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Landbouwpraktijk en waterkwaliteit in Nederland; toestand (2016-2019) en trend (1992-2019) : De Nitraatrapportage 2020 met de resultaten van de monitoring van de effecten van de EU Nitraatrichtlijn actieprogramma's
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Series / Report no.
RIVM rapport 2020-0121
Open Access
Type
Report
Language
nl
Date
2020-11-23
Research Projects
Organizational Units
Journal Issue
Title
Landbouwpraktijk en waterkwaliteit in Nederland; toestand (2016-2019) en trend (1992-2019) : De Nitraatrapportage 2020 met de resultaten van de monitoring van de effecten van de EU Nitraatrichtlijn actieprogramma's
Translated Title
Agricultural practices and water quality in the Netherlands; status (2016-2019) and trend (1992-2019) : The Nitrate rapport 2020 containing the results of monitoring effects of the EU Nitrates Directive action programmes
Published in
Abstract
De afgelopen dertig jaar heeft de Nederlandse overheid maatregelen genomen waardoor de concentraties stikstof en fosfor sterk zijn gedaald. Hierdoor is de kwaliteit van het grond- en oppervlaktewater verbeterd.
Maar de waterkwaliteit is nog niet overal voldoende. In de bovenste meter van het grondwater van meer dan de helft van de landbouwbedrijven in de Zand- en Lössregio is de nitraatconcentratie te hoog. Dit geldt ook voor de bovenste meter van het grondwater in ruim dertig van de circa 200 grondwaterbeschermingsgebieden. Ook voldoet een groot deel van de oppervlaktewateren nog niet aan de gewenste kwaliteit en zijn de concentraties stikstof en fosfor er te hoog.
Na 2015 neemt het teveel aan stikstof en fosfor toe. Dit is vanaf 2018 versterkt door de droge zomers. Bij droogte groeien planten minder goed, waardoor ze minder stikstof en fosfor uit de bodem opnemen. Ook wordt er minder nitraat in de bodem afgebroken en spoelt er meer weg naar het grond- en oppervlaktewater. Zo verdubbelde de nitraatconcentratie in het slootwater op landbouwbedrijven in de periode 2016 tot en met 2019. Toch was de nitraatconcentratie in het grond- en oppervlaktewater in deze periode gemiddeld genomen lager dan in de vier jaar ervoor.
Stikstof en fosfor zijn stoffen in mest die landbouwbedrijven gebruiken om gewassen beter te laten groeien. Een teveel aan stikstof en fosfor kan wegspoelen naar het grond- en oppervlaktewater en dat vervuilen. Nitraat is een van de vormen waarin stikstof voorkomt in de bodem en het water.
De verbeterde waterkwaliteit komt vooral doordat boeren steeds minder mest zijn gaan gebruiken. Hierdoor nam het te veel aan stikstof en fosfor in de bodem af. Dit betekent ook dat er minder nitraat met regenwater wegzakt naar diepere lagen in de bodem en zo in het grondwater terechtkomt. Hoe minder stikstof en fosfor in de bodem en in het grondwater zit, hoe minder er naar het oppervlaktewater stroomt.
Het is belangrijk om schoon grond- en oppervlaktewater te hebben waar drinkwater van kan worden gemaakt. Ook zorgt schoon oppervlaktewater ervoor dat er meer verschillende planten en dieren kunnen leven in het water.
Over the past thirty years, the Netherlands government has taken measures to reduce nitrogen and phosphorus concentrations. This has improved the quality of ground and surface water. However water quality is not yet adequate everywhere. The nitrate concentration is too high in the upper metre of groundwater of more than half of the farms in the Sand and Loess regions. This also applies to the upper metre of groundwater in more than 30 of the approximately 200 groundwater protection areas. Also, a large part of the surface waters is not yet of the desired quality, and the concentrations of nitrogen and phosphorus are too high. After 2015, the excess of nitrogen and phosphorus increased. Since 2018 this has been reinforced by the dry summers. During drought, plants grow less well, so that they take up less nitrogen and phosphorus from the soil. Also less nitrate is broken down in the soil, which means that more leaches to ground and surface water. For example, the nitrate concentration in ditch water on farms doubled in the period 2016 to 2019. Nevertheless, the nitrate concentration in ground and surface water in this period was on average lower than in the four years before. Nitrogen and phosphorus are substances in fertilisers that farmers use to make crops grow better. An excess of nitrogen and phosphorus can leach to ground and surface water and pollute it. Nitrate is one of the forms in which nitrogen occurs in the soil and water. The improved water quality is mainly due to farmers having used increasingly less fertiliser. This reduced the excess of nitrogen and phosphorus in the soil. This also means that less nitrate leaches with rainwater to deeper layers in the soil and ends up in the groundwater. The less nitrogen and phosphorus there is in soil and groundwater, the less flows to surface water. It is important to have clean ground and surface water that can be used for the production of drinking water. Clean surface water also ensures that a larger variety of plants and animals can live in the water.
Over the past thirty years, the Netherlands government has taken measures to reduce nitrogen and phosphorus concentrations. This has improved the quality of ground and surface water. However water quality is not yet adequate everywhere. The nitrate concentration is too high in the upper metre of groundwater of more than half of the farms in the Sand and Loess regions. This also applies to the upper metre of groundwater in more than 30 of the approximately 200 groundwater protection areas. Also, a large part of the surface waters is not yet of the desired quality, and the concentrations of nitrogen and phosphorus are too high. After 2015, the excess of nitrogen and phosphorus increased. Since 2018 this has been reinforced by the dry summers. During drought, plants grow less well, so that they take up less nitrogen and phosphorus from the soil. Also less nitrate is broken down in the soil, which means that more leaches to ground and surface water. For example, the nitrate concentration in ditch water on farms doubled in the period 2016 to 2019. Nevertheless, the nitrate concentration in ground and surface water in this period was on average lower than in the four years before. Nitrogen and phosphorus are substances in fertilisers that farmers use to make crops grow better. An excess of nitrogen and phosphorus can leach to ground and surface water and pollute it. Nitrate is one of the forms in which nitrogen occurs in the soil and water. The improved water quality is mainly due to farmers having used increasingly less fertiliser. This reduced the excess of nitrogen and phosphorus in the soil. This also means that less nitrate leaches with rainwater to deeper layers in the soil and ends up in the groundwater. The less nitrogen and phosphorus there is in soil and groundwater, the less flows to surface water. It is important to have clean ground and surface water that can be used for the production of drinking water. Clean surface water also ensures that a larger variety of plants and animals can live in the water.
Description
Publisher
Rijksinstituut voor Volksgezondheid en Milieu RIVM
Sponsors
Ministerie van I&W ; Ministerie van LNV