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article and photos by Liza Burger

Managing manure and effluent becomes a very concentrated problem if there is no natural outlet for the mounting masses of waste generated such as those on pasture-based farms. Extracting the good from this situation has been mastered by many. The Dairy Mail takes a closer look at how some European countries handle manure.

New solutions, new rules
Environmental policies in the EU are most relevant to milk producers and focuses mainly on water pollution and ammonia emissions, and more recently on biodiversity and green-house gas emissions.

Regulations were first introduced to limit primary pollution, for example by prohibiting or limiting the direct discharge of dairy cow manure into waterways. More regulations have been steadily introduced to limit secondary source pollution, for example by monitoring the quantity of manure that can be produced, the quantity that can be spread and the way in which it is spread.

A greater number of measures and generally of a more restrictive nature have been applied to producers in northern European countries. Variations on these rules are found in the different countries, but the basic laws protecting communities and the environment hold true for all in the EU. While regulations remain an important tool for controlling negative external effects, there is a trend towards taxation of environmental damage and incentives for environmental benefits.

Countries such as Holland and Belgium, being just above sea level, have shallow water tables and mostly sandy soil. Reaching the filled-to-the-brim stage, where the ungoverned spread of manure on fields could no longer safely be tolerated, the EU member states implemented environmental policy measures that are predominately regulatory, but which are increasing in severity and complexity.

South Africa has its own laws regarding the treatment and use of wastewater, effluent and manure [the National Environmental Management Waste Act, 2008 (Act No. 59 of 2008) and the Fertilisers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947]. These laws are mainly focused on keeping water sources unpolluted, preventing the possible spread of disease and bacteria and keeping both animals and humans free from nuisance factors such as bad odours and flies and health risks associated with animal waste.

One of the things in our favour is that we have the space to spread manure safely on fields and pastures. We also generally have a deep water table that helps prevent ground water pollution and using manure as fertiliser adds to the organic content of the soil.

Basic manure treatment can also separate the liquid content of effluent from natural fibres, leaving perfectly dried manure that can be used as bedding material in cow houses. Hence, spreading manure on fields to fertilise crops, for instance, is seen as making good use of natural resources.

Collecting manure
A gutter system is used on the majority of farms with concrete slabs with narrow slats on the floor of cow houses or smaller cow sheds. A centralised sewage system collects the manure in an underground sump, where a slurry tanker will collect the sludge.

The honeysucker will transport the manure either to a processing plant where liquid manure will be extracted for fertilisation purposes or to a bio-digester where methane gas is produced for alternative energy uses.

Inventive manure handling
The problem for farmers in the EU is that manure may not be used as fertiliser without proper handling according to strict manure management protocols. Owing to their success as milk producers, their use of intensive farming methods as well as the added problems regarding soil type and low water table, Dutch and Belgian milk producers have to be on the ball when dealing with manure.

Being inventive was a prerequisite for these farmers. One of the big challenges is to adhere to the many regulations regarding manure handling and use as fertiliser. Among others, the rules dictate that farmers may not use manure as fertiliser unless it is either inserted directly or ploughed into the soil immediately after spreading occurs. While this normally would only entail attaching an extra implement behind the manure spreader, the tractor and its heavy load in tow causes too much soil compaction.

To overcome this problem the dragline method was developed. A powerful pump is used to drain the liquid manure from the tanker parked at the side of the field and pump it all the way across the land to where it is needed to fertilise the soil. Usually, a double-wheeled tractor (this lessens the compaction effect) is used to drag the hose that can stretch for kilometres on end. A sturdy ripper with nozzles is used to break the ground and directly insert the manure into the soil.

The quantity of manure used to fertilise fields are monitored closely, inspectors oversee manure handling at random and heavy fines are given to transgressors.

One of the main concerns is the release of ammonia into the atmosphere, hence the immediate tilling after manure spreading.

Ammonia (NH3) emissions occur during manure storage and application to lands. There is higher risk of volatilisation after manure application and the time-lag between application and incorporation of the manure through tillage substantially affects the total NH3 volatilisation. The injection of manure into the soil leads to a reduction in NH3 emissions of up to 90% compared to conventional distribution techniques.

Research done at the Wageningen University in the Netherlands confirms that NH3 volatilisation is substantially reduced by application techniques such as narrow-band application and shallow injection, and by effective manure incorporation techniques. Manure composition, the application rate and the weather conditions substantially influence the NH3 volatilisation rate.

Liza Burger paid a visit to farms in Belgium, Luxemburg and Holland on invitation during the International Federation for Agricultural Journalists’ annual congress and tour in April this year.