Improved nursery management further enhances the productivity of stress-tolerant rice varieties in coastal rainfed lowlands

Abstract

a b s t r a c tThe productivity of rice in most tropical coastal areas of Asia is low because of the predominance of several abiotic and biotic stresses, use of long duration traditional landraces or old varieties and suboptimal management practices. A combination of high-yielding, stress-tolerant rice varieties and good management practices is necessary to enhance the productivity of these areas. Suboptimal nursery management using traditional methods practiced in these areas often leads to a reduced plant population because of seedling mortality leading to poor yields. Nursery management practices that suit the new stresstolerant varieties recently becoming available need to be developed to increase the productivity of rice. On-station and on-farm trials on nursery management were conducted using improved rice varieties to study the effect of seed density, nutrient management in the nursery, and seedling age at transplanting on grain yield. Lower seed density and application of balanced nutrients produced healthy and taller seedlings with high seedling vigor index (SVI) in the nursery and with subsequent significant increase in grain yield after transplanting in the main field. Combining inorganic and organic fertilizers in the seedbed (50-30-15 kg N-P 2 O 5 -K 2 O ha -1 + 5 t ha -1 farm yard manures; FYM) enhanced seedling growth (dry weight, shoot and root length, number of green leaves, leaf area) and leaf nitrogen concentration. Forty-d-old seedlings produced significantly higher yield than 25-d-old seedlings. Transplanting older seedlings is important in systems without good water control, un-leveled fields, and soils affected by salt stress; and taller seedlings help avoid losses caused by floods. The highest benefit/cost ratios of 1.82, 1.72 and 1.91 were observed when transplanting 40-d-old seedlings using a seed density of 25 g m −2 and with balanced nutrient application of 50-30-15 kg N-P 2 O 5 -K 2 O + 5 t FYM ha −1 , respectively. In the on-farm trials, the yield advantages when using new stress-tolerant rice varieties Swarna-Sub1 and Amal-Mana with improved nursery management practices were 23% and 47%, in comparison with farmers' nursery management and farmers' variety, respectively. These cost-effective nursery management approaches have great potential for enhancing yield in stress-prone rainfed coastal areas and will help sustain rice yield while ensuring sustainability of the cropping system.

Crop Performance and Water Productivity of Transplanted Rice as Affected by Seedling Age and Seedling Density under Alternate Wetting and Drying Conditions in Lao PDR

“…Many research studies have shown that the use of younger seedlings (not older than 25 d old) produced positive impacts on grain yield [21][22][23], although many authors have also contradicted this [24][25][26]. In our study, a significant SA × V interaction on grain yield was found in both years.…”

Challenges and opportunities for improving N use efficiency for rice production in sub-Saharan Africa

“…Rice cultivation in SSA is seriously undermined not only by nutrient-deficient soils but also by abiotic stresses at the initial growth stage (Seck et al, 2013). In this respect, the improvement of seedling quality by optimizing nutrient management in the nursery has been documented as an effective measure to overcome abiotic stresses such as submergence (Bhowmick, Dhara, Singh, Dar & Singh, 2014;Ella & Ismail, 2006;Jackson & Ram, 2003;Ram et al, 2009;Singh, Hong, Sharma & Dhanapala, 2004), salinity (Sarangi et al, 2015), and drought stress (Ros et al, 2015). Panda, Reddy and Sharma (1991) demonstrated the large yield gains by 0.4-2.1 t ha −1 and AE N at 40-210 kg kg −1 with the nursery application of 100 kg N ha −1 (roughly equivalent to 10 kg N ha −1 in main field) at submergenceprone fields in the initial growth stage.…”

Post-submergence Nitrogen Fertilizer Management for Enhancing Rainfed Lowland Rice Productivity in Eastern India

“…Submergence tolerance in rice is highly dependent on several environmental conditions including temperature, irradiance during submergence, submergence depth (Palada and Vergara, 1972;Adkins et al, 1990;Singh et al, 2009), flood water CO 2 concentrations (Setter et al, 1987), as well as the physiological condition of the plant material such as age (Adkins et al, 1990, Sarangi et al, 2015, carbohydrate content and nutrient status (Jackson and Ram 2003;Singh et al, 2014a;Gautam et al, 2014aGautam et al, , 2014b. Additional doses of 20 and 30 kg post-flood N ha -1 applied 7-10 DAD significantly…”

“…These varieties are being adopted on a large scale in South Asia, given that they retain their other main agronomic and quality traits (Xu et al, 2006;Neeraja et al, 2007;Singh et al, 2009Singh et al, , 2011Singh et al, , 2014bSeptiningsih et al, 2009). However, tolerance level and productive potential of such newly released varieties can be further enhanced through matching crop and nutrient management (Ismail et al, 2013;Bhowmick et al, 2014;Singh et al, 2014a, Sarangi et al, 2015.…”