Evaluation of biological fertilizers on growth of African daisies (Gazania rigens L.)

Nowadays, fertilizers are one of the factors affecting the yield of plants, but their high use, especially when combined with inappropriate management practices such as burning of plant residues, drastically reduce soil organic matter. Long-term use of chemical fertilizers also results in the leaching and contamination of groundwater. Using biofertilizers to reduce chemical fertilizer use and increase crop yields is an important strategy to move towards sustainable agriculture. So far, no research has been conducted on the effect of vermicompost and vermiwash on the growth and development of African daisies. Therefore, the present study was conducted to investigate the effects of vermicompost and vermiwash on growth and development of African daisies plant.

The present study was conducted to assess the effect of vermicompost and vermiwash on morphological and physiological properties of African daisies (Gazania rigens L.) in 2018. For this purpose, vermicompost was applied at 4 levels (control, 20, 40, and 60 % V/V), and vermiwash was applied at 4 levels (control, 50, 100, and 200 mg/l) as a factorial based on randomized block design. Plant height, number of flowers, flower diameter, root volume, fresh and dry weight of shoot and root, chlorophyll content, insoluble sugar, K, N and P concentration were studied. Statistical analysis of the data was performed using SAS software version 9.1 and comparison of means by Duncan’s Multiple Range Test at 5% probability level.

Vermicompost and vermiwash treatments had significant effects on morphological and physiological properties of African daisies. Interaction effect of vermicompost and vermiwash was significant for all studied traits except P concentration. The highest number of flowers (10) was observed in 60% vermicompost and vermiwash treatment at 100 mg/l. There were no significant differences between 40 and 60% vermicompost volume and also between 100 and 200 mg/ l vermiwash in flower number and diameter. Therefore, increasing the amount of vermicompost and vermiwash to some extent increase the reproductive properties of the plant and higher than that amount can even reduce related traits. By increasing the volume of vermicompost from 20% to 40%, the root volume of African daisies significantly changed. The fresh and dry weight of shoots also showed a similar response to vermicompost and vermiwash treatments. By increasing vermicompost volume from 20 to 40%, the soluble sugar increased significantly in African daisies. Vermicompost and vermiwash increased chlorophyll content in African daisies. The highest amount of chlorophyll b was observed in vermicompost treatment at 60% volume and 50 mg/ l vermiwash.

According to the results of the experiment, vermicompost and vermiwash, with effective nutrient absorption and high water absorption and storage capacity, increased the reproductive traits of African daisies. The effect of vermicompost was higher than vermiwash on studied traits. Treatment of 40% vermicompost and 200 mg/l vermiwash was the best treatment for improvement of African daisies growth