Manure has been used as a fertiliser for more than 5000 years. Without it, agriculture and permanent settlements would have never been possible. Manure is chock full of precious nutrients, especially nitrogen, which plants need to grow. A little more than a century ago however we figured out how to produce nitrogen synthetically. The age of artificial fertilisers was born. Manure gradually lots its status as a valuable resource and especially in the past 60 our industrialised agriculture has come to view manure more as waste - a problem to managed. Manure would be stored in ever larger manure pools with fewer and fewer farmers piling manure up in a manure heap - with devastating consequences.
Manure that is stored in a manure pool sits there anaerobically until it is brought out. When it comes to manure, which is a nutrient bomb, nature takes care of it by letting aerobic bacteria and insects do their work. Nitrogen is turned into protein, which then gets distributed by the insects.
On a lot of farms today cows spend most of their time in the stables, especially in winter time. This was true 500 years ago as well, but then the farmer would take every single manure pat out of the sables by hand and pile it up, gradually. Insects and bacteria had enough time to do their work on the manure heap in aerobic conditions - these insects and bacteria need air to work. On the overwhelming majority of farms today however manure heaps do not exist at all any more. Instead, all maure gets shoved down a hole and into a manure pool. Inside that manure pool, no aerobic bacteria can survive, instead anaerobic, rotting bacteria multiply.
The problem is that the precious nitrogen in the manure turns into volatile substances like ammonia. Ammonia is an aggressive compound which literally burns plants. Nitrogen in the form ammonia would never exist in nature in anything more than trace amounts. Nature does not know how to deal with it. So when the manure is being brought out to the fields, that manure turns out to be extremely aggressive not only on the plants, but the soil as well. Earthworms, which are the backbone of a fertile soil, literally burn their skin. They come rushing to the surface, suffocating. The anaerobic, rotting bacteria which habe multiplied in the manure pools are detrimental to soil fertility as well. They inhibit the healthy aerobic microbial life in the soil. To top it off, a good 30% of the precious nitrogen evaporates into the air in the form of ammonia - more than 750 000 tons of it every year in Germany alone - causing acid rain and that awful smell we all have to endure when we drive through the country side in spring time.
It is said that Aristoteles called referred to the soil as our planets stomach. Following that line of though, if our soils could vomit, we would surely suffer a flood of biblical proportions.
In the past 60 years, we have seen humus levels (a measure of fertility) and microbial activity in agricultural soils drop by around 50% in Switzerland. At the same time most agricultural soils as well as non agricultural soils have a massive oversupply of nitrogen. This has lead to a dramatic loss in biodiversity of plants as well as animals and insects.
Rudolf Steiner, the father of the bio-dynamic movement realised at a very early stage that the modern, chemical-based industrial agriculture was heading down the wrong path. In 1923 he held a series of lectures where, among other things, he emphasised the importance of composting and keeping our precious nutrients in a cycle - the natural cycle of life, death, transformation and re-birth. Rudolf Steiner realised the importance of composting in this cycle and put some quite emphasis on it. He created what I would call a ritual around composting which included among other things the creating of the horn-manure. I interpret this is a spiritual addition to a physical process.
In Rudolf Steiner's days, composting was an incredibly strenuous physical process. Without today's technical aids such as the tractor and mechanical compost turner, the manure heap would be turned and aerated by hand. Nonetheless, a core group of farmers formed around Rudolf Steiner's philosophy and started implementing his ideas. This from of agriculture came to be known as bio-dynamic agriculture.
The art of composting experienced its second great impulse when Ehrenfried Pfeiffer started using technical/mechanical aids. His goal was the meticulous documentation of the aerobic composting process and devising a methodology for producing universally high quality compost. After a period of little progress in the field of composting in the 1960s, Uta and Siegried Lübke from Austria became the composting movements torch-bearers in the 1970s for an entire generation. Their daughter Angelina Lübke and her husband Urs Hildbrand have ever since been tireless working on scientifically exploring and documenting the art of aerobic composting. Thogether they have started hundreds of composting projects world-wide and pass on their knowledge in regular week-long workshops.
I learned composting from Angelina Lübke and Urs Hildebrand and from the master farmer Martin Hegglin on whose farm I worked full time for 18 months. Martin Hegglin learned the art of aerobic composting from Uta and Siegried Lübke in 1997 at a compost course in Austria. Martin immediately recognised the tremendous value in composting his manure and completely adapted his stables and changed his manure management in a way that he produces no liquid manure at all.
The goals of composting
- Build-up of a stable clay-humus and soil structure
- Increase water-retention capacity of the soil
- Healthy fertiliser for plants in the form of humus (not the "force-feeding" of nutrients int eh from of chemical fertilisers of water soluble nutrients in manure)
- Keep nutrients in the nutrient-cycle - reduce nutrient loss in the form of run-off or evaporation (Ammonia emissions)
- Increase microbial activity in the soil (breathe life into the soil)
- Destroy weed seeds
- Destroy pathogen bacteria
According to calculations by the German Federal Environment Agency, the environmental costs per kg of ammonia emissions amount to 27 euros - for an average Swiss farm with 20 cows that amounts to 30,000 euros environmental damage per year - these could be avoided by composting. Additionally, composting builds up humus in the soil, which stores enormous amounts of carbon - CO2 from the atmosphere. Agricultural soil can store up to 300-500 tons of CO2 per hectare, depending on the soil type. Today, conventional agricultural soils store between 40 and 100 tons of CO on average.
The environmental, animal welfare and human health benefits of composting are truly enormous.
Pre-requisites for successful composting
A number of parameters must be considered in order to compost successfully: the materials to be composted must be available in the right ratios, the proper mechanisation must be invested in, as well as a proper composting site. But even when all these pre-requisites are given, the most important component for successful composting is the experience and dedication of the person taking care of the compost.
Spacial requirements for composting
Wayside composting offers a cheap and uncomplicated introduction to composting for farmers. While it is possible to compost on wayside, this form of composting is more challenging than composting on a dedicated concrete composting sire. Several limitations must be kept in mind with wayside composting:
- Because the windrow sits on top of uncompacted soil, the compost can only be turned when weather conditions are dry in order to avoid turning the composting site into a muddy mess.
- It is essential that the water from the road does not flow into the windrow - it is therefore important that the road has a lengthwise slope of 2-5% for the water to run off
- The land next to the road where the windrow is placed must not have a sideways slope, otherwise the windrow will start to "wander" sideways away from the road while turning the windrow. This will force the composter to drive the tractor off the asphalted road and on top of the soil - this will turn the whole site intoa mess very quickly and prevent a good composting process.
- Due to legal restrictions, the wayside site of composting must be changed every year (in Switzerland) - this causes a logistical problem, as there might only a be a few site which fulfill all the requrements for a good wayside site.
For the reasons listed above, it is recommended that a dedicated concrete composting site be built. The site should be at least 65 meters long in order to place 50 meter long windrows on the site and work efficiently. A composting site of 115 meters length would be even more ideal.
On the farm Oberbrämen the composting sie is about 10x 110 meters big, allowing for two 100 meter long windrows to be set up at any one time.
Important points to consider for a concrete composting site:
- The composting site must have a lengthwise slope of 2-3% in order for rainwater to run off and not get absorbed by the windrow.
- Under no circumstance should the composting site have a sideways slope - otherwise the windrow starts to "wander" sideways
- The composting site must be protected from wind, otherwise the windrows will dry out very quickly. A row of hedges does this job well and also looks good. A concrete wall would also do the job.
- The composting site must be large enough in order to process all of the available material. As a rule of thumb, it takes an average of 1m2 of concrete space per m3 of material to be processed per year.
- While proper composting does not create wastewater, regulations require a wastewater treatment solution
I am not going to recommend a specific brand of tractor, but you will need a tractor that can go at "supercreep" speeds of as little as 100-150 meters per second
Materials to compost
The Carbon to Nitrogen ratio is a very important factor in successful composting. We all know that Carbon is the element which makes up the framework of all living matter. If you take away the water, our body is made up for more than 70% carbon. Nitrogen generally is the second most important element for living being - it is a key element in protein.
Most of the work done in the aerobic composting process is the result of micro-organisms multiplying,eating up all the organic matter around them, dying and being eaten up by other micro-organisms. In this life and death cycle of the micro-organims some amazing processes occur where complex organic compounds such as parts of proteins start to bond with clay particles to from stable humus compounds. All nutrients become part of a living and dynamic cycle.
Experience has shown that the micro-organisms need a certain amount of nitrogen and carbon in order to multiply and function optimally - the optimal ratio has proven to be 30-35 perts of carbon for every one part of nitrogen. The carbon and nitrogen can be thought of the carbohydrates and protein in our diet. The carbon offers the micro-organisms the energy to metabolise and live, while the nitrogen build the basis of forming protein for micro-organisms to multiply. It takes a certain number of micro-organisms to metabolise a certain amount of carbon and keep it in a living cycle. If the source material of the compost has too little nitrogen but a lot of carbon, then the micro-organisms cannot multiply enough because they are missing the nitrogen to build proteins. So instead they become super-active, eating up all the carbon. This causes the process to overheat, which in turn causes a lot the microorganisms to die in the heat. A lot of the carbon will turn into CO2 and dissipate and in the worst case, the compost becomes so hot that with all those micro-organisms dying, a lot of the nitrogen evaporates as well.
If on the other hand there is too much nitrogen and too little carbon available in the source material, then the micro-organisms simply dont have enough carbon available to build the proteins necessary to bind the nitrogen. As a result, a lot of the nitrogen will dissipate, causing a loss of nutrients and potentially harmful emissions. It is therefore important to pay careful attention to achieving the correct C:N ratio of your source Material before you compost it.
Narrow C:N ratio
- manure (cow, pig, horse, chicken, etc)
- kitchen waste
- green cuttings (grass, fresh leafs, green manure)
Green cuttings can be very useful to the composting process, as it acts as a perfect substrate for micro-organisms to multiply quickly. The optimal temperature for composting of 62 degrees C can be reached within 24 hours.
Wide C:N ratio
- woody material
Woody material must be first be shredded to smaller pieces. It is important that this work is done by a hammer shredder and not a cutting shredder. The difference between the two is that the hammer shredder smashes the wood to pieces, exposing the wood fibre and offering the micro-organisms a lot of surface area to "attack" the wood. The cutting shredder on the other hand makes a smooth cut of the wood. These clean-cut pieces offer very little open surface area and will be quite impossible for the micro-organisms to process. Sawdust and shaving have proven to be very ineffective in the composting process as well.
· clay - Without clay it is not possible to create high-quality compost with stabilised nutrients. Clay has some fascinating properties. Unlike sand or slit, clay does not originate from mechanical abrasion, but rather from chemical "abrasion". We know that if we let water run over a stone for long enough, the water will dissolve after a few million years. Molecule by molecule, the H2O takes apart the stone. But some molecules are more susceptible to be carried off by (become dissolved in) water - for example lime stone will "melt away" hundreds of times faster than granite. And so it happens that as the water carries off molecules of of the stone at different rates, grooves and furrows start to appear in the stone. The same process happens with pieces of sand and slit. At a certain point that piece of slit is not like a small round and smooth stone anymore, but like an interlocked plate structure - this creates an enormous amount of surface area. Imagine a box full of 2,500 single sheets of paper. The box has a total surface area of maybe 0.5 m2.
But when you add up the total surface area of the 2,500 sheets of paper it amounts to more than 300 m2 of surface area. In the case of clay, the sheets are even much thinner than paper and when you cant the total surface area of the interlocked plates of 1 gram of clay it amounts to 700-900 m2. It is this amazing property which makes clay so special and so important in the composting process. Because clay has such a large surface area, lots of "stuff" can stick to it. In the literature this is what is being referred to when they say clay has a high cation exchange capacity: lots and lots of molecules can attach to and don't easily get washed off. The microorganisms "use" the clay particles to attach "their" nutrients to it, stopping them from leaching out or evaporating.
An addition of 10% of clay (by volume, not by wight) is highly recommended.
· Biochar - In many areas such as the rainforest of South America or the Jurassic mountain range in Europe (limestone) clay contents in the soil can be very low. It is therefore either very expensive or even impossible to find clay to add to the composting process. In this case, biochar can be a fantastic supplement. Biochar has a surface area of about 300 m2 per gram and therefore also has a very high cation exchange capacity. You can read more about biochar at this article from the Biochar Journal. An addition of 10% of biochar by volume (not weight) is recommended.
- Bone meal - it has a high concentration of minerals which helps to enrich the soil even more. The stone meal used at the Farm Oberbraemen comes from the company Eifelgold and is made up of the following minerals:
Silicium (SiO2): 41%
Magnesium (MgO): 8%
Calcium (CaO): 16%
Aluminium (Al2O3): 14%
Iron (Fe2O3): 12%
Potassium (K2O): 2,7%
Phosphorus (P2O5): 1%
Trace minerals: copper, bor, zinc, manganese, titan
Please keep in mind that stone meal is not in any way a substitute for clay. Stone meal is basically ground stone, which means it is pulverised mechanically, not chemically - it has not plate structure and therefore almost no cation exchange capacity.
An addition of 1% bone meal is recommended
- Finished (ripe) compost: The last crucial element for successful composting is adding some finished compost to your new windrow. The finished compost contains a high concentration of the positive micro-organisms which will quickly multiply in our new windrow and really get the process going without any delays or inconsistencies. An addition of 10% of ripe compost is recommended.
On the Farm Oberbrämen local gardeners bring their wood cuttings from trees and bushes to the farm. This woody material gets shredded on site. This is an additional revenue stream for the farm and is a win-win situation for all parties involved.
This shredded wood is being used as litter in the stables. A new layer of wood chips is added every day or every second day.
Because of the low temperatures and deep snow cover (the farm is at 1000 meters above sea level), no composting is possible from November to March. It is therefore sensible to set up the last windrow at the latest in mid September, in oder to finish it by November. From November to March no material is taken out of the stables. With each new layer of wood chips being added to the stables, the layer of litter becomes ever higher, reaching over 1 - 1.5 meters in height by springtime.
The cows continuously trample the litter into a compact layer. This conserves the manure and stops nearly all emissions. There is no perceivable ammonia or other bad smell in the stables. This deep litter is a very comfortable surface for the cows to lie and walk on. The cows do not have any hoof problems and are very healthy.
C:N ratio of different materials
Setting up a windrow
When setting up a windrow, the following points should be taken into consideration:
- The different components of material to be composted (ie, litter, kitchen waste, green cuttings, old compost, clay etc) should be set up layer by layer, this way and even distribution of all materials along the windrow can be ensured.
- The bottom layer of the windrow should be the least wet material, like litter with a high straw and wood-chip content. This material will be able to absorb moisture from the top and will ensure that the material in the windrow gets mixed evenly after only a few turns.
- The heaviest material, clay, should be added last on top of the windrow.
- It is possible to add the clay part one week after the composting process started. This can make sense if the windrow would otherwise be too large to be able to handle it with the turner. After the first week the windrow will lose some volume, which makes room for the added clay.
- The windrow should be set up as straight as possible. Correcting any unwanted curves in the windrow later on is tedious work
- The overall C:N ratio of the sum of materials should be 30-35:1 C:N and have a moisture content of 55-65%.
- 10% (by volume, not wight) old (finished) compost should be added to inoculate the windrow with the wanted microorganisms - this will give the windrow a quick start into the rotting process
- The addition of at least 10% clay (volume, not weight) is essential to ensure a good quality of the finished compost
- Addition of 1% stone-meal
- Materials such as kitchen waste and chicken manure are good sources of nitrogen, but they are not so easy to compost. When setting up a windrow a maximum of 10% of either material should be added. An additional 10% can be added in two one week intervals for a total of 30%.
- As a rule of thumb, your materials should be dryer than you think at first. Once the composting process starts, a lot of moisture will come out of the materials, and some of the carbon-rich material such as straw will dissipate. If the windrow is still too dry, you can easily add water. If on the other hand the windrow is too wet at some point, temperature will drop immediately and the microorganisms wont be able to work properly. Getting that temperature up again by adding dryer materials is extremely tedious and oftentimes not even possible because there is no material available in the needed amounts.
The right size for a windrow
Composting is an aerobic process, meaning the microorganisms doing the work breathe air. Ideally, the windrow has a sufficient amount of oxygen available for the microorganisms at all times. To ensure that this is the case, the windrow can not be made larger than a maximum 1.4m in height. Otherwise the weight of the material compacts the bottom too much, pressing out the air and suffocating the microorganisms. When this happens, anaerobic processes start to take place. These process, such as the formation of methane are unwanted and cause harmful emissions.
- It is essential that the compost be turned by a compost turner that is able to go as slowly as 120 meters per hour (maximum 200m per hour). The drum of the compost turner should be moving at 180 rotations per minute.
- The blades of the compost turner must be in good shape (none missing or broken or missing more than 1cm in length). This is quite important, because the blades throw the material from the sides to the center. With missing blades, the windrow will become askew.
- The windrow should be turned at least 3 times per week for the first 3 weeks.
- On the first day the windrow can be turned two times to ensure a good mixing of the source materials.
- After the sanitisation phase of the composting process is over, the compost turner can move faster (400-600m per hour) and the rotations of the drum can be reduced to 100 per minute.
- From the 4th week onwards, turning the windrow 1-2 per week is sufficient
Covering the windrow
Generally a windrow should always be covered by a fleece. This prevents the windrow from drying out (wind) or getting too wet (rain).
Very good materials have been developed for exactly this purpose - in Europe they are known as tartex fleece. This material is gas permeable but does not let water through. This means that the CO2 which the microorganisms breathe out does not get trapped in the windrow, suffocating them.
The most practical approach with covering the windrow is to leave the fleece on top of the windrow while the turner goes under it.
Stages of the composting process
Roughly speaking there are two stages to the composting process. These two phases can not be viewed separately from one another and happen simultaneously in different parts of the windrow.
The first phase of the process is called the "hot rotting", "sanitisation" or "dismantling" phase. During this phase the core of the windrow will optimally have a constant temperature of 60-62 degrees Celcius. This temperature should be reached withing 48-72 hours of setting up the windrow and turning it for the first time. After about 3 weeks a majority of the available nutrients have been devoured by the microorganisms and turned into less volatile compounds. A new army of microorganisms starts to become active which build long chained compounds which attach to the clay, turning it into what we call humus. This second phase is called the "build-up" or "construction" phase.
During the sanitisation phase all pathogen bacteria, viruses, fungi, protozia, intestinal worms etc are being broken down and devoured by the positive microorganisms of the composting process. This is possible because the positive composting microorganisms are extremely heat resistant and can survive and be active in up to 65 degrees Celcius. Moth other organisms, virtually all disease causing organisms die at 58 degrees Celcius.
In order to prevent killing off the positive microorganisms it is essential to monitor the temperature of the windrow and make sure it does not become hotter than 65 degrees.
During the hot rotting phase of the process, virtually every single nutrient (especially nitrogen) becomes disassembled and reassembled in the form of the microorganism's body-own proteins. As microorganisms compete for resources, they also start to devour each other. Transitional phases of these nutrients (short-chained molecules) become available in this process - these are directly available to plants. The longer this transformation of nutrients take place, the more long-chained molecules will get attached to the clay and from a very stable from of humus.
The entire composting process is finished after about 6 to 7 weeks. At this point there are no more volatile compounds present at all. All nutrients are either locked up in the microorganisms themselves or in short and long chained molecules which have started to combine with the clay to form the clay-humus-complex.
Once brought out to the field, plants are able to actively access these nutrients through their symbiosis with mycorrhizal fungi as opposed to being force-fed water-soluble nutrients like petro-chemical fertilisers or liquid manure.
Controlling the rotting process
In order to successfuly compost it is essential to monitor the progress at every stage. Ideally, the texture, moisture, temperature and CO2 level of the windrow will be monitored and documented before each turning of the windrow. It is important to take several sample measurements in the windrow in order to get a full picture and make sure the process is progressing homogeneously.
Measuring the moisture content: This can be done very accurately by taking a sample, weighing it, drying it in an oven and then weighing the remaining dry mass. Since this is quite labor intensive, there is also a more practical alternative which will require some experience to give you an accurate picture. This method is called the "fist test" in German. Take a handful of material from the windrow and press it in your hand as strongly as possible. If you are able to press water out of the material, it is definitely too wet. If after pressing the material your palm is very moist, the material is probably too moist as well. Ideally, you should be able to press the material into a ball which sticks together compactly. The material is moist, but your hand does not get wet.
The temperature is best measured with a thermometer which has a sensor stick that can be stuck into the core of the windrow. The temperture relevant to us is the highest temperature at the core of the windrow, not at the sides. There are many reasons why the temperature of the windrow could be too low or too hot. I will just mention a couple of these. If the temperature is too low, the material could be too moist. In order to raise the temperature, the windrow should be turned less frequently. If the temperature is too high, the windrow could have a C:N ratio that is too wide and the material might be too dry. Adding moisture will help.
Lastly, measuring the CO2 content at the bottom of the windrow will give you an idea of how much oxygen the microorganisms still have available. At a concentration of 8% CO2 microorganisms start to die off. At a concentration of 15% most of them will be dead. If concentrations become too hight, the windrow must be turned more frequently.
All these measurements should be documented on a dedicated spreadsheet.
Sieving the compost
If you are composting woody material it is inevitable that some larger pieces of wood will not be "digested". This does not in any way detract from the quality of the compost and is irrelevant when it is bing used for agricultural purposes. If the compost is to be sold to gardeners and private persons however, it is sensible to sieve out larger pieces of wood in order to sell a pure Humus compost with a fine crumb structure - a bit like cottage cheese.
On the farm Oberbrämen we use a 25mm sieve.
Measuring parameters for finished compost
It is important to monitor the quality of finished compost on a regular basis, especially if the compost is to be sold. According to Urs Hildebrand, the following parameters are critical in determining the quality of the finished compost. Depending on which of the parameters are deviating from the optimum, a lot can be said about what went wrong in the composting process and consequently what could be improved.
The above measurements need quite a lot of equipment which is quite expensive and also quite time consuming. It is not practicable to expect anyone to perform these measurements for every single windrow, but especially when one starts out with composting, it is important to get these numbers every once in a while to get an idea of where you are at. Once you have accumulated some experience and have optimised your composting process, it become much easier to get a feeling for the quality of the compost without performing all these tests.
If it is not possible to perform the above tests, there is a much simpler, free alternative called the "cress test". For this test all you need is two jars and some cress seeds. Both glasses are filled about 1/4 with compost and some cress seeds are scattered on top of the compost. One of the two jars needs to be closed with an air-tight lid, while the other one remains open.
If the compost is of good quality, all of the volatile nutrients like sulphides, NO2, NH4, etc will have been converted into longer-chained molecules which combine with the clay to from the clay-humus complex. The concentration of volatile nutrients which turn in to gases will be much higher in the closed jar. This will give you quite an accurate scale as to how good the compost is. If the cress grows well in both the open as well as the closed jar, the compost is of very good quality. If the cress grows in the open jar, but not the closed jar, the quality is questionable. If the compost grows in neither jar, the quality is unacceptable.
Soil fertility and healthy animals
The farm Oberbrämen started composting in 1998. Previously the farm was non-organic and brought out manure in a liquid form. Since turning organic and composting, the farm has seen an increase in humus content in their soils from 3.5 to 6.5% as well as their raising their soil's pH value from 5.0 to 6.7. The humus layer itself has increased from previously 20cm to 30-35cm currently. The results have been quite astonishing. So astonishing in fact that Switzerland's leading university, the ETH Zürich will do a workshop on the farm in 2016 with its students and closely document its soils and compare them to neighbouring farm's soils.
It can already be said that the composting and subsequent improvement in soil fertility have resulted in:
- a soil with a very fine crumb structure (cottage cheese) down to 30 cm
- a very high number of earthworms
- a fantastic water retention capacity
- very high carbon sequestration
- very healthy pH value (without using limestone powder)
As a result, the farm Oberbrämen is the only farm in its vicinity which is able to grow alfalfa. Alfalfa will not grow if the sol pH is below 5.5 and the plant can not bear any waterlogging. With 1800mm of rain per year (Swiss average: 800m) the soils are literally drenched in water. If the soil would not have absolutely fantastic drainage due to the fantastic crumb structure of the soil, the alfalfa would not have a chance to grow.
Even though the farm is located at 935 meters above sea level and therefore has 6 weeks a vegetation period that is 6 weeks shorter than in the valleys (300 meters above sea level), the alfalfa yields rival those of the most intensively producing conventional farms in the valley (more than 15 tons of dry mass per year).
It is this wonderfully fertile soil which produces these fantastic yields of healthy, naturally growing plants. I strongly believe that the plants growing on healthy soil without chemical fertilisers, pesticides, fungicides and insecticides are of a much higher quality which as a result produces healthy, vital animals. In my two years working on the farm Oberbrämen I have never seen nothing but healthy, vital animals, some of the mother cows older than 15 years.
Even the stables are surprisingly free of flies, another indication that the cows live in a healthy environment.
Nitrogen loss form manure
Excessive nitrogen loss from manure is not only aggravating to a farmer, because it is the most important nutrient plants need to grow, but also because nitrogen emissions into the air, rivers and groundwater are extremely harmful to the environment. The most harmful of these nitrogen compounds is Ammonia.
High concentrations of ammonia leads to the acidification and eutrophication of soils resulting in devastating damage to the surrounding vegetation and entire ecosystems. The result is a dramatic loss in biodiversity, pollution of groundwater reserves and acute damage to forests and rivers and has strongly contributed to the emergence of dead zones in the world's oceans and lakes. In addition, ammonia is a precursor for the formation of secondary aerosols (liquid particles such as sulfic or nitric acid) which are very harmful to human and animal health (Federal OFFICE for the Environment, Switzerland, 2015). According to calculations by the German Federal Environmental Agency, environmental and health costs per kg of ammonia emissions amount to 27 Euros (Neue Osnabrückner Zeitung, 2015). In Germany alone, liquid manure from animals husbandry causes 700,000,000 kg of Ammonia emissions annually, causing more then 20 billion Euros in damages.
Where do all these emissions come from?
Ammonia is a result of bacterial and enzymatic degradation processes of nitrogen compounds, especially of nitrogen and urea - this only happens in anaerobic conditions (no air, liquid). During storage of the manure in a manure pool, an average of 10% of the nitrogen will be lost in the form of gaseous ammonia. When the manure is brought out by a deflector plate (standard) another 20% of the nitrogen will be lost in the from of ammonia (J.-L, Hersener, 2002). Total emissions: 30%
Studies have shown (M. Käck, 1992; Hentschel, 1993) that properly managed aerobic composting with a C:N ratio of 30-35:1 will result in total emissions of 4.1-6.5% - an 80% reduction from liquid manure!
The importance of following strict rules from composting can not be underestimated, as I have seen dozens of farms which compost out of ideological conviction, but do not follow the basic rules. The results can be quite disastrous with very high emissions and loss of nutrients in many cases, maybe even higher than emissions from liquid manure!
I am very much looking forward to having the ETH Zurich on the farm Oberbrämen next year and will gladly publish the results from their analysis.