Benifits of biochar application for sandy loam Albic Luvisol

Abstract

The effect of a slow pyrolisys biochar on the watercress (Lepidium sativum L) root growth, on the sandy loam Albic Luvisol water retention, leachate acidity and mineral nitrogen leaching were studied in a six-week laboratory experiment. The experiment included four treatments: control soil; soil + biochar (20 t ha^-1); soil + fertiliser (120 kg N ha^-1); soil + biochar (20 t ha^-1) + fertiliser (120 N kg ha^-1). Spring wheat (Triticum aestivum L) was sown to all the experimental pots. The soil in the pots was regularly watered to keep the water content at the field capacity level. When the wheat plants were strong with well-developed root systems, mineral fertiliser was added to the soil in liquid form according to the experiment setup. On the days 1, 3, 7, 14, 21, 28 and 41 after the fertilizer application high rates of water (400 cm³) were applied to the soil. The leachate was collected and was tested for acidity (pH), available nitrogen in ammonium (N-NH₄⁺) and nitrate (N-NO₃⁻) forms. The water retention capacity of the soil samples was measured at water potentials between -5, and -300 kPa. The results have shown that the extract from the biochar had a stimulating effect on the watercress root growth. Water-holding capacity of the sandy loam Albic Luvisol was increasing after biochar application only at water potentials of –5 kPa and –10 kPa that corresponded to the soil capillary water. The studied biochar did not help in preventing N-NO₃⁻ or N-NH₄⁺ leaching from sandy loam Albic Luvisol.