Effect of Vermicompost and Irrigation with Contaminated Water on Yields and Yield Components of Tomato and Okra

In this research, the effect of vemicompost on yield and yield components of tomato and okra was investigated under irrigation with contaminated water. The experiment included two treatments using vermicompost and control with three replications; and it was conducted at the Campus of Agriculture and Natural Resources of Razi University. Vermicompost was applied at 25 ton per hectare in two stages: 10 t/ha at the crop cultivation period, and 15 t/ha one month after cultivating. The effect of vermicompost growth indexes including plant height, stem diameter, fruit diameter and weight, chlorophyll index, stem and leaf dry matter percentage and yield were investigated. The comparison of the average yield of tomato and okra showed that only fruit weight of tomatoes was statistically significantly different, and there was no statistically significant difference between the two treatments in other characteristics. In tomatoes treated with vermicompost, plant height, stem diameter, chlorophyll index, stem and leaves dry matter percentage were increased by 2.3%, 0.3%, 7.3%, 5.6% and 9.1 percent and fruit diameter, fruit weight and yield were decreased 25.5%, 42.6% and 73.2 percent, respectively compared with the control. Also, in okra under application of vermicompost, plant height, stem diameter, fruit diameter, fruit weight, chlorophyll index and yield were increased by 10.3%, 1.2%, 10.4%, 13.3%, 3% and 35.7%, while stem and leaves dry matter percentages were increased by 5.5% and 11.7%, respectively, compared with the control. Considering the significant reduction in tomato fruit weight and reduction of its fruit diameter and yield, as well as reduction of stem and leaves dry matter in okra, and in light of the high risk of using contaminated water and possible contamination of the fruit and reduction of its quality and health, the use of vermicompost for these crops under irrigation with contaminated water is not recommended. In general, the use of contaminated water is unacceptable for human and animal foods.