三江平原碟形洼地-岛状林土壤氮磷空间分布及生态化学计量特征

为阐明由碟形洼地-岛状林方向土壤养分的空间分布特征,选取非生长季中国科学院三江平原沼泽湿地生态试验站内的碟形洼地为研究对象,探讨土壤全氮和全磷含量及其化学计量比的空间分布特征及其影响因素。结果表明:由碟形洼地-岛状林方向,全氮、全磷和氮磷比在各样点的平均值分别呈"V"字、倒"N"字和"V"字型分布,土壤全氮、全磷与氮磷比含量的平均值分别为2278.11 mg/kg、820.50 mg/kg与2.44,变异系数为全氮(51.77%)氮磷比(36.07%)全磷(13.65%)。在0—50 cm土层内,全氮、全磷和氮磷比总体呈随土壤深度增加而逐渐降低的趋势,其中全氮主要集中于不同样点土壤的中上层,各样点的最高值均分布在土壤表层区域;全磷的富集深度与全氮相同,但在土壤20 cm深度各样点含量相近,后在20—50 cm深度内呈逐渐下降趋势;氮磷比在各样点的最高值与全氮和全磷分布总体一致,富集深度与两元素呈基本一致趋势。相关性分析表明,碟形洼地-岛状林方向土壤全氮与全磷之间均呈现出良好的相关关系,其中土壤有机质的分布,植物与水文状况、季节变化和土壤温度也在养分分布中起重要作用。

Spatial distribution and ecological stoichiometric characteristics of nitrogen and phosphorus in soils from saucer-shaped depressions to island forests in the Sanjiang Plain

In order to illuminate the spatial distribution characteristics of soil nutrients from saucer-shaped depressions to island forests, this paper chose the saucer-shaped depression within the wetland ecological test station on the Sanjiang Plain, part of the Chinese academy of sciences, as a study site during the non-growing season, and discusses the spatial distribution characteristics of total nitrogen (TN) content, total phosphorus (TP) content, and their stoichiometric ratios and influential factors. The results showed that the average TN, TP and N/P, respectively, displayed a tendency towards "V", inverted "N", and "V" type distributions in soil from saucer-shaped depression to island forests, the average of each was 2278.11 mg/kg, 820.50 mg/kg and 2.44 respectively, and the Coefficient of Variation (CV) was TN (51.77%) > N/P (36.07%) > TP (13.65%). In soil layers from 0 to 50 cm, TN, TP, and N/P decreased gradually with increasing soil depth, but TN was mainly concentrated in the upper middle layer of soil at the different points, and the highest values at all points were found in the surface area of soil. The enrichment depth of total phosphorus was the same as that of TN, but the content was similar at various points at the depth of 20 cm in the soil, and gradually decreased within the depth of 20-50 cm. The maximum value of N/P at various points was consistent with the distribution of TN and TP, and the enrichment depth was consistent with the two elements. The correlation analysis showed that TN and TP in soils both had a good correlation from saucer-shaped depressions to island forests, and the distribution of soil organic matter (SOM), plants, hydrological conditions, seasonal variation, and soil temperature played an important role in nutrient distribution.