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

ورقة مؤتمر

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.