Soil compaction and fertilisation effects on nutrient content and cellular fluid pH of spring barley (Hordeum vulgare L.)
¹Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, Kreutzwaldi Str. 64, 51014 Tartu, Estonia; e-mail: email@example.com
²Estonian Institute of Agricultural Engineering, Teaduse 13, 75501 Saku, Harjumaa, Estonia
The main objective of this work was to investigate the effect of soil bulk density on nutrient (N, P, K) assimilation and on cellular fluid pH of spring barley (Hordeum vulgare L.) with different levels of fertilisation. Data were collected from the research fields of the Estonian University of Life Sciences (58o23´N, 26o44´E) with four different levels of soil compaction on sandy loam Stagnic Luvisol from 2001 to 2003. The soil was compacted by a tractor MTZ-82 (with loader; total weight 4.9 Mg) before spring sowing. Four levels of fertilisation (N0P0K0, N40P7K20; N80P14K40; N120P21K80) were applied using N20: P3.5: K10 fertiliser. Results of our experiments showed a high positive correlation between soil bulk density and cellular fluid pH (average r = 0.87) and negative correlation between soil bulk density and nutrient content (average r = –0.88) at highest rates of fertilisation (N80P14K40; N120P21K80) and positive correlation (r = 0.84) at lower rates of fertilisation (N0P0K0, N40P7K20) in the earing phase of barley. If the soil bulk density increased up to the level 1.56 Mg m-3, there was a sudden increase of cellular fluid pH without fertiliser use. Use of fertilisers decreased the barley stress. A sudden increase of cellular fluid pH started after soil bulk density 1.61 Mg m-3. The greatest impact of soil compaction was on nitrogen and potassium content in barley dry matter in all fertilisation levels. The nitrogen and potassium content in barley dry matter decreased up to 37% by high soil bulk density depending on fertilisation. The experiment showed that the higher decrease of nutrient content and the sudden increase of cellular fluid pH started at the same soil bulk density value.