HomeInternational Rice Research Notesvol. 28 no. 2 (2003)

Impact of Pulse Applications of Herbicides on Biomass of Grasses and Sedges and their Effects on the Yield and Yield Components of Direct Wet-Seeded Rice

I. U. Awan | M. A. Nadim | F. Anjam | Khansa Hayat

Discipline: Agriculture, Management



Because rice is a staple and an important export commodity for Pakistan, an economical and time-saving cultivation method becomes indispensable. This study aimed to develop a package of technologies to support direct seeding by identifying weed management strategies, establishing appropriate time and date of seeding, and promoting efficient application of herbicides.

An experiment using a splitplot design with three replications was conducted in 1999 and 2000. A subplot size of 5 × 3 m2 was used in each treatment. Main plots were assigned to different herbicide application times (3, 6, and 9 wk after seeding [WAS]), whereas the subplots comprised four herbicides (Ronstar-12 L at 2 L ha–1, Topstar-800 WG at 100 g ha–1, Rifit-500 EC at 1 L ha–1, and Acelor-50 EC at 250 mL ha–1) with one control treatment. Fertilizers at 120-39.6-49.8 kg NPK ha–1 were used. Full doses of P and K and half of N were applied at the time of planting, while the remaining half of N was applied at panicle initiation. Pregerminated seeds of IR6 (100 kg ha–1) were used. The soil is mostly silty clay. Annual precipitation (250–300 mm) mostly occurs in July and August. The 1999 experiments took place on a field where the previous crop was Brassica napus, while the 2000 experiments followed a wheat crop. Soil under the experiments during both years (1999-2000) had a pH of 8.2 and 8.5, respectively.