Abstract:

To investigate the changes in soil physicochemical properties and its ecological stoichiometric characteristics in different stand ages,the contents of pH,total dissolved salt (TDS),organic carbon (SOC),total nitrogen (TN),available nitrogen (AN),total phosphorus (TP),available phosphorus (AP),total potassium (TK),and available potassium (AK)of the 0~30 cm soil layer of three stand ages of 10,15,and 22 a were measured,the stoichiometric ratios were calculated,and the correlation between each index was analyzed.The results showed that:1)After afforestation,soil pH showed a decrease followed by an increase and then a decrease,soil nutrients increased significantly,SOC and TN were higher than the national soil average,and TP was slightly lower than the national soil average,indicating that the soil C and N content in the study area was relatively high;2)there were significant differences in soil physicochemical properties and ecological stoichiometric ratios among different stand ages;with the increase of stand age,soil pH increased and then decreased,SOC,TN,AN,TP and AK contents decreased and then increased,and the changes of TK and AP were not obvious;3)The growth and development of Sonneratia apetala forest may be limited by N,especially in the period of young and middle stand age.The plantation of Sonneratia apetala forest had a significant regulatory effect on the restoration of soil nutrients in mangrove wetlands.

Key words: eastern Guangdong, Sonneratia apetala, different stand ages, soil nutrients, ecological stoichiometry