Biochar amount and Particle Sizes Effects on Plant Available Water, Stomatal Resistance, Root Dry Weight and Water Use Efficiency of Wheat

Biochar contributes to sustainable production by improving soil and plant characteristics. In previous studies, less attention has been paid to the effect of particle size and amount of biochar on soil hydraulic properties and plant water use efficiency. The aim of this field study was to investigate the effect of different amounts of biochar with different particle sizes on plant available water (PAW) and stomatal resistance, root dry weight, yield and Wheat water use efficiency (WUE). Factorial experiment with a randomized complete block design was performed with three factors of type, amount and particle size of biochar. Wheat straw and apricot firewood biochar, in the sizes of 0- 0.5 (S1), 0.5-1 (S2) and 1-2 (S3) mm with amount ​​of 0.5 (R1), 1.5 (R2) and 3 (R3) percent were added to the loamy sand soil. Wheat straw biochar with S2 particle size in R3 amount and apricot firewood biochar with S1 particle size in R3 amount further increased PAW. The lowest stomatal resistance in S3 particle size of wheat straw and apricot firewood biochar was observed in R1 and R2 amounts ​​of these biochars, respectively. Wheat root dry weight was less affected by the amount and particle size of those biochars. A significant increase in wheat yield compared to the control was observed in wheat straw biochar with S2 particle size at amount of R3. In some treatments, the yield was significantly lower than the control. The results of this study showed the greater effectiveness of wheat straw biochar in particle size of S2 and amount of R3 on WUE increase.  The effect of a change in the particle size of biochar on studying properties varied depending on the amount of biochar that added to the soil and the characteristics of raw materials for biochar production. The results of this study showed that the effect of biochar on soil properties is not the same.