Reducing Ammonia Emissions in Polish Agriculture, the Implementation of the NEC Directive, and the Context of Sustainable Development—Pilot Studies

Abstract

Reducing environmental pollution, including air pollution, contributes to improving people’s health and quality of life, which is one of the goals of sustainable development. One of the important air pollutants is ammonia, which is mainly emitted from the agriculture sector. This sector is responsible for over 81% of global ammonia emissions. The aim of this research was a preliminary assessment of the implementation status of methods for reducing ammonia emissions on farms and to learn the views and awareness of agricultural producers on reducing emissions of pollutants into the air. The research was conducted using a survey questionnaire that was made available to farmers in various ways. Based on the results, it can be concluded that farmers have knowledge of environmental protection and agree that people have an impact on the environment. Low-emission practices to reduce ammonia emissions from agricultural sources are not widely used. The best situation is considering reduction practices in the storage of natural fertilizers and the use of low-emission fertilizer application techniques. The results of this type of monitoring research may be useful in determining the level of ammonia emission reduction. In the future, the data may be used during air pollution inventories conducted by state institutions.

1. Introduction

Clean air is one of the key issues of the European Union (EU) environmental policy. The goal is to achieve air quality levels that do not cause significant negative effects or threats to human health and the environment. Reducing environmental pollution, including air pollution, contributes to improving people’s health and quality of life, which is one of the goals of sustainable development. One of the important air pollutants is ammonia (NH₃), which is mainly emitted from the agriculture sector. This sector is responsible for over 81% of global NH₃ emissions [1]. According to data published by the National Center for Emissions Management (KOBIZE), in 2021, agriculture was responsible for 96% of national emissions of this gas. The largest share of emissions is related to the use of mineral and organic fertilizers, including natural fertilizers from farm animals (50%), and 46% of emissions are related to the management of manure [2]. The literature also indicates non-agricultural sources of ammonia emissions [3,4]. However, it is the reduction in ammonia emissions from agriculture that is crucial in the context of improving air and water quality and the sustainable development of agriculture and rural areas. Reducing NH₃ emissions is one of the most difficult challenges facing countries around the world [5]. Ammonia has a negative impact on the environment both locally and globally. The main threat is soil acidification resulting from the nitrification processes of ammonium ions coming from the atmosphere and eutrophication related to the supply of biogenic compounds to water, including NH₃ from agricultural sources [6,7,8,9]. Ammonia is also highly reactive in creating aerosols (PM2.5) that move over large areas [10,11,12]. Moreover, this gas is easily transformed into other nitrogen compounds; therefore, it may be involved in global warming, the destruction of the ozone layer, and the creation of photochemical smog [13,14,15,16].

One of the main documents regulating issues related to ammonia emissions is the Directive (EU) 2016/2284 of the European Parliament and of the Council of 14 December 2016 on reducing national emissions of certain atmospheric pollutants, called the NEC Directive, which sets out ammonia emission reduction targets for member countries from 2020 and 2030.

The literature on the subject regarding methods of reducing ammonia emissions indicates nutritional methods, methods used during animal housing, methods used for storing fertilizers, and methods used for applying fertilizers on fields [17,18,19]. In the ammonia emission inventory, the KOBIZE considers the impact of some activities limiting NH₃ emissions, such as keeping pigs on partially slatted floors, covering the storage of solid natural fertilizers, covering slurry tanks, the three-phase feeding of laying hens (adapting the diet to their needs during their different laying periods), or the four-phase feeding of fattening pigs (adapting the diet in terms of total protein content to their needs in different phases of growth) [20]. The quantitative determination of the scope of the implementation of these techniques in practice was based on the synthesis of integrated databases from Statistics Poland (GUS) and the National Research Institute of Animal Production. It was decided that it would be interesting to supplement these activities with research on the state of awareness of agricultural producers regarding reducing air pollutant emissions and the scope of their use of methods for reducing NH₃ emissions.

The aim of this research was a preliminary assessment of the implementation status of methods for reducing NH₃ emissions on farms and to learn about the views and awareness of agricultural producers on reducing air pollutant emissions. Additionally, pilot studies will allow for testing the survey developed for this purpose.

2. Materials and Methods

Research on methods of reducing NH₃ emissions on Polish farms and farmers’ awareness of air pollutant emissions was carried out using a survey questionnaire that was made available to farmers in various ways. The surveys were collected in 2020–2021.

The subjective scope of the survey research included farms where animal production, plant production, or plant–animal production was carried out. The prepared questionnaire is original and does not use information from previous research. The survey consisted of two parts: the main part and the specifications. The main part of the survey consisted of two thematic sections: general questions regarding environmental protection, in particular reducing air pollutant emissions, and detailed questions regarding the methods used on farms to reduce ammonia emissions. Therefore, the scope of the research included the following information:

• General information about farm owners;
• General information about farms;
• The opinions and knowledge of agricultural producers regarding environmental protection;
• The knowledge of agricultural producers about ammonia emissions and related risks;
• The knowledge of agricultural producers about legal regulations regarding air protection and limiting air pollutant emissions;
• Activities undertaken on farms in terms of nitrogen management;
• Methods used on farms to reduce ammonia emissions in the field of livestock housing systems;
• Methods used on farms to reduce ammonia emissions in the field of farm animal feeding systems;
• Methods used on farms to reduce ammonia emissions in the field of the storage of natural fertilizers;
• Methods used on farms to reduce ammonia emissions during the application of natural fertilizers to fields;
• Methods used on farms to reduce ammonia emissions during the application of mineral nitrogen fertilizers to fields.

The main part of the survey on methods for reducing NH₃ emissions was developed based on the National Advisory Code of Good Agricultural Practice for Reducing Ammonia Emissions [20]. Unlike previously conducted research on agricultural practices regarding reducing ammonia emissions in Polish agriculture, e.g., by Piwowar [21], this research covers a wider range of methods for reducing ammonia emissions, including techniques used during fertilizer storage as well as low-emission techniques for applying natural and mineral fertilizers. Additionally, these studies also refer to the awareness of agricultural producers regarding environmental protection and reducing air pollution emissions.

The results collected in the survey were subjected to statistical analysis—χ2 independence tests. This was used to analyze two qualitative variables and determine whether there was a statistically significant relationship between them. The analysis was carried out at a significance level of α = 0.05. If the size of a given subgroup was limited, a correction for the chi-square independence test was applied, the so-called continuity correction. Additionally, to improve the quality of the statistical analysis, the number of groups was limited (to three in selected categories):

• Farm area: 0–40 ha, 40–80 ha, over 80 ha.
• Education: vocational, secondary, or higher.

This research will determine the impact of parameters such as farm area, age, animal species, and education on the following:

• The application of nutritional reduction techniques.
• Time of incorporation for the slurry.
• Time of incorporation for the manure.
• Type of slurry application method used.
• Use of reduction methods during the application of urea.

The research also allow to set what determines (age, education, farm area) the use of reduction techniques for groups of animals: cattle, pigs, poultry. Microsoft Excel was used to perform the statistical analysis.

3. Results and Discussion

The preliminary research was carried out on a group of 30 agricultural producers from the Greater Poland Voivodeship.

Table 1. General characteristics of the respondents and their farms.

Parameter	Share in the Study (%)
Age of respondents
18–35 years old	27
35–60 years old	63
>60 years old	10
Gender of respondents
Women	87
Men	13
Education level of respondents
Primary	0
Vocational school	4
Vocational school agricultural	14
Secondary	17
Secondary agricultural	41
Higher	7
Higher agricultural	17
Production profile
Crop production	10
Livestock production	0
Crop and livestock production	90
Total farm area (ha)
0–20.00	17
20.01–40.00	36
40.01–60.00	7
60.01–80.00	10
80.01–100.00	7
>100	13
No data	10
Livestock housing
Cattle	11
Swine	56
Poultry	4
Cattle and swine	15
Cattle and poultry	7
Swine and poultry	7

presents the general characteristics of the respondents participating in the study and their farms.

3.1. General Knowledge about Environmental Protection

First, the respondents were asked if they believed in their impact on the state of the environment. Most respondents (90%) stated that they had an influence, 3% believed that they had no influence, and 7% had no opinion on this matter. The results of the research showed the greatest threats to the environment were from waste management (40% of respondents), deforestation (20% of respondents), and emissions of air pollutants into the atmosphere (17% of respondents) (Figure 1).

According to the respondents, citizens (37% of responses) and state administration (37% of responses) are equally responsible for the state of the environment, followed by local government (13%) and industrial factories (7%). The respondents most frequently indicated raising ecological awareness (43%), followed by the creation of financial incentives (37%), controls and inevitable penalties (10%), and the use of local authorities (7%) as a way of improving the state of the environment. They stated that industrial processes were the largest source of ammonia emissions into the air (47%). Only 7% of the study participants indicated agriculture (correct answer) as the largest source of ammonia emissions (Figure 2). However, most respondents stated that the largest source of ammonia emissions from agriculture was the use of natural fertilizers (43% of respondents), which is the correct answer, followed by the use of mineral nitrogen fertilizers (27% of respondents) (Figure 3).

Only 30% of the respondents correctly indicated that ammonia emissions mainly cause the eutrophication of water reservoirs and soil acidification. Furthermore, 27% selected the intensification of the greenhouse effect, and 33% of respondents marked the answer “I don’t know” (Figure 4). In the question regarding sources of information on environmental pollution, methods of reducing air pollutant emissions, and legal regulations, three information sources could be indicated. The respondents mainly chose the Internet (67%), training (40%), and the press (37%) (Figure 5).

3.2. Legal Regulations about Ammonia Emissions

In relation to knowledge about applicable legal regulations regarding reducing ammonia emissions, the respondents’ knowledge was varied. While 93% of the respondents had heard about the Nitrate Program, only 33% had heard of the NEC directive.

The next part of the questionnaire comprised questions concerned with knowledge about applicable regulations regarding the maximum doses of manures used in agriculture, the storage of manures, and the dates when manures and mineral fertilizers can be applied on different kinds of agricultural lands. Most of the respondents had limited knowledge in this area. Most respondents (70%) gave the correct answer to the question regarding the possibility of storing solid manure directly on arable land. Also, a significant percentage of respondents (57%) gave the correct answer to the question regarding application dates for solid manure on arable land. For the rest of the questions, the percentage of correct answers was 40 (

Table 2. Questions regarding the storage and application dates of fertilizers on agricultural land.

Question	% of Correct Answers
What is the maximum annual dose of manure used in agriculture?	40
Is it possible to store solid manure directly on arable land?	70
When can mineral nitrogen fertilizers and slurry or other liquid manures be used on arable land?	40
When can solid manure be used on arable land?	57
When can mineral nitrogen fertilizers and slurry or other liquid manures be used on permanent crops, perennial crops, and permanent grasslands?	40
When can solid manure be used on permanent crops, perennial crops, and permanent grasslands?	40

).

3.3. Feeding Methods for Ammonia Reduction

The next series of questions were about ammonia reduction methods used on farms. The composition of animal feed directly affects emissions from animal excrements [22]. One way to reduce NH₃ emissions is to reduce crude protein (CP) in the diet [23,24]. One study showed that a 2% reduction in dietary CP reduced NH₃ concentrations at 1 cm and 10 cm above the fecal surface by 49% and 24%, respectively, and it also reduced NH₃ emissions from the floor and the fattening house by 46% and 31%, respectively [25]. The respondents showed that they used the following feeding ammonia reduction methods: low-protein feeding (23%), four-phase feeding for fattening pigs (23%), feed additives that reduce the total amount of nitrogen excreted (17%), three-phase feeding for piglets (13%), multiphase feeding of cattle (10%), adding controlled amounts of amino acids to a low-crude protein diet (7%), and others—indicated by 7% of the respondents. The respondents reported that they also used effective microorganisms. However, 27% of the respondents also stated that they did not use any feeding methods (Figure 6). Among the studied farms, only four of them used two nutritional methods to reduce NH₃ emissions; one farm used three methods; and one used six methods. Survey research on methods for reducing ammonia emissions in Polish agriculture was also conducted by another researcher. He asked respondents about the use of nitrogen-fixing preparations in animal nutrition (7% of respondents answered yes, 83%—no, and 10%—I don’t know among the 520 studied farms) and about the use of appropriately selected feed additives ensuring the effective functioning of the animals’ digestive tract (44%—yes, 51%—no, 5%—I don’t know among the same research population) [21]. According to the KOBIZE, the most frequently used feeding methods were the five-phase feeding of broilers (43.4% of the population), the three-phase feeding of laying hens (29.8%), the four-phase feeding of fattening pigs (25.1%), and the protein feeding of dairy cattle (25%) [2].

3.4. Animal Housing Methods for Ammonia Reduction

Animal housing is one of the stages at which ammonia emissions can be reduced. Some researchers have identified and analyzed in detail several effective technologies and mitigation practices for each stage of manure management. Their results identified several promising approaches to reducing many gas emissions from the entire manure management process. For example, removing excrement 2–3 times a week or daily when housing animals is an effective and simple way to reduce emissions of greenhouse gases and air pollutants [19].

Among cattle housing methods, the most used methods of reducing ammonia emissions were the frequent removal of manure from the barn (27%) and increased amounts of litter used in bedding systems (23%). The remaining methods were selected by several people. However, 67% of the respondents stated that this did not apply to them (Figure 7).

Three of the five respondents producing poultry stated that they do not use any methods; one keeping ducks indicated that he uses an increased amount of litter, and one person indicated that he used other methods (Figure 8).

The studied pig producers also used methods of reducing ammonia emissions, and they most often indicated the use of increased amounts of litter in bedding systems (40%) and the use of partially slatted floors when housing piglets (20%). The remaining methods were used by only a single farm. However, three respondents indicated that they did not use any methods, and 27% of the respondents indicated that this did not apply to them (Figure 9).

Also in one research project [21], not many of the 520 surveyed farms with animal production indicated the use of methods to reduce ammonia emissions while housing animals. The respondents using ammonia reduction methods applied the following techniques: adding microbiological and mineral–organic additives to animal faeces in livestock buildings (14%), underfloor heating (2.5%), mechanical ventilation with recirculation (34%), ultraviolet radiation (5%), and negative air ionization (2.5%). However, according to the KOBIZE, the use of partially slatted floors on pig farms covers 14.7% of the population, the fast removal of laying hens’ solid manure covers 29.6% of the population, and the ventilation of laying hens’ solid manure covers 10.2% of the population [2].

3.5. Low-Emission Manure Storage Systems

Storing manure is the next step in manure management where ammonia emissions can be reduced. One study identified and analyzed that acidification during slurry storage and treatment can reduce ammonia and methane emissions by 33–93% and 67–87%, respectively [19]. In the part of the study concerning the storage of manures, the respondents stated that all the studied farms had such storage. Out of all the respondents, 83% indicated that they had a manure plate, 90% had a slurry tank, and 24 of the studied farms were equipped with both. However, among the farms equipped with a slurry tank, the following types of cover were used: a rigid cover (67% of farms), floating plastic elements (3% of farms), and a natural crust on the surface of the slurry (3% of farms). However, 17% of the farms did not cover their slurry tank. The farms that used slurry did not use flexible bags to store this natural fertilizer. Ammonia reduction methods in the management of natural fertilizer, excluding storage, were also used, and the following were indicated: acidification of slurry in a slurry storage tank (11% of farms), dilution of slurry (15% of farms), and separation of slurry (11% of farms). According to the KOBIZE, a marginal percentage of the cattle, pig, and poultry population is characterized by the solid manure covering technique, while 46.1% of the cattle population and 72.8% of the pig population are characterized by the covering of slurry tanks [2].

3.6. Low-Emission Manure and Urea Application Techniques

The final stage of manure management in which ammonia emissions can be reduced is its application to fields. According to one research project [19], the use of a shallow slurry injection is the most effective method for reducing ammonia emissions by 62–70%. One study investigated reducing NH₃ emissions using trailing hoses, trailing shoes, and shallow open-slot injections, which led to 30%, 50%, and 70% ammonia reduction, respectively [26]. Similar results were obtained by [27]. They showed that the use of trailing hoses, trailing shoes, and shallow open-slot injections when applied to cattle slurry reduced NH₃ emissions by 35%, 46%, and 62%, respectively, compared to surface application. Very positive results regarding environmental awareness were given in the part of the study regarding ammonia reduction methods during the application of fertilizers to fields. Nitrogen fertilization plans were being developed in 87% of the surveyed farms. Moreover, 93% of respondents declared that in choosing the date for the application of fertilizers, they pay attention to the prevailing weather conditions, and 87% take into account the soil pH value when applying mineral nitrogen fertilizers. In terms of low-emission slurry application techniques, 41% of the respondents use a splash plate, 22% use slurry shallow (or slots) injectors, 15% use deep injectors, and 11% of respondents use trailing hoses or trailing shoes (Figure 10).

In the part of the study concerning the time between slurry application and its cover with soil, 48% of the respondents indicated immediate incorporation, and 19% indicated incorporation within 4 h of application (Figure 11).

However, in relation to the time between solid manure field application and it being covered with soil, the results were worse. Only 20% of respondents indicated immediate incorporation; the same number declared incorporation within 4 h of application; and 17% of respondents indicated incorporation within 12 h of application (Figure 12).

In turn, as the most popular methods of reducing ammonia during urea application, the respondents indicated replacing urea with ammonium nitrate (33%), the fast incorporation of urea (30%), not using urea (30%), and using the use of urease inhibitors (7%). In turn, the most popular ammonia reduction methods used during the application of urea in fields indicated by the respondents were replacing urea with ammonium nitrate (33%), the fast incorporation of urea (30%), not using urea (30%), and the use of urease inhibitors (7%) (Figure 13).

Research about the use of reduction methods among 1034 farms with plant production in Poland was also conducted by another researcher [21]. He showed that 75% of the applied reduction methods included the use of different doses of nitrogen fertilizers (depending on the plant vegetation period), 26% included the use of fertilizers with a slowed or controlled release of nutrients, and 21% had nitrogen balance at that time.

The results obtained in the pilot study were statistically analyzed. In a few cases, the size of the subgroups was less than five observations, which distorted the results of the analysis. Therefore, due to the limited size of the studied population, statistically significant conclusions cannot be drawn regarding the relationships between the studied variables.

4. Conclusions

Based on the results of pilot surveys on the methods used to reduce NH₃ emissions on Polish farms and farmers’ awareness of air pollutant emissions, it can be concluded that farmers have knowledge about environmental protection and generally agree that people have an impact on the environment. Farmers do not identify agriculture as the largest source of ammonia emissions, but they know what the largest source of ammonia emissions from agriculture is. The knowledge of the respondents about applicable legal regulations regarding reducing ammonia emissions is often limited. Low-emission practices to reduce ammonia emissions from agricultural sources are not widely used. In the area of animal production, the use of modern ventilation and air cleaning systems is marginal. The most frequently recommended method is to use more litter in bedding systems. Similarly, feeding methods were not often used by farmers. The situation is much more favorable with regard to the storage of manure and the use of low-emission fertilizer application techniques.

To summarize, it can be concluded that the survey is generally well designed and fulfils its purpose. Nevertheless, it requires corrections in some aspects, which will primarily aim to improve the readability and understandability of the questions for the respondent.

Currently, meeting the relatively high reduction target resulting from the NEC Directive may be difficult to achieve. The results of this type of monitoring research may be useful in determining the level of ammonia emission reduction. In the future, these data may be used during the air pollution inventory conducted by the KOBIZE, as well as in reports on the implementation of the National Air Pollution Control Program. Additionally, the data collected in this way will allow for the analysis of changes taking place in Polish agriculture resulting from the need for Poland to achieve the reduction goals specified in the NEC Directive. They will also allow administrative bodies to create a national agricultural policy that favors sustainable agricultural production (taking into account environmental aspects).

Moreover, in parallel with the examination of the implementation of the NEC directive in Poland, training for farmers should be conducted to disseminate the objectives and requirements of this directive and the effects on the environment that its implementation will have. Understanding the idea of sustainable agriculture will allow for the effective implementation of the NEC directive, which is often associated with additional costs and reduced economic efficiency in agricultural production