Effect of N-modified lignite granulates and composted biochar on plant growth, nitrogen and water use efficiency of spring wheat

ABSTRACT

Organic soil amendments such as biochar are increasingly used to improve the fertility of degraded soils and marginal lands, plant growth, water retention and carbon sequestration. The performance of biochar depends on the parent material, the pyrolysis conditions and the nutrient enrichment process, accounting for the variability of the final products. Recently lignite granulates came into focus offering an alternative characterised by homogeneity, vast availability of the raw material and a standardised production process including nitrogen enrichment through oxidative ammonolysis. In a greenhouse experiment the effects of N-modified lignite granulates (NLG) and composted biochar (BC) on the growth of spring wheat (Triticum aestivum) in a sandy, carbon-free substrate were compared. Additionally, the effect of different NLG application rates (5, 7.5, 11, 15, 28 t ha⁻¹) was investigated. Yields as well as nitrogen and water use efficiency of the soil-plant system were determined at the end of the experiment. Both organic amendments increased yields relative to control plants. An increase in yield, nitrogen and water use efficiency for NLG even at low application rates and a better growth performance compared to BC were observed. Present findings, therefore, indicate, that such granulates offer an alternative to existing organic soil amendments.

KEYWORDS:

• Brown coal (bc)
• organic soil amendment  (OSA)
• soil organic carbon (SOC)
• carbon-free sandy substrate (C-less Ss)

Acknowledgments

This work was supported by Association Climate-KIC (Pathfinder “Coal to Green”) and Novihum Technologies GmbH. We thank Prof. Dr. Bruno Glaser and SONNENERDE Gerald Dunst Kulturerden GmbH for their advice and support. We also thank Jonas-Vincent Schulz for his tireless support within his Bachelor-Thesis as well as Katja Boldt-Burisch and Mary T. Lavin-Zimmer for their comments on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was partly funded by Novihum Technologies GmbH; Association Climate-KIC [Pathfinder ‘Coal to Green’].