Title of document: Integrated Nutrient–Weed Management under mechanised Dry Direct Seeding (DDS) is essential for sustained smallholder adoption in rainfed lowland rice (Oryza Sativa L.)

Authors: Pheng Sengxua, Tamara Jackson, Phetsamone Simali, Leigh K. Vial, Khamsouk Douangboupha, Elizabeth Clarke, Dome Harnpichitvitaya and LEN J. WADE

Journal’s name if any:

Ministry/Government Agency/Organisation: Cambridge University Press

Year of publication: 2018

Geographic focus: Lao PDR

Main issues / topics addressed (for example: Introduction; Materials and Methods; Results and Discussion; Conclusion…)

School of agroecology (if any):

Web address to original document (if any): https://www.cambridge.org/core/journals/experimental-agriculture/article/integrated-nutrientweed-management-under-mechanised-dry-direct-seeding-dds-is-essential-for-sustained-smallholder-adoption-in-rainfed-lowland-rice-oryza-sativa-l/9BF9B05F08CFE5505AC994E5F1234274

Summary:

In rainfed lowland rice-based systems, increasing labour scarcity due to off-farm employment is encouraging farmers to switch from transplanting to dry direct seeding (DDS). To assure stable productivity at a level comparable with or superior to transplanting, DDS management must ensure rice seedlings have access to nutrients in order to be competitive with weeds, which must also be suppressed. This paper examined farmer perceptions of DDS using a farmer survey, and used on-farm experiments to examine responses of rainfed lowland rice to integrated nutrient–weed management, based around mechanized DDS. In the survey, weeds were the biggest problem faced by farmers in using DDS (61%). In 90% of cases, farmers reported that weeds had increased under DDS, with most farmers (78%) controlling weeds by hand. All farmers said they would use DDS in the following season (100%), due to labour savings (47%), timeliness of operations, improved productivity, low investment or a combination of these (44%). In on-farm experiments, banding nutrients with the seed at sowing enhanced early dry matter of rice, while early weed dry matter was reduced. Early weed control using ducklings or hand weeding reduced weed competition and increased rice growth, with ducklings providing additional yield benefits over hand weeding. Early increases in seedling vigour of rice, and in weed suppression, carried through to greater dry matter and yield of rice at maturity. Integrated nutrient–weed management in mechanized DDS increased DDS yields, reduced DDS yield variability and contributed to sustainability of DDS rice systems.