261.          Air is regarded as a never-failing, totally-regenerating medium and therefore much more attention is being paid to water than to air protection. However it is extremely important to understand the necessity of protecting air in open areas and especially in rural ones. In reality air both in the lower (just above the ground) and upper layers of the atmosphere is very often polluted with dust, microorganisms, and pollen as well as with volatile organic and inorganic substances. There are a lot of air-polluting substances that may come from agriculture. They are as follows: dust (including soil particles), smoke, volatile nitrogen compounds of unpleasant smell (so-called odour substances that derive from the decomposition of animal excrements ) and greenhouse gases: methane, nitrogen oxides and ammonia. 

 

II. LAW PROTECTING THE AIR

262.          Protection of air from pollution is covered by the Act on protection and modelling the environment of 1980 [3] with the further Decree of the Ministry of Environmental Protection of 1990 [3 b]. Such legal regulations say that it is necessary to prevent substances from occurring in the air at concentrations higher than admissible. The Ministry of Environmental Protection fixes the norms for various kinds of substances and their concentrations, and Voivodship Inspectors of Environmental Protection are obliged to measure air pollution and make appropriate decisions if it is high.

 

III. PROTECTION OF AIR FROM DUSTS AND SMOKES

263.          Air becomes polluted with dust as a result of wind erosion, transport and application of some fertilisers, especially soil lime and powdery superphosphate. Agricultural equipment moving on dry soil as well as harvesting operations may also lead to air dustiness.

265.          In order to avoid polluting air, it is necessary to:

§         conduct all agrotechnical treatments at optimum soil humidity, 

§         protect properly solid fertilisers that are transported in bulk so as they do not spread or form dust,

§         spread powdery fertilisers on windless days of high relative air humidity. Therefore it is the best to apply such fertilisers in the evenings,

§         maintain plant cover for as much of the year as possible.

266.          Although all the recommendations mentioned above must be obeyed, it is not possible to eliminate air dustiness completely.

267.          Air pollution with smoke is even more burdensome for the environment due to the toxic substances that are emitted during the burning of wastes.

 268.          In order to eliminate air pollution with smoke it is necessary to:

§         control and reduce, wherever it is possible, the burning of wastes and rubbish [13,32],

§         re-use, within a farm, litter and wastes which may be composted, 

§         choose containers and foils (e.g. for wrapping haysilage bales) that will biodegrade and be safe for the environment,

§         burn wastes that cannot be managed in any other way provided there is no smoke containing toxic intermediate products,

§         control the process of burning.

269.          Harmful wastes such as tyres or other rubber products should be burnt only in proper machines at waste storage yards [13].

 

 

Tyre yard

 

 

270.          Empty containers that cannot be re-used (for example those of pesticides) must be collected either by a producer or by a distributor [13].

271.          It is not allowed to burn plants on meadows, pastures, idle lands, or in ditches or near roads. Also, it is not allowed to set fire to stubble mulch, cereal straw, or to rape, corn or potato stalks [3a].

272.          Straw surplus to farmer's requirements may be sold to other farmers, who do not have at their disposal enough straw for bedding.

273.          Some farmers consider straw as a cheap source of energy and use it for heating. In order to avoid harmful smoke, it must be burnt in special stoves.

 

ODOROUS SUBSTANCES AND AMMONIA

274.          Unpleasant smells cannot be completely eliminated from agricultural production, especially from livestock houses and places for silage.

 276.          In order to reduce the spread of odours, all farm buildings as well as their surroundings must be kept clean and tidy. Ventilation devices have to be efficient to maintain temperature and air humidity as well as gas concentrations to the levels which ensure comfort and health for animals. [8 b, 34]

277.          Therefore it is essential to:

§         make sure that animal excrements are removed from bedless cow houses to special collection tanks every day,

§         keep all hardened surfaces both inside and outside buildings clean,

§         keep automatic drinking bowls efficient,

§         use appropriate amounts of dry straw in bedless cow houses to prevent animals from being covered with excrements,

§         clean and disinfect all livestock houses. Special attention must be paid to places wheremilk and milking machines are stored.

278.          Semi-liquid feeds (stillage, molasses) should be kept in leak-proof tanks or silos. If concentrates or silage are stored/gathered inappropriately, they may be a source of unpleasant smells within a farm. 

279.          Most odours are emitted when organic fertilisers are being spread on the field. They may be detected over long distances subject to the kind of excrement, the weather conditions and the type of the equipment used [29].

280.          Slurry stored in a tank equipped with a stirrer should be mixed shortly before emptying the tank. It is advisable to do this on cloudy days so that odour emissions from the slurry are minimized.

281.          Slurry and manure should be applied on cloudy days and distributed with spreaders or liquid manure distributors, which act directly on the ground (trailing hoses) or close to the soil surface.

282.          It is not allowed to overload spreaders or tanks in order to avoid pollution of roads during transport.

283.          Manure/slurry should be mixed as quickly as possible with the soil to limit emissions of odours.

284.          Odorous emissions from FYM will be significantly reduced if manure is composted. Furthermore properly - composted manure shrinks, so it is easier to transport to the field.

285.          Odorous emissions coming from farm buildings, FYM and slurry tanks may be to some extent be difficult to deal with. The difficulty depends on:

§         distance from the neighbour's houses and the land relief,

§         number and categories of animals (pighouses are the most difficult to tolerate),

§         wind direction predominant in relation to the neighbours,

§         kinds and sizes of tanks used for slurry and manure pits,

§         the method of feeding animals. [8 b]

286.          Animal production is the main source of emissions of ammonia to the atmosphere. Ammonia is emitted from livestock buildings, places where excrements are being stored as well as during their application on the field. Nitrogen losses (as ammonia) from organic fertilisers decrease their fertilisation value. Ammonia (as a gas or as ammonium salts) drops to the surface of open waters leading to their contamination. Ammonia ions that fall on the soil surface become nitrified and can cause soil acidity.

288.          Ammonia losses from animal effluents (feces, urine, and droppings) may be considerably reduced, if farmers obey hygiene rules in livestock houses. In shallow livestock and pig houses, solid effluents must be regularly removed to dung pits, and surplus urine must be quickly directed to a tank for liquid manure. In bedless houses - effluents should drop through grids to discharge channels as rapidly as possible.

289.          It is essential to remember that ammonia losses from animal effluents are proportional to their surface areas, and the drier they are, the higher the losses are.

290.          The highest losses of ammonia from organic fertilisers take place during their transport and use as well as 12 hours after they have been applied. Ammonia losses will be significantly reduced if organic fertilisers are covered (mixed) with the soil as quickly as possible.

291.          Ammonia losses may also take place from mineral fertiliser such as urea, which is applied before sowing. Therefore it is essential to mix it with the soil immediately after application. It is not advisable to apply urea on neutral and alkaline soils or to use it and lime in the same year because of the resultant high ammonia losses.

292.          Urea may be top-dressed in the early spring, when the soil is humid and average day temperatures do not exceed 10°C. In fact, top dressing of urea is limited only to winter cereals, rape and to the first application of nitrogen on permanent grasslands.

293.          Ammonia losses may be reduced if the protein contained in the feed is utilised better.

294.          Diet (especially for pigs), if adjusted to animal requirements at different periods of development (stage feeding), may reduce the amounts of nitrogen emitted. Feed of relatively low protein content may reduce the amount of nitrogen contained in the excrements whilst keeping production at the same level.

295.          Increasing the efficiency of protein utilization by ruminants is much more difficult. It is only possible to use more maize silage.

 

GREENHOUSE GASES

296.          Methane as well as carbon dioxide and nitrogen oxides are regarded as so-called greenhouse gases. They gather in the upper layers of the atmosphere and make the climate become warmer. It is estimated that 50% of air pollution with methane comes from agriculture, which also significantly contributes to air pollution with nitrogen oxides.

297.          Methane - a scentless, colourless, thus "invisible" but inflammable gas is emitted as a product of the metabolic processes of farm animals, especially ruminants. Small amounts of methane are released by bacteria from slurry and manure. Dairy cows due to their high energetic requirements emit most methane. There are hardly any possibilities for reducing methane emissions by changing the diet.

298.          Controlled anaerobic fermentation of organic fertilisers that takes place in air-tight tanks may be used to produce methane as a source of energy on a farm. Unfortunately such devices (so-called biogas-plants) are very rare.

299.          Agriculture has better possibilities for reducing emissions of nitrogen oxides than emissions of methane.

 301.          The only method aimed at reducing gaseous nitrogen losses from the soil is to apply nitrogen fertilisers (mineral and organic) in a way adjusted to real plant requirements, so that losses are minimal. The amount of nitrogen (as protein) supplied in a diet should correspond with animal demands.

302.          Emission of nitrogen oxides from very wet soils may be reduced by improving the water-air relations, i.e. by drainage.

303.          On areas used for agriculture, carbon dioxide is released to the atmosphere during various treatments and transport. It is produced during consumption of fuels and the burning of waste plants and crop residues.

 305.          In order to reduce such unwanted emissions it is essential to:

§         ban the burning of plants,

§         reduce fuel consumption (lower-power tractors  with fewer empty journeys and agricultural treatments), and change systematically air filters and fuel injectors,

§         use non-conventional sources of energy for heating (biogas, straw, solar energy, wind and water power),

§         reduce losses of heat from buildings through the use of efficient ventilation systems.

306.          Admissible concentrations of substances polluting the air (Annex 13) are fixed for specially-protected areas and for all other ones [3b].

 

PESTICIDES

307.          Pesticides may be harmful for people and the environment (including the air) if they are diluted with insufficient water (the solution is too concentrated). Therefore it is not allowed to use working liquids in concentrations higher than those recommended on the label. 

309.          To achieve this it is essential to:

§         get acquainted with the weather forecast, particularly with the speed and direction of the wind,

§         check that the equipment is technically efficient,

§         set the sprayer boom to the appropriate position,

§         maintain speed and pressure in the sprayer so it keeps the appropriate application rate and volume for the particular pesticide.

310.          Pesticides may be used only on the areas and crops which are to be treated and using the amount of pesticide that will ensure a high effectiveness of the treatment.

311.          Low volume sprays (mist, haze or smoke (fumigation)) are usually carried-out in closed rooms, which reduces the blowing away of pesticide particles but may cause a person applying the pesticide to breathe air containing a suspension.

312.          Equipment used for applying pesticides should be checked by qualified organizational units authorized by the Inspector of Plant Protection in the appropriate Voivodship [11].

313.          Such treatments cannot be done without proper protection (a mask), and equipment which guarantees a safe treatment. A room, in which it is done, must have an efficient ventilation system [12a].

314.          Good agricultural practice as regards plant protection is to obey all the legal rules that protect the people conducting the treatments, the environment, and the consumers of agricultural products from negative consequences.