Plant pathogenic nematodes play an important role in crop production and are difficult to control. One of them is Heterodera schachtii—a cyst nematode, pathogenic to sugar beet. Nature suggests a natural way to resolve this problem by using nematode-trapping fungi, one of which is Pleurotus ostreatus. It is one of the most widespread mushrooms in the world. It is a valuable and widely cultivated edible mushroom with nematocidal properties. The mycelium of this mushroom produces toxin droplets that paralyze nematodes, after which the nematodes become infected with the hyphae filament, resulting in their death. This feature can be put to practical use as a natural nematocidal agent. In this paper, we have described studies on the variability of the nematocidal properties in the progeny of three wild strains of P. ostreatus (Po1, Po2, Po4), obtained by crossing dikaryons with monokaryons (Buller phenomenon). The toxicity of mycelium was tested against the model organism Caenorhabditis elegans and against sugar beet pest—H. schachtii. The results of the study allowed the selection of the progeny heterokaryotic mycelia with the best parameters useful for in vitro control of both nematodes. They differed in the activity against C. elegans and H. schachtii, and in the toxic knobs production. The results indicated that the progeny of the Po1 strain presented a good ability to produce hyphal knobs in the presence of C. elegans, and progenies of the Po4 strain presented good quality of growth in preferred temperatures (10–25 °C). Three strains Po1 5dix27, Po2 20dix21, and Po4 2dix1, as well as a maternal strain Po4 controlled H. schachtii by entwining cysts better than other strains. These strains were moderately effective against C. elegans. Strains Po2 15dix17, Po4 1dix18, and Po4 1dix30 may be considered good controlling isolates against both tested organisms. The results of the research also clearly suggest that the killing properties of P. ostreatus mycelia should not be assessed only by their ability to produce toxic hyphal knobs. Their nematocidal properties also depend on other mechanisms developed by mycelia, which is observed as the lethality of nematodes. The results of this research will lead to a natural way to protect plants against nematodes. The research also proved the nematocidal properties of the wild strains to reduce the H. schachtii population in the soil.

In the period of 2016–2018, two series of field studies on organic sugar beet growing (Beta vulgaris L.) were carried out in northern Poland on Luvisol loamy soil (medium–heavy) soil in Bałcyny and Płonne. The aim of this study was to decrease the yield gap between organic and conventional beets. Factors to increase the yield of organic beet were differentiated fertilization (cattle farmyard manure (FYM), compost, and Bioilsa) and choice of varieties (Eliska, Jampol, and Sobieski). The reference point was the conventional cultivation of the same sugar beet varieties, fertilized with manure and NPK mineral fertilizers, the prevailing standard of sugar beet cultivation in Poland. High sugar beet root yields exceeding the average yield in Poland by 25–30% were obtained in both studies, both in conventional and organic cultivation. Higher root and white sugar yields were obtained in the study conducted at Płonne (with similar soil conditions to those at Bałcyny), but they were characterized by higher temperatures during the growing season. The lowest root yields in both experiments were obtained by fertilizing the organic beet with compost (66.1 t per ha in Bałcyny and 78.13 t per ha in Płonne), which were 10.8% and 8.5% lower than the conventional crop, respectively. Higher root yields in organic cultivation were obtained by fertilizing the sugar beet with FYM, which reduced the differences from conventional beet to 7.7% in the study in Bałcyny and 2.1% in the study in Płonne. Thus, the results showed no need to convert cattle FYM to compost. The highest root yields in organic cultivation were obtained by fertilizing the sugar beet with Bioilsa N 12.5 supplemented with mineral fertilization of K, Mg, and S (Patentkali). This fertilization provided a yield of 78.1 t of roots per ha in Bałcyny, which is a reduction in the yield gap to 1.4%, a statistically insignificant value. Moreover, in the study at Płonne, organic sugar beet fertilized with Bioilsa and Patentkali yielded 86.7 t of roots per ha, compared to 85.6 t per ha of conventional beet, so a yield gap was not seen here. The choice of varieties was also of great importance for root and pure sugar yields in both farming systems. The lowest yields were obtained from the Eliska variety, and at Bałcyny, a change of beet cultivar to Jampol increased the organic root yield from 68.8 t per ha to 76.0 t per ha, while reducing the yield gap from 10.1% to 2.2%. At Płonne, replacing the Eliska variety with Jampol reduced the yield gap between organic and conventional roots from 6.6% to 0.3%.

Weed competition restricts organic cereal production. In our study on the mechanical control of weeds, classic (tined weeder) and modern machines were used (spring-tined weeder, rotary weeder and camera-guided hoe). The study was conducted in two growing seasons, 2023–2024 and 2024–2025, on an organic farm, with medium-heavy soil in central Poland. Precision weed control included the following treatments: the first pass was done using a precision spring-tined weeder, the second using a rotary weeder, the third using a camera-guided precision hoe, and the fourth using the rotary weeder once more. Precision weed control compared to classic weed control resulted in a 5.5-times lower number of weeds per 1 m² and an 8.6-times lower weed biomass. Precision weed control resulted in higher yields—in a classic weed control scheme, spelt wheat yielded almost 4.5 t of dehulled grain per ha, and in precision weed control, yields were ca. 10% higher. Grain quality was high—protein content was approximately 14%, gluten content 28.8% and the Zeleny index was 53.8 mL.