This study estimated the mass accumulation rates of sediment (MAR), carbon (CMAR), and phosphorus (PMAR) in small Finnish lakes with agricultural clayey catchments over a 25-year period (1986–2011) and compared these with the conditions before major agricultural land use. Twenty-two lakes were cored for recent and reference (pre-disturbance) sediments. The recent sediment section was selected based on the 1986 ¹³⁷Cs fallout peak (TOP), whereas the pre-disturbance section (REF) was selected immediately below the first signs of human-induced erosion. The 50-cm reference section was dated with ¹⁴C at both ends. The mass accumulation rates were estimated based on dating, weighing, and chemical analysis for both sediment sections. Furthermore, sediment-penetrating echo soundings were used to estimate the amount of sediment in the whole lake basins. These data were used to examine area-specific loading from clay-rich catchments. The average whole-basin pre-disturbance MAR, PMAR, and CMAR were 62 g m⁻² a⁻¹, 0.06 g m⁻² a⁻¹, and 4.7 g m⁻² a⁻¹, respectively. The corresponding recent rates were 11, 13, and 8-fold (693 g m⁻² a⁻¹, 0.79 g m⁻² a⁻¹, and 37 g m⁻² a⁻¹). In the recent conditions, sediments were generally more minerogenic and MAR, PMAR, and CMAR were higher in lakes with more arable fields in their catchments. Average area-specific suspended sediment load from the catchment for the region (∼39% clayey soils) was approximately 69–137 kg ha⁻¹ a⁻¹ in the undisturbed state and 767–1534 kg ha⁻¹ a⁻¹ in recent conditions based on 100–50% retention. The results demonstrate that the increases in sediment, nutrient, and organic matter accumulation due to agriculture can be several fold over undisturbed state.

本研究估计了 25 年（1986 年至 2011 年）内具有农业粘土流域的芬兰小湖泊中沉积物 (MAR)、碳 (CMAR) 和磷 (PMAR) 的质量积累率，并将这些值与重大事件之前的条件进行了比较。农业土地利用。对二十二个湖泊进行了取芯，以获取近期沉积物和参考（扰动前）沉积物。最近的沉积物部分是根据 1986 ¹³⁷ Cs 沉降峰 (TOP) 选择的，而扰动前部分 (REF) 是在人类引起的侵蚀的第一个迹象下方选择的。50 厘米参考截面两端均标有^{14 C 日期。}根据两个沉积物部分的年代测定、称重和化学分析来估计质量积累率。此外，利用沉积物穿透回波探测来估计整个湖盆的沉积物量。这些数据用于检查富含粘土的流域的特定区域负荷。全流域平均扰动前MAR、PMAR和CMAR分别为62 g m ^-2 a ^-1、0.06 g m ^-2 a ^-1和4.7 g m ^-2 a ^-1。相应的近期比率为11、13和8倍（693 g m ^-2 a ^-1、0.79 g m ^-2 a ^-1和37 g m ^-2 a ^-1）。在最近的条件下，流域内耕地较多的湖泊沉积物普遍成矿作用更强，MAR、PMAR 和 CMAR 较高。该地区流域的平均特定区域悬浮泥沙量（约 39% 粘土）在未受干扰的状态下约为 69–137 kg ha ⁻¹ a ⁻¹ ，在最近的条件下约为 767–1534 kg ha ⁻¹ a ⁻¹基于 100–50% 保留率。结果表明，农业造成的沉积物、养分和有机物积累的增加可能是未受干扰状态的几倍。