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WATER PROTECTION
I. INTRODUCTION 150. The community has a right to claim an access to pure water for drinking, bathing and recreation purposes. Water is also an element of the pure natural environment. The majority of surface waters in Poland, except for those occurring at the seaside and in mountainous areas, do not meet such requirements. A monitoring investigation showed that 50 - 60% of the total nitrogen and 30 - 40% of the phosphorus that reach the Baltic Sea from Poland's territory comes from point and surface pollution and is deriving from the areas used for agriculture. Point pollution usually comes from farms, especially from septic tanks and places where wastes, domestic sewage, and organic fertilisers are gathered and stored as well as from animal houses and yards. On many farms, wells supplying the people with drinking water are located next to the sources of water pollution. Such close proximity may be very threatening for people's, especially children's, health. Water becomes polluted with nitrates leaching from nitrogen fertilisers and other harmful compounds such as: phosphates, grease, oils and pesticides. The nutrients may lead to eutrophication of open water and to the development of microorganisms that may be harmful for people and animals. The Code presents methods, the aims of which are to reduce water pollution caused by agricultural production.
II. LAW PROTECTING WATER QUALITY 151. Both Polish and European Union law as well as HELCOM regulations pay special attention to water purity. It seems to be the branch of the environment that is the most thoroughly protected. The most significant regulation within Polish legislation is the Water law of 1974 with further decrees of the Ministry of Environment Protection and the Ministry of Health [2a,b,c,d]. They say that the degree of water purity is indicated by the concentration of both organic and inorganic compounds as well as number of harmful microrganisms existing in water. According to decree of the Ministry of Health, drinking water cannot contain more than 10 mg of nitrate nitrogen or 0,5 mg of ammonium nitrogen per litre and must be microbiologically clean [2a]. Water purity is also regulated by the Act on fertilisers and fertilisation [15], the Act on wastes [13] and the Building law [8]. Water purity and its protection is presented in many regulations of the European Union, the most important of which is the Nitrogen Directive of 1991 [21]. It regulates water protection from nitrates coming from agriculture, stating their maximum admissible content in drinking water at 50 mg/l. All the regulations mentioned above as well as some HELCOM regulations [27,30,31,33], which consider agricultural production to be a threat to water purity were taken into consideration in the following chapter.
III. PROTECTION OF WATER FROM POINT POLLUTION 152. Protection of water within a farm is much more effective if livestock houses as well as tanks for storing both solid and liquid excrements, septic tanks and places for washing agricultural equipment are located properly. 153. All liquid excrements and wastes of animal origin produced on a farm must be stored in special tanks located away from the farmhouses and from the farm boundary [8 b]. 154. Each farm should have enough tanks so as to provide a high level of use of the nitrogen contained in excrements. 155. Liquid excrements and wastes include slurry, liquid and water manure, silage effluents and domestic sewage that is not directed to the main sewage system. 156. Solid excrements and domestic wastes are as follows: farmyard manure, composts and litter. All the substances must be gathered, stored and recycled in special pits or in other areas which have previously been segregated [8b,15,26].
157. Tanks for storing liquid animal excrements should have waterproof walls and leak-proof bottoms. They should be covered with a tight plate, fitted with entrance and ventilating holes or a floating roof [8b]. 158. The capacity of the tank must be large enough to store slurry for at least 6 months a year. Any other liquids such as household wastewater cannot be added to this tank [15]. 159. It is necessary to reduce the amount of slurry within a farm by rationing the quantity of water used for sanitary purposes and reducing the leakage from drinking troughs so as not to increase the volume of liquid that is transported into the field.
160. Liquid manure together with water manure must be stored, if necessary, only in leak-proof, underground tanks especially constructed for this purpose. Tanks must be large enough to store liquid manure for at least 6 months a year. In practice at least 3 m3 of tank is needed for each large unit of animal [8b,15]. 161. Amounts of dense slurry, liquid manure with water manure from one animal as well as quantities of mineral elements that they contain are presented in Annexes 4 and 5. 162. It is advisable to divert silage effluents to sumps, which are a part of the silos for storing silage in order to avoid direct pollution of water. 163. Amount of silage effluents is about 0,2 m3 per 1 tonne of fresh matter. Such effluents should be taken to the field from which the fresh matter comes. The other method of bulky feed conversion, which is safer for the environment, is making hay-silage. There are no silage effluents from that kind of silage.
Hay-silage wrapping machine
Hay-silage piles
PITS FOR SOLID EXCREMENTS AND SEPTIC TANKS 164. Farmyard manure may be gathered, stored and fermented only in farm buildings or in waterproof pits fitted with sidewalls. All outflows must be diverted to water-tight tanks, preferably to the tanks used for slurry [8b,15].
Dung board with liquid manure tank
165. A manure pit must not be any source of infection for people and animals. It should be properly built to protect manure from both drying and flooding. 166. The area around the manure pit as well as access roads to livestock houses should be hardened. It makes it easier to deliver and remove manure, and to keep the surroundings clean. 167. A dung pit should be big enough to accumulate and store farmyard manure for at least 6 months a year. Its capacity depends on the height of the manure heap.
168. The size of the pit must be planned so that the excrements from each large unit of animal can occupy 3 m2. Such an area is proportionally reduced according to the length of grazing period. 169. Storing FYM in heaps in the field is not admissible as it may lead to the contamination of ground water with nitrogen and phosphorus compounds. 170. Storage and application of organic fertilisers should be done in such a way as to prevent the nitrogen losses that can occur in livestock houses, in piles and containers, and during application in the field (Figure).
Methods of storing manure
171. Amounts of manure from single animals as well as the quantities of mineral nutrients it contains are given in Annex 9. 172. On farms which are provided with a piped water supply but which are not connected to the public sewage system, it is necessary to build cesspools or septic tanks with water-tight walls and bottom. They should be covered and equipped with a hole to allow the removal of wastes. 173. Farms which have a piped water supply use more water and this results in a greater amount of sewage. 174. Sewage that is not diverted to a local sewage system may reach open water in which case the environment may be seriously threatened. 175. Farms not connected to the public sewage system, should neutralise sewage on the farm with special treatment plants. 176. Ground-root sewage plants with willow or common reed beds seem to be especially efficient. In densely-populated areas where the buildings have sewage systems, the local community authorities together with the farmers, should try to build communal sewage disposal systems.
Ground-root sewage plant
177. Waste oils must not be allowed to flow to open water storages because they may cause very serious water contamination [3 a]. 178. Waste oils should be collected in a separate tank and delivered to the petrol station.
OTHER BUILDING CONNECTED WITH WATER PROTECTION 179. Water may become heavily polluted if agricultural equipment and other machines, especially those used for applying fertilisers (spreaders, slurry tankers, and distributors) or pesticides (sprayers) are being washed at places inappropriate for such purposes. Places, where mineral fertilisers are being stored may be potential sources of water pollution. 180. Mineral fertilisers must be stored in original containers inside storehouses or roofed buildings. The pile of ammonium nitrate and other fertilisers containing ammonium nitrate must not exceed the height of 4 bags [12a,15]. 181. Fertilisers delivered separately should be kept in the storehouses or under a roof. It is permissible to store such fertilisers in heaps formed on hardened and sealed ground. Heaps must not be formed on slopes, or within zones of indirect protection, or in water-sensitive areas [12 a, 15]. 182. Liquid fertilisers must be stored in original containers or in leak-proof tanks. Such a tank must be located on a leak-proof tray of total capacity not less than that of the tank [15].
A tray with containers of liquid fertilizer
183. Solid fertilisers should be loaded and unloaded, and liquid ones should be poured very carefully, so they do not reach the soil surface. 184. Agricultural equipment, especially sprayers for applying fertilisers and pesticides must not be washed in the farmyard, but only at an appropriate washing place. 185. Stands for the washing of machines and agricultural equipment should be built so that no harmful substances can penetrate into ground water. 186. The optimum solution with regard to environmental protection is to construct a so-called biological bed with a thickness of 50 cm. Such a bed should contain 50% of cut straw, 25% of upland peat and 25% of soil. It should be underlain by a 10 cm permeable layer (e.g. gravel) for drainage. The surface, on which such a construction (platform) is placed should be planted with grass. 187. If there is no washing stand in a farm, spreaders and sprayers should be washed in the field after they have been used. 188. Spreaders or sprayers should be washed by filling the tank with pure water (it must be at least half-full) and moving on the field until the tank is empty. The treatment should then be repeated on another part of the field.
Washing stand
IV. WATER PROTECTION FROM NON-POINT SOURCE POLLUTION 189. Surface pollution may result from applying excessive rates of fertilisers (organic or mineral) and pesticides, as well as inappropriate methods or timing of their application. Sludge or sewage applied on agricultural lands may be other potential sources of water pollution. 190. In order to avoid pollution of surface water it is necessary to leave a buffer zone at least 1,5 m wide between the edge of the water and a field on which fertilisers are applied.
Various extents of nutrient leaching to ground waters
191. The width of the direct protection zone may be from 15 to 20 metres and depends on the soil type, field inclination and whether it is covered with plants or not.
TIMES AND RATES OF APPLICATION OF MINERAL AND ORGANIC FERTILISERS 192. Soil and plants may be fertilised only with fertilisers that have gained appropriate market access and are listed in the official register as well as with natural fertilisers of agricultural origin. Use of sewage requires a special waste-disposal license [2a,15]. 193. Rates and methods of application of organic and mineral fertilisers should be chosen so that the nutrients (especially nitrogen and phosphorus) that they contain are prevented from leaching to open and ground waters. 194. Liquid manure or slurry may be top-dressed on all crops at times when the requirements for mineral nutrients are maximum. Such an application minimises the risk of water contamination. 195. Single slurry and manure application rates should not exceed 40 m3/ha and 30 t/ha, respectively. Slurry should not be applied more often than once every 3 weeks. 196. At least half of the slurry produced on the farm during winter should be transported into the field before 1 July and the second part no later than the end of September. The earliest slurry may be applied on permanent grasslands. If weather conditions are favourable it is possible to do it in March. 197. Manure should be applied on the fields where the use of nutrients by plants is expected to be the highest. 198. Manure may be transported into the field in late autumn (November) or even in winter provided that it is ploughed-in immediately. 199. It is advisable to avoid transporting manure in early autumn because of the possibility of high losses of nutrients. 200. Mineral fertilisers containing nitrogen must be applied directly before the beginning of the vegetation season. 201. It is necessary to avoid using mineral fertilisers during long periods of drought. 202. On permanent grasslands nitrogen fertilisers may be applied until the beginning of September if temperatures in September and October will favour grass growth. 203. In order to avoid water contamination it not advisable to apply any fertilisers if heavy rain is likely to occur. 204. It is necessary to avoid applying either organic or mineral fertilisers: § to soils which are flooded or saturated to full field capacity, § to soils which are frozen or covered with snow, § to bare soils located on slopes (in the direction of open water tanks) if there is no possibility § of mixing them with soil immediately, § to permanent grasslands if the level of ground water reaches 20 - 40 cm. 205. Slurry and other liquid mineral fertilisers, should be applied with special spreaders or sprayers fitted with field beams with either appropriate endings or trailing hoses. 206. Fertilisers must not be overdosed. 207. Equipment used for organic and mineral fertilisers must be technically efficient to apply them evenly. 208. Loss of nitrates can be prevented if the soil is covered with plants during winter. Wherever it is possible winter crops or various cover crops should be grown. 209. The level of fertilisation should be adjusted to the plant nutritional requirements at the appropriate growth stage, under the particular soil conditions. Such a fertilisation programme should lead to economically optimum and environmentally friendly yield. 210. According to the EU Nitrogen Directive, the amount of natural fertiliser applied during one year cannot contain more than 170 kg of N (mass of the pure element) per 1 ha of agricultural land. 211. If the total amount of nitrogen produced on a farm (as natural fertilisers) divided by the area of agricultural land is greater than 170 kg N/ha, it shows that the animal stocking rate is too high. Then number of animals should be reduced or the excess amount of animal manure can, if possible, be distributed to neighbouring farms. 212. Rates of application of natural fertilisers should not exceed plant fertilisation requirements that are expressed as so-called active nitrogen (kg/ha). This has the same fertilisation activity as the nitrogen in mineral fertilisers. 213. Active nitrogen may be calculated as shown in the following example: Active nitrogen = (total nitrogen) x (fertilisation equivalent)
214. Silage juices have some fertilisation value. It is estimated that the juice from 25 tons of silage biomass contains about 14 kg of nitrogen. If nitrogen reaches open water storages, it may rapidly reduce the amount of oxygen and lead to the death of fish. 215. Application rates of nitrogen (mineral fertilisers) should meet plant fertilisation requirements and be based on advice. 216. Annual applications of nitrogen fertilisers should be divided into several parts and used in accordance with the uptake by the plants. The first application should be before the sowing (planting) of spring crops or at the beginning of the growth of winter crops. The following applications should be in periods of intensive plant growth. 217. Late application of nitrogen fertilisers is risky and may cause accumulation of mineral nitrogen forms in the soil after harvest and then their leaching to ground waters. Such fertilisation is permissible only for plants which, for technological reasons, should contain high amounts of protein. 218. Liquid fertilisers may be applied together with pesticides, provided that it is stated that this is permissible in the instructions for their use [15a].
APPLICATION OF SEWAGE AND SLUDGE 219. Sewage is used in agriculture to irrigate and fertilise agricultural land and ponds for fish breeding. Each person, who wants to use sewage, is obliged to obtain a waste-disposal license, issued by the competent departments of environmental protection [2a,18]. 220. Sewage dehydration or its treatment results in the development of sludge, which may be used in agriculture, provided that it meets sanitary requirements and that the contents of heavy metals in the surface layer of the soil do not exceed the values given in Annex 10. 221. Sanitary requirements for sewage and sludge that are intended for use in agriculture are presented in Annex 11 [2a]. 222. It is not allowed to apply sewage on soils containing higher than admissible amounts of heavy metals. Such amounts are given in Annex 12 [2a]. 223. Sewage cannot be used on slopes and on grasslands inclined at more than 10% and 20%, respectively. It must be applied neither on arable lands nor on grasslands if the level of ground water is not deeper than 1.2 m and 1 m, respectively [2a]. 224. It is not allowed to use sewage for plants (vegetables) that will be eaten raw [2a]. 225. According to proposed legal regulations, slurry and liquid manure are not regarded as sewage and they must be applied in the same way as natural fertilisers. [15]. 226. Sludge that is up to sanitary standards and has an appropriate chemical composition may be converted into organic fertilisers. They are being admitted to the market according to general rules and can be applied in the same way as solid natural fertilisers - farmyard manure and composts.
V. AGROTECHNICAL METHODS AIMED AT PROTECTING WATER FROM POLLUTION 227. Appropriate succession of plants and proper organisation of the whole crop rotation on arable lands seem to be very important ways to protect water from pollution, especially with nitrates. 228. Water pollution will be significantly reduced if the amount of mineral nitrogen remaining in the soil after harvest is decreased. Such forms of nitrogen should be taken-up by the following crop as quickly as possible.
Extent of nitrate leaching during the year
229. Increasing the proportion of so-called "green fields" i.e. winter, perennial crops and aftercrops in the crop rotation leads to a decrease in the amount of mineral nitrogen leaching to ground water. 230. At least 60 - 65% of arable land on plain areas and 75 - 80% on areas threatened with erosion should be left in autumn and winter under plant cover. 231. Intercrops (so-called cover plants) play a very important role in preventing nitrates from leaching in the following sequence of crop rotation: winter crops (or spring crops) - spring crops. Full protection activity of intercrops is shown in the spring when they are ploughed in. 232. Mineral nitrogen may be prevented from leaching by ploughing-in the straw of cereals, rape or corn. Each tonne of straw may, as a result of so-called immobilisation, fix about 10 kg of mineral nitrogen from the soil. 233. Up to 20% of the area that should be covered with plants during autumn and winter may be replaced by ploughing-in cereals, rape or corn straw, but it has to be remembered that such an effect is smaller than the effect of a "green field". 1 ha of "green field" = 1.6 ha with the straw ploughed in 234. It is essential to plough in papilionaceous plants in late autumn and assign the site for spring crops such as potato, beetroot or corn (they have high nitrogen fertilisation requirements). In this part of a crop rotation organic fertilisers must not be used. 235. Appropriate management that is based on the use of cut grasslands or pastures may reduce nitrogen losses and potential water pollution. 236. Rotation grazing (either in pens or by fodder dosing) should be done during the grazing season. Number of sections = (period of sward regrowth (days)/ number of grazing days) + 1
Pasture divided into sections for rotational grazing
237. It is not advisable to graze cattle on soils which are too moist or later than the middle of October as nutrients contained in excrements are likely to leach to ground water.
Mobile watering place in a pasture
238. Animals grazing on a pasture must have constant and unimpeded approach to water provided that its quality is not worsened. 239. Natural storages or water courses cannot be regarded as watering places. Water troughs should be moved from place to place, as there is a danger of a point concentration of excrements being produced where the animals are drinking. 240. Sheep should be grazed in loose pens (2 - 3 m2/sheep/day) excluding well-head areas and those located within water courses or on slopes. 241. Permanent grasslands of degraded sward or sod should be restored. The basic methods aimed at improving the sward are as follows: undersowing, if necessary with fragmentary damage of old sward, as well as its proper management and fertilisation. 242. Under exceptional circumstances the sward can be ploughed and re-sown. If such an operation is done, the considerable amounts of nitrogen that are released may pollute ground water, especially when its level is shallow. 243. The number of agricultural treatments aimed at restoring the sward completely should be as few as possible and sowing must be completed so that the soil is completely covered with plants before the end of September. 244. Grassland should be converted into arable land only in exceptional cases and taking into account the effects that the inevitable mineralisation of large amounts of nitrogen will have. 245. If precipitation in autumn and winter is greater than the water-holding capacity of the soil, the excess of rain water with nitrogen compounds diluted in it, leaches to ground water and causes its pollution. 246. Small grasslands or areas located within farm yard areas should not be used as yards for animals. 247. Yards should be constructed, wherever they are necessary and should form an extension of farm buildings. 248. It is necessary to remember that permanent grasslands, particularly those located within protective and sensitive zones play both productive and protective roles as regards open and ground waters.
APPLICATION OF PESTICIDES 249. Although use of pesticides in Poland is not very high (0,5 kg a.i./ha) they may occasionally lead to water contamination, mainly because they are inappropriately stored, spilt/spread or blown away to water during application. 250. Pesticides used for crop protection must be officially registered. With regard to the safety of people and animals, and also to the protection of the natural environment, it is allowed to apply pesticides only for the purposes stated on the label or in the instructions for use [11,12a]. 251. It is extremely important to obey the time lag between the last application of pesticides and harvesting and between the last application and bee flights. [11]
A sprayer
252. Each sprayer used for crop protection must have a certificate of efficiency, issued by the authorised service station. Pesticides may be applied only by people specially trained or by the qualified workers of specialised service plants [11,12a]. 253. Field sprayers may be used only on fields located at least 5 m from public roads and at least 20 m from houses, gardens, bee yards, open water and direct protection zones of water intakes [11]. 254. Pesticides should be applied on windless days (wind speed cannot exceed 3m/s), either early in the morning or in the evening when the air humidity is high [11, 12a]. 255. A producer or a distributor of a particular pesticide is obliged to collect empty containers. Such containers must not be washed and used for other purposes and must not be burnt, thrown-out or buried [13]. 256. Pesticides must be stored in special, hard- and even-floored closed rooms protected from frost. The floor must be a kind of "tray" which is able to retain the pesticide in case it is spilled [12a]. 257. Pesticides may only be stored in original containers properly marked or labelled [12 a]. 258. Risks of air, soil and water pollution (by leaching, run-off or volatilisation) may be minimised by avoiding using pesticides that decompose slowly, have low selectivity or must be applied at high rates. 259. The method of pesticide application must be chosen to reduce pollution of air, water and soil. 260. After the work has been completed, all the machines must be washed with water, which may be spread on the treated field or on another one covered with plants, on which such a pesticide may be used. Under no circumstances may water leak to surface water or wells. | |||||||||||||||||||||||||||||||||||||
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