The biochar option to improve plant yields: first results from some field experiments in Italy

The pyrolysis conversion of agricultural residues into biochar and its incorporation in agricultural soil, avoids CO2 emissions providing a safe long-term soil carbon sequestration. Furthermore, biochar application to soil seems to increase nutrient stocks in the rooting zone, to reduce nutrient leaching and to improve crop yields. This study re- ports some preliminary results obtained using biochar in two typical Italian agricultural crops. Two field experiments were made on durum wheat (Triticum durum L.) in Central Italy and maize (Zea mays L.) in Northern Italy. In both the field experiments, an increase in yields (+ 10% and + 6% in terms of grain production, respectively) was detected after a biochar application of 10 t ha-1. A further increase in grain production (+24%) was detected when biochar was added with maize residues. The biochar dose-effect curve was studied on perennial ryegrass (Lolium perenne L.) in a pot experiment. The highest increase of dry matter (+120%) was obtained at a biochar rate of 60 t ha-1 and above this threshold, a general reduction of biomass was observed. Results demonstrate the potential of biochar applications to improve in terms of dry matter production, while pointing out the needs for long-term field studies to better understand the effects of biochar on soil.