Vol. 11, Issue 11 (2022)

Author(s):
K Chelladurai

Abstract:
Field experiments were conducted to “Integration of varying weed and pest management in rice based cropping system of Sornavari season” at Department of agronomy, Annamalai university experimental farm, Annamalai Nagar during Sornavari (2010 march – July) with rice cultivars of ADT 43. The experiments were taken up in a split plot design with the main treatments viz., during Sornavari untreated fallow during off- season (M_­­­­­₁), allowing pigs into the puddle field for burrowing the soil for 3 days (M₂), duck scavenging in puddled field for 10 days (M₃), duck scavenging in cropped field (M₄), glyphosate spraying @ 1.0 kg ai ha^-1 at 45 days before transplanting (M₅), which where compared with an Weed control and cultural measures taken up during the compared with unweeded control (S₁), twice hand weeding at 20 and 40 DAT (S­­­­­₂), brown manuring application @ 25 kg / ha^-1 (S3). Interculturing with conoweeder using 30 and 45 DAS (S₄). Brown manuring + one hand weeding (S₅), and conoweeder + one hand weeding (S₆) were as sub treatments. Among the off- season practices compared as main treatments, duck scavenging in puddled field for 10 days excelled the other treatments registered significantly higher growth attributes and grain yield (3.97 t ha^-1) in Sornavari . Glyphosate spraying @ 2.0 kg ai ha^-1 45 days before transplanting was next in order. Off- season ploughing 30 days before transplanting was also reduced the weed biomass and favored the grain yield significantly, when compared to leaving the land fallow in the off-season. Leaving the land fallow during the preceding off-season encouraged all types of weeds with the highest weed counts, weed dry matter production and lowest weed control index resulting in poor grain yield. Among the rice weed control measures conoweeder + one hand weeding was superior and was on bar with brown manuring + one hand weeding recording higher growth attributes and grain yield (3.87 t ha^-1) in Sornavari. These treatments were significantly superior than the rest in reducing the weed infestation and ultimately increasing grain yield. Unweeded control recorded the highest weed counts, weed biomass resulting in the least grain yield. Significant interaction effects between the main treatments and sub treatments were also observed.