The failure of ammonia (NH₃) to be released properly in phase 2 can cause sleepless nights. During conditioning, the amount of ammonia is normally halved every day. After 2 to 4 days of conditioning, the measured concentration should be below 5 ppm. Only then can you start cooling. But what if the NH₃ concentration does not fall below 15 or 20 ppm? Then there is a problem. In that case, you can do the following:
- Postpone inoculation for one day.
- Provide a little more fresh air.
- If necessary, lower the compost temperature by a few degrees, for example slightly below the usual 48°C, so that the areas in the compost that are too warm also fall below 50°C.
These measures increase the chance that the ammonia will continue to decrease and the compost will condition properly.
If the ammonia value does not decrease further despite the previous measures, it can sometimes help to temporarily allow the temperature to rise slightly. This “shocks” the micro-organisms awake, as it were, after which you can lower the temperature again to around 45°C. Sometimes these kinds of tricks work, but be careful: do not use them as standard, even if they seem effective. It remains a risky intervention.
In some cases, you may decide to cool down anyway, even if the ammonia value is still a little higher. With a bit of luck, you will not see any consequences later, especially if the problem only occurs in part of the tunnel and does not affect the entire batch.
Some companies also add gypsum during inoculation to protect the spawn and bind the last NH3, but the yields will not be optimal. Ammonia is toxic to fungi, so our mushroom mycelium will also die as a result.
Always look for the cause
It is important not only to respond to the problem, but above all to look for the cause.
Start by checking the filling of the tunnel. Is it filled evenly, in layers, as if you were building a stone wall, with the same height everywhere and layers of different lengths? Uneven filling can lead to temperature differences and uneven air flow, disrupting the breakdown of ammonia.
If the cause is not related to filling, look at phase 1
If the filling process went well, the cause of the problem is likely to be in phase 1. Various factors can play a role in this phase. Therefore, check the following:
- Distribution of chicken manure: The manure must be evenly distributed, each strip of straw must be covered with chicken manure.
- Anaerobic process and water management: Prevent parts of the mixture from becoming too wet and oxygen-deficient.
- Aeration during phase 1: Ensure sufficient and even air supply to support microbial activity.
- Composition and analysis of chicken manure: Check that the manure used meets the desired values and calculations so that the process remains predictable.
Even a small deviation in one of these points can result in ammonia not being released properly in phase 2.
Prevention is better than cure
In other words, there are many reasons why ammonia (NH₃) may not be released during phase 2. The most important thing is to prevent errors through good organisation and a reliable data system.
Ensure that all data for each batch of compost is clearly recorded. By closely monitoring and comparing this information, you can detect and correct deviations or “errors” during the composting process much earlier.
Mushroom Blog | Mark den Ouden
