THE FUNDAMENTALS OF MUSHRROM FEEDING AND FARMING TECHNOLOGY DEVELOPMENTS

Introduction

The changes in technology that ensure greater technical and economic efficiency are the conditions for an industry is the development in any given production. In recent years a clear standstill can be observed in the production of mushrooms. It is a result of a crisis in the satellite model for mushroom production in Europe. It is particularly evident in the Netherlands and even more so in Poland. It stems from the fact that in the satellite system it is difficult to create innovations without the help from the government, which cannot be commercialised directly and develop the mushroom production based on these innovations. The division of production at individual stages into sectors that function independently does not create conditions for development through innovation.

The exhaustion of the current system’s capacity to generate innovation based on current theoretical assumptions (a paradigm) has also its merits and it can be described as a controlled process of composting with the involvement of mushrooms (in oxygen conditions). The basic reason for this is the lack of new ideas for the development in technology in the production of mushroom substrate. This technology would ensure its stable yield and the opportunity to increase the use of substrate. The stagnation in mushroom farming cannot be disregarded, it does not offer strains of higher and better quality mushroom yield taking into account the current condition for substrate production technology and a more effective navigation of mushroom behaviour while cropping.

It does not mean there is no need for innovations. The economic situation of producers is constantly getting worse. The mushroom producers constantly need to aim at lowering the production costs. The decrease in profitability results from ever increasing production costs, however the price offered by stronger and stronger business retailers involved in mushroom trade is unchanged. Unless a more efficient solution is found to this problem, in the current situation the industry is threatened by the loss of profitability in a few years to come.

What conditions will decide upon the mushroom technology development in the nearest future?

1.            The industrial development of mushroom production in the closed cycle with an introduction of an individual developmental policy and the use of your own funds on research and development and the capacity to generate innovations yourself.

2.            The change in theoretical assumptions (the paradigm) into a new described as a control process for mushroom feeding or a different competitive process.

3.            The method: a repetitive method to control the development process – the control of changes in the mushroom farming technology applied in an entrepreneurship and the evaluation of proposed changes. This method involves a repetitive mushroom farming technology development process through gaining theoretical knowledge of mushrooms, using it to build models of solutions and based on them – the creation of new effective technologies. The need for new technologies can in return stimulate the development of scientific research.

Why is the technology development not noted? The limitations of current attitudes.

It is not only the satellite system in its current form that is a limiting factor for the mushroom technology production development, but also the technologies used for substrate production. The limitation in the increase in yield is merely the composting process. The substrate prepared in the hot composting phase has a yield generating potential for the mushroom resulting from its sheer essence of its course which requires a necessary carbon to nitrogen proportion such as 30:1 and continuous access to oxygen. These determine the correct course. This means that the amount of nutrients available for mushrooms depends on the result of this process and the quantity of the substrate used and not the actual needs and capacity for mushroom cropping. The possible change in the C/N proportion interferes with the composting process, which leads to substrate production with a significantly lower yield generating potential.  Apart from that, the technologies used nowadays do not allow for a full control of the substrate production process. This creates its significant inconsistency. It is also accompanied by the lack of knowledge on how to possibly standardise substrate prior to mycelium cropping so it will have a repetitive production potential. Looking from this perspective, the production of standard substrate is virtually unprofitable due to large inconsistency in raw materials as well as the costs of eliminating the influence of atmospheric conditions. Also, the knowledge on the composting process is still small or it is not transferable in practical work. Although it is true that the increase in yield can be achieved by using big doses of substrate as is done by the Americans (120kg/m2 of Phase II substrate allows for a yield on the level of 38kg/m2). This practice may lead to bigger yield but it usually means the decreased level of its use. Considering current substrate prices and energy costs, the increase in the amount of substrate is not profitable.

The situation on the supplements market is also not favourable. The supplements used so far are by definition products designed to enrich the substrate. Its aim is to supplement nutrients in the substrate in relation to the accepted standard. However the lack of suitable methods of identification results in the fact that the supplements are applied routinely regardless of the substrate characteristics. Nutrients, mainly protein, are produced in two different types depending on the type of substrate for which they are used. The difference is in the dose if formalin used. The higher dosage (6000ppm) is used for supplements in Phase II substrate and the lower (3000ppm) in Phase III substrate. The available literature indicates that the effectiveness of using the supplements in Phase II is significantly lower.

When analysing the composition of supplements, the knowledge about them nowadays and the production practice, a conclusion can be drawn that they have not fulfilled their role or only to a limited extent. It results from the fact that when they were used for the first time about 30 years ago the achieved yield was the effect of the fact that the substrates compared to today’s standards were poor and the yield low. Currently the substrates produced now are much richer which makes their effectiveness nowadays relatively small. They cannot be used in higher dosage than up to 1.75% of the substrate mass in Phase III. This results in high increase in temperature in substrate that accompanies larger and larger dosage of supplements above their recommended share in the substrate. This increase may lead to overheating of the substrate and a substantial decrease in yield. The question whether we can interfere with the composition of substrate if it is fully colonised by the mushroom mycelium is a separate issue. In this situation we need to ask a fundamental question – what is the sense of using protein supplements? The primary assumption supplementation refers to making a change to the substrate composition and should be carried out until the start of the pasteurisation and growing process. However from the moment the mycelium colonises the substrate we should use a term such as feeding. In this situation it is easy to explain the low effectiveness of the use of protein supplements. Their role is to change the C/N ratio by the increase in nitrogen share which can be obtained from HP soya or other protein balanced to the value of 46-48% regardless of the mushroom digestibility. The impact of protein diet on the development of green competitor mould should not be disregarded. It can be assumed that the presence of the extra protein from the supplement and the increase in substrate temperature may favour the growth of green mould. It is a different species from the mushrooms and the main way to reduce its growth in substrate should be an energetic diet easily absorbable by the mushrooms.

The main characteristic of the supplements used nowadays is the focus on using soya. Even when making changes in the supplement composition which was caused by the price increase and the GMO problem, the introduced new components should ensure that protein at an accepted level would be present in its composition. As a substitute meat and bone meals were temporarily introduced as well as cruciferous plant meal. The use of bone and meat meals to produce food was questioned between 2012/2013. No other solutions were explored in spite of the fact that in “The Mushroom Cultivation (1988)” you can find a long list of other products that can fulfil the role of supplements and which come from plants found in Europe such as corn, potato, wheat, sunflower, sugar beet.

The next factor is the availability period for the mycelium in the process of mushroom feeding. Supplements by definition are to work with delay, which is why they are treated with formaldehyde. The same effect can be achieved by heat treatment and carboxylic acid salt. However their actual mycelium digestive period is short; from the application of casing till the end of shock. Consequently, the impact on yield in the first and second flush is limited.

However the main cause of dissatisfaction with the currently used technologies is the lack of progress when it comes to yield. The average higher yield rarely exceed 32kg/m2 and it is only provided that the yield in the first flush is high and usually a higher than usual fill rate of substrate is used which is more than 85kg/m2 of substrate in Phase III.  Although there are technical conditions available to achieve yield in the amount of 20 – 25kg/m2 in each flush, then in every subsequent flush it is usually lower. For example, the yield of 30kg/m2 is divided into flushes of 15, 10 and 5kg/m2. This means that the substrate use is between 30-40%, and the desired maximum is 50%. The fact that in subsequent flush the achieved yield can be about 5kg/m2 means that the amount of nutrients absorbed during the enzymatic decay – the growth of mycelium are too small to achieve higher yield. There is a lack of biomass whose amount in the substrate does not exceed 2% of its dry mass. This creates a need to provide extra nutrients into the substrate that will be responsible for the yield increase especially in the second and third flush.

The significant part of the substrate is still removed beyond the system of its production, regardless of the level of its use. As waste it should be considered as a part of the mushroom diet. The substrate that is not used after the cultivation is finished, especially after two flushes, seems to be a very interesting diet because of its composition and more importantly its selectiveness for the mushroom.

The analysed limitations do not allow for further increase in yield and the effectiveness of substrate use when considering ever growing substrate as well as mushroom production costs. The further development may ensure a new attitude for the mushroom yield navigation process.

 

The change of the paradigm

The current attitude towards mushroom production can be defined as a controlled composting process with the use of mushroom. There is a suggestion to change this into a new definition which would involve a controlled process of mushroom feeding. With the adoption of this definition the mushroom is in the focal point of the production process. This means that the feeding, growth and development control methods is dependent on the mushroom needs as well as the amount of planned yield, range and the qualities of fruiting bodies that are going to be achieved in the process of cultivation. The activities carried out during production and ensuring the increase in yield and better quality of fruiting bodies are at the essence of the changing attitudes.

  1. The use of supplements containing carbohydrates as an ingredient for the energy increase necessary for the mushroom survival as saprophyte mushroom.
  2. Mushroom feeding through the use of nutrients in the casing.
  3. The use of nutrients in a liquid form.
  4. The initiation and control of the mushroom feeding cycle process in flushes.
  5. The counteraction for the limitation of pin growth through the change in the cultivation conditions.

An important cultivation activity that is directed to the change of attitudes are some promising effects of compost use after the cultivation is finished, the compost is treated as a valuable source of food for the mushroom.

THE THEORETICAL BASIS FOR MUSHROOM FEEDING – INFORMATION ON FEEDING

The basic meaning for the development of this assumption described as mushroom controlled feeding has the knowledge of the process of feeding mushroom as well as the knowledge of factors influencing the course and the growth and development processes resulting from them. It is my own outlook on it based on selected literature.

The process of feeding

In the past the concept of mushroom feeding needs had quite a lot of attention especially by carrying research to create a feeding base for the mushroom mycelium. Mushroom in order to live and reproduce needs:

  1. Water. It serves a few roles: a cell juice component, a means of transport for nutrients, temperature regulator. The most important is active water at least in mushroom feed is not completely clear.
  2. Nutrients, diet. The mushroom diet is similar to animal diet and the vocabulary describing mushroom feeding should be in accordance with this context. The nutrients are absorbed in the form of water solutions:

a)      the energy substances are the source of energy and carbon in the form of polysaccharides absorbed as glucose or fat decomposed by lipase and then absorbed mainly in the form of fatty acids and glycerol. The mushroom’s demand for energy has not enjoyed much attention. The observations from the carried out feeding tests show that it is the lack of mushroom mycelium access in the period of its enzyme activity to fully meet the demand for energy limits the use of substrate in its first three flushes.

b)      Nitrogen in the mineral and organic form, mainly in the form of ammonium ion for making endogenous amino acids and in the form of exogenous amino acids (from protein). The role of a few amino acids present in the mushroom diet is important, asparagine especially. The wider the spectrum of amino acids, the bigger effect of absorbing the asparagine.

c)       Other mineral elements including mainly phosphor, sulphur, potassium, magnesium, sodium, calcium, manganese. The role of calcium in regulating the substrate and casing reaction and the impact on developing fruiting bodies are very important. The majority of microelements influence the feeding process through their presence in the enzymes. The role of manganese is particularly important.

d)      Regulatory substances (vitamins, mainly biotin and aneurin, growth substances,).

The starting point to determine the mushroom feeding demand can be its composition. The average assumption is that mushroom consists of 90% of water, protein and other organic compounds, 2-4.3% of carbohydrates 0.2-0.7%, mineral salts 0.05-1.1%, including mainly phosphor, magnesium, potassium, calcium, iron and other microelements, vitamins, biologically active substances (whether they are the effect of metabolism in the mushroom fruiting body or whether they are transported with water as an effect of digestion and the composting process cycle by the microorganism that accompany mushroom; commensalism). The regulatory substances have a very important role in promoting mushroom feeding as an important element influencing the functioning of human bodies. Considering the highest recommended content of mushroom nutrients means that with the yield of 40kg/m2 the mushroom absorbs from substrate and casing 36kg of water, nitrogen, amino acids needed to produce 1.7 kg of protein, glucose and other sugars to produce 2kg of carbohydrates and in order to maintain life functions, unsaturated fatty acids to produce 0.28kg of fat, mineral salts which it absorbs 0.44kg.

When programming the feeding process the ability to deal with antagonisms that are created by different diet elements, for example calcium and magnesium.  The fact that mushroom is prone to higher yield when exposed to rich multi element diet rather than enriched with a single element; mono diet is also worth considering. This statement can be settled in tests.

  1. The environment for mycelium growth and feeding; substrate in experimental sciences stands for a starting element (an object, material, basis) being a basis on which other elements or substances are laid. It is to ensure a gas exchange (oxygen/carbon dioxide), and the source of water. Its basic element is a carrier, a construction for mycelium placing, reaction between 5.5 and 6.5 (low acidic) as the best for the mushroom enzymes to function in and CaCO3 for the reaction to remain stable. The substrate should also ensure the maintenance of required spectrum of temperature. Mushroom as a psychrophilic species can tolerate the maximum temperature up to 30°C where all the living process can take place without any disruption. The high level of moisture in the atmosphere for the mycelium to vegetate is also required so as to protect the mycelium from drying out.
  1.   The initiation and fruiting bodies development environment. This should be populated by microorganisms necessary for the creation of fruiting bodies; Pseudomonas putida. The number of fruiting bodies depends on salinity, pH reaction of 7.5, the concentration of CO2 (below 2000ppm) and breed. The formation of fruiting bodies takes place at the air-casing contact point. The change in the CO2 concentration and the air temperature initiate the process. The layer where the fruiting bodies are formed; the primordia are between from surface to 2 – 3cm in deep.  The casing layer is the source of water. In this layer the calcium content is important.
  1. Mycelium as the tool for feeding, making an environment for feeding. The mushroom mycelium is its feeding tool. There is a dependency between a dry mycelium mass and a dry fruiting body mass. It is responsible for digesting nutrients and their absorption when dissolved in water. The effect of feeding depends mainly on its area and life activity. During the substrate overgrowth the mushroom changes the microflora present in a substrate. On the one hand, it stops the development of adverse microorganisms – biosuppression, and on the other hand, it promotes the growth of micro flora which is used by the mycelium in the feeding process as the effect of cold composting, defined as commensalism. Biosuppression is an activity carried out by the mushroom while populating the environment that involves the elimination of competitor microflora that have remained after the pasteurisation and growing process, in particular microflora that is competitive towards mushroom and after the thermophile organisms are changed into biomass. How it is done? In my mind this is done by lowering the 6.4 pH reaction of the environment in which it absorbs nutrients, or by destroying using an active oxygen (creating hydrogen peroxide) in the enzyme digestion process and maintaining a high CO2 concentration level? This process is ended with the mycelium growth being stopped in the temperature below 23°C; after the shock phase is finished. During the overgrowth and in the process of commensalism there is a change in microflora in substrate. The aim of this change is to create conditions for the development of the microflora that is going to provide mushroom with easily absorbable nutrients in the process of cold composting. Commensalism is defined as a loose and non-obligatory relationship between species in which the two partners involved can exist independently of each other, and both partners can benefit from each other, and have a biological advantage over specimen of other species who do not remain in such a relationship. A commensal (a benefiting organism) can live in the body of its host or the host’s environment. This means that an indispensable element for mycelium feeding and hyphosphere creation is the presence of other organisms, and in particular bacteria. In the case of mushroom such relationship is with Scytalidium thermophilum. It is responsible for providing mushroom with nutrients soluble in water that are released during the cold composting phase. Scytalidium thermophilum develops best in temperatures between 19 to 24°C.

The strains of mycelium are different depending on their capacity to use substrate – biomass. It is indicated that the cultivation of new breeds is necessary for different feeding methods. They generally refer to various methods of using sources of sugar, demand for growth substances and a stimulating role of lipids.

  1. Digestion and absorption of nutrients dissolved in water.  Saprophytes are heterotrophic organisms absorbing energy from dead organic waste, their decomposition into simple compounds. It has been take place during and after hyphosphere is created – the mycelium. Mushroom, being a saprophyte fungus can be nourished due to osmotrophy; the uptake of liquid matter that is decomposed by means of external digestion through osmosis into the mycelium. The acquisition of energy through the decomposition and modification of carbohydrates is done through enzymes that make up the Carbohydrate Active enzyme system – CAZyme. The external digestion in case of mushroom is carried out by 24 types of peroxidases discovered so far, mainly manganese peroxidase and laccase, enzymes responsible for the decomposition of lignin during the mycelium growth. Cellulose and hemicelluloses are degraded after the application of casing. At the beginning of fructification the activity of cellulose – the enzyme degrading cellulose is increasing. Xylose presents a similar behaviour.  Its activity is greater when there is less hemicellulose in the substrate. The addition of a small amount of lipids into the substrate at spawning may stimulate its growth.

The mushroom mycelium is capable of recognising the type of energy material needed for decomposition and depending on its composition the mycelium can generate a suitable set of enzymes. Currently the source of dead organic waste is substrate and products used as supplements. This statement indicates that the mushroom yield depends mainly on energy elements such as cellulose and hemicellulose that are present in the substrate and decomposed by peroxidases and other enzymes.  The second type of feeding resulting from a simultaneous course of cold composting process is the absorption of nutrients created by organisms coexisting with the mushroom and participating in the cold composting process (commensalism). It is beginning to dominate in subsequent flushes, starting from the end of the first flush. Scytalidium thermophilum has a particularly important role here. The change in the feeding method results from the fact that the nutrients gathered in mycelium before the first flush run out and there is no possibility or strong limitation of enzyme digestion (CAZyme) and their longer transport from substrate to fruiting bodies – the exhaustion of sources of easily available energy elements. In turn the dying microorganisms may become a food base for osmotrophic feeding with elements that were made during the cold composting process by the commensal. Here a question arises: During the periods between flushes you can return, just for a short moment, to enzymatic digestion just like during the phase of mycelium vegetative growth; between flushes creating the so called feeding cycle. This would involve mushroom renewing the enzyme activity from time to time during the generative phase and runs internal feeding in between if suitable temperature conditions in the substrate are created.  The fact that there is no rise in temperature in the substrate after the second and subsequent flushes can be a cause for the drop in yield, as mushroom can only use from the cold composting effects by active microflora; oxygen conditions. This can be illustrated by the fact that the used substrate after the third flush which was later on used for further cultivation; the casing being taken off and then put back on again, the return to the vegetative phase and the continuation of cultivation as if it was new substrate allowed for gaining higher yield that from a subsequent flush in which feeding took place only through commensalism. The other explanation for the increase in temperature between flushes is the increase in the mushroom activity in obtaining nutrients to support the growth of pins in the next flush which can be accompanied by Scytalidium thermophilum.

This perception of feeding indicates that the main aim of cultivation should be providing missing nutrients in every flush and maintaining enzymatic feeding in each of them. It is, after a careful consideration of mushroom feeding, the basis for the mushroom cultivation environment construction without compost. The knowledge on molecular feeding, on elements dissolved in water and directly absorbed by mushroom ensuring a mycelium vegetative growth is rich. It is connected with the research on mushroom mycelium production. But it still has not been successful to transfer it into practical activities.   If the barrier was broken this would make it possible to provide nutrients in the form that would be directly absorbed with water. This would mean an opportunity for mushroom feeding throughout the cultivation time after mycelium is fully grown in substrate. The feeding would involve the introduction of a nourishing substance with water when watering and/or flood irrigation from hoses installed in substrate or casing or at the point of contact. The dissolved nutrients are accumulated in the mycelium and then used in feeding. There is a close relationship between the mycelium mass and the yield mainly in flush one and two. The mass of mycelium depends on the available nutrients as well as the supplements used and the period when the mass of mycelium increases.

The formation and growth of fruiting bodies.

The formation of pins. There is an assumption that all pins are formed before and during shock (aggregating – “starring”). Then the pins are released in individual flushes. The number of formed pins allow achieving yield of 175kg/m2, which to a significant extent corresponds to the substrate’s potential to give crops.

The growth of pins. A fruiting body is a fungus whose diameter does not exceed 1cm. The growth of a fruiting body deprived of a sufficient amount of nutrients of undefined qualities may be stopped and the fruiting body may die. It is most probably related to the phase of their growth. The fruiting body is a homogenous mass until the moment when the stem and cap can be differentiated. Probably this moment decides which pins exceed their critical developmental stage and are able to develop further as fruiting bodies. The changes in temperature play a very important role here. The temperature of 16°C is beneficial for pins of 2 and 6mm for about 2 -3 days and then the return to higher temperatures in which the pins develop quickest (22-24°C). The presence of volatile chemical substances such as chlorine can also influence the number of growing pins.

Probably there is a relationship between the process of stem and cap differentiation and Verticillium. Probably its hypha gets into the pins being the mycelium mass without the differentiation into a cap and stem.

There is some competition between the pins formed during individual generations to obtain nutrients. As a result the growth is stopped or slowed down. If it is stopped for longer, the pins die. The pins in next generations are formed on day two after the fruiting body crops. This behaviour depends on the availability of nutrients as well as growth conditions created by microclimate, the flow of air and the mycelium activity in the substrate.

The transport of nutrients and metabolism products.

The transport of nutrients. Mushroom can transport nutrients from substrate into the fruiting bodies even to greater distances. It is accepted that it is about 2cm per day. In order to achieve this it is necessary to keep the water evaporation from the surface of fruiting bodies on the level of 6mg/cm2/h. This way of transport is called passive. Unlike higher plant, on their surface there are no stomata. This means that the transport is proportionate to the water evaporation pace from the surface of the skin. If the evaporation is too rapid a form of shell is formed to reduce the evaporation. The lack of evaporation results in the water transportation being stopped. Due to the transportation time, the height of the substrate and casing layers should be adjusted accordingly. The shorter the cultivation period, the smaller the layers, a thinner as usually substrate layer may be applied without any losses to the yield. Only if the cultivation is for 4 flushes or more, it makes more sense to make the layer larger. The nutrients will simply be supplied to those flushes. Thus the utilisation of substrate should increase. As mentioned earlier the basic mechanism for the transportation of nutrients stored in mycelium during the fructification period is the evaporation of water from the surface of a forming pin and growing fruiting body. The necessary condition for feeding is also an active transport based on osmotic pressure differences between the environment in the substrate and the mycelium cells. It is a basic form of transport in the period of mycelium vegetative growth.

The energetic costs you need to incur during the transport of nutrients should also be noted as well as the use of casing as a feeding environment. The shortest transport. The nutritive substances are introduced into the mushroom cells, nutrients are introduced, the formation of mass.

The fruiting bodies growth process is regulated just like in the case of higher plants – through growth hormones. The nutrients supplied to the cells are used to form cytoplasm and cell membranes and to keep the cells vital function.

The transition to form spores

The aspect that has not been considered so far that is important from the point of yield is the moment when the body growth is finished and the transition to form spores takes place. In practice we can observe very big differences in the size of fruiting bodies which undergo this phase. The aim of cultivation is to gather fruiting bodies which have the largest specific weight, closed, snow-white (or of a different colour depending on breed) of a specified diameter.  If these qualities are lost too early causes losses in the quantity and quality of the achieved yield and disrupts the organisation of crops. There is a question: what signals will have to reach a fruiting body in order for it to move into the phase of forming spores if they are not noticed earlier? Probably it is the decrease in the nutrients concentration supplied to the fruiting body. Below a certain threshold that signalizes a further drop, the overgrowth of mass is stopped and the transition to form spores begins.

The effects of feeding, the increase in body mass, the formation of spores.

The fruiting body mass increases in the pace of 50% every day, until the moment of transition to form spores and when the stored nutrients are used for this purpose.  This is accompanied by a tense membrane that snaps. For mushroom cultivation this means a moment for crop apart from the production of open fruiting bodies referred to as portabella. The formation of fruiting body volume has a fundamental importance from the point of view of mushroom cultivation.

The differences may reach even to 20% between fruiting bodies having full access to nutrients and those which have a limited access. The main aim of feeding is to maintain the maximum volume of fruiting bodies throughout the year. An important effect of feeding is colour. The whiter and maintained white after the harvest the better the feeding conditions were.

Feeding and flushes

Crops of mushrooms appear in flushes. This phenomenon is not fully known. The conditions for crops and the level of temperatures are also very important. The gathered nutrients are used during crops. During the break period in yielding nutrients are gathered from the reserves in mycelium ready for the next flush. Mannitol plays an important role in controlling this process. The amount of amino acids, mainly arginine and other also influence the quality. The yield in individual flushes are characterised by a downward tendency. The highest yield is achieved in the first and then the second flushes then they stabilize to similar levels from the third to the fifth flush.

What is the connection between the feeding process and the changes in yield in individual flushes? The amount of nutrients gathered in mycelium (substrate and casing) and distance influence this process; the ability to transport them in time. The first flush has the largest access to the nutrients gathered in the maximum stored source and it is the closest to the flush. This flush is the effect of accumulation in the process of mycelium overgrowth in substrate. Flush two – the yield starts to reflect the shortages in available nutrients. Flush three begins to stabilize on the level of 5-7kg and subsequently as an effect of exhaustion of nutrients accumulated in the mycelium of cold composting and transport. The main characteristics of the substrate behaviour during subsequent flushes is a decrease in its volume, mainly the layer’s height, and thus making the route shorter and at the same time maintaining the capacity for mushroom to feed using the process of cold composting. The role of ash in substrate is increasing. You can risk a statement that the use of the substrate changes along with its changes in volume. This results from the fact that the biggest decrease applies to energy elements stored in straw and polysaccharides that are decomposed into carbon dioxide and water and energy that is released in the process, however the height of the substrate diminishes.

The use of substrate and yield.

When analysing achieved yield in relations to the substrate used per a unit of area or a unit of weight, a statement can be made that the crops grow as the amount of substrate is increasing, but its use is decreasing. This in return makes it necessary to optimise substrate expense and the results gained and the costs of controlling temperature in substrate and the possibilities of ensuring a required microclimate as well as increasing the need for air flow as the crops grow.

The substrate after the cultivation

The substrate after the cultivation even after flush four maintains a similar makeup. This means that its use is equal not random. Its mass is smaller but the nutritious value remains the same. In the process of cold composting with mushrooms the substrate is used and not wasted. At least up to flush four. Some information on how to use substrate after cultivation can be found in available literature. The data analysis indicates that its value is high. The ash contribution is increasing higher. The average compost of phase III utilization during mushroom cultivation is about 35% of filing mass.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 The relation among the feeding system elements

The use of elements depend on: 1. The amount of nutrients that can be absorbed and accumulated in mycelium and access to water, 2. The amount of produced mycelium, 3. The environment mycelium vegetates in, 4. The feeding process, 5. The transport of nutrients, 6. The mass of produced fruiting bodies.

Bibliography:

Bonnet, A.M., Anton L.H., Orth, A.B., 1994. Lignin-degrading enzymes of commercial button mushroom, Agaricus bisporus. Applied and Environmental Microbiology, Mar. 1994,p. 960-965

Chen,Y., Chefetz, B., Rosario, R., Heemst van, J.D.H., Romaine, C.P., Hatcher P.G., 2000. Chemical Nature and Composting of Compost During Mushroom Growth, Vol.8, No. 4.

Dijkstra, F.I.J., 1976. Submerged cultures of mushroom mycelium as sources of protein and flavor compounds, Dissertation Delft

Flegg, P.B., Spencer, D.M., Wood, D.A., 1985. The biology and technology of the cultivated mushroom

Gapiński M., Wożniak W., 1999. Pieczarka technologia uprawy i przetwarzania (Mushrooms. The cultivation and processing technology).

Griensven, van L.J.L.D., 1988. The cultivation of mushrooms

Ilyama, K., Stone, B.A., Macaukey, B.J., 1994. Compositional Changes in Compost during Composting and Growth of Agaricus bisporus, Applied and Environmental Microbiology, 1538-1546

Patyshakulyeva, A.,  and an others, Carbohydrate utilization and metabolism highly differentiated in Agaricus bisporus, BMC Genomics

Strarsma, g., Sonnenberg, A. S. M., Grievsen, van L.J.L.D., 2013. Development and growth of fruit bodies and crops of the button mushroom Agaricus bisporus, Fungal Biology

Weail, D.A., Beelman, R.B., Beyer D.M., 2006. Manganese and micronutrient additions to improve yield of Agaricus bisporus, Bioresurce Technology, 97,1012-1017

Trechow, C., 1944. Nutrient of the cultivated mushroom. Dansk Botanisk Arkiv, 11,

Zied,D.C., Savoie, J-M.,A., 2011.  Soybean the Main Nitrogen Source in Cultivation Substrates of Edible and medicinal Mushrooms, Agriculture and Biological Science, Chapter 22

My propositions for feeding of mushroom in practice

The new attitude towards cultivation where feeding is a process, which we control and propose a possibility for cultivation without composting, requires a fresh look at the composing elements for mushroom feeding and crop processes.

  1. 1.                  Aims
  2. Crop and structure. The crop is the number of fruiting bodies and their weight. For example, the minimum level in three flushes is 40kg/m2. The increase in yield is going to be achieved by the maximisation of the fruiting body volumetric weight and through the increase of their amount in the second and subsequent flushes. In order to achieve yield of 40kg/m2 you need to collect 8 fruiting bodies weighing 50g to 20 fruiting bodies weighing 20g on the area of 10cm2. Now a day is possible to obtain yield 20 kg\m2 in first flush regularly, why not it is not possible in second and 10 kg\m2 in three and four if would be enough of nutrients?
  3. The quality and composition of fruiting bodies through the production of fruiting bodies with a maximum possible volumetric weight and a dry mass component throughout the cultivation. This allows achieving a long, at least 7-day turn. The changes in the supplements’ composition will allow the modification of the fruiting bodies’ composition that will be rich in substances that are desired in the human diet, for example microelements. Such substances may be those that contain micro- and macro elements dissolved in water and are already manufactured. An appropriate diet for healing mushrooms can improve their yield and composition. There can also be an increase in cultivation of other species of mushrooms that can be characterised by special features, e.g. meadow mushrooms have a very intense smell but they require a very demanding control of absorbed ingredients, especially heavy metals.
  4. The wholesomeness of cultivation through the increase in efficiency of mushroom self defence mechanisms and the change of diet improving the selectiveness of substrate; feeding environment.
  5. The decrease in production costs through the increase in yield and quality; the higher sale price with a minimum increase in costs, decrease in the energy costs during cultivation and decreasing the amount or giving up altogether of more and more expensive substrate.
  6. Additional effects of compost supplements:
  7. The increase in substrate selectiveness in relations to competitor mushroom, for example protein diet favours Trichoderma development; whilst others like Nutrigain don’t.
  8. Can deter flies
  9. Impact on the advanced regeneration of mycelium after being torn during its transfer from the tunnel or after it is mixed with the Phase II overgrown substrate
  10. They speed up the regeneration of substrate used in CACing
  11. They speed up the colonisation of casing, the shock phase can begin even in the period of three days.

Other aims can also be identified, such as:

  1. The increase in the area capacity for ecological cultivation due to an easy access to raw materials that meet the requirements for ecological farming.
  2. The production of mushroom mycelium as a raw material in processing industries.
  1. 2.                  Structure
  2. a.       Spawn. It is a mycelium carrier that is used for mushroom vegetative reproduction. A mushroom has different carriers, mainly grains. Commercial mycelium used to speed up the overgrowth of substrate is called speed spawn. They differ depending on the mushroom strain that is going to be grown. Currently heterotic breeds are farmed and they have various requirements in regards to substrate and the capacity for their use. From the point of view of feeding it is important to lengthen the overgrowth period which means the prolongation of the enzymatic feeding process and the breed requirements in regards to structure and the availability of nutrients (from start finished colonisation of substrate till end of aeration). For example the Heirloom mushroom breed has currently the highest nutritious requirements. These characteristics can be found in white mushrooms from the U-1 Group. In the past it was impossible to meet their needs, the cultivation of this particular mushroom was stopped. This aspect deserves a further investigation. A special casing spawn or colonised compost are used for an advanced casing colonisation.

 

  1. b.      Substrate. The substrate used nowadays and its assessment. Currently the substrate in which mushrooms exist and feed on is compost which is structured appropriately as it is loaded onto the shelves (trays) in a specified amount, height and composition and diet and the casing is made from different type of peat. Nowadays the compost also fulfils the role of substrate and diet and that is why its use is limited. If it was entirely absorbable, it would cause the loss of its structure disrupting for example gas exchange in a very short period of time. The difficult to absorb structural part (straw in compost) is the mushroom’s source of food that is supplied to the substrate solution during cropping. Theoretically, the substrate can be used for feeding until the total of biomass runs out; a complete mineralisation of compost. It is a specific characteristic of compost as substrate and the fact that it is produced from agricultural farming renewable ingredients. This feature is hard to replace. The casings do not have such features. Casing is a kind of substrate in this meaning, from which the mycelium absorbs water and also the fruiting bodies are beginning to develop. The question is: Can casing partly fulfil the role of a nutritious environment as a mixture of substrate and casing in different proportions and doses of supplement. The carried out tests indicate that it is possible when the supplements are in the form of suspension or just liquid. The condition is that they have to be absorbed by mycelium until the moment of forming fruiting bodies. Apart from that the supplements cannot change the form of casing structure. A very important feature of substrate is the mass and area of the mycelium in it. The attempt to find a different material than peat. The synthetic casing did not bring desired effects. The phytosanitary conditions on the casing surface cannot be compromised and the casing cannot influence on the loss in quality of fruiting bodies that are left on a shelf during its introduction.
  1. c.       Water. The availability of water in the mushroom feeding process is currently a minimum factor and decides on the feeding process. Its availability in substrate and difficulties to introduce it into the substrate that is overgrown with mycelium make it impossible to use higher dosage of supplements. Nowadays, the highest dose of supplement is 1.6%. This allows for yield of 32kg/m2 in three flushes in Phase III substrate taking into account the substrate produced nowadays and procedures to introduce water into the substrate and casing. With the yield of 40 kg/m2 on a Phase III substrate in three flushes you need to use higher dosage of supplement of at least 2% and higher. This in effect means a higher than current demand for water. Theoretically the use of water to produce 40kg/m2 of fruiting bodies is 80l/m2 of water in the period of a complete cultivation cycle. In practice on a farm with the 2% of supplement, the amount of water in substrate to be introduced in a very short time should be 35l/m2. The Phase III substrate has about 50% of water capacity. The first initial estimates indicate that for every 0.1% of dosage over 1.6% you need about 3-4 l to maintain the digestion process and accumulation of nutrients in mycelium. Currently the maximum is a 2% share in substrate. The very feeding process has specific needs. As the doses of supplement increase, a decrease in the amount of water in substrate is observed until its complete drying out. Water and the nutrients are stored in mycelium. An appropriate process of transport of accumulated elements to the fruiting bodies determines the mycelium access to water. As this problem remains unsolved, it is a major hurdle in the increase of yield regardless of where the nutrients come from- the substrate or supplements. This also explains the problems with exceeding the 32kg/m2 limit. Currently some tests are being carried out to find an appropriate solution. The doses of supplements in the substrate and casing before the beginning of shock must be correlated. Otherwise the substrate may dry out or overheat and the yield may be significantly lower than predicted. However too high dosage of water and a poor method of applying it may cause the substrate to rot. The water capacity of the substrate may become its feature in the future.

 

  1. d.      Diet. The term diet must be introduced to identify the supplement feeding process. According to the adopted assumption the mushroom nutrition is of the same type as the animals’. Diet is a way of nourishment adjusted to the mushroom type that is cultivated and the aim to be achieved, the quantity and quality of yield. The basic diet contains all nutrients in amount stipulated for mushrooms. The diet can also be special if we want to achieve an additional aim in the fruiting bodies composition or for the mushrooms to be immune to competitor organisms, etc. Diet is an inseparable element of growth and development ensuring the capacity to maximum production and maintenance of good condition. It refers to the environment in which mushrooms feed on and the type of nutrients that are available.

 

 

  1. e.      The type of diet currently used and its assessment. Nowadays we can talk about the substrate diet, soya enriched compost diet or protein diet. How can we assess it from the point of view of the feeding concept in mushroom cultivation? It has many disadvantages. The main one is the lack of efficiency considering the high substrate price. The price for the nutrients is the same as for the structure elements that create the mushrooms’ environment. Protein is not easily absorbed by mushrooms but it is a perfect environment for the competitor fungus, especially green moulds. Some with a large amount of feather meal for example are not easy to absorb. Substrate is the effect of composting and for the process to be carried out properly it has to have a specified proportion of carbon to nitrogen. This can only be enriched when it is taken over by mycelium. The protein supplements even more so can diminish the substrate selectiveness for mushrooms. Polysaccharides and their decomposition products are soluble in water and are easily absorbable. They may be useful in the substrate colonisation phase to improve and  stimulate growth.
  2. f.        Supplements – the elements of diet. The supplements should allow to achieve adopted production goals not causing any side effects such as thermal effect, worsening of the nutrition conditions or the selectiveness of substrate, should be free of diseases and mushroom pests, should have qualities of food eaten by people. Supplements are characterised by a different level of their use. You can also consider applying supplements or substrate and the digestive value of each supplement component just like it is done in case of animal fodder. An example of this is the Nutrigain Gold product.

Type and composition.

The supplements may vary in their features. They can be classified according to these features.

Depending on the type of nutrients:

a)      Balanced, completely rationed meeting every nutritious need of mushrooms

b)      One or multi ingredient

– organic containing carbohydrates, protein and fat

– mineral containing macro and microelements, for example manganese improving the production of Mn peroxidase, other salts that can be found in MycroNutrient speeding up the mycelium growth and the use of food which can be demonstrated by a whiter colour and a higher volumetric weight of a fruiting body.

– vitamins, regulators, enzymes, growth substances

Compost:

a)      Solids. Solid supplements characteristics. The granulation of a supplements impacts on their use in solid form. The finer, the easier to absorb.

b)      Liquids. Synthetic liquids added at spawning can be much quicker reacting and more efficient than solids. The benefit is they go directly into the ‘straws’ of the compost so directly feeding mycelium not competitors on the outside. This could explain the ‘speed up’ in spawn run by 2-3 days.

Casing:

–          Carriers in a granulated form eg Mycrogranules for delayed release

–          Solutions may also be used for watering through the casing into the compost or directly on the compost surface at head fill eg Mycrofeeder.

–          Suspensions. In case of applying supplements in the period between flushes in the form of suspension, the supplement  should not cause changes in casing structure and must be safe if it leaches on the floor of the growing room. If the second requirement is not met, some diseases can spread, mainly Verticillium and Dactylium and requires special measures to remove sediment. Products like Sporekill can be used safely during cropping to minimise this.

Depending on origin

–          Natural

–          Synthetic

Compost supplements subject to treatment before application

a)      Subject to chemical treatment such as formalin

b)      Thermal treatment

c)       Natural acid salt treatment

Aim of Application

a)      Substrate standardisation

b)      Yield growth

c)       Special effects

-deterrence of flies

-competitor fungus development prevention, mainly Trichoderma type

-to improve the taste, healing, dietary value and appearance

Depending on the place of application:

a)      Into substrate

b)      Into casing

 

Determination of dosage

In my experience, the doses are established proportionally to the substrate weight and usually they are from 0.5 to 1.7% of currently used protein supplements. New methods are needed to determine the doses and composition of supplements to meet the nourishment needs. For example based on balances: energy, water, mineral elements and organic. The substrate energy balance as it is estimated for example for corn, the energy amount absorbed by mushrooms is 220g per 1 kg, the balance of energy to be absorbed during mushroom feeding process. With the load of for example of 30kg/m2 of dry substrate mass, the dry mass would allow to produce 180kg/m2,  and assuming the total use of dry mass. However, substrate cannot be used fully, because some parts of it, the organic elements that are the most difficult to decompose make the compost structure. Besides, the substrate is the environment for biological life which also absorbs some part of the dry mass. My idea is that the theoretical degree of the maximum dry mass use is not known. The balance looks totally different if we can assume that a mushroom contains 10% of dry mass. This means that it absorbs 4kg of dry mass with the yield of 40kg/m2. Assuming that the same amount is needed to maintain living functions and 1 kg absorbs the energy needed for maintaining life by microorganisms; this means that the effective use will be about 9kg. How much dry mass do you need to provide for mushrooms to produce 40kg/m2? You need to consider the efficiency of systems; I presume on the level of 50%, the answer would be about 13.5kg/m2. This is the amount of dry mass rich with energy substances that has to be provided to mushrooms to achieve the indicated yield without the substrate. The question of the level of substrate absorption in feeding is still not resolved. Also, the usefulness of compost rich with biomass has not been considered either. The amount of supplement dosage must be correlated with the access to water that is necessary for the supplement use.

Mushrooms can be fed with nutrients in a solid powdery or liquid form of a different level of granulation and as a suspension. If the substance is a liquid or powdered it speeds up digestion. The nutrients can be directly dissolved and absorbed is by osmosis . This without the involvement of mushroom enzymes.

 

Time of use

It can be applied during different phases of cultivation but the feeding takes place from the moment the mycelium is in contact with food; during the substrate and casing overgrowth, after the application of nutrient solution between flushes.

 

A new methodology and vision for the future

The feeding technique

Solid supplements are applied to the substrate in measured up dosage and mixed while taking the substrate out from the tunnel or when it is put on shelves or cases after the Phase II overgrowth in accordance to the same principles as the supplements. The solid supplements for the casing eg MycroNutrient can be applied in the farm directly on the shelves; as well as a suspension or solution in its liquid form, through the systems used for watering. The irrigation system from a hose requires testing.

The feeding cycle as the basis for feeding.

The definition of a cycle. For the purposes of cultivation technology development based on mushroom feeding concepts it is important to recognise and define the mushroom’s feeding cycle to explain the phenomenon of cyclic cropping. The mushroom cropping is done in flushes. The break in fructification allows transferring the nutrients as close as possible to fruiting bodies to ensure the best feeding conditions.  In order to control this process the term feeding cycle needs to be explained. The feeding cycle – a repetitive process to obtain nutrients in direct feeding. It starts with the application of nutrients also the conditions in the substrate. It starts after the shock phase is finished until the end of flush one. The feeding cycle is conducted in subsequent flushes when the supplements are used in periods between flushes and is combined with the development of pins. The development of stem and cap; this involves the pins with the diameter of 2 to 6 mm to be kept in temperature of 16° for 2-3 days and then you need to return to higher temperatures in which the fruiting bodies grow the fastest. Between flushes the increase in substrate temperature to 23-30°C is to activate the mycelium without it growing on the casing surface.

  1. 3.                  The results of feeding.

The symptoms of full access to nutrients. The basic indicator for the feeding process. The key element for the assessment of the feeding cycle is to evaluate the access to nutrients by observing the behaviour of mushrooms starting from the development of pins to fruiting bodies. For this purpose the term mushroom wellbeing can be used. The basic aim for the controlled mushroom feeding process is to ensure the growth of all pins in every flush and ensure the wellbeing of fruiting bodies: the white colour, the maximum volumetric weight, the stem’s bottle shape until the moment of crop with water in body cells without any surplus in cell cavities. An important indicator is to keep the rise in temperature that ensures 50% increase in body weight, every day. The wellbeing is disrupted when the mushrooms grow too fast, change colour from white to grey and red, their stem is straight and long, the membrane is tight and their cap is flat. If the wellbeing is lost prematurely this indicates malnutrition or an adverse condition for vegetation that initiates a signal in the fruiting body to stop growing and initiates the transfer into the phase in which spores are produced. Malnutrition is manifested by the fact that pins stop developing in spite of good conditions for their growth and it is viewed as an effect of their battle for nutrients.

The number of fruiting bodies.

Yield and its evaluation. Recommendations for further feeding cycles.

The model verification through testing in production conditions.

 

The draft for the construction of proposed new cultivation model

  1. The establishment of the cultivation aim, the size and quality of yield, the length of cycle and the amount of substrate needed, the risk assessment for diseases and pests.
  2. The standardisation of substrate prior to or after overgrowth through the application of full or partial diet. The determination of water dosage. The assistance in selectiveness and pests deterrence.
  3. The application of supplements at overgrowth of casing. The control over the growth of pins with liquid supplements. The liquids additions can be combined with substrate being dosed with eg lipids in the compost and polysaccharides on the compost top prior to casing.
  4. The application of liquid supplements through the casing in flush two and carrying out the feeding cycle in flush 2. The control over the growth of pins with liquid supplements.
  5. The application of liquid supplements in flush III and carrying out the feeding cycle in flush III. The control over the growth of pins with liquid supplements. The application of liquid supplements during the growth of fruiting bodies based on their appearance and behaviour.
  6. The cycle is repeated just like in flush 3, 4 and 5. The control over the growth of pins and liquid application of supplements. The application of liquid supplements during the growth of fruiting bodies based on their appearance and behaviour.

The development of models based on different substrates.

Currently the production of mushrooms is based only on one substrate – compost. In the past and present there have been some search carried out to find other substrate however it was unsuccessful given a production scale of the task. If the attitudes change, we can look for new types of substrate.

  1. The cultivation using the current amount of substrates and the application of a feeding cycle with solid and liquid supplements.

The effect of growing influences the amount of nutrients in the first phase of feeding; the amount of biomass and the availability of water in the substrate for the mushrooms. The initial composting phase, the opening of straw, its decay in the process of ammonification and the application of water influence the possibility for obtaining nutrients in the first and second feeding phase.

The development of cultivation models based on the use of compost at the average dose of 85kg/m2 of Phase III substrate.

The proposed model assumptions.

  1. The yield up to 40kg/m2 in three flushes with the maximum volumetric weight.
  2. The mycelium with the highest level of absorption of nutrients.
  3. The application of supplements: full portions, energy oriented liquid and suspension fully absorbable in the period of 10 days.
  4. The maximum temperature rise by 2°C.
  5. Protection against competitor fungus, a diet useless for Trichoderma, the dosage increases along with the threat with protein products but not with other products.
  6. The arrangement making it possible for the mycelium to overgrow in volume, especially with lipid products like Liquid Gold.
  1. The cultivation without compost and with the use of peat or straw as a structure for feeding and the procedure for feeding cycle based on the use of solid and liquid feeders which if soluble would not need enzymatic feeding which normally constitutes 95% of the mushroom feeding process.
  2. The cultivation using a liquid diet only and the enzymatic feeding process in a newly designed mycelium vegetative environment. However in the carried out research the achieved effects were not satisfactory on the level of mushroom cropping.

This means that it is necessary to look for new attitudes for cultivation without substrate. This answers two questions:

  1.  Can an artificial environment be built for the mycelium vegetation?
  2. How to feed in this environment?

How to achieve yield just like in traditional cultivation at a lower production costs? However the major problem is the fact that the cultivation based on substrate ensuring access to renewables means that the barrier of running out of resources is non-existent. A separate issue is casing. There is a question of whether the unrenewable sources can be replaced?

Every model requires verification in the cultivation conditions.

Feeding technology

The technology should be built according to the following steps:

  1. Specification of resources at hand: technical equipment, spawns, substrate, cultivation and cropping capacity, hygiene levels.
  2. Specification of aim to be achieved. It is worth remembering that every change entails expected and positive effects as well as the unexpected and negative ones. In other words there is always some risk that should be estimated and minimised through the change implementation control.
  3. Feeding needs diagnostics.
  4. The choice of supplements.
  5. Formulas.
  6. Doses and schedule for adding water to substrate and casing.
  7. The technique for adding supplements.
  8. Feeding schedule.
  9. Collecting data on the course of cultivation.
  10. Evaluation of the achieved yield.

Cultivation technologies for white mushrooms

The following cultivation technologies have to be prepared based on models’ test results:

  1. Two flushes mushroom cultivation technology
    1. For the fresh market
    2. For processing industries
    3. Two or more flush mushroom cultivation technology
      1. For the fresh market
      2. For processing industries
      3. Brown mushrooms cultivation technology

Summary

Some tests have been carried out for the last six months. The tests were done on individual a commercial white mushroom farm in Poland, producing for the fresh market. The supplement based on carbohydrates applied to the production practice in the first three days from putting the casing on. This allowed achieving higher than average yield by about 5kg/m2 of high level fruiting bodies achieving the yield of 37kg/m2. An additional effect of the diet was that the mushrooms were less affected by insects. The diet works as a deterrent. The situation was stable of the substrate was of a good quality.

If the substrate was of a poor quality, the more nutrition has to be used. The tests are pending. However it is known now that if the problem of how to supply water necessary to use the substrate to the fullest in the mycelium and how to apply supplements, we won’t achieve a further growth in yield.

The question of applying supplements through casing after shock is still not resolved. This way we expect to achieve an extra 3kg/m2 up to 40kg\m2. There are high hopes with the development of a new range of Nutrigain products, a company that specialises in liquid supplements. The task of preparing a fully portioned diet is very important as well as the change of Phase III production allowing for a greater accumulation of nutrients in mycelium before the casing in applied.

There is an interesting question to be answered: if the supplements are near the fruiting bodies will it allowed for an increase in yield? This question will be answered after carrying out two tests with a two-layer casing; one lower zone with nutrients with a traditional casing layer on top.

The breeds of mycelium are still an unused source of increased productivity. The testing of their usability is limited by the substrate production strategy based on one mycelium breed.

This study is an introduction to the development of a new approach in mushroom cultivation. Only the quantity and incremental changes may ensure the increase in yield and the improvement in the economic effect in the industry.


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