围垦对杭州湾南岸滨海湿地土壤养分分布的影响

在杭州湾南岸典型滨海湿地以空间代时间的方法,采集不同围垦年代的自然湿地土壤和围垦后利用土壤,研究了湿地土壤有机质、N和P的空间分布规律及围垦利用对养分空间分布的影响。结果表明,随围垦时间的增加,土壤表层全P含量表现为增加的趋势,围垦5年、25年和50年土壤全P含量比未围垦光滩分别增加12%、25%和76%;土壤有机质则表现为先降低后增加趋势,围垦5年和围垦25年土壤有机质相比未围垦光滩分别减少14%和50%,围垦50年则比未围垦光滩增加87%;土壤全N的分布趋势和有机质基本一致。对养分剖面分布的分析表明,围垦及其利用等人为干扰活动对养分的影响主要集中于土壤表层。相关性分析显示,土壤中全N含量与有机质含量呈现出显著的正相关,说明在土壤中N主要是以有机N的形态存在,而全P含量与有机质含量的关系不显著。土壤颗粒组成与土壤中有机质、N素等养分含量有较为明显的关系,有机质、全N与物理性黏粒(<0.01mm)的各组分都表现为显著或极显著正相关;土壤中P素与土壤质地的关系则并不是很密切。研究表明,围垦及其利用引起的土壤水分和质地等物理性质的变化以及不同围垦历史是影响湿地土壤养分空间分布的主要因素。

Effects of reclamation on soil nutrients distribution of coastal wetland in south Hangzhou Bay

Based on the analyses of soils with different reclamation years in Hangzhou Bay coastal wetland,the spatial distribution of nutrients and reclamation effects on nutrients such as nitrogen,phosphorous and organic matter were studied.The results indicated that soil total phosphorous(TP) content increased with the increase of reclamation year.Compared to the tideland(CK),TP in surface layers of soils reclaimed for 5,25 and 50 years increased by 12%,25% and 76% respectively.Soil organic matter(OM) decreased at first then increased.Compared to CK,soil OM in surface layers reclaimed for 5 and 25 years decreased by 14% and 50% respectively,while OM in soils reclaimed for 50 years increased by 87%.And soil total nitrogen showed a similar tendency to OM.The nutrients distribution in soil profiles indicated that reclamation effects on soil nutrients were significant in soil surface layers.There was a significantly positive correlation between soil TN and soil OM,but no between TP and soil OM.There was a significant correlation between particles of less than 0.01 mm and soil OM and TN.No significant correlation between textures and soil TP.Changes of soil water,texture,and reclamation year were the main factors that influence the nutrient distribution.