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Project Record

Objectives:

To validate and promote weed management practices which will lead to an increase in the productivity and stability of rice-based livelihoods among resource-poor farm households in Comilla Region (rice-rice) the High Barind Tract (rice-fallow or rice-rabi based systems).

Background:

Widespread adoption of fertiliser-responsive modern varieties (MVs) and, the expansion of the area under irrigation have driven the increase in rice production over the past 20 years in Bangladesh. To keep pace with internal demand it has been estimated that paddy production will need to increase from the current level of 22 million to 50 million tons by 2020. This represents an annual growth in yield of 1.5 to 2.0 % per year and will require per ha yields from the rainfed aman and irrigated boro crops to increase by 29 and 17 % respectively. While plant breeding will continue to play a pivotal role, there has already been extensive adoption of high yielding MVs, which accounted for 56% of the total area planted to rice by 1998. In Comilla District for example, which has long been in the forefront of adoption of modern rice production practices, 80% and 100% of aman and boro crops respectively were planted to MVs by 1999 (BBS, 1999). Future increases in rice production will therefore also depend on improvements in the efficiency with which inputs are used. Closing the gap between the rice yields achieved by the best farmers and those with only average yields has now become a high priority. Reducing this yield gap will largely depend on improvements in farmers' management practices. Studies undertaken by CPP funded project R7471 in single, double and triple rice crop systems in Rajshahi and Comilla districts have demonstrated that much of the yield gap can be explained by sub-optimal weed control. Indeed more than one-third of farmers lose more than 500 kg ha-1 to weeds with existing weed management practices. The variation between farmers' current weed management practice is influenced by household resources, land tenure and critically knowledge about the effects of delayed weeding. This suggests that there is considerable scope for raising average rice yields by improving weed management. The project will scale-up the testing and promotion of outputs from CPP project R747 in Bangladesh in intensive irrigated rice (Comilla District) and rain-fed rice-rabi systems (High Barind Tract) by working with farmer groups supported by Extension, NGOs, Bangladesh Rice Research Institute and the private sector. The objective will be to disseminate improved practices for sustainable, cost-effective integrated weed management, including herbicides and mechanical weeding. The project will collaborate with the private sector to develop 'best-practice' in information dissemination along the product supply chain to empower farmers to make informed decisions about herbicide use.

Intended Outputs:

Validation and promotion of the sustainable intensification of rice-rice farming systems through integrated management of weeds and water.

Validation and promotion of the sustainable intensification of rice-fallow farming systems through expanded winter cropping.

Progress and Impact:

1. Validation and promotion of the sustainable intensification of rice-rice farming systems through integrated management of weeds and water : On-farm trials at 20 sites over two years have shown herbicide use to be a robust, effective and profitable technology under various water management scenarios in both aman (rainfed monsoon season) and boro (irrigated dry season). Herbicide use has been demonstrated in transplanted rice in collaboration with DAE at 60 sites per season in four upazillas (local government areas) in Comilla District (S.E Bangladesh). Training of extension officers in safe, efficient use of herbicides prior to each season and farmer field days have been undertaken as components of the demonstration programme. Rice herbicide promotion by the private sector led to 43% increase in sales between 2002 and 2003. Both farmers and extension workers need information about safe and profitable herbicide use and on the integration of herbicides with cultural practices. R8234 has collaborated with the NGO SAFE, to examine a partnership between the NGO and the herbicide manufacturer Syngenta, resulting in the preparation of a training manual on herbicide use that has been distributed to all upazilla agricultural offices in Bangladesh. The project has also raised awareness of information issues in the private sector by a seminar and discussions with 9 companies selling herbicides. A poster covering key issues on safe and efficient use of herbicides has been prepared and distributed for display in pesticide dealers stores throughout Comilla District, making use of the Syngenta dealer network.

2. Validation and promotion of the sustainable intensification of rice-fallow farming systems through improved weed management and expanded winter cropping: The challenge in the drought-prone rain-fed agriculture of the Barind Tract is to simultaneously improve the reliability and yield of monsoon rice while improving total system productivity by increasing the area planted to drought tolerant post-rice crops. Research trials at 25 sites and field-scale evaluation by farmers at 30 sites has demonstrated that dry direct seeding or wet seeding of pre-germinated seed reduces labour for crop establishment, results in rice yields similar to or that are higher than conventional transplanting and advances harvest by a week to 10 days. Earlier harvest reduces the risk of terminal drought in rice when the monsoon ends abruptly and increases the opportunity for establishing a post-rice crop of chickpea on residual moisture. Field work has demonstrated that herbicide use is essential to facilitate direct seeding and this further reduces rice production costs. Herbicide use, to overcome late weeding due to labour constraints in transplanted rice, was demonstrated by DAE and the NGO PROVA at 100 sites across three districts in the Barind Tract, in collaboration with a Plant Sciences Research Programme funded project working on rabi crops. Herbicide use and the modified rice/rabi system, using direct seeding is knowledge intensive. A shift in weed species abundance has been described with long-term use of direct seeding and needs to be factored into farmer training. Widespread sustained adoption will depend on farmers undertaking timely tillage, adequate land levelling and timely application of herbicides. A seminar with DAE and other stakeholders established the need for extension/farmer training supported by clear decision support frameworks. Information collected on farmer decision making for aman and rabi plantings will provide the basis for validation of decision trees to be incorporated into extension materials in the coming months.

Project Conclusions:

In collaboration with NGOs and the Department of Agricultural Extension, research partners in project R8234 (and during previous three years under R7471) developed and promoted a range of sustainable weed management options for rice. This has improved understanding of the agronomic, technical and socio-economic opportunities for productivity gains in two widespread rice-based systems in Bangladesh. These are: a) labour-efficient weed management facilitating the introduction of direct seeding of rice in rainfed Aman-fallow or aman-rabi (monsoon and post-rice seasons found on 1.4 million ha) and, b) improved weed management practices for intensive transplanted Aman - Boro rice systems (monsoon and irrigated seasons found on 2 million ha). Improved weed management will benefit poor rice farmers and sharecroppers directly by reducing unit costs for rice production and, in the Barind Tract, enhancing land productivity and income from rabi cropping. By helping to maintain rice productivity growth and lower rice prices, improved weed management will also benefit poor consumers. The social costs of labour displacement from herbicides and DSR will be reduced by the rapid growth of non-farm rural employment. Adoption of labour-saving technology in rice reflects growing livelihood diversification and the diminishing importance of agricultural labour among the rural poor.

Publications:

MAZID, M., JABBER, M.A., MORTIMER, M., WADE, L., RICHES, C.R. and ORR, A.W. (2003) Developing rice-based cropping systems in north-west Bangladesh: diversification and management. The BCPC International Congress - Crop Science and Technology, Glasgow, 10-12 November 2003, 1029-1034. [Edited conference proceedings]. work ex project R8234.



MAZID, M.A., ANSAR Ali, M., KARMAKAR, B., SALAM, M.A., RICHES, C.R., MORTIMER, A.M. and ATLIN, G. (2004) Cultivars, crop establishment and weed management for a rain-fed rice-chickpea system in the High Barind Tract of Bangladesh. Presentation at: International Symposium on Rainfed Rice Ecosystems - Perspective and Potential, Raipur, India, 11-13 October 2004.



MAZID, M.A., MORTIMER, A.M., RICHES, C.R., ORR, A., KARMAKAR, B., JABBAR, M.A. and WADE, L.J. (2004) Issues related to rice establishment in drought prone areas of Bangladesh. World Rice Congress, Tokyo and Tsukuba, Japan, 4-7 November 2004

Associated References:

R7471