@misc{12854,
  abstract     = {{Assessing nutrient loading and processing is crucial for water quality management in lakes and reservoirs. Quantifying and reducing external nutrient inputs in these systems remains a significant challenge. The difficulty arises from low monitoring frequencies of the highly dynamic external inputs and the limited availability of measures to reduce diffuse source loading. One option for the latter is the use of pre-dams, i.e. small impoundments at the inflow points into reservoirs, designed to retain nutrients by algal uptake and sedimentation. This study analyzes long-term (ranging from 8 to 22 years) nutrient and discharge time series for nine German pre-dams to assess their retention capacity. For that, we (i) quantified nutrient loading using four different mathematical methods, (ii) derived their retention efficiencies, and (iii) identified environmental factors determining the retention of nitrogen (N), phosphorus (P), and silica (Si). We show that retention of soluble reactive phosphorus (SRP) (43.6 %) and total phosphorus (TP) (39.9 %) is far higher than for nitrate (NO3) (15.3 %) and Si (15.9 %). The retention efficiency for SRP and TP was higher during the warm seasons because of higher algal nutrient uptake and thus higher nutrient sedimentation. Mixed effects models documented a significant positive effect of the pre-dams' hydraulic residence time (HRT) on retention efficiency. Pre-dams provide substantial service in retaining nutrients and help to protect downstream waterbodies from nutrient inputs. They provide effective measures for trapping nutrients including those originating from non-point sources.}},
  author       = {{Fernandes, Taynara and Shatwell, Tom and Schultze, Martin and Mi, Chenxi and Determann, Maria and Rinke, Karsten}},
  booktitle    = {{Water research : a journal of the International Water Association}},
  issn         = {{1879-2448}},
  keywords     = {{Nutrient load calculation, Phosphorus, Nitrogen, Silica, Retention efficiency, Lakes}},
  publisher    = {{Elsevier BV}},
  title        = {{{How efficient are pre-dams as reservoir guardians? A long-term study on nutrient retention}}},
  doi          = {{10.1016/j.watres.2024.122864}},
  volume       = {{272}},
  year         = {{2024}},
}

@misc{12825,
  abstract     = {{Agriculture is a major contributor to nitrate groundwater contamination. Hence, farmers are demanded to reduce the environmental impact but simultaneously must provide sufficient food products. One important building block for this "sustainable intensification" are appropriate cropping strategies. The potential of modified crop rotations was evaluated in a high-yielding environment in Northern Germany. Therefore, in five consecutive growing seasons (2016/2017 - 2020/2021) three crop rotations were grown in a field trial and compared with respect to agronomic (cereal unit), economic (gross margin) and environmental (N surplus) parameters. A standard crop rotation, typical for the region of the study, was compared with rearranged and augmented crop rotations. Therefore, crops with a high autumnal N uptake (winter oilseed rape and catch crops) were grown after crops with typically high soil mineral N (SMN) amounts after harvest (faba bean and winter oilseed rape). Due to the change of preceding and subsequent crops, an increased N transfer was supposed to prevent N from leaching and a lower N fertilizer demand of the subsequent crop was expected. On average, the modified crop rotations achieved significantly higher cereal units (9.3 and 10.8 t center dot ha -1) compared to the local crop rotation (8.5 t center dot ha -1). The gross margin of the local crop rotation was 1474 euro center dot ha- 1 and the other crop rotations maintained (1443 euro center dot ha -1) or significantly increased (1572 euro center dot ha -1) this value, respectively. The local crop rotation had a N surplus of 47 kg N center dot ha -1. In contrast, the N surplus of the modified crop rotations was significantly lower (10 and 28 kg N center dot ha -1). In summary, the results showed that a thoughtful rearrangement of crop rotations is an appropriate measure to simultaneously improve yields and gross margins with less unfavorable environmental impacts.}},
  author       = {{Rose, Maren and Pahlmann, Ingo and Kage, Henning}},
  booktitle    = {{European Journal of Agronomy}},
  issn         = {{1873-7331}},
  keywords     = {{Crop rotation, Sustainable intensification, Cereal unit, Gross margin, Nitrogen surplus, Effective net nitrogen mineralization}},
  publisher    = {{Elsevier BV}},
  title        = {{{Modified crop rotations for a sustainable intensification? A case study in a high-yielding environment with recurrent nitrogen surplus}}},
  doi          = {{10.1016/j.eja.2022.126644}},
  volume       = {{142}},
  year         = {{2022}},
}