Residual effect of nitrogen fertilizers formulated with biochar

Abstract

Biochar-based nitrogen fertilizers provide productivity and efficiency of nitrogen use gains, but knowledge is scarce about the residual effect for subsequent crops. We evaluated the residual effect of biochar-based nitrogen fertilizers formulated with urea and charcoal fines residues from the coal manufacturing process for the supply of the Brazilian steel park. The treatments tested were related to the residual effect of 80 kg Nha-1 applied via side dressing in an experiment with corn cultivation under field conditions. After corn harvesting, soil samples from the 0-15 cm layer were collected from each experimental plot, respecting the treatments represented by the following sources of N, besides the control: ammonium nitrate, urea and three biochar-based fertilizers r (F51/10, F40/17, and F29/20). The soil was placed in pots (3L) and fertilized with macronutrients (except N) and micronutrients. The test plant was black oats (Avena strigosa Schreb) and three shoot cuts of the plants were performed during 84 days of experimentation. The initial levels of inorganic N in soil, dry mass produced (shoot and root) and N content absorbed by black oats were analyzed.