Adaptation of rice (<i>Oryza sativa</i> L.) genotypes in the rainfed lowlands of Lao PDR

Sengxua, Pheng; Samson, Benjamin; Bounphanousay, Chay; Xayavong, Sisavanh; Douangboupha, Khamsouk; Harnpichitvitaya, Dome; Jackson, Tamara; Wade, Leonard

doi:10.1080/1343943x.2017.1403290

Cited by 10 publications

(3 citation statements)

References 22 publications

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“…The soils used in Champhone A and B and Phalanxay were generally more fertile than those in Phin and Phonthong, where organic C levels were extremely low (Table 1). DDS was always conducted in early June, and the chosen cultivars were similar in time to flowering (Table 1), although TSN9 and VT450-2 may be higher yielding than TSN7 and TDK8 (Sengxua et al ., 2017). All of these sites were quite sandy in texture (Linquist and Sengxua, 2001), and toposequence position could be an important influence on crop duration (Wade et al ., 1999).…”

Section: Discussionmentioning

confidence: 99%

Integrated Nutrient–weed Management Under Mechanised Dry Direct Seeding (Dds) Is Essential for Sustained Smallholder Adoption in Rainfed Lowland Rice (Oryza Sativa L.)

Sengxua

Jackson

Simali³

et al. 2018

Ex. Agric.

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SUMMARYIn 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 mechanised 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 mechanised DDS increased DDS yields, reduced DDS yield variability and contributed to sustainability of DDS rice systems.

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Section: Discussionmentioning

confidence: 99%

Integrated Nutrient–weed Management Under Mechanised Dry Direct Seeding (Dds) Is Essential for Sustained Smallholder Adoption in Rainfed Lowland Rice (Oryza Sativa L.)

Sengxua

Jackson

Simali³

et al. 2018

Ex. Agric.

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“…In contrast, there are many limiting factors in other local cultivars, and therefore, the R 2 might be lower than improved cultivars. The global production constraints in lowland paddy fields contributing to low rice yield include poor soil fertility, drought, flooding, and diseases (Fukai & Ouk, 2013;Manzanilla et al, 2011;Sengxua et al, 2017). However, information regarding the cultivation environment and management and their effects on rice productivity in farmers' fields is quite limited (Tsujimoto et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

A leaf area‐based non‐destructive approach to predict rice productivity

2021

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Leaf canopy dynamicsare associated with crop productivity. Frequent, nondestructive measurements of the leaf canopy using a plant canopy analyzer, followed by parameterization using a mathematical model, enabled the quantification of leaf area growth characteristics. However, an understanding of the rice (Oryza sativa L.) cultivar effect under various field conditions is limited. Therefore, this study aimed to compare leaf area growth parameters with rice productivity and analyze the cultivar differences in these relationships. In a 3-yr field experiment, six rice cultivars were grown under environments with different nutrient provisions. Two leaf area growth parameters (maximum leaf area index growth rate and maximum interception rate) were determined from the measurements obtained using a plant canopy analyzer.They were compared with five crop growth parameters for rice productivity (yield, total dry weight, crop growth rate, nitrogen uptake rate, and radiation use efficiency).A logarithmic relationship exists between leaf area growth and crop growth parameters, which varied among rice cultivars. In addition, the leaf nitrogen content at the heading stage was associated with the cultivar variations. After considering the cultivar differences, yield prediction accuracy was improved using leaf area growth parameters (from R 2 = .428 to R 2 = .752). This indicates that these parameters are considered efficient indicators of rice productivity with regard to cultivar differences and leaf nitrogen content. The evaluation method using the parameters calculated with non-destructive measurements could be a standard for crop monitoring in field experiments and will be useful for estimating crop productivity.

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“…The results from economic analysis demonstrate the economic advantages to the farmer of growing perennial rice, which accrue predominately via savings in labour and labour intensity by not having to sow and transplant in each crop cycle (Tables 8 and 9). Labour scarcity is increasingly an issue in rice production [20][21][22], so it is not surprising that farmers liked the capacity of PR23 to regrow after harvest (Table 10), thereby reducing labour demand, and also the drudgery implicit in transplanting, especially for women and children.…”

Section: Economics and Farmer Preference Of Pr23 Perennial Rice Versumentioning

confidence: 99%

Performance, Economics and Potential Impact of Perennial Rice PR23 Relative to Annual Rice Cultivars at Multiple Locations in Yunnan Province of China

et al. 2018

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Perennial grain crops hold the promise of stabilizing fragile lands, while contributing grain and grazing in mixed farming systems. Recently, perennial rice was reported to successfully survive, regrow, and yield across a diverse range of environments in Southern China and Laos, with perennial rice PR23 being identified as a prime candidate for release to farmers. This paper reports the evaluation of PR23 for release, by (1) comparing its survival, regrowth, performance, and adaptation with preferred annual rices across nine ecological regions in southern Yunnan Province of China; (2) examining the economic costs and benefits of perennial versus annual rice there; and (3) discussing the evidence for the release of PR23 as a broadly adapted and acceptable cultivar for farmers. Overall, the grain yield of PR23 was similar to those of the preferred annual rice cultivars RD23 and HXR7, but the economic analysis indicated substantial labour savings for farmers by growing the perennial instead of the annual. PR23 was comparable to the annuals in phenology, plant height, grain yield, and grain size, and was acceptable in grain and cooking quality. Farmers were keen to grow it because of reduced costs and especially savings in labour. PR23 is proposed for release to farmers because of its comparable grain yields to annual rices, its acceptable grain and milling quality, its cost and labour savings, and the likely benefits to soil stability and ecological sustainability, along with more flexible farming systems.

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Adaptation of rice (Oryza sativa L.) genotypes in the rainfed lowlands of Lao PDR

Cited by 10 publications

References 22 publications

Integrated Nutrient–weed Management Under Mechanised Dry Direct Seeding (Dds) Is Essential for Sustained Smallholder Adoption in Rainfed Lowland Rice (Oryza Sativa L.)

Integrated Nutrient–weed Management Under Mechanised Dry Direct Seeding (Dds) Is Essential for Sustained Smallholder Adoption in Rainfed Lowland Rice (Oryza Sativa L.)

A leaf area‐based non‐destructive approach to predict rice productivity

Performance, Economics and Potential Impact of Perennial Rice PR23 Relative to Annual Rice Cultivars at Multiple Locations in Yunnan Province of China

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