Dynamics of Reductive Organic Acid and the Relationship with Growth of Rice in Cold-waterlogged Paddy Soil

Cold-waterlogged paddy field with low-yield are very common in south China.During growing period of the single-crop rice in Minhou County of Fujian,the kinds,concentrations and dynamics of reductive organic acids were analyzed in the soil around the rice roots grown in the cold-waterlogged paddy fields comparing to that of the non-cold soak fields within the same micro-geomorphic units,and the relationship between reductive organic and rice growth were also detected.The results showed that the organic reducing acids in the cold soak fields were mainly consist of oxalic acids,accounting for more than 80% of the total organic acids.Amount of organic acids in cold soak fields developed in different terrains significantly were higher than those in non-cold soak fields.As the rice growing,the amounts of organic acids and sodium manganese were correspondingly increasing,while ferrous decreasing.Significantly negative correlation between organic reducing acids and rice biomass and grain yield was found.Regression equations indicated that organic reducing acids showed higher inhibitive effect on the grain yield,compared to ferrous and manganite.