ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 101, No. 2 (2014), p. 133–138
The interdependence of mineral nitrogen content in different soil layers of Lithuanian agricultural lands
Jonas Arbačiauskas, Gediminas Staugaitis, Zigmas Vaišvila, Jonas Mažvila, Tomas Adomaitis, Donatas ŠUMSKIS, Lina ŽIČKIENĖ, Jadvyga LubytĖ, Romas Mažeika
The aim of this work was to investigate the interdependence of mineral nitrogen (Nmin) content in 0–60 and 0–90 cm soil layers and in 0–30 cm soil layer in order to see whether it would be possible to predict the Nmin content in the deeper soil layers based on the Nmin content determined in 0–30 cm soil layer and thus to get a possibility to skip the soil sampling from the deeper layers of soil.
The experiment was carried out in 2009–2012 in 156 monitoring plots of 20 × 20 m size located in 63 regions of Lithuania characterized by the different prevailing soil types and the different soil texture: Eastern Lithuania – Arenosols (AR) and Planosols (PL) – sand, Luvisols (LV) and Albeluvisols (AB) – sandy loam and light loam; Central Lithuania – Cambisols (CM) and Luvisols – light loam, loam, medium loam, clay loam and clay; Western Lithuania – Albeluvisols and Luvisols – sandy loam and light loam. The data obtained from the long-term fertilisation experiment conducted in Central Lithuania on the light loam Cambisol were used in this study as well. Soil samples for the determination of Nmin content were taken from 0–30, 30–60 and 60–90 cm soil layers.
Higher levels of Nmin were found in the soils of heavier texture as well as in the soils of plots treated once with Nmin fertiliser at the rates not lower than 90 kg ha-1. Significant correlations were determined between the Nmin content in 0–60 or 0–90 cm soil layers and in 0–30 cm soil layer: in spring r2 = 0.837, P < 0.01 and r2 = 0.687, P < 0.01, respectively, in autumn r2 = 0.833, P < 0.01 and r2 = 0.723, P < 0.01, respectively. The ratios of Nmin content (as dependent on the Nmin content in 0–30 cm soil layer) in the 0–60 and 0–90 cm soil layers were calculated; when the content of Nmin in 0–30 cm soil layer increased from 6 to 12 mg kg-1, the 0–60 and 0–30 cm soil layer Nmin content ratio decreased from 0.85 ± 0.25 to 0.75 ± 0.13 in spring and from 0.87 ± 0.21 to 0.82 ± 0.17 in autumn. These ratios or regression equations can be used for the calculation of Nmin content in the deeper soil layers based on the available data on the Nmin content in 0–30 cm soil layer. Strong correlations were determined between the nitrate N and Nmin contents in 0–60 and 0–90 cm soil layers in spring and in autumn; the corresponding ratios were calculated. The content of nitrates in soil increases as the Nmin level in soil rises.
Key words: fertilisation, Nmin, N-NO3, sampling depth, soil.
Full text: 101_2_str17.pdf