Liquid manure

As far back as 1980, Vogelsang presented a dribble bar system, thus laying the foundation for exact, low-emission spreading of liquid manure – this means we have been working on how best to make use of liquid manure for almost 40 years.

Liquid manure: “Wholemeal bread for the field”

Scientists all agree that, when used according to good professional practice1, the ingredients in liquid manure not only have the desired positive effect on the growth of plants – they also help the soil! In addition to liquid manures produced by animals, such as muck, dung and other liquid manures, plant-based substances such as straw, cattle mulch and plant residue also fall into this category. As such, liquid manure is a natural source of a variety of organic substances that contribute to humus formation in the soil. It’s no coincidence that liquid manure is referred to as “wholemeal bread for the field!” There should be more focus on this often overlooked added benefit of liquid manure in the economic and ecological debate, in order to improve its standing in public opinion. Liquid manures are not waste – they are a valuable resource for crop cultivation. The alternatives are manures that are either artificially manufactured or the results of natural decomposition. In addition to the poor energy balance of some of these manufacturing processes, the resources required for them are also a problem. For example, approx. 80% of global phosphate deposits today are turned into fertilizer. This is a waste of a raw material that is crucial to our lives – a substance whose rarity is already leading experts to make worrying predictions for the future, as there are no known substitute sources of it.

Liquid manure as part of the recycling economy

A gainst the background of the current debate regarding intensive livestock farming, the associated excess of food in certain regions and the nitrate pollution of groundwater wells, it is important to note that there are already ways of solving these problems. In particular, those in the industry have been working on rethinking how we handle liquid manure for many years now. However, the tone of this debate remains overwhelmingly negative. There is insufficient acknowledgment of what we have already achieved, and little talk of the steps that still need to be taken. Despite all this, the solution to the problem is relatively simple: the recycling economy promoted by so many simply needs to be applied on a larger scale. In its current form, it is designed to be used within an agricultural business that is unable to adapt to the focuses of the agricultural economy. The current situation, where some regions focus on livestock farming while others are used predominantly for crop cultivation, did not come about by chance – it is mainly the result of the local conditions in each area. For example, crop cultivation is less effective in areas with lighter, low-yield soil, which is why agriculture in such regions focuses on livestock. In areas with more fertile, heavy soil, on the other hand, food crops take priority. However, if the grain grown in these areas does not comply with the requirements of the food industry, it is sent in huge quantities to livestock farming regions for use as feed for pigs, poultry and cattle. As such, the resulting liquid manure could – and should – be sent back to the crop cultivation regions in order to complete the food cycle. Another factor that must be taken into account in the debate on organic liquid manure is that liquid manure contributes to the production of renewable energy, and biogas plants account for approx. 7% of all the power generated in Germany (renewable energies make up 30%)2.

Why does this recycling economy not work as well as it could?

The facts:

  1. In crop cultivating regions, the main concern is supplying the field cultures with the exact nutrients they need. As such, liquid manure must be made more interesting by providing an exact declaration of its ingredients in order to enable it to compete with inorganic fertilizers.
  2. Due to their low dry matter content, liquid manures are difficult to transport; delivery to other regions would involve budgeting for too many journeys, which makes it economically unfeasible.
  3. Some of the liquid manure will remain in the regions with an excess in food production in order to provide nutrients for their own crops. Efficient spreading techniques for liquid manures are already widespread in these areas.

As a result, we need to take action in the following areas:

  1. The definition of the ingredients in the liquid manure, which is the responsibility of each individual farmer according to the German fertilizer regulations of 2017, is a process that requires further simplification and standardization. The first steps have already been taken with the introduction of NIRS measuring equipment, and can be seen as ready for use in practice, at least for the nitrogen portion, which is of particular ecological importance. Farms receiving these deliveries are already being given exact information on their ingredients by certified businesses.
  2. There are already many ways of disintegrating liquid manures in order to make them easier to transport. Use of these technologies will become more widespread over the next few years, and those which are most cost efficient for the operations delivering the manure, and which can provide the recipients with standardized products, will enter into common usage.
  3. The use of exact, low-emission spreading techniques will become more widespread. Even today, every operation is able to choose the spreading technique that best suits its needs. The available options include the universally suitable dribble bar systems and special equipment such as trailing shoes, liquid manure strip tillage and disk harrows/cultivators with a liquid manure attachment.

Agriculture 4.0

As in many other industries, the digitalization and automation of the agricultural sector continues inexorably. “Smart farming” is also becoming increasingly important in the spreading of liquid manure. The more data that is available on the spreading of existing liquid manures and the condition of the crop cultures, the more accurately we will be able to determine the correct quantity and position of the manure. It is safe to assume that, in the future, liquid manures will be spread with the same precision as some agricultural operations are able to spread their inorganic fertilizers today.

Societal demands

The over-fertilization of fields, nitrate pollution in the groundwater, odor problems, mass livestock farming, the well-being of animals and the agricultural industry are all the subject of criticism and debate among those outside the industry. More than ever, modern agriculture is in the firing line, and unfortunately, many seem to forget the radical changes this sector has already undergone in recent decades. Agricultural businesses and farmers are more than happy to continue adapting to the demands of society at large. As a globally respected manufacturer of agricultural machinery, Vogelsang is also looking to enter into a dialog with the public. It should go without saying that we are looking at future-proof solutions for supplying the population with highquality, locally produced food while also continuing to improve agricultural sustainability.


Text: Dr. Thomas Gnosa, Sales Director Agriculture, Germany

1) The plant nutrients must be applied at the right time, in the right quantity and in the right place in order to ensure that the plants receive the food they need, increase the fertility of the soil and prevent or defend against the dangers to the ecosystem and human and animal health. (Source: www.bmel.de/DE/ Landwirtschaft/Pflanzenbau/Ackerbau/_Texte/Duengung.html)
2) www.bmwi.de/Redaktion/DE/Dossier/erneuerbare-energien.html Dossier – Renewable energies; gross power generation in Germany for 2016 in TWh; preliminary figures, partially based on estimates; regenerative portion; date: March 2017