Effects of municipal waste compost and farmyard manure on reducing drought stress in basil (Ocimum basilicum L)

Drought is one of the most common and important factors limiting production in arid and semi-arid regions. Some organic amendments can be used to reduce the effects of drought on plants. The aim of this study was to investigate the effect of municipal waste compost and farmyard manure on the growth characteristics of basil (Ocimum basilicum L) under water deficit. A factorial experiment was conducted based on a completely randomized design with three replications in 2022 in the greenhouse of Razi University, Kermanshah. The factors included water deficit (at three levels of 50, 75 and 100 % of field capacity (FC), farmyard manure (at three levels of 15, 30 and 45 ton/ha) and municipal waste compost (at three levels of 15, 30 and 45 ton/ha). For the manure, the treatment without manure and also for the compost, the treatment without compost is considered as the control. The results showed that the interaction effect of compost and farmyard manure under water deficit 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 (2.1 and 1.7 g, respectively), shoot height (24.1 cm), leaf area (75.5 cm2) and relative water content (29.3 %) were obtained with application of 45 tons/ha of compost, 45 tons/ha of manure and FC. Also, the highest amount of proline (9.78 μmol/g) and soluble sugars (1.06 mg/g) were found under 50% of FC, without the use of compost and manure. In general, the simultaneous use of municipal waste compost and farmyard manure is a simple, suitable and cheap strategy to reduce the effects of water deficit in basil.