Effects of poultry manure biochar amendment on tropical soil CO₂ emission and microbial biomass

• Main Author: Lee, Yin Yin
• Format: Thesis
• Language: English; English
• Published: 2017
• Subjects: QH540-549.5 Ecology
• Online Access: https://eprints.ums.edu.my/id/eprint/38498/1/ABSTRACT.pdf; https://eprints.ums.edu.my/id/eprint/38498/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/38498/
• Institution: Universiti Malaysia Sabah

Biochar is a type of charcoal product which is produced by pyrolysis of biomass under limited-oxygen conditions, and it is a carbon-rich residue. Biochar applied to soil enhances soil respiration by increasing the CO2 production. The objectives of this study are to evaluate the effects of poultry manure biochar amendment on soil CO2 emission and soil microbial biomass, to determine the relationship between soil temperature, moisture content, pH and CO2 emission as well as to evaluate the canopy effect on soil CO2 emission. This study was done at Faculty of Sustainable _Agriculture, Universiti Malaysia Sabah, Sandakan, Sabah, Malaysia (5 ° 55'47" N 118 ° 0'30" E). Twelve maize plots were randomly amended with poultry manure biochar at three rates of 0, 7.5, 15 t ha-1, with each replicated four times. Soil respiration rate was measured in the morning (6 a.m.) and evening (5 p.m.), weekly, for thirty-six weeks during the two crop cycles of the maize crop. Soil respiration was significantly different between the three biochar application rates for both the morning and evening measurements. Generally, the 15 t ha-1 biochar rate had the highest soil respiration rate compared to the others with a mean of 10.54 µmol m· 2s-1 (14.63 kg CO2 m-2 yr-1) over the 36 weeks observations. The 7.5 and 15 t ha-1 of biochar significantly increased the soil pH from 5.45 to 6.20 and 5.48 to 6.35 respectively. Soil microbial biomass and population were significantly affected by the 15 t ha·1 biochar application rate with an increase of about 130% (575.98 mg kg-1) during the second crop cycle. Further, 15 t ha-1 of biochar application resulted in the highest microbial population for both fungi ( 41.88 CFU mI·1) and bacteria (37.50 CFU mI-1) for the soil incubation study.