Current trends of N:P ratio in Chernozem under different fertiliser systems

Abstract

ABSTRACT Russia’s invasion and blockade of Ukraine has complicated the supply of fertilisers and much increased the price, which increases the risk of unbalanced crop nutrition in farmers’ fields. We summarise the stoichiometry of available nitrogen and phosphorus in the plough layer of Chernozem based on long-term field experiments in Forest-Steppe zone. The N:P ratio decreased significantly in the period after 2000, compared to 1971–1999: two-fold without fertilisation, by 1.8–2.7 times with an N background, and by 3.6 times with an NPK background. Possible reasons for the N:P decrease might be drier summers and the high crop demand for nitrogen. Changes of crop yield were inversely related to the N:P ratio in the soil.