Alterra, Wageningen Univ. and Research Centre, 6700 AA Wageningen, The Netherlands.
J Environ Qual. 2012 Jan-Feb;41(1):229-41. doi: 10.2134/jeq2011.0292.
In flat areas, transport of dissolved nutrients by water through the soil matrix to groundwater and drains is assumed to be the dominant pathway for nutrient losses to ground- and surface waters. However, long-term data on the losses of nutrients to surface water and the contribution of various pathways is limited. We studied nutrient losses and pathways on a heavy clay soil in a fluvial plain in The Netherlands during a 5-yr period. Average annual nitrogen (N) and phosphorus (P) losses to surface water were 15.1 and 3.0 kg ha(-1) yr(-1), respectively. Losses were dominated by particulate N (50%) and P (70%) forms. Rapid discharge through trenches was the dominant pathway (60-90%) for water and nutrient transport. The contribution of pipe drains to the total discharge of water and nutrients was strongly related to the length of the dry period in the preceding summer. This relationship can be explained by the very low conductivity of the soil matrix and the formation of shrinkage cracks during summer. Losses of dissolved reactive P through pipe drains appear to be dominated by preferential flow based on the low dissolved reactive P concentration in the soil matrix at this depth. Rainfall occurring after manure application played an important role with respect to the annual losses of N and P in spring when heavy rainfall occurred within 2 wk after manure application.
在平原地区，水通过土壤基质向地下水和排水系统输送溶解养分被认为是养分向地下水和地表水流失的主要途径。然而，关于养分向地表水的流失以及各种途径的贡献的长期数据是有限的。我们在荷兰的一个河流平原上的重粘土地上进行了为期 5 年的研究，研究了养分流失和途径。平均每年氮（N）和磷（P）向地表水的流失量分别为 15.1 和 3.0 公斤/公顷/年。流失主要由颗粒态 N（50%）和 P（70%）形式构成。通过沟渠的快速排放是水和养分运输的主要途径（60-90%）。管渠对水和养分总排放量的贡献与前一个夏季的干燥期长度密切相关。这种关系可以用土壤基质的极低电导率和夏季形成的收缩裂缝来解释。由于土壤基质在这个深度的溶解反应性 P 浓度较低，因此通过管渠流失的溶解反应性 P 似乎主要是优先流。在春季，粪肥施用后发生的降雨在 N 和 P 的年流失中起着重要作用，因为粪肥施用后 2 周内发生了强降雨。
