There was a significant correlation (r=0.984) between densities of wrinkle grass and paddy yield. Densities of 20, 40, 60, 80, 100, 120 and 140 plants/m2 of wrinkle grass in transplanted rice caused 12.5, 22.4, 30.5, 35.4, 38.9, 42.4 and 54.4 per cent reduction in yield of paddy over weed free conditions. Wrinkle grass at 140 plants/m2 removed 63 kg N, 63 kg P and 103.6 kg K/ha and greatly reduced nutrient uptake by the crop.
