ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 105, No. 2 (2018), p. 99–104
DOI  10.13080/z-a.2018.105.013

Mineral nitrogen in soils of Lithuania’s agricultural land: comparison of oven-dried and field-moist samples



Mineral nitrogen (Nmin = N-NH4+ + N-NO3) in oven-dried and field-moist samples was investigated in 2011–2014 in five areas of Lithuania with soils of different texture (sand, sandy loam, loam and clay) and different mineral nitrogen (Nmin) content. The samples were taken in spring (from late March to early April) and autumn (late October – early November), from the 0–30, 30–60 and 60–90 cm as well as from 0–60 cm soil layers. The aim of the research was to determine the influence of different methods of soil sample preparation on the concentrations of ammonium (N-NH4+) and nitrate (N-NO3) nitrogen in oven-dried and field-moist samples and to assess the suitability of the obtained results for the development of agricultural plant fertilisation plans.

According to the research results, drying of soil samples at a temperature of 35°C for 12 hours resulted in significantly higher levels of N-NH4+ compared to those of field-moist samples. The N-NO3 concentrations in the field-moist samples, when stored at a 4°C temperature for 3 days, increased marginally compared to the oven-dried soil samples. Weak or moderate, however, statistically significant correlations were observed between N-NH4+ concentrations in the oven-dried and field-moist samples. In order to perform faster chemical analyses of soil Nmin for making agricultural plant fertilisation plans, it is necessary to carry out analyses on oven-dried soil samples, and using the linear correlation equations, to convert the results of N-NH4+ analyses into field-moisture data.

Keywords: ammonium and nitrate nitrogen, preparation of samples for analysis.

Full text: 105_2_str13.pdf