Dynamics of the amounts of nitrogen, phosphorus and potassium available to plants in the field experiment of Haplic Vertisols

Iliana Gerassimova, Lyuba Nenova, Tsetska Simeonova, Martin Nenov, Vania Lozanova, Miladin Nazarkov, Zdravka Petkova

Abstract: Two tillage systems (conventional and minimum) were studied in two three-field crop rotations of the type “cereal crops – arable crops – cereal crops” differing in the type and depth of tillage for the crops included in rotation. The field experiment was conducted in the period 2019-2021 in the experimental base Bozhurishte of IPAZR “N. Pushkarov”, Sofia region. Wheat and triticale were grown in 2019-2020. For the economic year 2020, maize was grown in the experiment and again in 2021,triticale and wheat. Data from agrochemical soil analyzes were used to determine the content of essential nutrients in the soil. The aim of the study was to investigate the effect of fertilization on the amount of some agrochemical indicators in a three-field crop rotation for 3-year period under the soil and climatic conditions of the Sofia region. It was found that the amount of mineral nitrogen in the Haplic Vertisols maintains a relatively good level and there is a slight increase in the variants with the applied norms of mineral fertilizers. This increase is more noticeable in 2021 after triticale and wheat vegetation, which is most likely due to the more favorable weather conditions this year. The content of mobile phosphorus shows a certain increase, but the studied soil remains poorly stocked with this macronutrient. The content of available potassium is in a satisfactory reserve, with some equalization in both crop rotations. The content of organic matter remains good and even shows an increase due to the predominance of humification processes over mineralization in the decomposition of plant residues remaining in the soil after harvesting the main product.

Keywords: crop rotation; humus; macronutrients; maize; pH; wheat and triticale

Date published: 2022-08-16