The Effect of Various Types of Biochar Mixed with Mineral Fertilization on the Development and Ionome of Winter Wheat (Triticum aestivum L.) Seedlings and Soil Properties in a Pot Experiment

This paper focuses on the agronomic evaluation of a synthetic NPK (N in the form of urea, P and K in the form of phosphate monopotassium) fertilizers blended with four types of pine (Pinus sylvestris L.) wood biochar prepared at different thermal regimes (300 degrees C, 400 degrees C, 600 degrees C and 700 degrees C). The evaluation of benefits was done based on crop nutritional status and soil fertility. The pot experiment was set up with fertile Haplic Luvisol fertilized with 1.85 g kg(-1) of blends of biochar (1.25 g) with urea (310 mg) and KH2PO4 (290 mg), which is equivalent to 500 kg ha(-1) (biochar similar to 67.6%; N similar to 7.8%; P similar to 3.6%; K similar to 4.7%) applied before sowing. Only NPK blends made with biochar containing 75% or 85% carbon increased the biomass of 27-day old wheat seedlings from 12% to 20% in comparison to NPK applied alone. These blends raised the content of Mn and Fe in plants but decreased the contents of Ca and Mg. All the tested mixtures enhanced soil fertility by increasing the content of humic acids. Additionally, the content of potentially phytotoxic phenolic compounds was lower. In general, the addition of biochar to NPK fertilizer did not show a negative effect on crop quality. The overall results of the study suggest that the application of low doses of biochar to synthetic fertilizer can benefit crops and can support soil fertility.