Résumé
The application of synthetic fertilizers reduces the natural fertility of the soil and contaminates groundwater. Some photosynthesis inhibitors at ultra-high dilution (UHD) increase photosynthesis, growth, and yield of crops. A weedicide Paraquat at UHD enhanced the growth and yield of potatoes in fields. The objective is to see whether the UHD of Paraquat is also effective on rice. This weedicide was serially diluted with distilled water and manually succussed in 30 steps following the preparation of homeopathic dilutions called potencies. In this way, the 30thpotency of Paraquat called Paraquat 30 cH was prepared and preserved in 90 % ethanol. Paraquat 30 cH was diluted with water 1:1000 (v/v) and sprayed on rice plants in a field measuring 0.3125 acres. The control plot of the same area was situated 300 meters away from the test plot. Three treatments were given at an interval of 7 days. The treated plot showed increased growth, chlorophyll content, and rice yield significantlycompared to control. The UHD of the weedicide produced precisely the opposite effect of the crude material on plants. The increased growth and yield of rice by Paraquat 30 cH may be due to the enhancement of photosynthesis of treated plants. The UHD of Paraquat increased the yield of rice by 19.35% over the control.