Effect of Elevated Air Temperature and Carbon Dioxide Levels on Dry Season Irrigated Rice Productivity in Bangladesh

Abstract

Agricultural productivity is affected by air temperature and CO 2 concentration. The relationships among grain yields of dry season irrigated rice (Boro) varieties (BRRI dhan28, BRRI dhan29 and BRRI dhan58) with increased temperatures and CO 2 concentrations were investigated for futuristic crop management in six regions of Bangladesh using CERES-Rice model (DSSATv4.6). Maximum and minimum temperature increase rates considered were 0˚C, +1˚C, +2˚C, +3˚C and +4˚C and CO 2 concentrations were ambient (380), 421, 538, 670 and 936 ppm. At ambient temperature and CO 2 concentration, attainable grain yields varied from 6506 to 8076 kg·ha −1 depending on rice varieties. In general, grain yield reduction would be the highest (13% -23%) if temperature rises by 4˚C and growth duration reduction would be 23 -33 days. Grain yield reductions with 1˚C, 2˚C and 3˚C rise in temperature are likely to be compensated by increased CO 2 levels of 421, 538 and 670 ppm, respectively. In future, the highest reduction in grain yield and growth duration would be in cooler region and the least in warmer saline region of the country. Appropriate adaptive techniques like shifting in planting dates, water and nitrogen fertilizer management would be needed to overcome climate change impacts on rice production.

Yield, profitability, and prospects of irrigated Boro rice cultivation in the North-West region of Bangladesh

“…Biswas et al [ 68 ] also reported that rice growth duration and yield decrease with a delay in planting date. The delay in transplanting exposes the flowering stage of rice to extremely high temperature, which reduces the yield significantly [ 69 , 70 ]. So, the variation in actual yield between fields of the same variety can be attributed to some extent to variation in transplanting date, although the ANOVA test did not show a significant difference ( Table 4 ).…”

Response of Crop Water Requirement and Yield of Irrigated Rice to Elevated Temperature in Bangladesh

“…Growth duration of Boro rice decreased by 6.4 days per 1°C temperature rise. Maniruzzaman et al [24] showed similar findings of 7.45 days' growth duration reduction of BRRI dhan28 for 1°C temperature rise. Mahmud [37] also reported 7-8 days' growth duration reduction per 1°C temperature rise for BR23 cultivar.…”

“…Rising temperature accelerates the crop growth and development process, resulting in shortening the growth duration of irrigated rice [38]. However, growth duration contributes directly to the yield, but shorter life span due to rising temperature may affect the production in the future [24].…”

“…Bangladesh crop agriculture is considerably dominated by rice cultivation. Considering all rice growing season in Bangladesh, dry season rice (Boro rice) has the maximum share (53 percent) in total rice production [24]. As a major crop in dry season, Boro rice is fully dependent on irrigation, mostly from the month of January to May, because Boro rice gets a small portion of total annual rainfall in Bangladesh between January and May [7].…”

“…However, rice crop is sensitive to temperature during its critical stages and increased temperature above the optimum may reduce yield drastically [26]. Maniruzzaman et al [24] noticed yield loss and reduced growth duration of irrigated rice (Boro) in elevated air temperature over normal temperature in Bangladesh.…”