3.D - Agricultural Soils

In 2022, agricultural soils emitted 267.8 kt NH₃ or 57.1 % of the total agricultural NH₃ emissions in Germany (469.3 kt NH₃). The main contributions to the total NH₃ emissions from agricultural soils are the application of manure (3.D.a.2.a), with 165.8 kt (61.9 %) and the application of other organic N-fertilizers (3.D.a.2.c) with 54.2 kt (20.2 %).

Application of synthetic N-fertilizers (3.D.a.1) contributes 33.4 kt NH₃ (12.5 %). N excretions on pastures (3.D.a.3) have a share of 12.8 kt NH₃ (4.8 %) and the application of sewage sludge (3.D.a.2.b) leads to 1.6 kt NH₃ (0.6 %).

In 2022, agricultural soils were the source of 98.6 % (99.9 kt) of the total of NO_x emissions in the agricultural category (101.3 kt). The NO_x emissions from agricultural soils are primarily due to application of inorganic fertilizer (3.D.a.1) (45.5 kt) and manure (3.D.a.2.a) (35.2 kt) Application of other organic N-fertilizers (3.D.a.2.c) contributes 13.9 kt to agricultural soil emissions, 4.8 kt are due to excretions on pastures (3.D.a.3). Emissions from application of sewage sludge (3.D.a.2.b) contribute 0.5 kt.

In 2022, the category of agricultural soils contributed 8.9 kt NMVOC or 3.1 % to the total agricultural NMVOC emissions in Germany. The only emission source was cultivated crops (3.D.e).

In 2022, agricultural soils contributed, respectively, 35.6 % (21.0 kt), 63.4 % (21.0 kt) and 31.4 % (1.7 kt) to the total agricultural TSP, PM₁₀ and PM_2.5 emissions (59.1 kt, 33.1 kt, 5.3 kt, respectively). The emissions are reported in category 3.D.c (Farm-level agricultural operations including storage, handling and transport of agricultural products).

The calculation of NH₃ and NO_x (NO) emissions from the application of synthetic fertilizers is described in Vos et al. (2024), Chapters 5.2.1.2 and 5.2.2.2 1)¹⁾.

German statistics report the amounts of fertilizers sold which are assumed to equal the amounts that are applied. Since the 2021 submission, storage effects are approximated by applying a moving average to the sales data (moving centered three-year average, for the last year a weighted two-year average, which assigns 2/3 of the weight to the last year). Since the year 2022, data for the sales of urea that is stabilized with urease inhibitor is available. It cannot be published because of data-privacy issues. Therefore, the emissions are calculated and provided by the federal statistical office using the emission factors as described below. The activity data are published in aggregate for urea, urea+inhibitor and nitrogen solutions to maintain confidentiality. For details see Vos et al. (2024), Chapter 2.8.

Table 1: AD for the estimation of NH₃ and NO_x emissions from application of synthetic fertilizers

NH₃ emissions from the application of synthetic fertilizers are calculated using the Tier 2 approach according to EMEP (2019)-3D-14ff ¹⁾, distinguishing between various fertilizer types, see Table 2. For NO_x, the Tier 1 approach described in EMEP (2019) [10]-3D-11 is applied.

The emission factors for NH₃ depend on fertilizer type, see EMEP (2019)-3D-15. Table 2 lists the EMEP emission factors for the fertilizers used in the inventory. In order to reflect average German conditions, the emission factors for cool climate and a pH value lower than 7 was chosen. For urea fertilizer the German fertilizer ordinance prescribes the use of urease inhibitors or the immediate incorporation into the soil from 2020 onwards. The NH₃ emission factor for urea fertilizers is therefore reduced by 70% from 2020 onwards for the immediate incorporation of urea, according to Bittman et al. (2014, Table 15)²⁾. For the use of urease inhibitors the emission factor for urea fertilizer is reduced by 60%. For details see Vos et al. (2024), Chapter 5.2.1.2.

Table 2: Synthetic fertilizers, emission factors in kg NH₃ per kg fertilizer N

For NO_x, the simpler methodology by EMEP (2019)-3D-11 was used. The emission factor 0.040 from EMEP, 2019-3D, Table 3.1 has the unit of [kg N₂O per kg fertilizer N] and was derived from ³⁾.

The German inventory uses the emission factor 0.012 kg NO-N per kg N derived from Stehfest and Bouwman (2006). This is equivalent to an emission factor of 0.03943 kg NO_x per kg fertilizer N (obtained by multiplying 0.012 kg NO-N per kg N with the molar weight ratio 46/14 for NO₂: NO). The inventory uses the unrounded emission factor.

Table 3: Emission factor for NO_x emissions from fertilizer application

Since 2016, fertilizer sales have fallen dramatically (by around a third). Emissions have fallen accordingly. This is even more pronounced for NH₃ than for NO_x, as total NH₃ from the application of mineral fertilizers is, until the year 2019, very strongly correlated with the amount of urea applied (R<SUP>2</SUP> = 0.89), the sales of which have decreased more than for all other mineral fertilizers. Since 2020 the negative trend is reinforced as urea fertilizer have to be either used with urease inhibitors or have to be incorporated into the soil directly, which reduces emissions.

Table REC-1 shows the effects of recalculations on NH₃ and NO_x emissions. Major differences for NH₃ emissions occur in 2020 and 2021 because of the new reduction factor for the use of urease inhibitors and to a much lesser extent resulting from the moving average. The latter is the only reason for the differences of NO_x emissions in 2021. Minor differences occur in some years before 2008. They result from the correction of the applied amounts (recalculation No. 12).

Table 4: REC-1: Revised NH₃ and NO_x emissions, in kilotonnes

No improvements are planned at present.

In this sub-category Germany reports the NH₃ and NO_x (NO) emissions from application of manure (including application of anaerobically digested manure). An overview is given in Vos et al. (2024), Chapters 5.2.1.2 and 5.2.2.2. Germany uses the Tier 2 methodology for estimating NMVOC emissions for cattle in sector 3.B (manure management). The use of this methodology yields NMVOC emissions which formally could be reported in the sectors 3.D.a.2.a and 3.D.a.3 (grazing emissions). However, to be congruent with the NMVOC emissions for other animal categories, Germany reports these emissions in the NMVOC emissions reported from manure management (3.B). For the NFR codes 3.D.a.2.a and 3.D.a.3 the notation key IE is used for NMVOC emissions.

The calculation of the amount of N in manure applied is based on the N mass flow approach (see 3.B). It is the total of N excreted by animals in the housing and the N imported with bedding material minus N losses by emissions of N species from housing and storage. Hence, the amount of total N includes the N contained in anaerobically digested manures to be applied to the field.

The frequencies of application techniques and incorporation times as well as the underlying data sources are described in Vos et al. (2024), Chapter 2.5. The frequencies are provided. in the NID 2024⁴⁾, Chapter 17.3.1.

Table 5: AD for the estimation of NH₃ and NO_x emissions from application of manure

NH₃ emissions from manure application are calculated separately for each animal species in the mass flow approach by multiplying the respective TAN amount with NH₃ emission factors for the various manure application techniques. For details see [3-b-manure-management 3.B] and Vos et al. (2024), Chapter 5.2.1.2. For NO_x emissions from manure application the inventory calculates NO-N emissions (see Vos et al. (2024), Chapter 5.2.2.2, that are subsequently converted into NO_x emissions by multiplying with the molar weight ratio 46/14. The Tier 1 approach for the application of synthetic fertilizer as described in EMEP (2019)-3D-11 is used, as no specific methodology is available for manure application.

The following table shows the time series of the overall German NH₃ IEF defined as the ratio of total NH₃-N emission from manure application to the total amount of N spread with manure.

Table 6: IEF for NH₃–N from application of manure

Both NH₃ and NO_x emissions from the application of animal manures are key sources. Total NO_x is calculated proportionally to the total N in the manures applied which decreased remarkably from 1990 to 1991 due to the decline in animal numbers following the German reunification (reduction of livestock numbers in Eastern Germany). In the 1990s and 2000s this was followed by a weakened decline in animal manure amounts. From 2010 to 2014 there was a slight increase and since then the amount of N in manure applied has been declining again, see Table 5. The NO_x emissions follow these trends. For total NH₃ emissions there is a negative trend. This is due to the decreasing amounts of animal manures and the increasing use of application practices with lower NH₃ emission factors.

For all years, the total emissions of NH₃ and NO_x from application of manure are slightly higher than those of last year’s submission.

These differences are predominantly caused by a higher estimate of manure N, which is applied, compared to the last submission. Most of the recalculations (except No. 2, 11, 12) have an effect on this, some are increasing the emissions (esp. No. 1 (new animal categories) and No. 6 (correction of poultry numbers before 2013). Recalculation No. 13 (update of anaerobic digestion data) results to changes in both directions for different animal categories, see main page of the agricultural sector, list of recalculation reasons. Further details on recalculations are described in Vos et al. (2024), Chapter 1.3.

Table 7: REC-2: Revised NH₃ and NO_x emissions, in kilotonnes

No improvements are planned at present.

The calculation of NH₃ and NO_x (NO) emissions from application of sewage sludge is described in Vos et al. (2024), Chapters 5.2.1.2 and 5.2.2.2.

N quantities from application of sewage sludge were calculated from data of the German Environment Agency and (since 2009) from data of the Federal Statistical Office.

Table 8: AD for the estimation of NH₃ and NO_x emissions from application of sewage sludge

A Tier 1 methodology is used (EMEP, 2019, 3D, Chapter 3.3.1). NH₃ and NO_x emissions are calculated by multiplying the amounts of N in sewage sludge applied with the respective emission factors.

EMEP (2019)-3.D, Table 3-1 provides a Tier 1 emission factor for NH₃ (0.13 kg NH3 per kg N applied) emissions from application of sewage sludge. The German inventory uses the equivalent emission factor in NH₃-N units which is 0.11 kg NH₃-N per kg N applied (cf. the derivation of the emission factor described in the appendix of EMEP (2019)-3D, page 26-27). For NO_x the same emission factor like for the application of synthetic fertilizer was used (see Table 3).

NH₃ and NO_x emissions from the application of sewage sludge are no key sources.

Due to an update of the activity data, the emission estimates are different compared to the last submission in most years, sometimes higher and sometimes lower (see main page of the agricultural sector, recalculation No. 12). Further details on recalculations are described in Vos et al. (2024), Chapter 1.3.

Table 9: Revised NH₃ and NO_x emissions, in kilotonnes

No improvements are planned at present.

This sub category contains the total of Germany’s NH₃ and NO_x (NO) emissions from application of - residues from digested energy crops, - residues from digested waste, - compost from biowaste, - compost from green waste, and - imported animal manures. For details see Vos et al. (2024), Chapters 5.2.1.2 and 5.2.2.2.

Activity data is the amount of N in residues from anaerobic digestion of energy crops and waste and of compost from biowaste and green waste when leaving storage, as well as the amount of N in imported animal manures. For energy crops this is the N contained in the energy crops when being fed into the digestion process minus the N losses by emissions of N species from the storage of the residues (see 3.I). N losses from pre-storage are negligible and there are no N losses from fermenter (see Vos et al. (2024), Chapter 5.1). For residues from digested waste, compost from biowaste and compost from green waste the amount of N was derived from the waste statistics of the Federal Statistical Office (see Vos et al. (2024), Chapter 2.8). For imported manure the amounts of N were derived from statistics published by CBS (Statistics Netherlands) and RVO (Rijksdienst voor Ondernemend Nederland) The imported manure is categorized into cattle slurry, pig slurry, poultry manure, horse manure and mixed solid manure. Only imported manures from The Netherlands are taken into account, as for other countries the amounts of imported manures are unknown as are the amounts of exported manure. For details see Vos et al. (2024), Chapter 2.8.

Table 10: AD for the estimation of NH₃ and NO_x emissions emissions from application of other organic fertilizers

The NH₃ emissions are calculated the same way as the NH₃ emissions from application of animal manure (3.D.a.2.a). The frequencies of application techniques and incorporation times as well as the underlying data sources are provided e. g. in the NID 2024, Chapter 17.3.1. It is assumed that residues of digested waste are applied in the same way and have the same emission factors as residues from digested energy crops. For compost from biowaste and green waste it is assumed that they are applied in the same way and have the same emission factors as cattle solid manure. The amounts of TAN in the residues from digested energy crops applied are obtained from the calculations of emissions from the storage of the digested energy crops (3.I). The amounts of TAN in the residues from digested waste, compost from biowaste and compost from green waste are derived from industry data (provided by Bundesgütegemeinschaft Kompost, BGK). For the imported manures it is assumed that the different imported manure types (see above) were applied in the same way as the corresponding domestic animal manure types. Mixed manure was treated like solid manure from goats, sheep and horses. Corresponding TAN contents were derived from publications of the German federal states. As published TAN contents vary strongly, for each imported manure type the maximum of published TAN contents was assumed to prevent an underestimation of the NH₃ emissions. For details see Vos et al. 2024, Chapter 2.8.

For NO_x emissions the Tier 1 approach for the application of synthetic fertilizer as described in EMEP (2019)-3D-11 is used. The inventory calculates NO emissions that are subsequently converted into NO_x emissions by multiplying with the molar weight ratio 46/30.

For NH₃ the emission factors for untreated cattle slurry were adopted for residues from digested energy crops and residues from waste. The emission factors for cattle solid manure were adopted for compost from biowaste and compost from green waste, see Vos et al. (2024), Chapters 5.2.1.2 and 5.2.2.2. For imported manures the corresponding emission factors of the same type of domestic manure were used.

As the NO_x method for fertilizer application is used for the calculation of NO_x emissions from the application of residues, the emission factor for fertilizer application was used (see Table 3).

Table 11: IEF for NH₃-N emissions from application of other organic fertilizers

The application of other organic fertilizers is a key source for NH₃. Emissions are dominated by the emissions from digested energy crops. They have become important since about 2005 and have risen sharply until 2013. Since then, they have changed little each year and tend to decrease slightly in the last few years. The latter is mostly due to the increasing use of application practices with lower NH₃ emission factors.

For all years, total NH₃ and NO_x emissions from application of other organic fertilizers are higher than those of last year’s submission as the emissions from application of residues from digested waste, compost of biowaste and compost of green waste are reported for the first time in the agriculture sector (see main page of the agricultural sector, list of recalculation reasons, No 2, and Vos et al. (2024), Chapter 1.3)

Table 12:REC-4: Revised NH₃ and NO_x from application of other organic fertilizers, in kilotonnes

No improvements are planned at present.

The calculation of NH₃ and NO_x (NO) emissions from N excretions on pasture is described in Vos et al. (2024), Chapters 5.2.1.1 and 5.2.2.1.

Activity data for NH₃ emissions during grazing is the amount of TAN excreted on pasture, while for NO_x emissions it is the amount of N excreted.

The TAN excretions are derived by multiplying the share of N excretion on pastures with the N excretions and TAN contents provided in 3.B, Table 2.

Table 13: Shares of N excretions on pasture, in [%]

NH₃ emissions from grazing are calculated by multiplying the respective animal population (3.B, Table 1) with corresponding N excretions and relative TAN contents (3.B, Table 2) and the fraction of N excreted on pasture (Table 9). The result is multiplied with the animal specific emission factor (Table 10). NO emissions are calculated the same way with the exception that the emission factor is related to N excreted instead of TAN.

The emission factors for NH₃ are taken from EMEP (2019)-3B-31, Table 3.9. They relate to the amount of TAN excreted on pasture. For laying hens, deer and ostriches there are no emission factors given in this table. Germany uses for laying hens an emission factor of 0.35 kg NH₃-N per kg TAN excreted, based on an expert judgement from KTBL (see Vos et al. 2024, Chapter 5.2.1.1). The same EF is used by UK. It was also used for ostriches. For deer the emission factor of sheep was adopted.

Following the intention of EMEP, 2019-3D, Table 3.1, the inventory uses for NO_x the same emission factor as for the application of synthetic fertilizer (see Table 3). In order to obtain NO_x emissions (as NO₂) the NO-N emission factor of 0.12 kg NO-N per kg N excreted is multiplied by 46/14.

Table 14: Emission factors for emissions of NH₃ and NO from grazing

Emissions from urine and dung deposited by grazing animals are no key sources.

For all years, totals of NH₃ and NO_x emissions from grazing are slightly higher than those of last year’s submission.

The main reason for that is the introduction of the new animal categories “ostriches” and “deer”. It is assumed that rabbits and fur bearing animals do not have access to pasture (see main page of the agricultural sector, list of recalculations, No. 1). Further details on recalculations are described in Vos et al. (2024), Chapter 1.3.

Table 15: REC-5: Revised NH₃ and NO_x emissions, in kilotonnes

No improvements are planned at present.

In this category Germany reports TSP, PM₁₀ and PM_2.5 emissions from crop production according to EMEP (2019)-3D-17. For details see Vos et al. (2024), Chapter 5.2.4.

The activity data is the total area of agricultural land (arable land, grassland and horticultural land). This data is provided by official statistics.

Table 16: Arable land and grassland, in [1000*ha]

The Tier 2 methodology used is described in EMEP (2019)-3D-17.

Emission factors given in EMEP (2019)-3D-18, Tables 3.5 and 3.7 are used with the exception of „Harvesting“ PM₁₀-factors for Wheat, Rye, Barley and Oat which were taken from the Danish IIR. These Guidebook-EFs are obviously too high by a factor of 10 and were corrected in the Danish IIR.

The missing default-EFs for „other arable“ in the 2019 EMEP/EEA Guidebook were replaced with the average of the EFs of wheat, rye, barley and oat, as it was done in the Danish IIR. The PM₁₀ EFs were also used as TSP EFs. The Guidebook does not indicate whether EFs have considered the condensable component (with or without). For details on country specific numbers of agricultural crop operations see Vos et al. (2024), Chapter 5.2.4.

Table 17: Implied emission factors for PM emissions from agricultural soils, in kg ha^-1

TSP and PM₁₀ are key sources. Emissions depend on the areas covered, crop types and number of crop operations. With the exception of the numbers of soil cultivations, which is slightly decreasing, these data are relatively constant. Overall this is reflected in a slight decline of emissions in the last 12 years.

The only difference occurs for 2021, where the emissions are slightly higher than in the previous submission due to the correction of area data in one federal state. Further details on recalculations are described in Vos et al. (2024), Chapter 1.3.

Table 18: REC-6: Revised particle emissions (TSP, PM₁₀ & PM_2.5), in kilotonnes

No improvements are planned at present.

In this category Germany reports NMVOC emissions from crop production according to EMEP (2019)-3D-16. For details see Vos et al. (2024), Chapter 5.2.3.

The total area of arable land and grassland applied as activity data is provided by official statistics.

Table 19: Arable land and grassland, in [1000 ha]

The Tier 2 methodology described in EMEP (2019)-3D-16ff is used.

The emission factors for wheat, rye, rape and grass (15°C) given in EMEP (2019)-3D-16, Table 3.3 were used. For all grassland areas the grass (15°C) EF is used, for all other crops except rye and rape the EF of wheat is used.

The implied emission factors provided in thr following table are defined as ratio of the total NMVOC emissions from cultivated crops to the total area given by activity data.

Table 20: IEF for NMVOC emissions from crop production, in [kg ha-1]

NMVOC emissions from crop production are no key sources.

The only change with respect to last year’s submission occurs for 2021, where emissions are slightly higher in the present submission due to the correction of area data in one federal state. Further details on recalculations are described in Vos et al. (2024), Chapter 1.3.

Table 21: REC-7: Revised NMVOC emissions, in kilotonnes

No improvements are planned at present.

Details are described in chapter 1.7.