Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Managing Weeds in Flood-prone Rice Systems

G. Jashim
Principal Scientific Officer
Agronomy Division, Bangladesh Rice Research Institute, Gazipur-1701, Bangladesh

U. Ahmed
Senior Scientific Officer
Agronomy Division, Bangladesh Rice Research Institute, Gazipur-1701, Bangladesh

M. A. Jabbar
Senior Scientific Officer
Agronomy Division, Bangladesh Rice Research Institute, Gazipur-1701, Bangladesh

Abstract/ Executive Summary:

This paper reviews the weed control practices adopted by farmers and improved weed management for flood-prone rice. In flood-prone areas, four types of rice are grown: aus-aman mixed, single broadcast aman and deepwater aman, and boro. The first three are sown in dry soil. In dry seeding, weed competition occurs mostly during stand establishment and the early to mid- vegetative stages of the rice crop. In deepwater rice (DWR), a weed shift occurs when flooding starts. Terrestrial weeds disappear and aquatic weeds grow and compete with DWR. Roating weeds such as Eichhomia crassipes and Pistia stratiotes may intrude into the rice field along with floodwater and may cause serious problems. Wild rice species having tolerance for flooding and elongation ability are a serious threat to DWR. Farmers in these areas use tillage, raking, manual and mechanical weeding, and fencing devices to prevent the entry of floating weeds into rice fields. In dry-sown rice, hand weeding and raking are popular practices for weed control. Herbicides such as butachlor, thiobencarb, and oxadiazon (Ronstar 25EC) are also effective for controlling weeds in dry-seeded rice. To control floating weeds, fencing around the field is still a very popular method as no other costeffective weed control method is available to control them. In boro rice, farmers' weed control is gradually shifting from traditional practices to modern ones. Herbicides such as oxadiazon, cinosulfuron, and butachlor are effective in controlling weeds in boro rice and are gaining popularity day by day. The development of integrated weed control technology is essential for effective and economical weed control of rice in flood-prone lands.

Keywords: Pfood-prone, Rice, Weed management, Weed control

Location: Greater Dhaka and Mymensingh district, Bangladesh

Start Date:

End Date:

Program Area: Risk Management in Agriculture

Non-commodity: Weed management

Objectives:

To determine the weed control practices adopted by farmers and improved weed management for flood-prone rice.

Methodology:

A considerable area of Bangladesh is submerged annually from May to December or part of this period, with water depth varying from just inundation to more than 4 m under normal flooded conditions. The floodplain areas of the Ganges, Brahmaputra, Tista, Surma-Kushiyara, and other rivers occupy about 70% of the country. Contrary to the flatness of the floodplain, there are some saucer-shaped areas called haor and beel, which are chronically flood-prone. The Ganges, Brahmaputra, Meghna, Surma-Kushiyara, and their tributaries change the course of their channels, leaving behind vast basins and old channels. The Brahmaputra changed into its present Jamuna channel about 180 years ago, almost abandoning its former floodplain in Mymensingh and Dhaka. Almost all the big rivers have a history of changing course and they have left behind a vast area prone to flooding. So, natural depressions locally known as baors, haors, or beels are endowed with a flood-prone environment because of the changing course of the rivers. In addition, large areas flooded with large amounts of water from mighty river systems are also a part of the flood-prone environment. Since flooding occurs from May to November, it influences the whole cropping and farming system of the area. During flooding time, only the rice crop is grown in the basin under different flooding depths. Photoperiod-sensitive varieties with longer duration are grown at higher depth and with short duration at a shallow depth of water. After floodwater recedes in November and after harvest of the B. aman crop, the fields are prepared for the rabi crop or other rice cultivation. In some areas, after harvesting the rabi crop, these fields are used for a B. aman crop. After growing a short-duration rabi crop (pulse and mustard), some farmers grow a single aus crop or aus + B. a:man as a mixed crop. In deep places of haors and beels, after the recession of floodwater, only boro rice is grown. About three decades ago, DWR was the principal crop in the flood-prone areas, covering almost 2 million ha. Now, the area has decreased to about 0.8 million ha (Nasiruddin 1993). These areas may decline further with the cultivation of modem boro varieties. With this changing situation, farmers' weed control practices are also changing. Weed infestation in the flood-prone environment: In the flood-prone areas, both aquatic and terrestrial environments are present. After floodwater recedes, the land becomes terrestrial except in the central zones of deep haors. When the boro crop is grown with irrigation, it thrives in a semiaquatic environment. Since weed infestation depends on the environment and crop production practices, the weed species and their populations are also diverse in nature. and Weed control in different rice crops grown in flood-prone environments: Weed control in aus rice- After thorough land preparation, crop seeds are broadcast (70-90 kg ha^-1) over the fields. The weeds and crop seeds germinate and grow simultaneously. So, weeds are a serious problem and need early attention to control them.

Source of Information: Rice Research and Development in the Flood-Prone Ecosystem. Rice Research and Development in the flood-prone ecosystem, Proceedings of the international workshop on flood-prone rice systems held in Gazipur, Bangladesh, 9-11 January 2001, 283p, P237-249, ISBN 971-22-0197-X

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

It is essential to control weeds timely and properly. Under un weeded conditions, a serious yield loss (30-40%) can occur. Farmers practice weeding, but it is not done properly because of ignorance about appropriate techniques, timing, and various socioeconomic reasons. As a result, yield loss occurs. Mamun (1988) noted an average of about 10% yield loss in both local and modem boro rice because of weed competition. Samad et al (1992) observed a greater yield loss in indigenous varieties than in modem ones. They observed a higher competitive ability of modem varieties against weeds than local ones in this agroecological situation. The cost of weed control varies among varieties and other factors, including labor availability. The present practice of weed control is mostly hand weeding and use of a rotary weeder. The cost of weed control generally varies from Tk 2,500 to 3,500 per ha of land. Weeds are undoubtedly a serious problem in rice grown in the flood-prone environment. The current practice of weed control in dry-sown rice is hand weeding, which is laborious and expensive. Herbicide may be an alternative to hand weeding before flooding but there is still a need to protect the crop from water-borne weeds after flooding. Therefore, all pertinent factors that affect the weed problem in aus and DWR should be taken into consideration to develop effective weed control practices. Considerable research results on control of weeds in boro rice are available, but little is known about biological control.

Knowledge Management: Journal