The Progress in Improvement of High pH Saline-Alkali Soil in the Songnen Plain by Stress Tolerant Plants

The Songnen Plain of the Northeast China is the largest alkali soda soil distribution area in the world where the carbonates are the main composition salts.Soil pH in this area is higher than 8.5 and reaches 9.0—10.5 in the severe alkali land.The unreasonable human activities and arid climate in recent years increase the area and degree of alkalinity.This paper summarized the formation and hazard of saline-alkali soil in the Songnen Plain,and evaluated the traditional practices of improving saline-alkali soil.A review of research results was introduced in breeding for salt and alkali tolerant rice varieties and screening for alkali tolerant mutants,QTL mapping of the alkali tolerant genes,characteristics of saline-alkali tolerance and transplanting cultivation technologies in Leymus chinensis,the assessment of bioecological effects of transplanting L.chinensis in severe alkali soil and the physiological tolerant mechanisms to stress and the utilization of genetic variations of L.chinensis were carried out in the Northeast Institute of Geography and Agricultural Ecology of CAS.It also pointed out the importance of using alkali tolerant grass or rice to restore the ecological environment and improve the poor soil productivity.