3.D - Agricultural Soils

In 2021, agricultural soils emitted 270.8 kt NH₃ or 56.1 % of the total agricultural NH₃ emissions in Germany (482.3 kt NH₃). The main contributions to the total NH₃ emissions from agricultural soils are the application of manure (3.D.a.2.a), with 167.4 kt (61.8 %) and the application of other organic N-fertilizers (3.D.a.2.c) with 54.3 kt (20.1 %).

Application of synthetic N-fertilizers (3.D.a.1) contributes 34.9 kt NH₃ (12.9 %). N excretions on pastures (3.D.a.3) have a share of 12.5 kt NH₃ (4.6 %) and the application of sewage sludge (3.D.a.2.b) leads to 1.7 kt NH₃ (0.6 %).

In 2021, agricultural soils were the source of 98.6 % (106.5 kt) of the total of NO_x emissions in the agricultural category (108.0 kt). The NO_x emissions from agricultural soils are primarily due to application of inorganic fertilizer (3.D.a.1) (48.0 %) and manure (3.D.a.2.a) (34 %). Application of other organic N-fertilizers (3.D.a.2.c) contributes 13.1 % to agricultural soil emissions, 4.3 % are due to excretions on pastures (3.D.a.3). Emissions from application of sewage sludge (3.D.a.2.b) contribute 0.5 %.

In 2021, the category of agricultural soils contributed 9.4 kt NMVOC or 3.2 % to the total agricultural NMVOC emissions in Germany. The only emission source was cultivated crops (3.D.e).

In 2021, agricultural soils contributed, respectively, 34.6 % (21.0 kt), 63.0 % (21.0 kt) and 31.1 % (1.6 kt) to the total agricultural TSP, PM₁₀ and PM_2.5 emissions (60.6 kt, 33.3 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 NOx (NO) emissions from the application of synthetic fertilizers is described in Rösemann et al. (2023), Chapters 5.2.1.2 and 5.2.2.2 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).

Table 1: AD for the estimation of NH₃ and NOx 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 ²⁾, 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, according to Bittman et al. (2014, Table 15)³⁾.

Table 2: NH₃-EF for synthetic fertilizers

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 units of kg N₂O per kg fertilizer N and was derived from Stehfest and Bouwman (2006)⁴⁾. 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

In the last years (and ufrom 2016 to 2020 in dramatic fashion) fertilizer sales have decreased. 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 (R2 = 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 causes 70 % lower emissions (Bittman et al. 2014).

Table REC-1 shows the effects of recalculations on NH₃ and NO_x emissions. The only differences are in 200 as the year 2021 is now included in the weighted average.

Table REC-1: Comparison of NH₃ and NO_x emissions from fertilizer application of the submissions (SUB) 2022 and 2023

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 Rösemann et al. (2023), 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 Rösemann et al. (2023), Chapter 2.5. The frequencies are provided e. g. in the NIR 2023⁵⁾, Chapter 19.3.2.

Table 4: 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 Rösemann et al. (2023), Chapter 5.2.1.2. For NO_x emissions from manure application the inventory calculates NO-N emissions (see Rösemann et al. (2023), 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.

Table 5 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 5: IEF for NH₃–N from application of manure

For NO_x the same emission factor as for the application of synthetic fertilizer was used (see Table 3).

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 slightly declining again, see Table 4. The NO_x emissions follow these trends. For total NH₃ emissions there is a slight negative trend. This is due to the increasing use of application practices with lower NH₃ emission factors.

Table REC-2 shows the effects of recalculations on NH₃ and NO_x. For all years the total emissions of NH₃ and NO_x from application of manure are significantly higher than those of last year’s submission.

These differences are predominantly caused by recalculation No. 2 (deep bedding). Most of the other recalculations reasons (except No. 12-15) have an effect on emissions from application of manure, some are increasing the emissions (No.6 air scrubbing) others are lowering the emissions (No. 8 protein use in pig fattening), some lead to changes in both directions (No. 1 new interpolation of 2020 agricultural census data), see main page of the agricultural sector, list of recalculation reasons.

Further details on recalculations are described in Rösemann et al. (2023), Chapter 1.3.

Table REC-2: Comparison of the NH₃ and NO_x emissions of the submissions (SUB) 2022 and 2023

No improvements are planned at present.

The calculation of NH₃ and NO_x (NO) emissions from application of sewage sludge is described in Rösemann et al. (2023), 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 (see Table 6).

Table 6: 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.

Table REC-3 shows the effects of recalculations on NH₃ and NO_x emissions. The only change compared to last year’s submission occurs for the year 2020 due to the update of the activity data (see main page of the agricultural sector, recalculation No 13. Further details on recalculations are described in Rösemann et al. (2023), Chapter 1.3.

Table REC-3: Comparison of the NH₃ and NO_x emissions of the submissions (SUB) 2022 and 2023

No improvements are planned at present.

This sub category containes 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, and

- compost from green waste.

For details see Rösemann et al. (2023), 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. 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 Rösemann et al. (2023), 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 Rösemann et al. (2023), Chapter 2.8.4).

Table 7: 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 NIR 2023, Chapter 19.3.2. 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 like 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 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 Rösemann et al. (2023), Chapters 5.2.1.2 and 5.2.2.2 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 8 shows the implied emission factors for NH₃ emissions from application of other organic fertilizers.

Table 8: 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.

Table REC-4 shows the effects of recalculations on NH₃ and NO_x emissions. For all years the total emissions of NH₃ and NO_x from application of other organic fertilizers are significantly higher than those of last year’s submission. The main reason for that is, that 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 14, and Rösemann et al. (2023), Chapter 1.3)

Table REC-4: Comparison of the NH3 and NOx emissions from application of other organic fertilizers of the submissions (SUB) 2022 and 2023

No improvements are planned at present.

The calculation of NH₃ and NO_x (NO) emissions from N excretions on pasture is described in Rösemann et al. (2023), 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 on pasture.

Table 9 shows the share of N excretions on pasture. 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 9: Share of N excretions on pasture

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 there is no emission factor given in this table. Germany uses an emission factor of 0.35 kg NH3-N per kg TAN excreted, based on an expert judgement from KTBL (see Rösemann et al. 2023, Chapter 5.2.1.1). The same EF is used by UK. 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 10: Emission factors for emissions of NH₃ and NO from grazing

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

Table REC-5 shows the effects of recalculations on NH₃ and NO_x emissions.

For all years the total emissions of NH₃ and NO_x from grazing are slightly higher than those of last year’s submission. The main reason for that is the introduction of pasture emissions from free-range laying hens see (see main page of the agricultural sector, list of recalculations, No 10). Further details on recalculations are described in Rösemann et al. (2023), Chapter 1.3.

Table REC-5: Comparison of the NH₃ and NO_x emissions of the submissions (SUB) 2022 and 2023

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 Rösemann et al. (2023), 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 11: AD for the estimation of TSP, PM₁₀ and PM_2.5 emissions from soils

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 Rösemann et al. (2023), Chapter 5.2.4. Table 12 shows the implied emission factors for PM emissions from soils.

Table 12: Emission factors for PM emissions from agricultural soils

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.

Table REC-6 shows the effects of recalculations on particulate matter emissions. The emissions are considerably higher than those of submission 2022. In particular the PM_2.5 emissions are now more than twice as high. This is a consequence of changing the methodology to Tier 2 (see main page of the agricultural sector, list of recalculation reasons, No 12). Further details on recalculations are described in Rösemann et al. (2023), Chapter 1.3.

Table REC-6: Comparison of particle emissions (TSP, PM₁₀ & PM_2.5) of the submissions (SUB) 2022 and 2023

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 Rösemann et al. (2023), Chapter 5.2.3.

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

Table 13: AD for the estimation of NMVOC emissions from crop production

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. Table 14 shows the implied emission factors for NMVOC emissions from crop production. The implied emission factor is defined as ratio of the total NMVOC emissions from cultivated crops to the total area given by activity data.

Table 14: IEF for NMVOC emissions from crop production

NMVOC emissions from crop production are no key sources.

Table REC-7 shows the effects of recalculations on NMVOC emissions. There are no changes with respect to last year’s submission. Further details on recalculations are described in Rösemann et al. (2023), Chapter 1.3.

Table REC-7: Comparison of NMVOC emissions of the submissions (SUB) 2022 and 2023

No improvements are planned at present.

Details are described in chapter 1.7.