| Nitrogen soil surplus per ha - Derogation farms |
Nitrogen soil surplus increased in 2020
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07/09/2023
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In addition to the farm surplus, the input and output of nitrogen at farm level also largely determines the soil surplus. The nitrogen soil surplus on farms in the derogation monitoring network also depends on the nitrogen input via deposition, fixation (leguminous crops) and mineralisation, and on nitrogen output via gaseous losses. The nitrogen soil surplus on farms in the derogation monitoring network was 171 kg/ha in 2020.
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Nitrogen soil surplus higher in 2020
The average nitrogen surplus on the soil balance in 2020 was 171 kg nitrogen per hectare. That is 13 kg/ha more than in 2019, but 19 kg/ha less than in 2018. Over the entire period from 2006 to 2020, the nitrogen soil surplus shows a declining trend. The spread between farms is large for all years. In 2020, 25% of the farms in the derogation monitoring network realised a nitrogen soil surplus below 129 kg/ha, while the 25% farms with the highest nitrogen soil surplus were above 208 kg/ha. The nitrogen soil surplus was highest in all years in the Peat region as a result of the high calculated nitrogen input via mineralisation in this region (average 96 kg/ha in 2020). In 2020, the nitrogen soil surplus in the Peat region was on average 222 kg/ha. The nitrogen soil surplus was lowest in the Loess region with an average of 150 kg/ha. The Sand-250 region, the Sand-230 region and the Clay region were in between with a nitrogen soil surplus of 155, 157 and 161 kg/ha respectively. Over the entire period from 2006 to 2020, four of the five soil type regions show a declining trend in the nitrogen soil surplus. Only in the Loess region there is no downward (but also no increasing) trend.
Decrease in nitrogen deposition and nitrogen fixation
In addition to the input items that are included in the calculation of the nitrogen farm surplus (feed, fertiliser, animal manure, other organic manure, animals and other), the calculation of the nitrogen soil surplus also takes into account the input of nitrogen via deposition, nitrogen fixation via leguminous crops and mineralisation on farms with peaty and/or wetland soils. In the period 2006-2020, the nitrogen input via deposition on farms in the derogation monitoring network decreased on average by almost 14 kg/ha to 17 kg/ha. The input as a result of nitrogen fixation by leguminous crops was 12 kg/ha in the early years of the derogation monitoring network, from 2010 it is 8 kg/ha and from 2013 it is 6 to 7 kg/ha. On derogation farms in the Peat region, the nitrogen input due to mineralisation of organic soils varied from 80 to 96 kg/ha in the period 2006-2018, with 96 kg/ha referring to the year 2020. In the other soil type regions, mineralisation played a much smaller role. In 2020, this concerned 17, 5, 4 and 0 kg/ha respectively in the Sand-250 region, the Sand-230 region, the Clay region and the Loess region.
Nitrogen output steady due to gaseous emission
The output of nitrogen through pasture, stable and storage and manure application emissions amounted to an average of 58 kg/ha in 2020 on farms in the derogation monitoring network. The gaseous emissions from manure application on the one hand and from stables and storage on the other hand were 27 and 30 kg/ha respectively. The gaseous emission from pastures was only 1 kg/ha. In the period 2006-2020 the total emission varied from 55 to 62 kg nitrogen per hectare, with no increasing or decreasing trend. The total emissions in 2020 were lowest in the Loess region with 46 kg/ha and highest in the Sand-230 region and the Clay region with 62 and 61 kg/ha respectively.
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