Influence of pruning waste biochar and oyster shell on N2O and CO2 emissions from Japanese pear orchard soil

Abstract

Two incubation experiments were conducted under controlled moisture and temperature conditions to determine the effects of soil amendment treatments based on pruning waste biochar and oyster shell, on N2O and CO2 emissions from an orchard soil. In experiment 1, four treatments were tested including, control (CK), pruning waste biochar at 2% (B2%), at 10% (B10%), and oyster shell (OS), mixed with soil from two different depths, namely, from the 0–5 cm and the 0–10 cm layers. In experiment 2, only the 0–10 cm soil layer was used to study the effect of surface application of pruning waste biochar (B2% and B10%) on soil N2O and CO2 emissions. The results showed that soil pH, total C and C: N ratio increased with biochar amendment treatments. Significant reduction in soil NO3− content was observed for the B10% treatment. Although OS application increased soil pH, no effect was observed on soil mineral N content, total C or C: N ratio. The rate of N2O emissions from the 0–5 cm soil layer after B2% and B10% addition, significantly declined by 12.5% and 26.3%, respectively. However, only the B10% treatment caused significant reduction in N2O emissions from the 0–10 cm soil layer and from surface soil, by 15.1% and 13.8%, respectively. Oyster shell application had no effect on either soil N2O or CO2 emissions from either soil layer tested. Our results suggest that the addition of pruning waste biochar at a high rate has the potential to mitigate N2O emissions from orchard soils; while, oyster shell can be used for liming without altering soil N2O nor CO2 emissions.

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

“…The reduction in CO 2 emission upon biochar application on the soil surface has also been reported by Oo et al [39]. When pruning residue was returned to the soil as surface application, soil CO 2 was relatively higher compared to the control and biochar treatment.…”

“…When pruning residue was returned to the soil as surface application, soil N 2 O was relatively higher compared to the control and biochar amendment which was due to its low C/N ratio. Our previous study also showed that surface application of high rate (B10%) of pruning waste biochar to Japanese pear orchard soil significantly reduced N 2 O emission [39]. Decreased in N 2 O emission under surface application of biochar might be because of its high C/N ratio compared to C/N ratio of pruning residue.…”

“…The air samples were collected on 0, 1, 2, 3,4,7,11,14,18,25,28,32,36,39,43,47,50,57,63,68,75, 83 and 90 days of incubation. Before sampling, the jars were thoroughly flushed with ambient air and left opened for approximately 30 min to equilibrate with the atmosphere [23].…”

“…Tokuda and Hayatsu [38] reported a negative exponential relationship between soil pH and N 2 O emission potential in tea plantation soil. The N 2 O emissions can be decreased compared to the control due to an increase in soil pH by biochar amendment [20,39]. The likely reason is that low pH prevents the assembly of functional N 2 O reductase (N 2 OR), the enzyme that reduces N 2 O to N 2 in denitrification [40].…”

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].…”