Mr. Haonan Zheng1, Prof. Xiujun Wang1, Prof. Xiaodong Ding2
1Beijing Normal University, Haidian, China, 2Qingdao Agricultural University, Qingdao, China
There was evidence of positive relationships between soil organic carbon (SOC) and inorganic carbon (SIC) in saline-alkali lands of arid and semi-arid areas. However, little is done to evaluate the variations of SOC and SIC and their relationship in the coastal saline-alkali paddy, especially under different amelioration/fertilization practices. This study aims to assess the impacts of various combinations of organic amendment and phosphorus fertilization on SOC and SIC and other soil properties in a coastal saline-alkali paddy field of the Yellow River Delta. Our study showed that most of the amelioration methodologies couldn’t reduce soil pH and contents of salts effectively. Organic fertilization increased available phosphorus, total phosphorus and total nitrogen. Phosphorus fertilization led to an increase of SOC by 17% in subsoils， and organic amendment resulted in a further increase of SOC by 7-17% over 0-20 cm and14% over 20-100 cm. There were little differences in SIC over 0-20 cm among the treatments, but slight decreases in SIC over 20-100 cm under organic amendment combined with lower rate of phosphorus fertilization. On the other hand, .high rate of phosphorus fertilization combined with organic amendment caused a decrease in SOC stock but an increase in SIC stock in the subsoil. There was a significant negative relationship between SIC and SOC stocks in the saline-alkali paddy of the Yellow River Delta. We explore the underlying mechanisms influencing the dynamics of SOC and SIC in association with soil amelioration.
Xiujun Wang is a professor and chief scientist at the College of Global Change and Earth System Science, Beijing Normal University. Her recent research interests include the dynamics of organic and inorganic carbon in soils of the arid and semi-arid regions of China. One of her main accomplishments was the first assessment of the accumulation rate of soil carbonate in the cropland of north China.