Abstract: The present paper deals mainly with the absorption, distribution and biological cycles of K, Ca and Mg in Rhizophora stylosa mangrove community in Yingluo Bay of Guangxi, China. The results showed that: In standing crop of the community, the total amounts of K, Ca and Mg were 46.26 g·m-2, 276. 33 g·m-2 and 50. 43 g·m-2, respectively. The Biological cycles of K, Ca and Mg in this stand were:annual uptake 4.46 g· m-2 for K, 17.46 g·m-2 for Ca and 4.81 g·m-2 for Mg ;annual retention 1.67 g·m-2 for K, 10.83 g·m-2 for Ca and 1.39 g·m-2 for Mg; annual return 2.79 g·m-2 for K, 6.63 g·m-2 for Ca an 3.42 g·m-2 for Mg. The enrichment ratios of K, Ca and Mg in this community were 1. 81, 1.20 and 1.80, respectively. The speed of turnover period (yr) was 17, 42 and 15, respectively,in which the speed of Mg recycling was the fastest.

Key words: Mangrove, Rhizophora stylosa, K, Ca and Mg biological cycle