My previous blog described what the pH should do during the composting process. This blog examines the role of the raw materials, such as ammonium sulphate, gypsum and water.

Ammonium sulphate, (NH4)2SO2

During indoor composting, NH3 is removed from the air by a reaction of the air to sulphuric acid, H2SO4. The by-product resulting from this process is ammonium sulphate, (NH4)2SO2. ammonium sulphate can be added to compost as a source of nitrogen. This reduces the pH value of the compost.

Gypsum?

What is the principle property of gypsum? The acid binding capacity of gypsum neutralises the pH in the compost. So what does gypsum actually do? Gypsum also makes the chicken manure less sticky. The advantage of this is that the manure can be mixed through the decomposed straw better. The gypsum ensures the compost structure stays open and airy and is less inclined to become anaerobic. As the previous blog explained, this is a very important condition to ensure the pH falls during the process.

Water

Gigantic amounts of water are applied during phase I. The moisture content of the straw rises from 5- 20% to a moisture content of 74- 76% at the moment of filling into the phase II tunnel. That moisture is created by the added water. The pH of the water therefore has a far greater influence than you might think.

Rain water/groundwater

If a lot of rainwater, with a pH of 6 or even lower, is used during the rainy season, and more groundwater, with a pH of 7, during the dry season, you will also notice that the pH value gradually changes over time. The water is recycled at the composting plant, which explains the gradual change.

Anaerobic water

If the recycled water, or process water, is stored in a reservoir, it must not be allowed to become anaerobic. If water does become anaerobic, all the micro-organisms in the water will be destroyed and the pH value of the process water will fall sharply. This will cause poor results at the end of the composting process.

Mark den Ouden
www.mushroomoffice.com

It looks like we are not going to have any winter this season in Europe. On the contrary. It is very wet and humidity is very high.
This has its reflection on compost and casing.
If raw materials for compost are stored outside or under just a roof, they are evaporating less water and in the same time some materials get wet by the rain.
If the materials are not checked regularly (meaning every batch) before they are going into the system the compost manager cannot interact on this. If the composting is not adjusted this will result in a few percentage points more moisture. By itself no problem at all If the grower knows about it.
It gets more difficult though if also the casing is getting wetter.
As a normal result of the rain the peat gets wetter during storage.
And many casing yards have a big stock laying outside. Because of expected frost during winter they tend to build up stock. A normal procedure every year around this time.
Getting a casing wetter during production is fairly easy. But getting it drier is more difficult.
Mixing in dry white peat is normally the answer but this generally results in a finer mixture which most growers do not want.
Result for many growers is that first flushes have problems growing out. The numbers are too low and second flushes have a problem with quality. They mature too fast and picking time is too short.

So what can be done?
If a grower knows the compost is already a bit wetter he can adjust the watering schedule immediately. Less or no water during filling and a change in schedule of watering on the casing during case run.
Also the filling can be changed technically. A wetter casing can be more lumpy or even slightly anaerobic. Especially if casing is stored a while before filling.
It is possible to run the caccing spinner a bit faster to open up the layer of casing. More caccing, by putting the spinner deeper, is not always necessary. Caccing more has a fairly big impact on the growing.
At the same moment the levelling spinner should run slower to create a sort of “digging” effect. This is done to keep the surface of the casing open.
After filling and casing the total amount of water can be around 20 to 25 litres per m2. Depending on the amount of mycelium that is desired.
In outgrow make sure enough fresh air is taken in. especially on day 7 of the break this is essential. Rooms which have a hard time in growing out have a very low demand for fresh air because of lack of activity of compost. Make the minimum fresh air setpoint is at least 15%.

At the end of a year or at the start of a new one it is always a good thing to look back and forward. Look at it as an evaluation and re-focussing of targets. It is also a good time to give yourself and your team a feedback.
Looking back to 2021 it was a year of great challenges. We had our normal variations in compost and casing soil quality. It still is impossible to predict the weather so we still will have to cope with changes in raw materials due to the weather. And reacting to that always comes too late.
Another thing that kept us busy was Covid. Supermarkets stayed open but restaurants and hotels got closed down. For those delivering mushrooms to that restaurant sector life was hard. Due to that closure the demand of restaurants almost fell back to zero for those places who did not do food deliveries at home. Read catering. On the other hand, due to the closure of those restaurants the supermarket sold more. People preparing their own food tend to use more mushrooms in a dish. So farms who depended on supermarket supply had a benefit there. Plus we had the effect that people where looking for healthy food. The only thing was that demand was unpredictable. Sometimes supermarkets demanded a lot, sometimes they just cancelled the orders. A reason for that was the government of each individual country. The rules where different everywhere and nobody knew what was coming the next week. This was also the reason that many farms got in trouble with their workforce. Depending on foreign labour, many farms did not know if they had the pickers for next month. A test for negative result in their home country made sure they could come to your country. But on entry of the country or even your farm another test often gave another result, resulting in a quarantine for a week or so. A positive result on the test had big negative effects on the farms concerning picking. Another result of covid was that consultants like me had great difficulties traveling and visits where often cancelled. The sparring simply did not take place and many developments on farms where put on hold.

Look forward though we are facing a lot of challenges again. Covid will not go away for a while so restrictions will stay in place. A good reason to look very critical at the labour supply of the farms. Other countries? Fixed contracts to keep people there ? Find people in your own country despite of the mostly higher costs? In that case security of labour comes with a price but at least with a steady labour base. Already announced are the higher energy costs which will have an effect on the whole business. Because of transport costs rising everything will be more expensive. Direct energy costs will rise so your cost price will go up.
Talk to your clients about that before it really turns into a problem. Make good prognosis and a business plan based on the new situation. Experience of last year has learned me that supermarkets do think with you as long as you can present good figures, based on facts. So keep an eye on the ball and remember. Act before it is too late and do not act on emotion. Remember, you make a good product and they need it.

This leaves me with wishing you all the best for 2022. If traveling restrictions will loosen up we will probably meet again physically, if not we always have zoom.

Henk van Gerwen
Akkie's tuin

Tweeners

Dec 13, 2021

Mushrooms that grow between the 1st and 2nd break are called tweeners or in between mushrooms. They are very hard mushrooms because they had a lot of water at the end of the breaks but will discolor fast, once picked, because of that water. They are, however, white inside and are therefore extremely suitable to use for slicing. Many farms worldwide are growing tweeners, only to use them for their sliced product. However, if you have a lot of tweeners it can have a negative effect on the quantity of pins in 2nd breaks. You need to control the amount of tweeners that grow out and spread them out nicely over the whole shelf. If some spots have many tweeners together the 2nd break will not be able to develop well, and yield will be lost. On some farms I see harvest managers making some extra yield with tweeners but not realizing enough that that extra yield gets lost in the 2nd breaks, where you normally pick you nicest quality mushrooms.

That doesn’t mean you can’t grow tweeners. Some farms use them to control the quantity of the pins in 2nd breaks. Just by leaving them nicely spread over the beds you can control the amount of 2nd break mushrooms. Clean the beds good after the 1st break, don’t pick for 2 days and on the 3rd, day manage it well controlling the in between break. If you see the 2nd break coming up spontaneously you can leave some more tweeners, if the 2nd break is struggling on some spots, you must open the in between break up and pick some more there. That need to be planned and managed good to get the best benefits out of the total production.

Erik de Groot
Global Agriculture Services
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Generally picking is considered by many as a low education job. But on the other hand, we rely on our picking force to deliver a good quality mushroom, meeting the customer demands. No bruised mushrooms, no nail or knife damage, right stem length, straight cut stem, no weak mushrooms in the punnet and for all, the right size. And that is where many things go wrong. It is fairly easy to learn the pickers the right way of picking. Twist and do not pull. Do not take to many mushrooms in one hand so they do not get damaged and put them caps up into the punnet. But getting the calibration right is a constant struggle. Pickers tend to have the habit to pick too small and this will cost you money. They simply pick the mushrooms that were meant to be picked tomorrow. An extra thing to that is that pickers lose the bonus while working really hard.

For the right calibration there are many tools like fruit grading rings, grading cards and other different tools. But the easiest tool they have in their hands: the knife.
The knife most used in mushroom growing is the curved knife and the length of the blade is exactly 60 mm. The calibration most wanted on many farms is 55 to 60 mm. Generally, this size is picked first before thinning out. And this is just the size of mushroom that is as wide as the length of their knife. They just have to keep the knife just above the mushrooms to judge the size. This way the mushrooms can be calibrated before they are picked and they will not be damaged by any other form of grading tools. The rings only let mushrooms through which are small enough. The bigger mushrooms get stuck and will be damaged. But the mushrooms that go through easily are too small and that is the calibration the picker will harvest. By using the knife not only there will be no damage but it is also faster.

If a smaller calibration is harvested like a 40 mm mushroom, a line can be made on the blade with a marking pen. Especially new pickers will be very fast in learning this trick. By banning the calibration rings also, the hygiene on the farm is served. Because these rings are hard to clean and experience learns that they are always dirty and are taken from room to room.

Give it a try and your harvesting staff will be happy.


 

For optimal climate control, accurate and reliable measurements are of course very important and maintenance to the CO2 box should be standard on every farm.

First thing would be to check the tubes and the magnetic valves for leaks. If valves are leaking they need to be replaced immediately as they will cause mixed air in the tubes.

All the tubes can get condense inside and block the air flow, also causing mixed air going into the CO2 sensor and sending the wrong value to the climate control computer. You can avoid this by blowing the tubes out regularly with an air compressor to avoid condense to gather inside them. Especially when tubes are not placed correctly and have no filter at the end of the tube this will happen easy.

A good practice on every farm would be to check the reference measument value on your CO2 system daily. That value is the CO2 measured in your outside conditions which is either outside, in the central duct or wherever the outside measurements sensors and CO2 tube are placed. The ppm value depends on where it is placed but should be consistent and seeing inconsistent value there can be a first indication that there is something wrong with your CO2 meter and some maintenance is needed. A good portable, calibrated CO2 meter can be a great help and indicator. You can detect problems before any misreading’s will cause more damage than necessary.

When all the tubes are clean and no leaks are detected the CO2 meter needs to be calibrated using a zero cartridge for the low values and CO2 calibrated gas for the higher values. Ask your supplier for the exact instructions.

Erik de Groot
Global Agriculture Services
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