THE NUTRIENT MANAGEMENT PLAN AT FARM LEVEL PUBLISHEDSorina Dumitru, Irina Calciu, Catalin Simota, Mihail Dumitru, Marius Eftene
At European level, people and policy makers are very concerned with environment issues, one of the main problems being the nitrates contamination of groundwater. The agricultural activities are the main nitrogen supply in soil, due to the application of the mineral and organic fertilizers doses. In the last decades, worldwide there was an increasing tendency for using nitrogen based fertilizers, being well known that it represents an essential nutrient for conservation and/or amelioration the soil fertility state and for agricultural production, which has to satisfy the food needs of increasing population. The presence of the high nitrogen concentrations, exceeding the maximum admissible concentrations may have a negative impact of the environment through the possible losses in the ground and surface waters and/or atmosphere. In order to optimize the crop production and avoid the environmental contamination with nitrates, a nutrient management plan (NMP) at farm or village level has been developed. The need of such a tool is given by the fact that the polluted groundwater, mostly in the nitrates vulnerable communes (NUTS4 level), is used for potable water through the public or individual wells, most of them being placed not far from households. The management plan for (organic and mineral) nitrogen fertilizers is based on the description of N cycle in soil-plant-hydrosphere system, taking into account the following soil N forms: inorganic nitrogen (nitrates), organic nitrates from vegetal residues incorporated in soil, organic nitrates in active and stable form associated with soil humus stock, organic nitrates from organic manure. The nitrogen alteration processes between different N forms (humus mineralization, vegetal residues decomposition and the associated mineralization, denitrification and immobilization) are described through equations for chemical kinetic associated, the reaction speed being influenced by temperature, soil moisture, and the different nitrogen amount from each form types. Mineral nitrates flux percolating under the roots depth (leaching) is calculated as function of water drained flux and average nitrates concentration on soil profile. The nutrient management plan application has been developed as a MS Excel file, using VBA language. The NMP components, its inputs and outputs data, and the main worksheets are described. A case study for a commune is presented, highlighting the accessibility of the application and its usefulness for the farmers and other local stakeholders, as well as for local authorities.
nutrients management plan; nitrates pollution; soil and climate databases