Leaching of nitrogen from arable land can lead to pollution of groundwater and surface water. Various measures have been implemented in agriculture to reduce leaching, but there is still potential to do more. To find the best agricultural management regime to limit the problem, leaching from soils under different management must be measured. Different methods to estimate leaching are available, but they have not been thoroughly evaluated. This study compared (a) leaching of nitrogen from five different fertilizer treatments differing in amount and source (mineral and organic) of nitrogen and (b) two different methods for measuring leaching (tile-drained field plots and lysimeters). Nitrogen leaching from five different fertilizer treatments was studied for three years in a tile-drained field facility and for three of the treatments also for 16 months in a lysimeter facility. Leaching from organic and mineral nitrogen sources was similar in the three-year field study. Mineral nitrogen input above the economic optimum tended to give greater leaching (by 24%–43%) than nitrogen input at the expected optimum. Measurements in lysimeters and tile-drained field plots gave similar results, although leaching values tended to be slightly higher (by 18%–25%) in the tile-drained field. Overall, both facilities give reliable estimates of nitrogen leaching and are suitable for leaching studies.

中文翻译：

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从瓦片排水的田地和蒸渗仪中浸出的氮得到不同的氮速率和来源

从耕地中渗出氮会导致地下水和地表水的污染。在农业中已经实施了各种措施来减少浸出，但仍有可能做得更多。为了找到限制问题的最佳农业管理制度，必须测量不同管理下的土壤浸出。可以使用不同的方法来估计浸出，但尚未对其进行彻底评估。本研究比较了 (a) 来自五种不同肥料处理的氮浸出，这些肥料处理的氮的数量和来源（矿物和有机）不同，以及 (b) 测量浸出的两种不同方法（瓦片排水的田间地块和蒸渗仪）。在瓷砖排水的田间设施中研究了五种不同肥料处理的氮浸出三年，并在蒸渗仪设施中研究了其中三种处理的 16 个月。在为期三年的实地研究中，有机和矿物氮源的浸出情况相似。高于经济最优值的矿物氮输入往往比预期最优值的氮输入产生更大的浸出（24%–43%）。蒸渗仪和瓷砖排水田地的测量结果相似，尽管在瓷砖排水田中浸出值往往略高（18%–25%）。总体而言，这两个设施都对氮浸出提供了可靠的估计，并且适用于浸出研究。高于经济最优值的矿物氮输入往往比预期最优值的氮输入产生更大的浸出（24%–43%）。蒸渗仪和瓷砖排水田地的测量结果相似，尽管在瓷砖排水田中浸出值往往略高（18%–25%）。总体而言，这两个设施都对氮浸出提供了可靠的估计，并且适用于浸出研究。高于经济最优值的矿物氮输入往往比预期最优值的氮输入产生更大的浸出（24%–43%）。蒸渗仪和瓷砖排水田地的测量结果相似，尽管在瓷砖排水田中浸出值往往略高（18%–25%）。总体而言，这两个设施都对氮浸出提供了可靠的估计，并且适用于浸出研究。