退耕还湖后不同植被群落下湿地土壤有机质及磷素含量差异分析

以菜子湖地区退耕还湖后苔草、芦苇和酸模植被群落下的湿地土壤为研究对象,分析了3种植被群落类型对湿地土壤有机质、全磷、速效磷含量及其在土壤剖面分布特征的影响。结果表明:(1)0-6cm土层土壤有机质含量表现为:酸模>苔草>芦苇,而6-13cm,13-25cm,25-40cm,40-55cm土层均表现为:芦苇>苔草>酸模,总体表现为随着土壤剖面深度增加而下降(2)土壤全磷含量均为0-6cm土层全磷含量较高,6-13cm土层含量最低,全磷含量总体表现为随着剖面深度的增加而递增,递增趋势的强弱表现为:酸模>苔草>芦苇(3)土壤速效磷含量除酸模在0-6cm土层显著大于苔草和芦苇外,其它各个层次间土壤有效磷含量无显著性差异,总体上均表现为随土层加深而下降的趋势(4)除酸模在0-6cm和6-13cm土层的土壤磷素有效率显著高于苔草和芦苇外,其它不同土壤层次间无显著差异。(5)不同植被群落凋落物和根系分布特征差异是引起退耕后湿地土壤剖面有机质和磷素分布差异的主要原因,而水产养殖农家肥投放也促进了湿地表层土壤养分积累。

Variations of Soil Organic Matter and Phosphorus Contents in Wetlands with Different Vegetation Types After Returning Farmland to Lake

Soils in wetlands under returning farmland to lake with different vegetation types(Carex maximowzczii>Rumex acetosa Linn.and Phragmites australis)were sampled to analyze the effects of the three vegetation types on soil organic matter,total P and available P and their distributions in soil profiles in the Caizi Lake.Results showed that soil organic matter content in 0-6 cm layer were the highest under Rumex acetosa Linn. and the lowest under Phragmites australis.Moreover,soil organic matter contents in 6-13 cm,13-25cm,25-40 cm,and 40-55 cm layers were in the order of Phragmites australis and Carex maximowicziiand Rumex acetosa Linn.and decreased with soil depth under all the three vegetation types.The contents of total P under all the three vegetation types were high in 0-6 cm layers and the lowest in 6-13 cm layers,and then increased with soil depth.Available P contents decreased with soil depth in all the soil profiles,and there was no significant difference in the same soil layers under different vegetation types except that Rumex acetosa Linn.was higher than Phragmites australis and Carex maximowiczii in 0-6 cm layer. There was no significant difference of soil phosphorus efficiency in all the same soil layers under different vegetation types except that Rumex acetosa Linn. was higher than Phragmites australis and Carex maximowiczii in 0-6 cm and 6-13 cm layers.Litters and root distribution under different vegetation types were the cause of distribution variation of organic matter and phosphorus in soil profiles,and farmyard manure for the aquacul-ture also caused soil nutrient accumulation in surface soils.