Effect of fertilisers, dolomite lime, and crop by-products on crop productivity, phosphorus balance and content in Western Polissia’s Retisol of Ukraine

The experiment was conducted in the crop rotation of winter wheat, maize, spring barley, and winter rapeseed in the Albic Retisol from 2012 to 2019. During the experiment, crop by-products were left in the field annually as a common background for each treatment. Before the beginning of the experiment in 2011, dolomite lime was applied at three different doses based on the hydrolytic acidity (Hh) of the soil. Recommended fertiliser doses were applied to the crops with the average annual application of N 112 P 36 K 87 per unit area. The experiment included the following treatments: 1) without fertilisers, when only crop by-products were incorporated into the soil (control), 2) N 112 P 36 K 87 , 3) NPK + CaMg(CO 3 ) 2 (0.5 Hh), 4) NPK + CaMg(CO 3 ) 2 (1.0 Hh), and 5) NPK + CaMg(CO 3 ) 2 (1.5 Hh). Analysis of crop yield and the phosphorus (P) uptake by plant parts allowed to determine the level of P return with crop by-products using the Partial Nutrient Balance Intensity (PNBI) index. In the experiment, a negative PNBI was observed, when only crop by-products were incorporated into the soil (control treatment) or removed from the field, and all other treatments showed positive indices. The PNBI index increased by 1.7–2.8 times compared to the treatment, when by-products were removed. This result suggests that returning of crop by-products to the soil can be an alternative source of phosphorus. The results of the experiment determined the accumulation of total phosphorus (P tot ) and changes in the distribution of phosphorus due to the addition of NPK and CaMg(CO 3 ) 2 together with the by-products returned to the soil. Significant increases in organic (P org ), inorganic (P inorg ), and available (P avail ) P content indicate the accumulation of both phosphorus reserves and its available forms in acid soil. The use of mineral fertilisers and dolomite lime in combination with crop by-products is an effective approach to improve crop productivity and phosphate level in the soil.