Soil organic carbon (SOC) and mineral nitrogen (N_min), especially nitrates (NO₃⁻) in agroecosystems have attracted much attention over the past few decades due to their crucial roles in soil fertility, crop productivity, environmental quality, and/or climate change mitigation and adaptation. The aim of the study was to evaluate the contents of organic carbon, ammonium, and nitrate in soils under differentiated pH, texture, and fertilization rates. A large-scale environmental study was conducted in Polish arable lands. The spatial distribution of the sampling points reflected agricultural production conditions, variability of soil properties, and representativeness of textures that are characteristic of Poland. Our results indicated that SOC content was significantly affected by the soil pH and texture as well as mineral and organic fertilization. The same factors, except organic amendments, significantly supported mineral nitrogen concentration in the present study. The most important factors controlling SOC in the study were ranked as follows: soil pH > pre-crop N fertilization > crop N fertilization > N applied with manure > soil texture. In the case of N-NH₄ and N-NO₃, mineral fertilization was the most critical variable. The carbon and nitrogen governance in agroecosystems should consider the ranks of factors controlling their contents.

Soil acidification in agroecosystems is a natural process that could be accelerated, mainly by the inappropriate application of mineral fertilizers, or prevented, by sustainable management practices. On the basis of a three-year field study in a grassland agroecosystem, the impact of different rates of fertilization with nitrogen (N), phosphorus (P), and potassium (K) on soil chemical parameters related to soil acidity was evaluated. It was found that high-rate fertilization with ammonium nitrate accelerated the soil acidification process, which was additionally intensified by the application of superphosphate and potassium salt. The sum of exchangeable base cations, the values of base saturation and hydrolytic acidity in the soil reflected the interactions between the applied NPK-fertilizer levels. Considering chemical parameters related to soil acidity studied in this experiment, it seems that the best strategies for mitigating soil acidification in grasslands are reducing nitrate leaching, changing fertilizer types and increasing the input of base cations.

This study assessed the possibility of using iodine-containing fertilizers for agronomic biofortification of rye biomass used as fodder for cows, and establish the best application method and form and the optimal dose of iodine (I) under field conditions. The impact of iodine fertilization on grain iodine content was not studied. Results showed that agronomic biofortification of rye plants with iodine, influenced by its dose, form, and method of application was highly effective in increasing I shoot contents. Plant I-enrichment via foliar and soil application significantly affected I concentration in plant biomass even at a low dose (2.5 kg ha⁻¹). Soil I application as KI appeared optimal for rye plants used as fodder for cows, especially cropped under the soil with a neutral reaction. Iodine application improved the biological quality of rye plants by increasing concentrations of sugar, chlorophylls, and at a low rate, protein and total antioxidant capacity.

Carbon and nitrogen compounds in agroecosystems have attracted much attention in recent years due to their key roles in crop production and their impacts on environment quality and/or climate change. Since fertilization profoundly disrupted the C and N cycles, several mitigation and/or adaptation strategies, including the application of farmyard manure (FYM) and/or urease and nitrification inhibitors (UI and NI), have been developed. The aim of this study was to evaluate the contents of soil organic carbon and its fractions, the total and mineral forms of nitrogen, as well as CO₂ and N₂O emissions under mineral and organic fertilization with and without urease and nitrification inhibitors in a maize agroecosystem. A two-year field study was carried out on Cambisols (silt) in Poland. The experiment scheme included nine treatments: C (the control without fertilization), UAN (Urea Ammonium Nitrate), UAN+UI, UAN+NI, UAN+UI+NI, FYM with N mineral fertilizer base, FYM with N mineral fertilizer base+UI, FYM with N mineral fertilizer base+NI, and FYM with N mineral fertilizer base+UI+NI. It was found that treatments fertilized with cattle FYM were higher sinks and sources of C and N compounds in comparison to the UAN plots. The organic carbon, humic and humin acid, and total nitrogen concentrations, in contrast to ammonium and nitrate nitrogen, were not affected by the inhibitors added. Nitrification and urease inhibitors were effective in decreasing N₂O emissions only in treatments that were exclusively applied with UAN and had no significant influence on CO₂ emissions.

Land use changes inevitably lead to changes in the carbon stocks stored in the soil. However, despite numerous studies investigating soil organic carbon (SOC) dynamics following the afforestation of post-agricultural lands, findings remain diverse and often inconclusive. In this study, the effect of stand age on the carbon content and stock in Scots pine (Pinus sylvestris) stands located in the Dfb-climate zone was investigated. Five research plots, characterized by similar soil types, geological structures, and tree cover, but differing in stand age (14-, 27-, 37-, 55-, 90-year-old stands), were selected. Additionally, one plot was located at arable soil as a reference. The soil was sampled from both organic and mineral horizons. The content of organic carbon in the organic horizion increased with years that passed from afforestation and amounted to 234.0, 251.6, 255.0, 265.0 and 293.0 g·kg⁻¹ in 14-, 27-, 37-, 55- and 90-year-old stands, respectively. Such a pattern was also observed in the upper mineral horizons where the contents of SOC gradually increased from 7.27 g·kg⁻¹ up to 17.1 g·kg⁻¹. In the organic horizon, the stock of OC increased significantly with stand age up to 55 years after afforestation, while in the former plough layer, SOC stocks were found to slowly increase with stand age. The afforested soils, with the organic horizon, reached levels of carbon stocks observed on arable land after 17 years. Notably, the SOC stock in the mineral A horizon reach this level after 83 years. The obtained results indicate that in the years immediately following afforestation, SOC content is notably higher in arable soils compared to forest soils. However, as stand age increases, the SOC contents of upper horizons in forest soils surpass those of comparable agricultural soils. The observed SOC variability pinpoints the necessity of long-term monitoring in forest ecosystems in order to better understand the temporal dynamics of carbon turnover and to optimize afforestation strategies for long-term carbon sequestration.

Carbon farming and nutrient management, a sustainable pro-environmental and pro-climate approach to enhance soil quality and mitigate carbon losses, faces implementation challenges in the European Union. To explore potentially existing barriers, a survey involved 122 Polish farmers, representing diverse systems and land-use. Utilizing structured questionnaires, in-depth interviews,and Principal Component Analysis, we assessed farmers’ perceptions of six pro-environmental and pro-climate measures. The survey highlighted factors influencing farmers’ willingness to adopt surveyed practices, revealing that the potential to enhance soil carbon and nitrogen stocks outweighed the impact of subsidies, bureaucracy, age, and farm size. Barriers included technical challenges and machinery limitations, notably hindering manure and slurry incorporation. Conservation tillage was considered least feasible nationally, attributed to machinery needs and a preference for conventional practices. Addressing these challenges, especially in conservation tillage, requires targeted education. Raising awareness about measures’ impact on soil carbon stock emerged as a potent means to overcome identified barriers.