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Liquid manure - natural fertilizer or environmental toxin?

Liquid manure - natural fertilizer or dangerous environmental toxin?

What actually is liquid manure? And is it really a natural fertilizer - or rather environmentally harmful manure? If you're looking for answers to these questions, you've come to the right place! Anyone who has ever had to drive behind a slurry tanker or walked past a freshly filled field will be familiar with the particularly foul-smelling odour that the animal manure often preferred in agriculture brings with it. But apart from the stench, liquid manure has other clear disadvantages for humans, animals and the environment that are hazardous to health and the environment.

In this article, I would like to give you everything you need to know about the masses of liquid manure from factory farming. From the definition, extreme statistics, environmental hazards and advantages and disadvantages, to tips for a softer manure footprint. Let's go!

Here is a brief overview in advance:

  1. Definition
  2. Statistics
  3. Advantages and disadvantages
  4. Dangers
  5. Reducing the "manure footprint"
  6. Closing words

What exactly is liquid manure?

What is slurry actually?

The term liquid manure (often also referred to as slurry or odel) describes a liquid manure, which mainly consists of the Feces and urine of farm animals (e.g. cattle, pigs and chickens).

As it contains nitrogen (N), phosphorus (P), potassium (K), boron (B), iron (Fe) and magnesium (Mg), farmers use it - in line with the circular economy concept - primarily as a natural fertilizer and to increase the fertility of their fields and crop yields. This often also applies to parts of the waste that are fermented in biogas plants to generate energy and whose fermentation residues are then spread on the fields. The latter is usually done with tractors, a slurry tanker, as well as a slurry cultivator, wide spreader or drag hose.

Depending on the type of housing and the amount of bedding (e.g. straw and hay) and water added, one also speaks, for example, of Thick or thin slurry, liquid manure, flushed manure or liquid manure.₁ Manure is more solid and usually also consists of straw, while the leachate from the manure heap is more commonly referred to as slurry.

Meaningful statistics on the subject of liquid manure

To get a feeling for the extent to which the production of the mixture of manure and urine from farm animals has already reached, I would like to give you some facts and figures:

  • Liters of milk: Around three liters of manure are produced for every liter of cow's milk.₂
  • Kilogram of pork: The production of 400 g of pork produces about 10 liters of liquid manure. That's about 25 liters per kilo.₃
  • Greenhouse gas emissions: 22 percent of emissions from the average European's diet are due to manure.₄
  • In square kilometers: In the period from March 2019 to February 2020, 134,900 farms in Germany fertilized their fields with liquid manure, spreading around 187,754 square kilometers of animal manure.₅ By comparison, that is more than half of Germany's land area.

The advantages and disadvantages of liquid manure at a glance

Liquid manure is applied to the field as a natural fertilizer

Of course there are one or two reasons, why the excrement of cows, pigs and other "farm animals" is spread on the fields in the first place - but there are also plenty of arguments in favor of quitting. I would like to summarize them for you here and explain them briefly if necessary.

Advantages and opportunities

  • Cost-effective fertilizer in the sense of the circular economy
  • Usually contains all the important nutrients for plants
  • Increases soil fertility and builds up humus content
  • Is available in sufficient quantities (from the Factory farming)

Disadvantages and risks

  • Soil load (nitrogen inputs, soil acidification)
  • Climate impact (e.g. due to nitrous oxide, ammonia, particulate matter)
  • Transports (Liquid manure must be transported by truck)
  • Abundance (in Germany there are clearly more than sufficient quantities).
  • Groundwater contamination (e.g. with nitrates or antiobiotics from animal husbandry).
  • Overfertilization (due to excessive and frequent spreading of nitrogenous liquid manure)
  • Healthful (e.g. due to antibiotic resistance, nirat and particulate matter).
  • Exploitation (The existence of manure is based on the exploitation of animals)
  • Controls (Manure imports from abroad are difficult to control)
  • Consumer Costs (higher nitrate levels make drinking water more expensive)

Can you think of any other advantages or disadvantages of liquid manure? Then feel free to write me a comment under this post.

Overfertilization: Is liquid manure really so harmful to health and the environment?

Slurry is in small quantities actually a very good, natural and therefore harmless fertilizerwhich provides the most important nutrients for plant growth. If it really were a closed-loop economy, farmers could grow fodder, feed it and reuse the excrement from their cattle, pigs and chickens on the farm as fertilizer for growing animal feed.

But enough of the subjunctive! On the massive scale common today In factory farming, imported feed or synthetic fertilizers are used above all. In addition, there is so much liquid manure that farmers have to get rid of it as cheaply as possible. As a result, far too much is "disposed of" on fields and meadows, threatening the soil, groundwater, climate and, not least, our own health.

Dangers for the environment

The core of the problem is the horrendous number of farm animals that simply produce too much manure. That is why nowadays larger quantities of the fecal-urine mixture are available than can be absorbed by soils and plants. This over-fertilization also increases nitrogen inputs and the likelihood of soil acidification. Nitrous oxide vaporizes, causing the climate change is significantly driven forward. Ammonia is also produced and contributes to the formation of particulate matter and the air pollution at.

The transportation of liquid manure across Germany and Europe is also harmful to the climate. Farmers who have too much liquid manure available transport it to regions where it is needed. As there is even less land available in the Netherlands, for example, to "dispose" of the liquid manure, Germany even imported 2.2 million tons from there in 2016.₆ This so-called Slurry tourism naturally destroys the desired regional nutrient cycle and blows emissions into the atmosphere on a massive scale.

Good to know: Incidentally, soybean meal - the protein-rich and therefore preferred animal feed in livestock farming - also travels a lot. The extent to which feed fed to animals Soy destroys the rainforestyou can find out in the linked article.

Risks to general health

The excess liquid manure in the fields also increases the Nitrate content in groundwater.₇ The nitrogen compounds can be found in cultivated and fertilized spinach, for example, and can form nitrosamines, which are suspected carcinogens, in the body after consumption.₈ Nitrate in groundwater is a particular concern for infants.

A further health risk is posed by groundwater contamination with antibiotics used in factory farming. This can result in Antibiotic resistance that inhibit the effect of the drug when they are needed. The general public also bears the costs of drinking water treatment, which is intended to prevent serious health consequences.

These are just a few examples of how manure is harmful to health on an exorbitant scale. In principle, no one can expect to stay healthy in a sick environment. It is therefore important to minimize the quantities produced and ultimately applied.

How do I reduce my "manure footprint"?

Reduce manure footprint, live vegan

There is only so much manure because we humans consume animal products. If you want your lifestyle to cause less animal suffering and animal excrement, as well as reduce the burden on water bodies, ecosystems and the air you breathe, then you should choose a Prefer a plant-based diet, vegan life and simply leave the animals in peace. After all, we only breed and fatten cows, pigs and chickens so that we can eat them, their milk and their eggs later on.

And what can farmers do? Farmers are not dependent on liquid manure. Vegan organic farming shows how it's done. Green manure and compost, crop rotation and the cultivation of catch crops protect the soil, groundwater and air and at the same time save countless Plant and animal species preserved.

Liquid manure - A man-made danger for humans, animals and nature

At least in the quantities in which manure from cattle, pigs and chickens is produced, liquid manure from animal husbandry is a dangerous environmental toxin that endangers the soil, air and groundwater - and therefore both nature and our health. Added to this is the Moral question. This is because the animals usually have to live on hard, fully slatted floors in narrow stalls where their excrement falls into the manure basin below. Animals such as cows and pigs, which are actually quite clean creatures by nature.

Just by adopting a vegan lifestyle, you would have nothing to do with all these problems from one second to the next. Take a look at the following, further article an:

Do you have any questions, tips or suggestions? Then write me a comment as always.

Stay animal-friendly and sustainable,

Christoph from CareElite - Plastic-free living

PS.: You think on the road it is difficult to always find plant-based meals? In the post "Vegan in every restaurant - it's that easy" I'll show you why it's actually quite simple. Have fun!


₁ LUMITOS AG: Chemie, abrufbar unter [13.01.2022].

₂ PETA Germany e.V.: (2020): Liquid manure pollutes drinking water and increases water costs (as of July 2020), available at [12.01.2022].

₃ Florian Nöthe (2017): The slurry flood - danger for our drinking water? [25.11.2019].

₄ - Magazine of the vegan society, issue no. 34 - 2/2020, p. 12, available at [13.01.2022].

₅ Federal Statistical Office: Production methods (as of July 28, 2021), available at [13.01.2022].

₆ Greenpeace e. V.: Gülle-Importe aus den Niederlanden zusätzlich belasten deutsches Trinkwasser (as of September 2017), available at [13.01.2022].

₇ PETA Deutschland e.V.: Liquid manure pollutes soils and groundwater (as of July 14, 2020), available at [13.01.2022].

₈ Kilian Dreißig: Natural fertilizer or poison for the environment (as of 18.11.2019), available at [13.01.2022].

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* Links with asterisks are so-called Affiliate linksIf you click on it and buy something, you automatically and actively support my work with, as I receive a small share of the proceeds - and of course nothing changes in the product price. Many thanks for your support and best regards, Christoph!

Christoph Schulz

Christoph Schulz

I'm Christoph, an environmental scientist and author - and here at CareElite I'm campaigning against plastic waste in the environment, climate change and all the other major environmental problems of our time. Together with other environmentally conscious bloggers, I want to give you tips & tricks for a naturally healthy, sustainable life as well as your personal development.

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