## 4 Discussion
### Successful Afforestation Problem-Oriented Solution Approach  
Land designated for afforestation in Poland includes 2.3 million hectares of marginal land. These include infertile soils, soils contaminated with chemicals, damaged or mechanically transformed soils, and fallow land or land with unfavourable natural and topographic conditions [17]. The specific physico-chemical and biological conditions of former agricultural soils pose a risk of infection with root pathogens such as _Heterobasition_ spp. [18; 19; 20]. In Poland, biological control has been successfully introduced on a large scale [4], but nowadays the creation of natural soil resistance would probably be the best prevention method. The integrated approach to soil health assumes that soil is a living system whose equilibrium is determined by interactions between physical, chemical, and biological properties, with the activity of the soil microbiota playing an important role [21]. Fungi are an important component of soil health, with a high adaptability to habitat requirements [22]. They fulfil various ecological functions and occur as saprotrophs that transform dead organic matter and influence the carbon and nitrogen cycles of the ecosystem [22], as mycorrhizal fungi that form symbiotic relationships with plants [23], and as pathogens that cause major damage to forest stands [24]. The diversity and activity of soil fungi are influenced by various abiotic factors such as soil pH, moisture, salinity, soil structure, or temperature conditions [25]. Soil fungal populations are also influenced by targeted soil use, e.g., agricultural crops [26]. Optimising yields of agricultural crops requires the use of plant protection products, including fungicides. These can have negative impacts on the environment through leaching of their residues into the soil [27]. According to [PERSON] et al. [28], the use of fungicides in agroecosystems negatively affects soil microorganisms, which have important functions in the soil as they are involved in organic matter degradation and nutrient metabolism [29]. In a study by [PERSON] et al. [30], it was shown that the excessive use of triazole fungicides has harmful effects on both the population of microorganisms and the activity of their soil enzymes. Long-term nitrogen fertilisation, which is necessary for the production of high-quality agricultural products, leads to unfavourable changes in fungal populations in the soil. A study by [PERSON] et al. [31] showed that the most common classes of fungi in all the soils studied were _Dothideomycetes_, _Eurotiomycetes_, _Leotiomycetes_, _Sordariomycetes_, and _Agaricomycetes_. The results of the study confirmed that long-term application of nitrogen and phosphorus fertilisers reduces fungal biodiversity and significantly alters fungal community composition. In addition, higher fertiliser concentrations were found to have a greater impact on fungal communities than lower concentrations [31]. Our observations revealed a lower abundance of _Sordariomycetes_ in the control than in the treatments. A study by [PERSON] et al. [26] demonstrated that the application of sustainable management practices, mainly based on the use of organic fertilisers and reduced tillage, has a positive impact on the total number of microorganisms in the soil, including fungi and bacteria. Under our experimental conditions, the abundance of _Agaricomycetes_ in BCR, S, and WW and of _Tremellomycetes_ in BCS and WW, in particular, increased compared to C.  
The identified group of _Ascomycota_ forms ascocarps, usually in the form of a perithecium, rarely a cleistothecium, and the sacs are usually 8-spored, lack a lid (operculum), and are arranged at the base or margin of the hypennium. They are widespread and occur in virtually all ecosystems. They can be pathogens of plants (e.g., _Cryphonectria parasitic_, which causes chestnut blight, and _Magnaporthe grisea_, which attacks rice), arthropods or mannals, and parasites or saprotrophs.