Effect of chlorpyriphos in the soil on the onion cultivation and its declining

The use of chlorpyriphos to control the pest attack on onion is high. In certain concentrations, the chlorpyriphos is potentially toxic both to plant and soil organisms. It is important to know the effect of pesticide residue on the crop as supporting data to determine maximum residue limits in soil. This study aims were to 1) determine the effect of chlorpyriphos residues in the soil on the growth of onion 2) determine the effect of chlorpyriphos residues on pest attacks and onion damage 3) determine the level of declining of chlorpyriphos in the soil. The study was conducted in June-August 2018 at the Indonesian Agricultural Environment Research Institute by using a lysimeter as a test site. This study using nine lysimeter plots where 6 plots were polluted with 100 ppm of insecticides formulation solution with active ingredients chlorpyriphos and 3 plots were not polluted. The results showed that contamination of 100 ppm of insecticides formulations with active ingredients of chlorpyriphos into the soil did not inhibit the growth of onion plants, pest attack, and damage. Chlorpyriphos insecticide residue was still detected on the soil on day 7th with a decrease rate of 65.77 % and day 30th with a decrease rate of 99.63 %.