Phytate is a substance that has been considered mainly as an antinutrient, but at the same time it is a significant source of phosphorus and has several useful health-related properties that could be exploited. In this respect, a field experiment was conducted to study the effect of organic and conventional cropping systems with nitrogen (N) and phosphorus (P) amounts from 0 to 150 kg ha⁻¹ and 0–25 kg ha⁻¹, respectively, in six years (2017–2022) of weather conditions on phytate content in Estonia. Winter wheat had a higher phytate content of 1.9 ± 0.13 g 100 g⁻¹ compared to spring barley with 1.1 ± 0.05 g 100 g⁻¹. Fertilization with N or P did not affect phytate content in grains. Harvest year weather conditions (precipitation and air temperature) had a strong effect on phytate content. at a specific stage of plant development. Higher values of growing degree days in June and July, which sum in the experimental period varied between 609 and 978 °C, increased phytate content in winter wheat grains (flowering and grain filling stage), while the impact on spring barley phytate content was opposite (heading and flowering stage). Future research should study phytate content in grains grown on varying fertility level soils.

Water and N availability are key factors limiting crop yield, particularly in marginal soils. This study evaluated the effects of water and N stress on barley grown in marginal soils using field trials and the AgroC model. Experiments from 2020 to 2022 in Lithuania with spring barley cv. KWS Fantex under two N fertilization treatments on sandy soil provided data for model parameterization. The AgroC model simulated barley growth to assess yield potential and yield gaps due to water and N stress. Potential grain yields (assuming no water or N stress) ranged from 4.8 to 6.02 t DW ha⁻¹, with yield losses up to 54.4% assuming only N stress and 59.2% assuming only water stress, even with the N100 treatment (100 kg N ha⁻¹ yr⁻¹). A synthetic case study varying N fertilization from 0 to 200 kg N ha⁻¹ yr⁻¹ showed that increasing N still enhanced yield, but the optimal rate of 100–120 kg N ha⁻¹ yr⁻¹ depended on climatic conditions, leading to uncertainty in fertilization recommendations. This study underscores the importance of integrating advanced modeling techniques with sustainable agricultural practices to boost yield potential and resilience in marginal soils. Incorporating remote sensing data to capture soil and crop variability is recommended for improving simulation accuracy, contributing to sustainable agriculture strategies in the Baltic–Nordic region.