Effect of dolomite and biochar addition on N2O and CO2 emissions from acidic tea field soil

Abstract

A laboratory study was conducted to study the effects of liming and different biochar amendments on N2O and CO2 emissions from acidic tea field soil. The first experiment was done with three different rates of N treatment; N 300 (300 kg N ha-1), N 600 (600 kg N ha-1) and N 900 (900 kg N ha-1) and four different rates of bamboo biochar amendment; 0%, 0.5%, 1% and 2% biochar. The second experiment was done with three different biochars at a rate of 2% (rice husk, sawdust, and bamboo) and a control and lime treatment (dolomite) and control at two moisture levels (50% and 90% water filled pore space (WFPS)). The results showed that dolomite and biochar amendment significantly increased soil pH. However, only biochar amendment showed a significant increase in total carbon (C), C/N (the ratio of total carbon and total nitrogen), and C/IN ratio (the ratio of total carbon and inorganic nitrogen) at the end of incubation. Reduction in soil NO3--N concentration was observed under different biochar amendments. Bamboo biochar with the rates of 0.5, 1 and 2% reduced cumulative N2O emission by 38%, 48% and 61%, respectively, compare to the control soil in experiment 1. Dolomite and biochar, either alone or combined significantly reduced cumulative N2O emission by 4.6% to 32.7% in experiment 2. Reduction in N2O production under biochar amendment was due to increases in soil pH and decreases in the magnitude of mineral-N in soil. Although, both dolomite and biochar increased cumulative CO2 emission, only biochar amendment had a significant effect. The present study suggests that application of dolomite and biochar to acidic tea field soil can mitigate N2O emissions.

Returning Tea Pruning Residue and Its Biochar Had a Contrasting Effect on Soil N2O and CO2 Emissions from Tea Plantation Soil

“…This result was also supported by correlation analysis that N 2 O emission was inversely related with soil C/N ratio in this experiment ( Figure 7). Ernfors et al [44] and Oo et al [24] also reported that soil C/N ratio was negatively correlated with N 2 O emission, although no significant correlation was observed by Feng and Zhu [45]. Previous studies indicated that as the relative C content increases in soil, a higher proportion of ammonium is immobilized (or assimilated) by microbes instead of being nitrified (or mineralized), leading to a decrease in soil inorganic N and suppression of N 2 O emission [42].…”

“…Pruning residue of tea plants was about 4 t ha −1 in dry weight. Biochar was produced from carbonization of tea pruning residues under open fire using open burn kiln [24]. Pyrolysis temperature was approximately 500-600 • C and biochar yield was about 30% on a dry weight basis with this method.…”

“…However, biochar addition has been reported to have positive, negative, or negligible effects on soil N 2 O emissions [19][20][21][22][23][24]. This apparent inconsistency might be due to differences in biochar types and properties of the soils used.…”

“…Studies have reported that biochar amendment affects C and N turnover by influencing microbial community structure and biomass [17], and hence alters CO 2 and N 2 O emissions from soil [18]. Biochar addition has been reported to have positive, negative, or negligible effects on soil N 2 O emissions [19][20][21][22][23][24]. This apparent inconsistency might be due to differences in biochar types and properties of the soils used.…”

Aerated Irrigation and Pruning Residue Biochar on N2O Emission, Yield and Ion Uptake of Komatsuna

“…Recently, biochar has received attention for possible use in agricultural soils. Conversion of crop residue into biochar and its application in soil as a soil amendment is a novel approach as a soil improver, as well as for carbon sequestration, improved soil fertility and crop production [15] and decreased greenhouse gas emission [16][17][18][19]. However, no difference or even an increase in soil N 2 O emissions after biochar application was observed in other studies [20,21].…”