Distribution characteristics of organic carbon, nitrogen and phosphorus in the soils of herbaceous peat swamps in  the  Xiaoxing’an mountains

The distribution characteristics of organic carbon, nitrogen and phosphorus in soils were analyzed in two herbaceous peat swamps in the Xiaoxing’an mountains. The results show that the content of organic carbon in the Carex pseudocuraica wetland was higher than that in the C. schmidtii wetland. Carbon storage, average carbon content and carbon density of the C. pseudocuraica wetland were 35.40×103 t per km2, 438.40 g per kg and 88.99 kg per m3, respectively, while those of the C. schmidtii wetland were 20.03×103 t per km2, 98.74 g per kg  and 56.27 kg per m3. In the C. pseudocuraica wetland, the content of organic carbon was higher in the 10--20 cm soil layer, while in the C. schmidtii wetland, organic carbon content gradually decreased with increasing soil depth. The vertical changes of total nitrogen, hydrolyzable nitrogen and available phosphorus in both types of wetland showed a tendency to decrease with increasing soil depth. The contents of total nitrogen, hydrolyzable nitrogen, total and available phosphorus in the C. pseudocuraica wetland were higher than those in the C. schmidtii wetland by 271%, 548%, 32% and 216%, respectively. The storages of nitrogen and phosphorus in the 0--40 cm soil layer of the C. pseudocuraica wetland were 4.40 and 1.33 times larger than those in the C. schmidtii wetland. Carbon content in the soil was significantly and positively correlated (P0.01) with total nitrogen, hydrolyzable nitrogen, total phosphorus and available phosphorus, while the contents of organic carbon, nitrogen and phosphorus were significantly but negatively correlated (P0.01) with soil bulk density.