No abstract

The choice of appropriate agricultural practices has a significant impact on soil quality, crop productivity, or soil microbial community. Ten representative soil samples were collected in Wierzchucin Królewski (Kujawsko-Pomorskie Province, NW Poland), an agricultural area belonging to the Potulicka Foundation Group. The cropping systems included a maize monoculture grown continuously for over 30 years and an intercropping mixture (Gorzow mixture) applied in 2020. The study aimed to determine the effect of the intercropping system on the quality and biodiversity of the studied soils and to identify bacterial indicators of sensitivity and resistance to long-term maize monoculture. Therefore, in this study, the impact of the intercrop mixture application on the chemical and biological soil properties and on the diversity of the bacterial community was evaluated by amplifying the 16S rRNA gene sequences and indicators of sensitivity and resistance to long-term maize monoculture were recommended. The results showed that intercropping had a positive effect on soil features and increased the richness and diversity of soil bacteria at the taxonomic level of genera compared to the maize monoculture. Massilia and Haliangium were proposed to be bacterial indicators of sensitivity, while Sphingomonas was recommended to be an indicator of resistance to long-term maize monoculture. Overall, our results evidenced that using an intercropping system may be a sustainable agricultural practice in this area and in north-western Poland.

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One way to prevent the growing carbon dioxide amount in the atmosphere consists in afforestation of forest wastelands such as: heaths, peat bogs, swamps. Replacing such ecological systems by planting them with trees allows to increase the afforested area and, at the same time, to increase the accumulation of organic carbon in the plant biomass. The growing contribution of forest stands may lead to natural restoration, mostly by self-seeding. This study determined changes in the organic carbon resources at the following stages of the natural succession occurring on heaths. The changes were compared with values obtained for the pine cultivation developed from artificial afforestation of the inland dune.The study was conducted on the heathland near the southern boundary of Toruń. Four plots were established in the gradient of the increasing density of pine. The second object of the study was an artificial pine cultivation established on the suburban inland dune (Zadroże Dune). The heather was preserved in abundant quantities in places where wilding pine trees occurred in small numbers (plot I), whereas in places with older self-sown plants (plots III and IV), the heath covered only a small part of the study area, beneath the canopy gaps allowing greater sunlight penetration. The artificial forest cultivation established on a dry habitat with trees three times older compared to self-sown pines on the heathland accumulates similar amounts of carbon in the biomass. The performed analysis showed that there are no significant differences in the carbon resources accumulated in the artificial and well-developed forest ecosystem (ca. 108.30 t C org ./ha) compared to carbon resources in the naturally developing area (plot IV; 94.61 t C org ./ha).

The aim of the study was to verify whether a reduced nitrogen (N) fertilization rate according to the EU recommendation (“From field to table” directive) may guarantee good yields and will be sufficient to maintain soil fertility in monoculture maize cultivation in the no-tillage (NT) system versus the traditional plowing (P) system. Two fields (10 ha each) were established for P and NT maize cultivation where the following N doses were applied: 0.0; 69.0, 92.0, and 115.0 kg ha-1. Soils (0-20 cm) were sampled two times per year - in spring (before maize sowing) and in autumn (after maize harvesting). A broad range of chemical (reaction, water holding capacity, total and easily degradable carbon, ammonium, nitrates, magnesium, calcium, potassium, sulfur) and biological (respiration, humic acids) parameters were monitored during the experiment. The vast majority of these factors had higher values in autumn than in spring. Although the role of reduced fertilization was not shown to be significant, the correlation analysis revealed some relationships between yield and nutrient availability. The 20% reduction in N fertilization does not have an adverse effect on the chemistry and biological characteristics of soils and does not worsen their chemical and biological quality.