5%cinder significantly increased catalase activity;1.5%biochar significantly increased alkaline phosphatase activity but inhibited urease and catalase activity.Principal component analysis showed that the improved soil treatment was 1.5%,2%biochar and 2%gypsum(4)Different amendments not only had an improved effect on soil properties,but also had an effect on growth characteristics and yield of rice.The plant height,tiller number and biomass of rice treated with different amendments increased in different degrees.The nutrient accumulation and yield of rice increased with the addition of amendments.And GT2 treatment increased yield by 25.8%compared with the control,and GT3 treatment increased yield by 7.9%In conclusion,biochar+gypsum can promote the desalination and fertilization of coastal saline alkali soil in the east of Zhejiang Province and improve the yield of crops,so as to achieve the rational development and utilization of coastal saline alkali soil.