Integrated Weed Management in Summer Maize in Mid-Hills of Nepal

Abstract

Weed is one of the major problems in maize production. To develop an appropriate weed management practice, a field experiment was carried out during 2017 and 2018 at Khumaltar. Twelve different treatments, Pendimethalin as pre @ 1.0 kg a.i ha^-1, Atrazine as pre @ 1 kg a.i ha^-1, Metribuzine as pre @ 0.5 kg a.i ha^-1, Tembotrione as post @ 0.2 kg a.i ha^-1,  Pendimethalin followed by (fb) 1 HW, Atrazine fb 1 HW, Metribuzine fb 1 HW, Tembotrione fb 1 HW,  Atrazine + Metribuzine (early post ) as tank mixed, Straw mulch, Weed free (2 HW) and Weedy check (control) were evaluated in Randomized Complete Block Design (RCBD) with three replications. The experimental plot size was 12 m² and maize variety Manakamana -4 was sown on 21 and 26 May in 2017 and 2018 respectively. The  seed rate used was 20 kg ha^-1 with row spacing of 60 cm and plant to plant 20 cm. Fertilizers dose of 120:60:40 kg N:P₂O₅:K₂O kg ha^-1 was applied. Data on crop growth, weed and yields were recorded and analyzed. Weed count and biomass were recorded from a meter square quadrat and yield data taken from net plot of 5.4 m². Results showed that plant height with straw mulch was maximum of 294 cm. Weed density was significantly influenced by different weed management treatments. Metribuzine post fb 1 HW recorded the less weeds (52.8) and highest (258.5) in weedy check. The lowest weed dry biomass was recorded in Metribuzine post fb 1 HW (9.3 g m^-2). The highest grain yield (7.6 Mt ha^-1) was found in Metribuzine @ 0.5 kg a.i ha^-1 as post emergence. The increased in grain yield due to the application of Metribuzine @ 0.5 kg a.i ha^-1 as post emergence was 32.5% over the weedy check. Similarly, the highest weed control efficiency (77.1%) and the highest BC ratio (2.46) was also recorded in Metribuzine @ 0.5 kg a.i ha^-1 as post emergence.