## 1 Introduction
[PERSON] and [PERSON] [12] presented that amending pre-graded (0.13-0.36 mm) fine sand with 100 g kg\({}^{-1}\) of woodchip and forest residue BC resulted in an AWC increase from 15.7% to 24.8%. [PERSON] and [PERSON] [13] showed that an addition of 5% of BC (with particles < 63 \(\upmu\)m) produced from an old mango tree and pyrolyzed at 600 \({}^{\circ}\)C to sandy soil increased the AWC from 8.8 to 21%. [PERSON] et al. [2] found that the AWC increased from 4.5% to 11.4% when the olive waste-derived BC was added to the top 10 cm layer of sandy soil at a rate of 5%. [PERSON] et al. [14] presented that the increase in AWC was highest in treatments using the corn straw biochar rate of 4%; in these instances, for biochar particle sizes of 0-0.25, 0.25-1, and 1-2 mm significant increases of 65.3%, 51.4%, and 38.3%, respectively, were recorded. [PERSON] et al. [15] found that the increase in AWC was highest in treatments using the corn straw biochar rate of 4%; in these instances, for biochar particle sizes of 0-0.25, 0.25-1, and 1-2 mm significant increases of 65.3%, 51.4%, and 38.3%, respectively, were recorded. The saturated hydraulic conductivity \(K_{S}\) of sand-BC mixtures varied based on biochar particle size and application rate. [PERSON] and [PERSON] [12] found that amending the pre-graded (0.13-0.36 mm) fine sand with 100 g kg\({}^{-1}\) of woodchip and forest residue BC resulted in a decrease in \(K_{S}\) from 846 to 191 cm d\({}^{-1}\). [PERSON] et al. [16] used the BC produced by slow pyrolysis of pine wood at 300 \({}^{\circ}\)C and presented that the addition of fine BC (<2 mm) at different concentrations to pure silica sand with the median particle diameter of 0.90 mm reduced \(K_{S}\) from 25,900 cm d\({}^{-1}\) (control) to 18,100, 13,000, and 4300 cm d\({}^{-1}\) for 5%, 10%, and 20% concentrations of fine BC, respectively. However, the addition of coarse BC (>2 mm) at concentrations of 5%, 10%, or 20% to sand did not influence \(K_{S}\). [PERSON] and [PERSON] [13] showed that an addition of 5% of BC (with particles < 63 \(\upmu\)m) produced from an old mango tree and pyrolyzed at 600 \({}^{\circ}\)C to sandy soil reduced \(K_{S}\) from 1577 to 114 cm d\({}^{-1}\). [PERSON] et al. [2] presented that \(K_{S}\) acquired using a constant head test decreased from 389 to 52 cm d\({}^{-1}\) when the olive waste-derived BC was added to the top 10 cm layer of sandy soil at the rate of 5%. On the other hand, [PERSON] et al. [17] did not find statistically significant changes in \(K_{S}\) after an addition of wood BC at the equivalent field rate of 75 Mg ha\({}^{-1}\) to a calcareous sandy soil. The addition of water-repellent BC should increase the water repellency of sandy soil. [PERSON] et al. [18] added wheat, corn, and rice straw BC produced at a pyrolysis temperature of 350-450 \({}^{\circ}\)C with a contact angle CA = 107\({}^{\circ}\) to sandy soil and found that the CA of the BC-soil mixture was 55\({}^{\circ}\), 69\({}^{\circ}\), and 77\({}^{\circ}\) for the biochar application rate of 2%, 5%, and 10%, respectively. [PERSON] and [PERSON] [12] observed that the addition of 20, 50, and 100 g woodchip biochar to fine sand altered soil water repellency. The objective of this study was to assess the effects of particle size and application rate of biochar produced under different pyrolysis temperatures on the soil porosity, available water content for plants, saturated hydraulic conductivity, and contact angle of sandy soil. We hypothesized that biochar addition would increase available water content, porosity, and contact angle and reduce the saturated hydraulic conductivity of sandy soil. The effect of biochar would depend on its application rate, particle size, and pyrolysis temperature.