JOANNEUM RESEARCH Graz, RESOURCES, Institute for Water, Energy and Sustainability, Elisabethstraße 18/II, A-8010 Graz, Austria.
Sci Total Environ. 2014 Nov 15;499:448-62. doi: 10.1016/j.scitotenv.2014.06.009. Epub 2014 Jun 27.
The shallow Murtal aquifer south of Graz, Austria, provides easily withdrawable groundwater, which is supplied as drinking water without any chemical treatment. The aquifer is also used intensively by agriculture. Common agricultural management practices are the main source for diffuse nitrogen leaching and high groundwater nitrate concentrations. To safeguard the coexisting use of these two important resources, lysimeters are operated at the agricultural test site Wagna, Austria, and the influence of two beneficial management practices--low nitrogen input and organic farming--on nitrogen leaching towards groundwater is investigated. The technical lysimeter design as presented here consists of: (1) high-resolution weighing cells, (2) a suction controlled lower boundary condition for sucking off seepage water, thus emulating undisturbed field conditions, (3) comparative soil temperature, water content and matrix potential measurements inside and outside the lysimeter at different depths, (4) an installation of the lysimeters directly into test plots and (5) a removable upper lysimeter ring enabling machinery soil tillage. Our results indicate that oasis effects or fringe effects of the lysimeter cylinder on unsaturated water flow did not occur. Another lysimeter cultivated with lawn is operated for observing grass-reference evapotranspiration, which resulted in good agreement with calculated grass-reference evapotranspiration according to the FAO-Penman-Monteith method. We conclude that lysimeters installed at Wagna test site did not show any fringe effects and, thus, are appropriate tools for measuring water balance elements and nitrogen leaching of arable and grass land at point scale. Furthermore, our results for the period of 2005 to 2011 show that beneficial management practices reduced nitrate leaching and, hence, may allow for a sustainable coexistence of drinking water supply and agriculture in the Murtal aquifer.
奥地利格拉茨南部的浅层穆塔尔含水层提供了易于抽取的地下水，这些水未经任何化学处理就被用作饮用水。该含水层也被农业大量使用。常见的农业管理实践是导致硝酸盐扩散淋溶和地下水硝酸盐浓度过高的主要原因。为了保障这两种重要资源的共存利用，在奥地利的瓦格纳农业试验场运营了渗滤器，并研究了两种有益的管理实践——低氮投入和有机农业——对地下水硝酸盐淋溶的影响。这里呈现的技术渗滤器设计包括：（1）高分辨率称重单元，（2）用于抽吸渗出液的受控制的下部边界条件，从而模拟未受干扰的田间条件，（3）在不同深度的渗滤器内外进行土壤温度、含水量和基质势的对比测量，（4）将渗滤器直接安装在试验田中，（5）可移动的上渗滤器环，使机器土壤耕作成为可能。我们的结果表明，渗滤器圆柱对非饱和水流的绿洲效应或边缘效应并未发生。另一个用草坪耕种的渗滤器用于观测草地参考蒸散量，其结果与根据 FAO-Penman-Monteith 方法计算的草地参考蒸散量吻合良好。我们得出的结论是，瓦格纳试验场安装的渗滤器没有显示出任何边缘效应，因此是测量点尺度农田和草地水量平衡要素和硝酸盐淋溶的合适工具。此外，我们在 2005 年至 2011 年期间的结果表明，有益的管理实践减少了硝酸盐淋溶，因此可以在穆塔尔含水层中实现饮用水供应和农业的可持续共存。
