Abstract
Eight field experiments were conducted to study the effects of different crop establishment methods, nitrogen fertilizer and weed management practices on Boro rice in high and lowlands ecosystems from November 2004 to May 2007 at Gazipur. Four of the experiments were conducted at the Bangladesh Rice Research Institute Experimental Farm in highland ecosystem and the remaining four experiments at the farmers’ field of Pubail village in lowland ecosystem.The results indicated that in highland ecosystem, line sowing tilled wet soil method gave the highest agro-economic productivity compared to other methods. Among the weed control methods, Ronstar + one hand weeding gave the highest agro-economic productivity followed by two hand weeding and three hand weeding. In case of time of nitrogen application, four splits nitrogen applications (at 20, 40, 60 & 85 DAS) gave the highest agro-economic productivity than three splits and leaf colour chart (LCC) based nitrogen application. For level of nitrogen, 160 kg N ha⁻¹ gave the highest panicles/m⁻², grains m⁻² and agro-economic productivity of Boro rice compared to 120 kg N ha⁻¹ and 80 kg N ha⁻¹.The results also implied that in lowland ecosystem, line sowing zero tilled wet soil method gave the highest agro-economic productivity of Boro rice compared to broadcasting zero tilled wet soil method and transplanting method. For weed control, Ronstar + one hand weeding treatment gave the highest yield and agro-economic productivity of Boro rice compared to three and two hand weeding. For time of nitrogen application, LCC based nitrogen application treatment gave higher yield, less variable cost and higher gross margin compared to four splits nitrogen application. In case of level of nitrogen, 120 kg N ha⁻¹ gave higher panicles/m⁻², grains m⁻² and agro-economic productivity of Boro rice.