Water regimes and soil depth influence on seeds of blood grass (Isahcne miliacea roth ex roem et schult)

Blood grass (Isahcne miliacea Roth ex Roem et Schult) is most dominant perennial weed species in the rice under cultivated and fallow situations belongs to the family Poaceae. The laboratory experiment was conducted at the State seed farm, Kottarakkara, Kollam district, Kerala subjecting the weed seeds to varying soil and water depths. Blood grass free soil and water was used for the study. The design was completely randomised design with 3 replications and 25 treatments. Treatments were the combination of two factors (water depth at 5 levels (W_:: 0 cm, W₂: 2.5 cm, W₃: 5.0 cm, W₄: 7.5 cm, W₅:10 cm) and soil depth of 5 levels (S_:: 0 cm, S₂: 2.5 cm, S₃: 5.0 cm, S₄: 7.5 cm, S₅: 10 cm). Depth of water regime showed that the germination, shoot length and vigour index of weed had only limited sensitivity to shallow water column but when the flooding depth was increased further there was significant decline. When the moist seeds were placed on the soil surface > 95 per cent of the seeds germinated and declined their germination and vigour index on increasing the soil depth. All the seeds failed to germinate at 10 cm soil depth under water column of 7.5 cm (W₄S₅) and 10cm (W₅S₅).