Compost formula means an optimal quantitative ratio of the components of the used raw materials to prepare this compost.
Compost formula composition is the first step to a big crop. To make the fermentation process go in the correct direction, it’s very important to calculate the initial ratio of the raw materials’ components based on the quality of the existing raw materials. The correctness of selection is determined by the obtained ratio of carbon and nitrogen in the mass after filling and before the beginning of the fermentation process. Under the traditional method of compost preparation this ratio is equal to 30 : 1. That is, for one part of nitrogen, there should be 30 parts of carbon. A question automatically occurs: why not more or less? The answer lies in the practical experience of 1st phase compost preparation. Let’s consider that the primal amount of nitrogen used is greater. The composting process here starts rather actively, but sudden discharge of a big amount of ammonia can abruptly slow down the fermentation process, since the microorganisms will elementary die from a high concentration of ammonia in the mass of compost. It’s especially possible at using a big amount of mineral nitrogen. If excess nitrogen is applied in an organic form – in the form of poultry manure, the compost becomes «heavier» and the ash level increases. The compost becomes sticky and smeary, which has a bad effect on its aeration. The lack of oxygen unavoidably leads to anaerobic processes, which not be liked by the mushroom mycelium in the future. Increasing the doze of gypsum for the structurization of compost, is a serious topic for a separate conversation.
The relation of the carbon and nitrogen ratio to at compost filling to the duration and the preparation of phase I compost.
On the other hand, the use of excess nitrogen under the traditional method of compost preparation is meaningless. The point is that under an ordinary method, phase 1 lasts for 20-25, and sometimes more, days. During this time, the loss of dry material reaches an extremely high level, and the remaining amount of carbon in the end of the process can’t «undertake» this «excess» nitrogen. The «excess» nitrogen can show itself in phase 2 compost as a high content of ammonia nitrogen, or, what’s completely unallowable, as free ammonia.
The shortage of nitrogen at compost filling will have minor consequences anyway. In general – it’s the compost’s low activity on all stages of its preparation, the spawn growth and mushroom fruiting. In addition to this, a part of the lacking nitrogen be compensated with the application of various supplements.
The use of modern methods of 1st phase compost preparation decreases the time needed to prepare the compost. The total duration of phase 1, when using aerated floors and bunkers, is usually 12-14 days and can decreased to 5 days. The loss of dry material in this case is much less. More organic matter remain, along with carbon, which, in the end, serves as food for the fruit bodies of mushrooms. But to use this kind of nutrition more efficiently, there must be a suitable amount of nitrogen in the compost. Filling this «fast» compost by the standard formula of carbon and nitrogen ratio of 30 : 1, can have a negative effect on this compost’s productivity. In this case, it’s appropriate to think of increasing the nitrogen application norms. Here, it’s important to realize that if for some reason the fermentation process in the compost doesn’t go well, the consequences of additional nitrogen can be catastrophic. In the given graph 1, you can see the optimal ratio of carbon and nitrogen at compost filling, and the duration of the compost preparation process. And in graph 2, you can see the dependence of possible content of nitrogen in phase 2 compost on the ash level of this compost
The possible content of nitrogen in phase II compost depending on this compost’s ash content.
The raw materials’ parameters necessary to compose the compost’s formula are determined by laboratory tests. It’s especially important to know the quality of poultry manure – the basic source of nitrogen in compost. The basic poultry manure quality parameters, necessary for calculations are: nitrogen content, humidity and ash level. Determining the poultry manure quality is necessary every time a new batch arrives.
As for the straw, its quality parameters (similar to the ones of the poultry manure) are stable enough, and it’s not necessary to determine them every time. An exception can be the straw’s humidity, which the most important for compost formula composition.
The recycled water’s quality which is used to wet the straw at compost filling plays an important role. Therefore, it’s advisable to determine the nitrogen content in it and take it into account while composing the compost formula, one or two days before filling (so that there’s time left to bring the nitrogen content to an optimal level).
As for gypsum, we’re interested in two of its basic qualities: humidity and pH level.
If using any supplements at 1st phase compost preparation, they are tested using the same parameters as poultry manure.