三江湿地周边不同利用方式土壤理化性质及水稳性团聚体化学计量特征变化

选取黑龙江省三江湿地-洪河保护区3种土地利用方式,分析各类土壤水稳性团聚状态及其团聚体有机碳(SOC)、全氮(TN)、全磷(TP)含量和碳氮磷化学计量特征变化规律。结果表明,湿地土壤不同利用方式水稳定性团聚体组成发生显著变化,水稳性团聚体比例均表现为粉-粘团聚体(0.053 mm)比例最大,微团聚体(0.053~0.250 mm)次之,大团聚体(0.25 mm)比例最低。随土壤粒径递减,所有生态系统中土壤SOC、TN、TP含量以及C/N、C/P均降低,表现为大团聚体大于微团聚体,水稳性团聚体N/P变化较小,范围在1.33~2.08。相同土壤粒径下不同利用方式下土壤SOC、TN、TP含量及C/P、N/P最大值均出现在湿地土壤,C/N最大值出现在水田土壤。土壤养分含量最小值出现在旱田土壤。因此,湿地周边土壤对各粒径土壤团聚体全效养分分配及其平衡关系有负向影响,其中旱田和人工林土壤退化最为严重,1~2 mm粒径下碳氮损失量较大,化学计量不平衡。研究结果为湿地保护与合理利用提供科学依据。

Change of soil physiochemical properties and water-stable aggregates in different uses of Sanjiang Wetland

To reveal the impact of land use on soil aggregates,we examined the organic carbon (SOC),total nitrogen (TN),total phosphorus (TP) content,carbon and ecological stoichiometric characteristics of soil aggregates in paddy field,upland field and artificial forest in Sanjiang Wetland-Hong Lake reserve.The results showed that the proportion of powder-stick aggregates (0.053-0.250 mm) was the highest,followed by the micro-aggregates (0.053-0.250 mm),and the large aggregates (＞ 0.25 mm) was the lowest in all ecosystems.Soil SOC,TN,TP content and C/N,C/P decreased with decreasing size of soil aggregates in all ecosystems,whereas N/P of water stability agglomerates varied less,ranging from 1.33 to 2.08.Soil SOC,TN,TP content,C/P and N/P were the highest in wetland soil under the same soil particle size,while the highest C/N appeared in paddy soil.On the other hand,the lowest soil nutrients was found in upland field.Therefore,the soil around the wetland negatively affected the nutrient allocation and the equilibrium relationship of the soil aggregates in all particle sizes,resulting in serious soil degradation in upland field and artificial field.Furthermore,the loss of carbon and nitrogen in 1-2 mm soil particle was quite strong,which made the chemical measurement unbalanced.The results provide scientific basis for wetland protection and rational utilization.