Program of verification of paradigm, which assumes that the cultivation of mushrooms is a controlled process of its nutrition required changing the strategy with the start of 2014. While initially focused on the use of higher doses of supplement (crafted corn) in order to achieve the planned yields, during the summer months it became necessary to develop a new approach to control of the feeding process. Unstable yields were achieved despite fixed doses of the supplement.
As a basis for solving this problem it became necessary to adopt the law of Lebieg’s minimum. It states that the yield is proportional to the factor contained in the minimum. This means that when we provide mushrooms with access to the nutrients needed to achieve the desired yield and it is not achieved then the next step is to find those factors that limit its growth and to eliminate them. As long as the content of nutrients will be at the minimum, further increasing their availability will result in achieving higher and higher yields. The reasons for limiting the yield had its external sources such as the difficulty of equally mixing increasing doses of supplement, variable substrate characteristics, extreme weather conditions (hot summer) and inner sources when system of controlling the growth of pins and fruiting bodies proved to be not very effective.
- Unequal mixing of increasingly higher doses of supplement resulted in a return of the thermal effect in the substrate. On the one hand, this resulted in the need for increasingly higher doses of water and on the other hand to limit the dose of the supplement. These actions resulted in reduced yields and the need to return to a dose of 2.5% until the issue of equal mixing of supplement in phase III substrate could be resolved.
- Reduction of the water capacity of the substrate. Since the middle of the first flush a gradual accumulation of water in the lower layers of the substrate has been observed. The amount of water grew despite the reduction of its doses to the substrate and in spite of limiting of its applied amount between flushes. This resulted in the need of solving the problem of applying high doses of water without it collecting on the bottom shelf (on the foil) during successive flushes. What is interesting, it was not accompanied by occurring of the phenomenon of substrate’s rotting and the appearance of pepper mites. The solution turned up to be a system of holes in the foil. It provides the ability to control the amount of water introduced depending on the capacity of the substrate and prevents the accumulation of water during the growth process. This means that the substrate is an open system in which gas exchange must take place and anaerobic zones cannot occur. The material cushioning the substrate must provide for it to breathe, the spawn has to be bleached, small quantities of water accumulating on the bottom must have a golden color. Those observations indicate that the reduction of water capacity is a result of inability of defibration of straw which this year is very hard. The holes in the foil should not be too large so that the substrate is not drying from below.
- Lack of reproducibility of behavior of pins and fruiting bodies associated with unstable outdoor climate. It influenced achieved yields substantially, in particular the delay of yielding in the first flush, unstable arrangement of fruiting bodies on the second flush and often complete disappearance of the yield during third, despite a good yield on fourth.
- Interference of binding caused by the introduction of ice to the substrate in purpose to reduce temperature. Along the banks of the boxes it was the best closer to the center it was sparse. This problem also occurred in previous years.
- Race of Agaricus, whose characteristics do not allow to obtain high yields. This confirms the thesis that to the level of yield of 30 kg \ m2 the impact of race is small. Then it significantly rises. You can now confirm that the spawn significantly reduces the possibility of obtaining higher yields when it has a genetic defects and a weak vigor. Lack of access to the races from a group of U-1 does not allow to determine the effect of races with higher nutritional demands on the yield with full coverage of their nutritional needs.
The decrease in pH of the casing soil on the third and fourth flush. This resulted in the appearance of colonies of green mold on the surface of casing soil and faster development of outbreaks of dry rot.
As a result of actions taken another model of transition from the vegetative to generative phase of fruiting and system of control of the cultivation of mushrooms during fruiting phase was developed.
Model of transition between vegetative and fruiting phase.
The transition from the growth phase of the spawn into fruiting goes through three phases:
- Breaking down the temperature in the substrate. We start the shock practically on „black” and it is done in such way that to cause breaking of temperature in the substrate after 48 – 76 hours and for it to reach the level of 20 – 210 C. Otherwise continuous growth of spawn is observed, difficulty in binding occurs and delay of the start of the harvest. Mushroom having access to nutrients during recolonization period at substrate’s temperatures above 230 C continues vegetative growth and is reluctant to go to the generative phase of binding. The temperature drop of the air must periodically reach 160 C at the end of shock.
- Creation of primordia. It is done by changing of the color of the spawn from gray to white, thickening of hyphae and the formation of primordia on them. Controlling the process is done by not only changing the microclimate conditions but also maintaining dew on the surface and its gradual release. Too rapid removal of dew leads to a shortening of the period of formation of primordia and consequently reduces the number of generations. With too rapid decline in humidity of the air and extensive movement you can dry the spawn with primordia. This period requires special attention, as there is no sufficient knowledge of how to fully control it.
- Growth and differentiation of pins. Controlling the behavior of pins is easier because they are visible and one can assess their growth.
The course of shock is determined individually depending on the expected arrangement of fruiting bodies. You should always get at least three generations.
Considering the fact that it is known that we bind all shocked pins, that appear in the growing period, following question remains open: how does the course of a shock affect the formation of generations of pins during the second and subsequent flushes. Probably it has no effect. The mechanism of creating a generation is process of their release during periods of transitions between flushes.
Control of cultivation based on a constant level of water evaporation from the surface of the casing soil, pins and fruiting bodies.
Analyzing the behavior of mushrooms in the cultivation hall indicates that the current system of maintenance of water evaporation from the surface of the casing soil and fruiting bodies and pins needs to be rebuilt. Changes in relative humidity of the air, its movement and the concentration of carbon dioxide do not guarantee the achievement of reproducible effects in continuation of growth rates of fruiting bodies and pins. This is true especially in large changes in water content and energy in the outside air, and during periods of summer heat.
Successful control of behavior of mushrooms requires control of the substrate’s temperature and the evaporation of water from the surface of the casing soil and yielding fruiting bodies. The new system has the following assumptions with regard to the:
– Substrate. The substrate must not be too active. Conducted observations indicate that the recolonization process works best when the air temperature difference and the substrate is within the 230C in the air and 280C in the substrate. Interfering factor of recolonization is overly tamped substrate. Therefore, it is assumed that the standard dose of the substrate is 80 kg \ m2. This ensures that regardless of the structure and humidity of the substrate its expected compaction. The substrate, which releases after tamping up to 2 cm provides the best gas exchange, movement of water in the compost and provides adequate space to increase the volume of spawn. To compensate for nutrient loss relative to the higher amounts of substrate per area of unit new diets were developed and subjected to testing. Yield of 40kg \ m2 in this case, achieve the objective of 50% utilization of the substrate. In the summer it becomes possible to decrease the amount of substrate to 60 kg \ m2 in three flushes at 30 kg \ m2 of the substrate. This still means utilization of the substrate on 50% level.
– Evaporation process control. Evaporation process is controlled based on the content of water (12 g) in the air (absolute humidity) at a constant, low air movement. Changes in the content are held at 0.5g up or down. They are not periodically lower than 10.5 g and higher than 14 g. The movement of air from time to time is not increased for more than 15% (1 – 3 KHz) over the accepted minimum of the movement of air above the shelves. The primary symptom of excessive evaporation of water from the fruiting bodies is the loss of their original shape, usually round or oval, and their weight. The more fruiting bodies become flat and the stem begins to elongate the evaporation rate is higher in relation to the possibility of transportation of nutrients by the mushroom’s spawn.
The fixed level of the water content and minimal movement of air is maintained throughout the entire period from the first appearance of pins to elimination of cultivation. The water content is a priority and change of other parameters (air temperature, carbon dioxide content within physiological limits) aims to maintain a predetermined level of absolute humidity. Additionally, the process of evaporation, particularly under conditions of high water content is verified by water deficit (min 0.5-1 g \ m2). This situation results in a significant reduction in the demand for increasing air humidity, which contributes to the stabilization of the microclimate. Maintaining a constant flow of water from the substrate to the casing soil and keeping the casing coil constantly damp and also contribute to reduced need for increasing air humidity. At low air movement, it turned out that the coolers have limited scope for water condensation. During low movement it resulted with them being blocked by water and throwing it on the heater. This required periodic drainage of coolers (stopping the motion or retrograding the motion). Special coolers were constructed with large fin spacing, keeping the required surface. Besides it is not allowed to let the condensation of water in the sleeve.
The presence of after-flush mushrooms shows, that the functioning of microclimate was correct.
Behavior of fruiting bodies and pins was analyzed and tested with other parameters of microclimate:
- The temperature of air after the shock (appearance of the first fruiting bodies) is maintained at the highest possible; not less than 18,00C and may reach during the first flush up to 21 – 240C (second half of the set) to maintain 2-30 C difference between the temperature of the air and the substrate. Raising or lowering of the temperature for 0.50C is used to maintain the assumed water content. The temperature of the substrate is raised in accordance with the principles of the nutrition cycle between the flushes. The temperature drop should be quick after finishing pouring water for the next flush. Increasing the air movement in this period usually results in excessive growth and a simultaneous increase of the pins. The problem of the third flush doesn’t exist (delayed harvest, dying pins) if previously required level of water deficit, minimum air temperature, constant air movement and concentration of carbon dioxide are maintained. Under conditions of high doses of nutrition during the second flush a problem of excessive and simultaneous growth of pins can occur. This requires a different approach to their release and growth. The new procedure is tested.
- During the second and third flush a temperature of 190C in air is maintained. This allows to maintain the expected growth of fruiting bodies and to sustain expected water content in the air.
- Carbon dioxide during the period of yielding of a second half of the harvest; loosening the shelves is maintained at the surface of the casing soil at the level of 1 800 – 2 000 ppm. Although recently with accurate control of evaporating process I try to maximize the carbon content at the same level as during early period of harvest. At first period of harvest it can be kept temporarily at a much higher level of up to 4 000 ppm. The priority is to maintain the water content in the air with its constant motion.
- The appearance of colonies of Dactylium and rusty blight signify errors in the maintenance of evaporation.
- Maintaining a constant evaporation allows to water mushrooms during fruiting without losing its quality and shortening the shelf-life. Provided however that the proper procedure is kept after harvest; not putting refrigerated fruiting bodies near the once which had not been cooled in the refrigerator.
Currently available technology does not allow full control of the microclimate under the above assumptions. This requires much more frequent tampering with the settings and changing the parameters to achieve the primary objective of maintaining a predetermined level of the water content in the air in the cultivation hall. In addition, an important parameter in used controllers is relative humidity of the air. When controlling the water content in the air (absolute humidity), the settings are required to be read from the chart of Molière and set manually. Priority of water content in the air is also the reason for operating in its highest possible temperatures. This makes it easier to maintain the desired water content. In addition, the indicator for proper maintenance of the microclimate is rarely switching humidification. This is due to the fact that maintaining the soaking without drying the casing soil the water will be continuously filling the air from casing soil and substrate. It also stabilizes the temperature of the compost.
The goal which was previously assumed was to use a dose of nutrition at 5% of the fresh weight of the Phase III substrate. The main factor limiting the increase of dose is the thermal effect caused by growing microflora in the compost overgrown by spawn. Conducted observations indicate that the thermal effect is excessive (substrate temperature exceeding 270 C at air temperature of 22 – 230 C), when the amount of protein fed to the substrate Phase III exceeds 0.4% of its weight. In contrast, spontaneous build-up and drop in temperature during enzymatic nutrition does not exceed 2 – 2.50 C, and there is no need for it to be controlled by air temperature change or by strong increase in its movement. Another factor limiting the size of the dose is not being possible to introduce greater amounts of supplement than 2.5% due to the difficulty of mixing the substrate. As written above. It was necessary to look for a feeding substance with higher digestibility and accessibility to spawn for a longer period of time. So as to increase the dose of nutrients available to the mushrooms without increasing the total dose of feeding substance. In search of other supplements the assumption was used that Agaricus during digestion behaves like an animal organism and is mainly looking for energy in the environment. Hence the interest in high-energy feed, in which the ingredients are subjected to extrusion and are expanded after being added to the emulsifiers to improve their dissolution in the water or are granules. Such feed is provided by the feed industry. Using ready-made or ordered from known component mixtures means that they can be used in accordance with the principles of nutrition similar to animals. Feed and feeding substances are controlled by the same veterinary services. First of all, a new diet is used to obtain an answer to the question whether it is possible to construct a substrate for mushroom production without composting. First fruiting bodies were obtained in two flushes on substrates with different diets. Loss of yield followed a second flush. The main problem is the lack of the expected opening and defibrating straw and organic matter for the third and subsequent feeding flushes. Currently conducting tests are designed to give answer whether biological decomposition of straw can be replaced by a mechanical. It is also to ensure growth of its water capacity.
In the initial period of testing of mushrooms nutrition concept no special attention was paid to the impact of casing soil on the process of feeding. More recently a number of related aspects were brought to attention:
- The height of layer. Obtaining a higher yield of high quality requires access to large amounts of water. This causes the necessity of applying casing soil of not only a high water capacity, but also higher layer thereof. After watering during the first flush 6 cm is desirable.
- The presence of the spawn. Efforts should be made to the well-known principle that there cannot be too much of it in the casing soil: it limits the water capacity, but also tends to bing excessively. The adverse effects of excess of spawn is observed when it is on the surface of the casing soil; what occurs as a result of the excessive removal during the process of binding or revealing in the subsequent flushes. Unyielding spawn causes additional evaporation of significant amounts of water and unproductive consumption of nutrients for its vital functions in expense of feeding the fruiting bodies.
- Transport of nutrients. Excess of spawn interferes with the transport of nutrients to the fruiting bodies.
- The porous surface. With the porous surface when the “black” binding begins it is easier to create generations. Higher layer of casing soil should also be used when adding supplements to casing soil.
Supplement to the casing soil
In the first half of the year the use of feeding substance in a form of fluid added to the casing soil had to be abandoned. Positive results were obtained from the use of dietary wheat flour and molasses. However, the increase in the risk of diseases and the accompanying raids of dipteras resulted in stopping of using them because of the difficulty of their removal from boxes and floor structures. The issue of feeding through the casing soil was returned to in the last quarter of 2014.
Feeding substances with higher digestibility, which are introduced into the casing soil at the time of application, are currently being tested on production scale. First reported results of their application show earlier appearance of pins and better extension of a flush. Those feeding substances are corn and grains with higher digestibility at 0.2 -0.5 kg \ m2. It is currently unknown how will they affect the amount of spawn and its transport functions. With such an application no negative impact on the health of crops has been observed so far. There is also no influence on the thermal effect. During the 14 days of the application feeding substance disappears. Probably it is partly degraded microbiologically in the casing soil. There is no answer whether the products of decomposition have some significance in further nutrition of mushrooms yet. The interest in this form of feeding is due to inability to enter more supplements to the substrate because of the difficulty with proper mixing.
As a regular part of growing employed use of calcium chloride and salt to maintain the physical characteristics (pH, and salinity) of the casing soil, additionally it uses disinfectant properties of the surface of casing soil (used before every flush in different doses), and increasing the availability of calcium in the casing soil. This is to protect the surface layer of the casing soil against the development of colonies of green mold on the third and subsequent flushes. This also a search for an answer to the question how does calcium content affect absorption of nutrients in the casing soil.
Watering with warm water.
New treatment is watering crops with water at 200C after applying the casing soil to the end of the harvest of the second flush. Entering the heated water to the substrate through the casing soil after its application significantly shortens the period of recolonization and assimilation of nutrients. This method eliminates the stress of spawn caused by the sharp decrease in its temperature. There is no retreat of spawn the recolonization is continued until the shock without any interruptions and leaky water has golden color. Thus changes in the substrate temperature during the recolonization are eliminated. In addition, the process of assimilation of feeding substance in the casing soil is far more efficient. This results in the ability to start the shock on day 4 since the application of the casing soil.
Soaking water from the substrate
Keeping water in the cover; preventing it from drying is a very important factor influencing the effects of a nutrition of mushrooms. It is the water content in the casing soil that determines the living conditions of the spawn and start-up and growth of pins. In addition, the water content and its changes are important indicators of the process of evaporation of water. This makes it easier to control the temperature of the substrate and the surface of the casing soil and is a significant factor in the movement of nutrients from the third flush. It also affects the level of salinity; adjusting the amount of released pins. Parameterization attempts to change the contents of the casing soil have been undertaken before. In works on nutrition tensiometers have been implemented to control the water deficit in the casing soil. Their importance has declined since watering during fruiting has begun. This allowed to eliminate drying of surface casing soil (drying spawn disrupts the release of pins) and water deficit during the growth of fruiting bodies without decreasing the quality and shelf-life.
Relations between dry rot and an amount of flies.
Currently dry rot is the greatest danger of losses caused by diseases of mushrooms. It is observed that in the absence of attraction of substrate for flies, which is an effect of usage of corn, the increase in their raid and activity is associated with the presence of dry rot colony. Probably developing dry rot attracts flies. This results in further development of the colony of dry rot, because flies also carry its spores. Hence the importance of on one hand fast liquidation of the first colonies of dry rot and on the the other hand, preventing the departure of the adult insects from those halls. Using for this purpose a dishwashing liquid (Winnie in the UK) applied to the walls and doors once a week significantly reduces the spread of flies between halls.
Nutrition and the use of substrate.
Feeding process allows a development of a different perspective on the quality and use of the substrate. Starting with the basic finding that Agaricus as a saprophytic fungus feeds on dead organic matter of plant origin (place of occurrence and life, in which it has adopted in the process of evolution). Because of the way in which mushrooms feed we are interested in two types of organic matter; easily available in process of enzyme degradation during colonization and optionally recolonization and organic matter that is not used during this period and subjected to cold composting process by Scytalidium thermophilum. That means that Phase II substrate cultivation is defined by two types of material; its quantities and composition of the microflora. In case of Phase III substrate important factors are spawn’s mass and the presence of dead organic matter subjected to cold composting process and participation of the microflora responsible for the process. This means a necessity to look for new ways of analyzing the substrate. The effect of different types of organic matter was tested during usage of substrate without composting. When introducing straw, as a carrier and digestible organic fabrics in the process of enzymatic degradation, despite receiving fruiting bodies in the first and second flush during the third it disappeared completely and the substrate began to disintegrate.
A separate issue is the question of the composition of the substrate after the cultivation of mushrooms and its usefulness in the process of re-feeding after its introduction to the substrate.The used substrate consists of spawn and undegraded organic matter. This means that to assess the degree of utilization of the substrate the spawn’s mass remaining in the substrate has to be deducted.
Reflecting on the re-use of the substrate after cultivation the question arises of what is the nutritional value of mushrooms spawn without the degradation process. Could it be reused to feed after and administration of process of expansion when it has decayed as the effect of drying or thermal disinfection or cooking? In other words, could Agaricus be to some extent a cannibal? This question needs to be answer.
A separate issue carried out outside the mushroom plant is to build a model of the nutrition of mushrooms in a hypertrophic tunnel by enriching the phase II substrate.
For the past months conditions for the stable yield of mushrooms at the level of 40 kg \ m2 achieved in the process of feeding them has been sought – nowadays 34 -37 kg\m2 in tree flushes. At the end of 2014 an answer to the question how to cultivate mushrooms that in each flush there is adequate distribution of fruiting bodies and how to ensure mushrooms welfare has been reached. Yielding system intended to maintain in the coming period is 20 + 15 + 5 kg \ m2. It seems to be real, but many actions still need to be improved. Since the end of the year to mid-2015 the work is intended to focus on new diets that allow to increase the yield of the second flush to a level of 20 kg \ m2. The test will be conducted in the boxes on the introduction of organic matter which undergoes decomposition under cold composting process. Probably in a granular form.
Since the end of 2014 a new system of collection and control of yield is implemented. It is expected that from this moment it will be able to precisely define the effects of changes carried out.In connection with the proposed changes in the functioning of the Advisory a summary of the whole period of implementation of technologies of growing based on the paradigm of mushrooms nutrition is planned. The final report is planned for the day of May 30, 2015.