Effect of fertilisation and utilisation methods of red clover on surface nutrient balance

The research was conducted in a long-term stationary experiment established on light grey forest surface-gleyed soil in 1965. Data presented in this study were collected during 2022–2024 growing seasons within the framework of this long-term experiment. The experiment is registered in the NAAS long-term field experiments registry (certificate No. 29) and the Global Long-Term Agricultural Experiments Network (GLTEN). The study examined the effect of growing red clover in a four-field crop rotation on nutrient balance at different fertiliser and lime doses and ratios. Red clover was used for feed and feed-green manure purposes. The research aimed to substantiate optimal methods of utilising this valuable forage crop and optimise fertilisation systems to ensure sustainable agricultural development. Growing the first cut of red clover for feed purposes and the second as green manure with fertilisation (N105P101K101 + organic fertilisers + liming) ensures a positive surface balance of 402 kg/ha of nitrogen, 150 kg/ha of phosphorus, and 204 kg/ha of potassium. These data are almost twice higher than indicators under minimal fertilisation doses. Despite the reduction in symbiotic nitrogen fixation from 217 kg/ha to 147 kg/ha when growing red clover in crop rotation with intensive fertilisation, it remains an effective phytobiological ameliorant.