Effect of barley straw biochar application on greenhouse gas emissions from upland soil for Chinese cabbage cultivation in short-term laboratory experiments

Chinese cabbage was cultivated in upland soil with the addition of biochar in order to investigate the potential for reduction of greenhouse gas emissions. Barley straw biochar(BSB) was introduced in a Wagner pot(1/5000a) in amounts of 0(BSB0, control), 100(BSB100), 300(BSB300), and 500(BSB500) kg 10a^(-1). After the addition of BSB into the upland soil, carbon dioxide(CO_2) emission increased while methane(CH_4) and nitrous oxide(N_2O) emissions decreased. The highest CO2 flux was measured for the BSB500 sample,(84.6 g m^(-2)) followed by BSB300, BSB100, and BSB0 in decreasing order. Relative to those of control, the total CH_4 flux and N_2O flux for the BSB500 treatment were lower by 31.6% and 26.1%, respectively. The global warming potential(GWP) of the treatment without biochar was 281.4 g CO_2 m-2 and those for treatments with biochar were in the range from 194.1 to 224.9 g CO_2 m^(-2). Therefore, introducing BSB into upland soil to cultivate Chinese cabbages can reduce the global warming potential.

Biochar improves soil properties and corn productivity under drought conditions in South Korea

Biochar has been shown to improve soil properties and plant productivity in soils with inherently low fertility.However,little has been reported for upland corns under dry and wet precipitation regimes.This study investigates the effect of biochar addition on a range of soil physicochemical,biological,and hydrological properties,and corn growth and productivity under agrometeorological drought and wet conditions.Here,experiments were laid out in a randomized complete block design with three replications at two sites during 2017 and 2018 in South Korea.Treatments included(i)CN:control(ii)IF:inorganic fertilizer(N-P-K)at 145-30-60 kg ha^(−1);(iii)BS:barley straw at 5 t ha^(−1);(iv)CWBC:corn waste biochar at 5 t ha^(−1);(v)CWBC+IF:corn waste biochar+inorganic fertilizer;(vi)CWBC+BS:corn waste biochar+barley straw.The year 2017 was relatively dry,whereas the year 2018 was wet.Despite drought conditions in the year 2017,biochar facilitated soil water conservation.However,higher precipitation in 2018 increased the quantity and distribution of soil water and nutrients in the top 15 cm.Biochar reduced soil bulk density,and increased porosity,cation exchange capacity and total organic carbon in both years but increased total bacterial counts during the dry year only.Bacterial population was generally higher under wet conditions.Similarly,more soil CO_(2) was emitted in the wet year than in the dry year.Results further indicated that biochar can enhance corn biomass and grain yield regardless of precipitation conditions.The grain index was,however,affected by rainfall and was significantly different across treatments in the year 2018 only.All biomass,grain yield,and grain index were highest in CWBC+IF treatment and lowest under CN treatment.Indeed,biochar addition appeared to improve soil quality and soil conditioning effects in the drought and wet years,ameliorating soil and plant properties.Overall,biochar can improve water and nutrients storage,availability,and uptake,and therefore corn productivity during hydrological extremes.