Phenotyping of boro rice (Oryza sativa L.) cultivars in Assam based on its potential yield and variable component traits

The current environmental scenario and increased average yield rate has marked boro rice cultivars as a potent rice cultivar during rabi season. It serves to be an alternative to traditional sali rice and an escape to flood problems. The selection and development of potent boro rice cultivar among its diverse types has been an issue. In this study, 117 traditionally grown boro rice cultivars in different low-lying areas and newly developed irrigated areas of Assam were analyzed. The cultivars were analyzed based on yield and related component traits as per the standard evaluation system for rice. Grain yield and its related component traits showed a significant relationship among the cultivars. All the traits analyzed showed positive relationship with grain yield and harvest index except to time taken for flowering and maturity. Based on total yield, principal component and cluster analysis, Bahurupi, PSB 68, Mandhya Vijaya, Bahunipi, Pathariya showed to be best performing cultivars, with high yield and higher component traits performance. This study marks the significant association of grain yield with its component traits and further provides an insight to the selection of rice cultivars for breeding programmes.

Variability of Climate-Induced Rice Yields in Northwest Bangladesh Using Multiple Statistical Modeling

Because of evident climatic variations and significant contribution to national food production, Bangladesh is a climate extreme hotspot region of examination for climatic consequences for rice (Oryza Sativa) crop production. This study intends to explore the variability of climatic variables (e.g., variations in mean temperature, rainfall, relative humidity, and sunshine duration) with rice yields (e.g., Aus, Aman, and Boro rice varieties) in northwest Bangladesh. The modified Mann-Kendall test, Theil-Sen slope estimator, and multiple linear regression (MLR) modeling were used to estimate the association among these factors. Heteroskedasticity and autocorrelation constant standard error (HAC) and feasible generalized least square (FGLS) technique were adopted to measure the climate-rice crop nexus using the regional level dataset for 1976–2015. Furthermore, the spatiotemporal variation of rice yield trends with climatic variables was mapped and assessed by the coefficient of variation. The results show that observed temperature and humidity trends were beneficial for Aus and Aman yields but not Boro yields. In contrast, observed rainfall and sunshine trends were negative for all three rice seasons. The outcomes of the MLR model explained 67%, 92%, and 83% of the variability in Aus, Aman, and Boro rice yields in the study region. The model outcomes showed that humidity and rainfall have negatively affected Aus and Aman rice crops, while temperature and rainfall positively influence Boro rice yield. Regarding the climate change issues and safeguarding food safety at the regional level, the concerned authorities should provide substantial attention to improving heat and drought-tolerance high-yielding varieties against climate effects on Aus and Aman rice varieties.

Impact of seasonal climatic variability on rice yield in Bangladesh

In Bangladesh, 75% of the total cultivable area is under rice cultivation producing 25 million tons of rice and plays a vital role in the country’s GDP. The climatic variability is playing an important role in affecting the rice production. In this study, the impact of climatic variability (average maximum temperature (aMaxTemp), average minimum temperature (aMinTemp) and average rainfall (aRainfall)) on rice yield was determined in two different regions (northern and southern) of Bangladesh.The variability of rice yield and climate factors was determined by using the Ordinary Least Square (OLS) method. The data was analyzed over the 44-years period (1971 to 2014) in order to estimate the magnitude of these fluctuations statistically and graphically. We observed that the climate variables had significant effect on rice yield that varies among three rice crops (e.g., Aus, Aman, and Boro rice). We observed that, aMaxTemp has positive effects for Aus and Aman rice yield but negative effect on Boro rice yield. On the other hand, aMinTemp has negative effects on Aus and Aman rice yield but has positive effect on Boro rice yield. The aRainfall has a positive relationship with all rice yields in both the regions.

Big Boro rice harvest during COVID-19 pandemic: an optimism for resilient rice system in Bangladesh

The ‘big Boro rice harvest’ in 2021 amidst the COVID-19 pandemic has created new optimism for a resilient rice system in Bangladesh. Boro rice (dry season rice) has appeared as the strategic crop in sustaining resilience in the national rice system and food security with a steady rise in production trend. However, the prospect of Boro rice has been challenged by a myriad of factors such as changing climate, hydrological regimes, value-chain and crop diversification. Any unexpected production loss of Boro rice might bring about a big setback in total food security. Therefore, holistic policy planning and research supports, strong value-chain, efficient procurement system and, farmer’s capacity development have been suggested to sustain the production trend of Boro rice in the year to come.

Lime and Manure Amendment Improve Soil Fertility, Productivity and Nutrient Uptake of Rice–Mustard Cropping Pattern in an Acidic Terrace Soil

Acid soil is an obstacle to agricultural development and a concern regarding food and environmental security. Therefore, a study was carried out for two consecutive years to see how lime and organic manure (OM) amendments affect yield and nutrient absorption in the Transplanted (T.) Aman–Mustard–Boro cropping pattern in an acidic terrace soil. With nine treatments and three replications, the experiment was set in a randomized complete block design. The treatments were applied to the first crop, T. Aman, with different dosages of lime (dololime at the rate of 1 and 2 t ha−1), OM (cow dung at 5 t ha−1, poultry manure at 3 t ha−1) and lime–OM combination, and their residual effects were studied in the following mustard and boro rice crops. Results demonstrate that the effect of lime and manure was more pronounced in the case of the second and third crops in the first year and of all crops in the pattern in the second year. In the first year, grain and straw yield of T. Aman as well as the overall system productivity were not influenced significantly by the application of lime and manure, but significant increases were obtained in the second year. As an average of both years, the highest grain yield of 5.2 t ha−1 (12% over control) was recorded for T. Aman, 1.7 t ha−1 (41% over control) for mustard and 5.9 t ha−1 (47% over control, 3.9 t ha−1) for boro rice when dololime was applied in combination with poultry manure. In both years, N, P, K and S uptake were significantly increased compared to the control in all the crops due to the combined application of lime and cow dung or poultry manure. Combined application of lime and manure amendment significantly improved nutrient availability and soil quality. Therefore, applying lime in combination with manure can be practiced to uplift crop productivity in acidic terrace soils.

Alleviation of arsenic accumulation in rice by applying silicon-rich rice husk residues in Bangladesh soil

While the accumulation of arsenic in rice (Oryza sativa L.) has been highlighted as a major concern in Bangladesh, sustainable measures are critically needed to reduce the uptake of arsenic by rice plants. In the present study, a pot-experiment was conducted using a Boro rice variety (BRRI dhan-29) in two geomorphologically different soils from Holocene floodplains and Pleistocene terraces, in which silicon-rich fresh rice husk (FRH) and rice husk ash (RHA) were applied, as silicon fertilisers, in the soils at the rate of 1% (w/w) of rice residue:soil.In the Holocene floodplain soils, the application of FRH was found to decrease arsenic in grain, husk and straw by 42, 56 and 51%, respectively, whereas the soil incorporation of RHA decreased arsenic in grain, husk and straw by 26, 37.5 and 36%, respectively. In the Pleistocene terrace soils, the application of FRH reduced the grain, husk and straw arsenic by 38, 38 and 44%, respectively, whereas the RHA decreased the grain, husk and straw arsenic by 26, 30 and 29%, respectively. Fresh rice husk was found to be more effective in alleviating arsenic accumulation in rice than RHA. In both the Holocene floodplain and Pleistocene terrace soils, the grain concentrations of calcium, phosphorus, silicon, and zinc were found to be increased with the decrease of arsenic in the grain due to the use of FRH and RHA. The present study suggests that silicon-rich rice husk residue scan be used as silicon fertilisers to reduce arsenic accumulation in rice in Bangladesh. Bangladesh J. Sci. Ind. Res.56(3), 195-206, 2021

Response of nitrogen and potassium fertilization on the growth performance of aromatic Boro rice

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, during December 2017 to May 2018 to study growth performance of aromatic Boro rice (cv. BRRI dhan50) in response to nitrogen and potassium fertilization. The experiment consisted of four levels of nitrogen viz., 0, 50, 100 and 150 kg ha-1, and four levels of potassium viz., 0, 30, 60 and 90 kg ha-1. The experiment was laid out in a randomized complete block design with three replications. The results revealed that nitrogen and potassium fertilization and their interaction exerted significant influence on growth performance of BRRI dhan50. Application of 100 kg N ha-1 produced the tallest plant (82.17 cm), the highest number of tillers hill-1 (10.08) and chlorophyll content (52.21) at heading stage. While, application of 90 kg K ha-1 produced the tallest plant (81.44 cm) at physiological maturity stage, the highest number of tillers hill-1 (9.66) and chlorophyll content (51.54) at heading stage. In case of interaction, the tallest plant (85.33 cm), the highest number of tillers hill-1 (10.83) and chlorophyll content (58.28) were obtained from 100 kg N ha-1 along with 90 kg K ha-1 at heading stage. Therefore, application of 100 kg N ha-1 along with 90 kg K ha-1 interaction appeared as the promising practice in aromatic rice (cv. BRRI dhan50) cultivation in terms of growth performance.

Effects of Irrigation, Organic and Inorganic Nutrient Sources on the Growth, Yield and Soil Fertility Status With Rice-Rice Cropping

Continuous cultivation of highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (SOM) content. The experiment was laid out inasplit- plot design with irrigation (I1: traditional irrigation i.e. continuous flooding, I2: saturated condition, I3: Alternate wetting and drying) in main plots and fertilizers treatments: T0 = Control, T1 =100% (Recommended dose of chemical fertilizer), T2 =50% RDCF + 5 ton cowdung ha- 1, T3=70% RDCF + 3 ton cowdung ha-1, T4 =50% RDCF + 5 ton compost ha-1, T5 =70% RDCF + 3 ton compost ha-1, T6 = 50% RDCF + 3.5 ton poultry manure ha-1, T7 =70% RDCF + 2.1 ton poultry manure ha-1to the sub - plots. The rice yields were not significantly affected by different irrigation but higher grain yields were obtained in continuous flooded irrigation. The treatment T7 gave higher Boro and T. Aman rice yields. The higher Boro rice grain yields were obtained from I1T7 (70% RDCF + 2.1 ton poultry manure ha-1 with continuous flooded irrigation) followed by I3T7 (alternate wetting and drying + 70% RDCF + 2.1 ton poultry manure ha-1). The 100% RDCF was applied to T. Aman rice resulted residual effects of fertilizer and the higher T. Aman rice yields were recorded in I2T2 (saturated condition + 50% RDCF + 3 ton cowdungha-1) followed by I2T3 (saturated condition + 50% RDCF + 3 ton cowdungha-1) treatment combinations due to more residual effects of inorganic plus manure application during Boro rice cropping. The highest organic matter level was found in post-harvest soils where inorganic fertilizer plus cowdung were used and soil pH increased by using poultry manure. The higher levels of available P and K concentrations were observed in the post experiment soils where fertilizer and manure were applied. Bangladesh Agron. J. 2021, 24(1): 71-81

Management and Utilization Strategy of Water Resources for Rice Production

Declination of available water resources is threatening the dry season crop production in Bangladesh. Sustainable water management is crucial need to meet future food production. This study was aimed to determine futuristic water management strategy for rice cultivation. Both surface and groundwater is getting scarce in north-west region, whereas abundant of fresh surface water creating opportunities to irrigate dry season crops in south-central region. This study has outlined irrigation management for rice cultivation and groundwater utilization in water scarce area of north-west region. More than 75% of annual rainfall occurred during monsoon and crops other than monsoon often faced water shortage. Timely establishment of T. Aus rice on 01 May accounted average 183 mm supplemental irrigation for north-west and south-west region. Transplanting of T. Aman rice before 24 July found the low risk period of drought and gave about 1 t ha-1 yield advantage than late transplanting after 15 October. Supplemental irrigation in drought year gave up to 26% yield advantage than the rain-fed condition of T. Aman rice in experimental plot. Over exploitation of groundwater by famers for crop cultivation makes the groundwater status worsen. Farmers used 38% excess water than the actual requirement for Boro rice cultivation. For that annual groundwater withdrawal was higher than annual recharge causing groundwater level depletion in most of the districts. Groundwater table went below suction limit of shallow tubewell (STW) during dry season and thus it become unable to operate. Improved distribution system with plastic pipe, buried pipe could save about 25% of irrigation water. Alternate wetting and drying (AWD) irrigation method saved 20-25% water than farmer’s practice. Application of these on-farm water management technologies in Boro rice reduced water demand and made the groundwater balance positive as well as reduced the groundwater withdrawal pressure. On the contrary, irrigation with less saline surface water resources in river and canals of south central regions could expand Boro production and increased land productivity. Intervention of low lift pump with plastic pipe distribution in non-saline tidal areas could increase land productivity. Besides, trapped freshwater in to the canals inside the polders and re-excavation of these canals would make crop intensification. Thus, additional food production could help to achieve sustainable development goal and sustained food security. Bangladesh Rice J. 25 (1) : 37-50, 2021

Effects of partial quantity rationing of credit on technical efficiency of Boro rice growers in Bangladesh: Application of the stochastic frontier model

In this study, we analyzed the effects of the partial quantity rationing of credit on the technical efficiency of Boro rice growers in the Pabna district of Bangladesh. Before conducting the field survey, we designed a theoretical framework and identified farm households affected by the partial quantity rationing of credit. Data were collected from 174 Boro rice growers and analyzed in two stages, where the technical efficiency of Boro rice growers was assessed using stochastic frontier analysis, and the inefficiency effects model was then applied to evaluate determinants of the technical efficiency. The mean technical efficiency of Boro rice growers was 78%, which indicates that their technical efficiency was 22% beyond the production frontier curve. The variables comprising the household head’s age, education level, seed quality, formal training, access to the market, farm labor, tillage cost, fertilizer cost, irrigation cost, and price of seedlings significantly affected the technical efficiency of rice growers. The variables of interest comprising the rate and partial quantity rationing of credit had significant negative effects on the technical efficiency of rice growers. The findings obtained in this study will help to enhance the actual production level using the available resources and improve the food security situation in Bangladesh.