تأثیر بیوچار و اسید هیومیک بر كاهش تنش قلیائیت در گیاه ریحان ).L Basilicum Ocimum).

Some organic modifiers can be used to reduce the effects of alkalinity on plants. In this research, the effects of simultaneous application of biochar in the soil and foliar spraying with humic acid on the reduction of alkalinity stress in basil (Ocimum basilicum L.) were investigated. A factorial experiment was conducted based on a completely randomized design with three replications. The factors included alkalinity stress at three levels (0, 50, and 100 mM as NaHCO3 with irrigation water), biochar (at three levels of 0, 1.5, and 3% by weight mixed with soil) and humic acid at three levels (0, 150, and 300 mg/L as foliar spray). The results showed that the interaction effect of alkalinity, biochar and humic acid on most of the growth characteristics as well as the amounts of proline, soluble sugars and plant pigments were significant (P≤0.01). The highest shoot and root dry weight (0.88 and 0.39 g, respectively), shoot height (23.5 cm), root length (19.5 cm) and relative water content (86.4 %) were obtained with application of 3% of biochar and 300 mg/L of humic acid, without alkalinity. Also, the highest amount of proline (3.13 μmol/g) and soluble sugars (6.08 mg/g) were found under severe alkalinity stress (100 mM of NaHCO3), without the use of biochar and humic acid. In general, the simultaneous use of biochar and humic acid is a simple, suitable and cheap method to reduce the adverse effects of alkaline stress in basil. [ABSTRACT FROM AUTHOR]