Significance of Pyrolytic Temperature, Particle Size, and Application Rate of Biochar in Improving Hydro-Physical Properties of Calcareous Sandy Soil

Conference Paper

2021

Water management and irrigation conservation in calcareous sandy soil are of significant
importance for sustaining agricultural production, especially in arid and semi-arid region that facing
scarcity of water resources. The changes in hydro-physical characteristics of calcareous sand soil
were investigated after date palm waste-derived biochar application in column trials. Significance
of pyrolysis temperature (300 ◦C, 500 ◦C, and 700 ◦C), particle size [<0.5 mm (D0.5), 0.5–1 mm (D1
),
and 1–2 mm (D2
)], and application rate (1%, 2.5%, and 5%) were studied. Variations in infiltration
rate, intermittent evaporation, and saturated hydraulic conductivity as a function of aforementioned
factors were investigated. After amending the top 10-cm soil layer with different biochar and
application rates, the columns were subjected to six wetting and drying cycles by applying 25 cm3
tap
water per week over a 6-week period. Overall, biochar application resulted in decreased saturated
hydraulic conductivity, while improved cumulative evaporation. Specifically, biochar produced at
300 ◦C and 500 ◦C demonstrated 10.2% and 13.3% higher cumulative evaporation, respectively.,
whereas, biochar produced at 700 ◦C with 5% application rate resulted in decreased cumulative
evaporation. Cumulative evaporation increased by 5.0%, 7.7% and, 7.8% for D0.5, D1 and D2
(mm) on
average, respectively, as compared with the untreated soil. Thus, biochar with particle size 0.5–1 mm
significantly improved hydro-physical properties when applied at 1%. Generally, using biochar
produced at medium temperature and small particle size with appropriate application rates could
improve the soil hydro-physical properties.