| Ecological stoichiometry is used to study the relationship between the energy and several chemical elements(carbon(C),nitrogen(N)and p Hosp Horus(P))balance in ecological interaction.Mangroves communities are distributed in the intertidal zone of tropical and subtropical coasts,and are an important part of the offshore wetland ecosystem.In this study,in 2019,we conducted a full investigation and sampling of natural forests and plantations in the Mangrove Reserve of Beilun Estuary,Guangxi Northwest,and mangroves invaded by Spartina alterniflora in Qixing Island,Beihai,Guangxi.Through statistical testing and correlation analysis Differences in stoichiometric characteristics of leaves and soil profiles of different plants in different intertidal zones,differences in stoichiometric characteristics of leaves and soil of natural forests and plantations,and mangrove soil stoichiometry after being invaded by S.alterniflora to varying degrees The feature differences were studied and the following conclusions were drawn:(1)There is no significant difference in the mean contents of leaves C and N on the three tidal zones(P> 0.05),there is a significant difference between the P content(P <0.05).The average C content of the three tide zones is high tide zone> medium tide zone> low tide,the average N content is low tide zone> mid tide zone> high tide zone,and the average P content is in the order of low tide zone> mid tide zone> high tide zone.The contents of N and P in different intertidal zones was consistent.Different intertidal zones have different environments,resulting in differences in nutrient content.The average C: N ratio of the three tidal zones decreases with the decrease of elevation;the average ratio of N: P is the same as the average ratio of C: P,showing a trend of increasing first and then decreasing.There are significant differences in the average values of the Avicennia marina(Bruguiera gymnorrhiza)and the high,middle and low tidal zones of Avicennia and low tidal zone(P <0.05).(2)The leaf C content of the natural forest is 404.97 ± 4.15 mg / g,and the leaf C content of the artificial forest is 404.70 ± 3.29 mg / g,which is very different from the leaf C content of the natural forest,because it is in the same protected area,The climatic and hydrological conditions are the same;the leaf N content of natural forest and planted forest are 11.7 ± 0.86 mg / g and 9.97 ± 0.30 mg / g,respectively.The leaf N content of natural forest is higher than that of planted forest;natural forest The leaf P content of the plantation and plantation were 0.96 ± 0.02 mg / g and 1.08 ± 0.03 mg / g,respectively.The leaf P content of the plantation was slightly higher than that of the natural forest.The N: P of natural forest leaves and planted forest leaves is 12.21 ± 0.99,9.26 ± 0.18,which is obviously restricted by N.The average C content of natural mangrove and artificial mangrove soil in this study area was 18.94 mg / g and 10.99 mg / g,respectively.The average N and P content of natural mangrove and artificial mangrove soil were(0.90 mg / g,052 mg / g)and(0.24 mg / g,0.29 mg / g),the soil C content of natural forests and plantations is 30-40cm> 0-10 cm,which is mainly due to the plant roots distributed in 30-40 cm.The C: P of planted forest is lower than that of natural forest,which can reflect the high p Hosp Horus availability of planted forest to a certain extent.(3)The average content of soil TC,TN and TP under different degrees of S.alterniflora invasion in Beixing Qixing Island mangrove forest is 5.87 mg / g,0.34 mg / g,0.44 mg / g,surface soil(0-20cm)TC The contents of SOC and SOC showed that they were not invaded and slightly invaded by S.alterniflora than the other three,while the middle and bottom soils were reversed.The content of N and P is not affected by the invasion of S.alterniflora.The average C: N of 0-60 cm soil is 21.76,which is higher than the national average value of soil C: N(13),indicating that the mineralization of soil organic matter in this study area is slow and the soil N content is low. |
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