Gikas Georgios D, Tsihrintzis Vassilios A, Sykas Dimitrios
Department of Environmental Engineering, School of Engineering, Laboratory of Ecological Engineering and Technology, Democritus University of Thrace, 67100, Xanthi, Greece.
Centre for the Assessment of Natural Hazards and Proactive Planning and Laboratory of Reclamation Works and Water Resources Management, Department of Infrastructure and Rural Development, School of Rural and Surveying Engineering, National Technical University of Athens, 9 Iroon Polytechniou St., Zografou, 157 80, Athens, Greece.
Environ Monit Assess. 2016 Jun;188(6):327. doi: 10.1007/s10661-016-5325-0. Epub 2016 May 5.
The function of trees in reducing nutrient migration to groundwaters in cultivated areas, under Mediterranean climate conditions, is tested. Three cultivated fields were monitored for two cultivation periods. The common characteristic of the three fields was that on one side, they bordered with a poplar tree field. Four different crops were cultivated, and two cultivation periods were monitored. Based on the number of fields (i.e., three) and the cultivation periods (i.e., two), six different conditions (systems) were studied with four crops (i.e., sunflower, cotton, rapeseed, and corn). Soil samples were collected in all systems at the beginning, the middle, and the end of the cultivation period at various sampling sites (i.e., various distances from the tree row) and at various depths, and were analyzed in the laboratory for the determination of ΝΟ3-Ν and P-Olsen. In all systems, the greatest concentration of P-Olsen was measured in the surface layers (0-5, 10-15, and 30-35 cm) and was gradually decreased in the deeper layers (55-60 and 75-80 cm) indicating that P mobility is low. The ΝΟ3-Ν concentration in the deeper layers (55-60 and 75-80 cm) at all sampling sites was equal to or greater than that of the surface layers, indicating that ΝΟ3-Ν has high mobility in soils. At the sampling sites in the soil zone near the tree row, the ΝΟ3-Ν concentration in the deeper layers was lower than that of the surface, indicating that the tree root system takes up nutrients which otherwise would move toward the water table. There was also a reduction observed of the depth-averaged P-Olsen and ΝΟ3-Ν concentrations at the soil zone at a distance of 2.0-3.5 m from the tree row compared to locations more distant from the trees; this reduction ranged between 15 and 50 % and 36 and 54 %, respectively. The results indicate that planting of trees in cultivated fields can contribute to the reduction of nitrate pollution of groundwaters.
对地中海气候条件下树木在减少养分向耕地地下水迁移方面的作用进行了测试。对三块耕地进行了两个种植期的监测。这三块田地的共同特点是，它们一侧与杨树林地接壤。种植了四种不同的作物，并监测了两个种植期。基于田地数量（即三块）和种植期（即两个），对四种作物（即向日葵、棉花、油菜籽和玉米）研究了六种不同的条件（系统）。在种植期开始、中间和结束时，在所有系统的不同采样点（即距树行的不同距离）和不同深度采集土壤样本，并在实验室进行分析，以测定NO₃-N和有效磷。在所有系统中，有效磷的最大浓度在表层（0-5、10-15和30-35厘米）测得，并在较深层（55-60和75-80厘米）逐渐降低，这表明磷的迁移性较低。所有采样点较深层（55-60和75-80厘米）的NO₃-N浓度等于或高于表层，这表明NO₃-N在土壤中具有较高的迁移性。在靠近树行的土壤区域的采样点，较深层的NO₃-N浓度低于表层，这表明树木根系吸收了否则会向地下水位移动的养分。与距树木较远的位置相比，在距树行2.0-3.5米处的土壤区域，有效磷和NO₃-N的深度平均浓度也有所降低；这种降低分别在15%至50%和36%至54%之间。结果表明，在耕地上种树有助于减少地下水的硝酸盐污染。
