Projects / Programmes
Nitrate migration in a plant-soil-groundwater system
| Code |
Science |
Field |
Subfield |
| 1.08.00 |
Natural sciences and mathematics |
Control and care of the environment |
|
| Code |
Science |
Field |
| P000 |
Natural sciences and mathematics |
|
| P005 |
Natural sciences and mathematics |
Geology, physical geography |
| P470 |
Natural sciences and mathematics |
Hydrogeology, geographical and geological engineering |
| B006 |
Biomedical sciences |
Agronomics |
| B410 |
Biomedical sciences |
Soil science, agricultural hydrology |
nitrate, plant, soil water, groundwater, fertilization, irrigation, isotopes
Researchers (16)
Organisations (3)
Abstract
The circulation of nitrogen is a very complex system of chemical, physical and biochemical reactions. One of the most common nitrogen compounds in nature is nitrate, which is a result of natural and artificial processes in nitrogen’s biogeochemical cycle. Unsuitable agricultural practices are one of the main sources of pollution. Although a nature-friendly agricultural practice cannot completely eliminate nitrate from water, it can nevertheless decrease their presence to a non-hazardous level. The proposed research will be focused on the entire system plant-soil solution-groundwater. For this purpose, a suitable experimental field in the area of the Ljubljana aquifer will be chosen to monitor substance flows of nitrogen in different cultivation techniques and their possible impact on groundwater. Processes in nitrogen cycle will be monitored by means of changes in the concentration and isotope composition of nitrogen compounds in the soil, in water-soluble nitrogen, root system, plant (leaf) and groundwater. Mass and isotope balance of the system will be elaborated. Stable isotope 15N will be used as tracer, because it is completely unharmful for nature, as it occurs in a natural concentration of about 0.368at%. The use of stable isotopes as natural or artificial tracers which are added in the form of heavy-isotope enriched compounds is the most accurate way of determining the source of nitrate and reactions influencing its isotope composition. The isotope composition of nitrogen in the system soil-solution-plant is influenced by several interrelated processes. They change the isotope composition of nitrogen in predictable, yet different directions, therefore long-term monitoring of several parameters is required to determine the ways of transport of nitrogen through the ecosystem. Additionally, stable isotopes of oxygen (18O) and carbon (13C) will be used to estimate the recharge source of the shallow aquifer and the main biogeochemical processes occurring in groundwater. The tracing experiment on the Selniška Dobrava lysimeter has the objective to investigate the transport of nitrates in the unsaturated and saturated system of the aquifer and the consequences of these interactions on the quality of groundwater resource as a whole. Results of the tracing experiment will be used as input parameters for the modelling of transport processes of water and nitrate nitrogen in the unsaturated and saturated zone. On the basis of data and estimations of surplus nitrogen in soil and unsaturated zone, a model of nitrate transport through the aquifer will be developed. The intergranular aquifer of Ljubljansko polje will be used as model case. Special attention will be given to the stratification of nitrate concentrations along the aquifer’s profile, which will be studied with an environmental probe. When nitrogen mass flows in different parts of the system are known, a combined model will be made in connection with the existing hydraulic model of the Ljubljansko polje aquifer, which will be used for future needs of aquifer management or protection. The model will enable a more precise determination of adequate agricultural practices in individual groundwater protection areas. It is expected that the model will be, with some adjustments, useful for the evaluation of conditions in other Slovenian aquifers and groundwater bodies.
