The experiments were performed in stationary cylindrical lysimeters, which were filled with soil typical of the Eastern Lithuanian region: sandy loam and loamy sand soil (Haplic Luvisol). In the experiment, the main aim was to investigate the balance of nitrogen (N), phosphorus (P) and potassium (K) in the sandy loam and loamy sand Haplic Luvisol and to evaluate their effectiveness and suitability for the light texture soil and agricultural crop harvest in organic agriculture. It was found that, in general, during the three years of the experiment, the balance of N in the sandy loam and loamy sand soil was negative, but fertilization with organic sapropel showed the positive results: less N leaching losses content, compared to other organic-organic fertilizers. Fertilization with cattle manure did not ensure the P positive element balance, in both types of soils, due to a small amount of P in the fertilizer and a high accumulation in the yield. The amount of potassium added each year with NPK fertilizer ensured a positive element balance only in the sandy loam soil.

The aim of this work was to show that fertilization of lightly structured soils (Haplic Luvisol), according to the principles of sustainable agriculture can facilitate achieving more valuable results with lower nutrient leaching losses. The research was performed in stationary concrete cylindrical lysimeters (n = 24, 1.35 m depth) plots in were filled the Haplic Luvisol sandy loam (n = 12, surface area 1.75 m²) and loamy sand (n = 12, surface area 1.75 m²) soil, typical to the Eastern Lithuanian area. Scheme of the experiment: 1) control (no fertilizer), 2) NPK fertilizers (Provita, phosphorite powder and potassium magnesia), 3) 40 t/ha sapropel and 4) 60 t/ha manure. Fertilization with 40 t/ha sapropel was found to significantly reduce nitrate leaching losses in sandy loam and loamy sand soils, compared to other applied fertilizers. 60 t/ha manure tended to reduce potassium leaching content in sandy loam soil. The highest phosphorus leaching losses found in two types of soils with incorporated organic NPK fertilizer (Provita, phosphorite powder and potassium magnesia).

The aim of the study was to evaluate the influence of organic fertilizers on the potato tubers yield and nutrient accumulation. Experiments were carried out at the Vokė Branch of the Lithuanian Research Centre for Agriculture and Forestry in 2016–2018. The experiments were performed in stationary concrete cylindrical 24 lysimeters on sandy loam and loamy sand Haplic Luvisol, with a surface area of 1.75 m2 and a test soil layer of 1.35 cm. Fertilization with three randomized replications on each side of lysimeters were the following: 1) control (no fertilizer); 2) NPK organic fertilizers (Provita, phosphorite powder, potassium magnesia); 3) 40 t ha–1 sapropel; 4) 60 t ha–1 manure. The results of the experiments suggest that 40 t ha–1 sapropel and 60 t ha–1 manure fertilizers increase potato tuber yields in both soils (sandy loam soil and loamy sand soil). Inserted NPK fertilizers produced the highest yield (in 2017 and 2019) of a small fraction of potato tubers. The findings suggest that during the drier period, in 2019, the accumulation of all elements increased about 0.7–7 times in both soils. The starch content in the tubers was dependent mostly on the meteorological conditions.