Watershed land cover affects in-stream water quality and sediment nutrient dynamics. The presence of natural land cover in the riparian zone can reduce the negative effects of agricultural land use on water quality; however, literature evaluating the effects of natural riparian land cover on stream sediment nutrient dynamics is scarce. The objective of this study was to assess if stream sediment phosphorus retention and nitrogen removal varies with riparian forest cover in agricultural watersheds. Stream sediment nutrient dynamics from 28 sites with mixed land cover were sampled three times during the growing season. Phosphorus dynamics and nitrification rates did not change considerably throughout the study period. Sediment total phosphorus concentrations and nitrification rates decreased as riparian forest cover increased likely due to a decline in fine, organic material. Denitrification rates were strongly correlated to surface water nitrate concentrations. Denitrification rate and denitrification enzyme activity decreased with an increase in forest cover during the first sampling period only. The first sampling period coincided with the greatest connectivity between the watershed and in-stream processing, indicating that riparian forest cover indirectly decreased denitrification rates by reducing the concentrations of dissolved nutrients entering the stream. This reduction in load may allow the sediment to maintain greater nitrogen removal efficiency, because bacteria are not saturated with nitrogen. Riparian forest cover also appeared to lessen the effect of agriculture in the watershed by decreasing the amount of fine material in the stream, resulting in reduced phosphorus storage in the stream sediment.

流域土地覆盖影响河流水质和沉积物养分动态。河岸带自然土地覆盖的存在可以减少农业用地对水质的负面影响；然而，评估自然河岸土地覆盖对河流沉积物养分动态影响的文献很少。本研究的目的是评估河流沉积物磷保留和氮去除是否随农业流域的河岸森林覆盖而变化。在生长季节对来自 28 个混合土地覆盖点的河流沉积物养分动态进行了 3 次采样。在整个研究期间，磷动态和硝化速率没有发生很大变化。沉积物总磷浓度和硝化率下降，因为河岸森林覆盖率可能由于精细有机材料的减少而增加。反硝化率与地表水硝酸盐浓度密切相关。仅在第一个采样期间，反硝化率和反硝化酶活性随着森林覆盖率的增加而下降。第一个采样期恰逢流域和河流处理之间的最大连通性，表明河岸森林覆盖通过降低进入河流的溶解养分浓度间接降低了反硝化率。这种负荷的减少可以使沉积物保持更高的脱氮效率，因为细菌没有被氮饱和。