The Effect of Spent Coffee Residues on the Growth and Productivity of Watercress and Swiss Chard Plants

Abstract

This study was conducted to evaluate the effect of fertilization with spent coffee residues on soil properties, growth and productivity of watercress and Swiss chard. Cultivation was done in pots and different amounts of coffee residues were added to the soil (0%, 2.25%, 4.5%, 6.5%). Conductivity, pH, calcium, magnesium, sodium, potassium and exchange capacity in the soil were measured, in addition to measuring plant height, number of leaves, chlorophyll content of leaves and their content. of sodium and potassium. The pH results showed a gradient in the pH rise with the increase in the concentration of coffee in the watercress soil, but the effect was not uniform in the Swiss chard soil, in addition to that the statistical analysis did not show a significant effect for neither the plant factor nor the concentration factor, where the values ranged between 6.8 to 7.6. Regarding conductivity in the soil, no significant differences were found between the average of the two soils of Swiss chard and watercress. Regarding the concentration of sodium in the soil in general, it was higher in watercress soil compared to Swiss chard, and this may be due to the fact that the sodium concentration in Swiss chard is more than in watercress, and the highest concentration was 2172.22 ppm in watercress soil. In general, the addition of coffee has increased the soil's potassium content with significant differences between the control and the rest of the concentrations, whether for total, exchangeable or dissolved potassium. As for the plant, the chard content of sodium and potassium was higher than that of watercress. As for chlorophyll, it did not show any significant difference with the concentrations. It was found that there was an inverse relationship to plant height with an increase in concentrations and number of leaves in Swiss chard, while there was no significant effect for watercress.