Wheat Straw Biochar Increases Potassium Concentration, Root Density, and Yield of Faba Bean in a Sandy Loam Soil

ABSTRACT

A greenhouse experiment was conducted to study the effect of different irrigation levels (100%, 75%, and 50% of water requirement) and wheat straw biochar levels (0%, 1.25%, 2.5%, 3.75%, and 5% w/w) on faba bean yield, water productivity, root length density, and different ions concentration in soil solution, using a factorial arrangement in complete randomized design with three replications. Results showed that application of high level of biochar (5% w/w) destroyed the plants before they reached maturity. The maximum yield was obtained in 1.25% w/w biochar under full irrigation, while the maximum water productivity was obtained in 2.5% w/w biochar and 50% of water requirement. Further, the root length density in soil top layer (0–8 cm) was significantly more than those in 8–16 cm, due to holding more water content in top layer and no drainage from the pots. Sodium, potassium, calcium and magnesium ions’ concentrations in soil solution were significantly increased by increasing biochar levels; however, the rate of increase in potassium was higher than other ions due to high potassium concentration in biochar in comparison with the soil. In conclusion, application of biochar in the level of 1.25% w/w is suggested as a suitable agent to decrease water consumption and improving the crop performance.

KEYWORDS:

• Root dry weight
• soil saturated electrical conductivity
• salinity –yield function
• sodium and potassium concentration
• water productivity

Acknowledgments

This research was funded by Shiraz University under Grant no. 93GCU2M222407. The authors also appreciate the support of Drought Research Center and Center of Excellence for On-Farm Water Management. The third author also acknowledges the support of Iran National Science Foundation (INSF).

Additional information

Funding

This work was supported by the Shiraz University [93GCU2M222407].