6.   STORAGE AND HANDLING OF MANURE AND SILAGE

Appropriate handling of manure guarantees that the plants receive necessary nutrients and water will not be polluted. If the amount of manure applied is too big, then plants cannot absorb all the nutrients and part of them will leach into surface water or groundwater. Springs, sinkholes and water bodies in pastures must be protected against pollution. The restrictions are stricter in nitrate sensitive zones, because in these regions surplus nutrients can quickly cause extensive pollution. County Environmental Departments give information about the regions, which have already been declared nitrate sensitive zones or can be declared as such in future.

In Estonia the number of animals per hectare of cultivated land must not exceed 1,5 livestock units. In nitrate sensitive zones the limit is 1 livestock unit per hectare.

One livestock unit corresponds to 1 head of dairy cattle or horse (500 kg of weight), or 2 heads of young or beef cattle, or 5 calves, or 2 heads of boar or sow with piglets, or 6 fattening pigs, or 10 sheep, or 100 heads of laying hen, or 400 heads of broilers.

If the capacity of the manure storage is sufficient and the cattle breeder has valid contracts, which show that other consumers are utilizing the manure that comes from his farm, the number of livestock units per hectare of cultivated land may be higher on the condition that only the permitted amount of manure is used.

The exact procedure for storage of manure and fertilizing with manure shall be established by the Regulation of the Government of the Republic on water protection requirements for fertilizer and manure storage and silage storage depots, and requirements for the use and storage of mineral fertilizers, manure and silage juice.

Manure, which has been appropriately stored and utilised, represents a valuable source of plant nutrients, which helps to increase soil fertility, to improve the physical, chemical and biological characteristics of the soil and to restore its energetic resources. The farmer must take measures to avoid the possible danger to the environment. The best way to take advantage of the nutrients in manure is to utilize it for fertilizing the crops.

Manure can be either solid or liquid depending on the content of litter. If the amount of litter is sufficient, then solid manure is the result. If, however, the content of litter is smaller, we receive semi-solid manure or slurry. If solid manure is stored, it is also necessary to build a storage depot for urine. The advantages and disadvantages of the manure of different types are shown in Table 2.

Table 2. Advantages and disadvantages of different types of manure.

When plans for manure management are made, all the problems connected with handling manure in livestock housing (including the use of litter), in storage facilities and while transporting it to the fields have to be taken into account simultaneously. The choice of the equipment to be used depends on the type of manure.

The floors of cattle breeding facilities must be watertight, the litter used dry and dust-free.

The floor constructions must be strong enough to carry the weight of the animals and technological equipment. Animal places must be dry and of appropriate size and they must not cause injuries to the animals.

To decrease emissions of ammonia and methane gas in a cattle shed the feeding rations must be balanced, appropriate quantity of litter has to be used and manure has to be removed as quickly as possible, at least twice a day. Urine has to be separated from solid manure and directed into a urine depot.

All farm buildings for livestock where more than 10 livestock units of animals are kept must have a manure storage facility and a urine depot. The minimum capacity for the manure storage facility must correspond to the amount of cattle, horse or sheep manure produced in 8 months and the amount of pig or poultry manure produced in 10 months. The minimum capacity for the urine depot must correspond to the amount of urine produced in 10 months. In case of keeping animals on deep litter and in case the capacity of the shed is one year, there is no need for a manure storage or urine storage depot (Water Act). 

The pump station for urine or slurry must accommodate at least the amount of urine or slurry produced in two days. All the buildings where manure is stored or handled must meet the requirements established for buildings of this type.

A manure storage facility must be designed, built and maintained so that to avoid pollution of surface water or groundwater, influx of precipitation and surface water into the storage and to prevent the leakage of manure stored there. 

The floors and walls must be waterproof, with the exception of storages for solid and semi-solid manure where walls are penetrable for urine and it flows to the urine depot through the impermeable canals.

For decreasing the emission of ammonia the storage depots for slurry and urine must be covered. 

Some examples of suitable materials: 10 cm layer of fine gravel or chopped straw, 0,5 cm layer of oil seed rape, floating membrane, air-proof tent used as roof, or some other material. The inlet of such depot must be near the floor.

Only solid manure may be stored outside the storages, in the form of manure heaps until 1 January 2005 and in the amount not exceeding the vegetation period need. The ground under the heap must be level and manure heaps must not be made on an area, which may be flooded in spring. 

For decreasing the emissions of gases the manure heap must be covered with a foil or with a layer of peat, straw or soil at least 20 cm thick. Every year the manure heap must be made in a new place. 

It is prohibited to make manure heaps on a shore or bank of a water body, in a sanitary protection zone of a water intake or in an area where groundwater is not protected. 

In the vicinity of densely populated areas and summer cottage districts also the wellbeing of neighbors must be taken into account, the prevailing winds have to be considered and, if possible, transporting and spreading of manure should not be done during the weekend. The best time for spreading manure, especially slurry and urine, is in cool, damp and calm weather.

Silage must not be stored on shores and banks of water bodies or in sanitary protection zones of water intake. Silage effluent must be collected into a waterproof tank or directed into a urine depot. The capacity of a silage effluent tank must be at least 10 litres of silage effluent per each m³ of the silage depot. 

The silage depot must be designed, built and maintained in such a manner that it will not cause pollution of surface or ground water. It must be waterproof.