A/Prof. Zita Kriaučiūnienė1, Dr. Laura Masilionytė2, Prof. Egidijus Šarauskis1, Dr. Aušra Arlauskienė2
1Vytautas Magnus University, Akademija, Lithuania, 2Lithuanian Research Centre for Agriculture and Forestry, Joniškėlis, Lithuania
Long-term field experiments were conducted at Joniskelis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry in 2006–2017 on clay loam Endocalcary-Endohypogleyic Cambisol. Organic and mineral fertilisers were applied with the aim to identify the effects of sustainable (S) and organic (O) agricultural systems on humus stability and its composition in soils with low (LH) and moderate humus (MH) content. Investigations were carried out in crop rotation: spring barley (Hordeum vulgare L.) with undercropped red clover (Trifolium pretense L.), red clover, winter wheat (Triticum aestivum L.) with catch crops, and field peas (Pisum sativum L.). Green-manure catch crops were grown during the winter wheat post-harvest period.
During the studies, after the 1st crop rotation, it was established that alternative systems of agriculture, fertilisation and catch crops had a positive influence on humus content in soils with low and medium humus levels. Further research in the 2nd crop rotation revealed a decrease in humus content compared to both the initial data (from 0.01 to 0.15 percentage points) and the humus content after the 1st crop rotation (from 0.05 to 0.27 percentage points). After the 3rd crop rotation, the positive effect of the applied agro-means was revealed, especially that of manure. The mineral fertilisers used in sustainable system of agriculture II were not effective, but the soil was distinguished by a higher organic carbon content in the first and second humic acid fractions compared to organic system I. Statistically significant negative correlations (from r=-0.654 to r=-0.812) were found between soil humus content and hydrothermal coefficient in all agricultural systems in soils with low and moderate humus levels, except LH OI.
Senior Researcher at Agroecosystems and Soil Sciences Institute of Agriculture Academy, Vytautas Magnus University (Lithuania). Vice-Dean for R&D of Agronomy Faculty. Main research area: crop residue management, innovative oilseed rape growing technologies in intensive and organic farming, oilseed rape allelopathy, sustainable soil management, use of biological preparations in crop management, precision agriculture.