The effect of different potassium fertilization of forecrop on the enzymatic activity of soil in spring barley cultivation

Abstract

The aim of the study was to determine changes of enzymatic activity of soil during spring barley vegetation. The field experiment was carried out in 2011 and 2013 with a completely randomised method, in four replicates, on the experimental plots of the Siedlce University of Natural Sciences and Humanities. The forecrop was pea (Pisum sativum L.), for which the following fertilisation was applied: NK0, NK1, NK2, NK3, NK4, NK5 (N-20; K1-41.5; K2-83; K3-124; K4-166; K5-207,5 kg ha–1). In spring barley (Hordeum vulgare L.) cultivation, six levels of fertilisation were applied: N1K0, N1K1, N1K1, N1K1, N1K1, N1K1 (N1-50, K1-41.5 kg ha–1). The activity of the enzymes was determined four times during vegetation, in soil samples taken from the Ap horizon (0-30 cm layer). The soil was characterised by very high urease act ivity (average 365.5 mg N-NH4 h–1 kg–1 dm of soil.) The highest activity of dehydrogenases was determined in the soil sampled in June from the N1K1 fertiliser treatment (NK3 forecrop). Alkaline phosphatase activity was twice as high as that of acid phosphatase. The highest activity of alkaline phosphatase (0.46-0.64 mmol PNP h–1 kg–1 dm of soil) and acidic (0.26-0.31 mmol PNP h–1 kg–1dm of soil) was characterized by soil taken from the fertiliser treatment N1K1 (spring barley) NK1 (forecrop-pea).

Keywords

• potassium fertilisation
• enzymatic activity
• forecrop
• spring barley