The Biochar Option to Improve Plant Yields: First Results From Some Field and Pot Experiments in Italy

Abstract

The pyrolysis conversion of agricultural residues into biochar and its incorporation in agricultural soil, avoids CO 2 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 reports 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.

Crop response to soils amended with biochar: expected benefits and unintended risks

“…The yield rose to 300% when cattle urine was added to this BC before soil application. Similar yield increases have been reported by Baronti et al (2010) in maize, in Chenopodium, and Alburquerque et al (2013) in wheat when BC was combined with either organic residues/compost or mineral fertiliser, and indicate that wood BC may raise nutrient use efficiency when added to organic/inorganic fertiliser/crop residues.…”

“…Many recent studies have reported increased crop yield (Subedi et al, 2016a;Vaccari et al, 2011;Usman et al, 2016;Kammann et al, 2012;Baronti et al, 2010;Uzoma et al, 2011;Houben et al, 2013;Genesio et al, 2015;Cornelissen et al, 2013;De La Rosa et al, 2014;Fox et al, 2014;Gregory et al, 2014;Lin et al, 2015;Schmidt et al, 2015;Butnan et al, 2015;Laghari et al, 2015;Mandal et al, 2016). Others have reported no yield effect (Cornelissen et al, 2013;Uzoma et al, 2011;Nelissen et al, 2015;Subedi et al, 2016aSubedi et al, , 2016bNielsen et al, 2014;Tammeorg et al, 2014;Suddick and Six, 2013;Schmidt et al, 2014;Bass et al, 2016).…”

“…Others have reported no yield effect (Cornelissen et al, 2013;Uzoma et al, 2011;Nelissen et al, 2015;Subedi et al, 2016aSubedi et al, , 2016bNielsen et al, 2014;Tammeorg et al, 2014;Suddick and Six, 2013;Schmidt et al, 2014;Bass et al, 2016). Conversly, few studies have instead described reduced crop yields (Deenik et al, 2010;Baronti et al, 2010;Marks et al, 2014;Nelissen et al, 2014;Bass et al, 2016;Butnan et al, 2015;Laghari et al, 2015). Therefore, interest has emerged to study BC effects that negatively alter crop growth (Jeffery et al, 2011(Jeffery et al, , 2015aSpokas et al, 2012;Biederman and Harpole, 2013;Wang et al, 2016, Olmo et al, 2016.…”

“…Other negative effects from plant-and wood-based BCs are due to one of the following causes: high application rates, high volatile matter contents detrimental to crop growth, reduced plant available N, or negative liming effect in alkaline and calcareous (Deenik et al, 2010;Nelissen et al, 2014;Laghari et al, 2015;Bass et al, 2016;Marks et al, 2014). Baronti et al (2010), in a pot experiment with high BC rates, reported a perennial ryegrass yield increase by 29−120% after BC derived from orchard pruning was applied at between 30-60 t ha −1 to sandy-loam soil with sub-acid pH. When the application rate was raised to between 100 and 120 t ha −1 , a 10-20% decrease in yield was observed.…”

Use of biochar as peat substitute for growing substrates of Euphorbia × lomi potted plants

“…Results from Baronti et al (2010) showed that a 1.7% coppiced woodland-biochar application to soil caused the maximum dry matter production in potted perennial ryegrass, due to an overall amelioration of growth condition, but above this threshold a general reduction of biomass was observed, probably because of changes in some soil properties. Lower performances of Euphorbia × lomi grown in the substrate containing 100% biochar are probably due to the deterioration of chemical (alkaline pH, higher EC and Na) and physical conditions (lower water content and its availability for plants, excessive air content); this response is in line with that from Rondon et al (2007) who observed that the addition of high rate of Eucalyptus wood biochar to a poor soil in a pot experiment resulted in a decrease of crop yield probably due to a micronutrient deficiency induced by increasing soil pH.…”