Yield Of Aman Rice Research Articles

Enhancing Transplant Aman Rice Productivity through NPK Fertilizer Split Application Scheduling Under Zero Till Non-Puddled Condition

This experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the varietal response of split application of NPK fertilizer application schedule on transplant aman rice under zero till non-puddled condition. The experiment comprised three rice varieties viz. Bashiraj (local), BRRI dhan49 (inbred), Dhanigold (hybrid); and seven NPK fertilizer application schedules. The experiment was laid out in a randomized complete block design with three replications. The effect of variety, NPK fertilizer split application schedule and their interaction showed significant variation on the yield attributes and yield of aman rice. In interaction, the highest number of effective tillers hill-1 (11.66), total spikelets panicle-1 (164.00), grains panicle-1 (151.22), 1000-grain weight (38.70 g), grain yield (5.67 t ha-1) and harvest index (60.36%) were obtained from hybrid variety Dhanigold when fertilized following 3-splits of N [1/3 at 14 days after transplanting (DAT) + 1/3 at maximum tillering (MT)+ 1/3 at panicle initiation (PI)] and P (1/3 as basal + 1/3 at MT + 1/3 at PI ), and single split of K as basal (full dose). Same treatment combination also provides the highest yield of BRRI dhan49, but the local Bashiraj gave the highest yield at recommended practice where only N was top-dressed at 3 splits. Based on this result, it may be concluded that for better productivity hybrid Dhanigold and inbred BRRI dhan49 might be fertilized with 3-splits of N (1/3 at 14 DAT + 1/3 at MT + 1/3 at PI) and P (1/3 as basal + 1/3 at MT + 1/3 at PI) and full dose of K as basal during aman season under zero till non-puddled condition. On the other hand, for local variety Bashiraj 3-spilts of N either [½ as basal + ¼ at active tillering (AT) + ¼ at PI] or N (1/3 at 7 DAT + 1/3 at MT + 1/3 at PI) and P, K as single split as basal appeared as the best application schedule.

Survival, Growth and Yield of Aman Rice Under Varied Duration of Submergence

Sixteen aman rice varieties were screened against two and three weeks of submergence based on their survival, growth and yield performance following split-plot design with three replications. Rice varieties AZ7006, BRRI dhan49, BRRI dhan52 and BRRI dhan57 exhibited the highest survival rate and minimum lodging that were associated with greater dry matter production under two weeks of submergence. Submergence affected the production of tillers, panicle and spikelets resulting lower grain yield than control. All the rice varieties except AZ7006 and BRRI dhan52 died under three weeks of submergence, where a small shoot of these varieties lived. These two varieties took longer time for producing shoot dry matter, tiller, panicle and maturity. Though they produced spikelets, but these were sterile due to low air temperature at flowering stage. Moreover, rice varieties BRRI dhan52, BRRI dhan57, BRRI dhan90 and AZ7006 under two weeks; and BRRI dhan52 and AZ7006 under three weeks of submergence acquired a combination of morphological and yield contributing response that ultimately induced a higher level of submergence tolerance. As the study revealed that BRRI dhan52 and AZ7006 were submergence tolerant, they could be incorporated in breeding program to develop rice variety for submergence tolerant up to three weeks. Ann. Bangladesh Agric. (2022) 26 (2) : 51-70

Influence of Climate Factors on Aman Rice Yield in Bangladesh: Co-Integration and Vector Error Correction Model Approach

Climate factors’ consequence on human performance has occurred as a worldwide apprehension in the earlier 30 years. This study explores climate factors’ influence on Aman rice production in Bangladesh. Co-integration and Vector Error Correction Model approximation procedure is applied to measure the climate-crop harvest interrelation on the basis of country-level time series data for the time 1972-2019. Changing in mean maximum and minimum temperature, annual men rainfall, and average humidity are used as characteristic variables for climate factors. The result of the vector error correction model denotes that both in the long-run and short-run, average maximum temperature and average total rainfall inversely affect Aman rice yield in Bangladesh respectively. Average minimum temperature and average humidity positively affect Aman rice production in the short run respectively. Fertilizers and irrigation have a positive influence on Aman rice yield in the short-run correspondingly. Conversely, labor has a robust negative consequence on Aman rice yield in the short-run in Bangladesh agriculture. Policymakers would develop policies to control temperature and introduce heat-tolerant rice varieties and adaptation measures to sustain Aman rice production in Bangladesh.

Assessment of combined effect of Eleocharis atropurpurea and Fimbristylis dichotoma residues on the yield performance of T. aman rice

The current agricultural system is seeking a biological solution to lesson hazardous impacts from the use of chemicals to control weeds in rice production. Plant allelopathy is one of the ways where allelopathic plant inhibits its surrounding plants by releasing allelopathic substances. The present experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from July to December 2019 to study the allelopathic effects of the and residues of Eleocharis atropurpureaandFimbristylisdichotomaonweedmanagementandtheyieldperformance of amanrice. The field experiment consisted of three rice varieties i.e BRRI dhan34, Nizershail and Kalozira and five treatments such as 0, 1.0, 2.0, 3.0 t ha-1and farmer’s practices. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The highest grain yield (4.44 t ha-1)as well as the yield contributing character was recorded in Kalozira and the lowest grain yield (3.94 t ha-1) was obtained in the BBRI dhan34. The highest number of effective tillers hill-1, number of grains panicle-1, 1000-grain weight, grain and straw yields were observed when the residue of E.atropurpureaandF.dichotomawas applied at 3tha-1.Ricecultivarkalozira with the incorporation of E. atropurpurea and F. dichotoma residue at 3 t ha-1produced the highest grain yield (5.08 tha-1) and straw yield (6.77 tha-1). Results of this study indicate that E. atropurpureaand F. dichotomaresidue showed potentiality to inhibit weed growth and it has a significant effect on yield of amanrice.

Response of Biochar on Growth and Yield of Aman Rice Under Salt Stress

A pot experiment was conducted in Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during aman season, 2018 to assess the effect of biochar on rice (BRRI dhan62) under salt stress conditions. The factorial experiment was laid out in Randomized Complete Block Design (RCBD) with four replications. Three levels of salinity were used viz. Control (S0), 1600 ppm NaCl (S1), and 2800 ppm NaCl (S2) under factor A and four levels of biochar were applied viz. 0 t ha−1 (B0), 2 t ha−1 (B1), 4 t ha−1 (B2) and 6 t ha−1 (B3) under factor B. The salt materials were added on pot in two installments at 20 and 30 days after transplanting (DAT). Exposure to salinity decreased growth and yield of rice including plant height, tillers hill-1, effective tillers hill-1, grains panicle-1, 1000-grain weight, grain yield and straw yield. The magnitude of growth and yield reduction increased with increasing the salinity level. Exposure of 1600 ppm and 2800 ppm NaCl declined the grain yield of rice by 28 and 100%, respectively. Straw yield (18 and 100%, respectively) and other yield contributing parameters declined by these two levels of salinity in the same way. Application of different levels of biochar ameliorated saltinduced damages to a certain extent. Under 2800 ppm NaCl stress, application of biochar extended life duration of rice plant upto 80 DAT, whereas without biochar application rice plant died after 60 DAT. Upon exposure to 1600 ppm NaCl stress, application of 2, 4 and 6 t ha−1 of biochar increased grain yield by 37, 42 and 30%, respectively, compared with the respective salt treatments (without biochar). Biochar enhanced yield of rice under saline conditions by enhancing yield contributing attributes including effective tillers and 1000-grain weight and by reducing salt-induced damages. However, response of 4 t ha−1 of biochar was best among the biochar levels (2, 4 and 6 t ha−1 of biochar) under both saline and non-saline conditions. Bangladesh Agron. J. 2022, 25(1): 105-113

Long-term spatio-temporal variability and trends in rainfall and temperature extremes and their potential risk to rice production in Bangladesh

Understanding the historical and future spatio-temporal changes in climate extremes and their potential risk to rice production is crucial for achieving food security in Bangladesh. This paper presents results from a study on trend analysis for 13 climate metrics that significantly influence rice production. The analysis was conducted using the non-parametric Mann-Kendall test and the Theil-Sen slope estimator methods. The study included data from all available weather stations in Bangladesh and the assessment was done for both the wet (May to October) and dry (November to April) seasons, which cover the growing seasons of the country’s three types of rice: Aus, Aman and Boro. Results show significant decreasing trends for wet season rainfall (>12 mm/season/year in some stations) in the central and north regions. In addition, dry season rainfall is decreasing significantly in many areas, whilst dry season dry spells are increasing throughout Bangladesh. Decrease in rainfall in some of these areas are of concern because of its impacts on rainfed Aus rice and in the sowing/planting of rainfed Aman rice and irrigated dry season Boro rice. The maximum temperatures in the wet season are increasing throughout the country at 0.5°C every ten years, significantly at most of the climate stations. The analysis shows that the number of days with temperature >36°C has significantly increased in 18 stations over the last three decades, which implies a serious risk to Aman rice yield. The current maximum temperatures (both in the wet and dry seasons) are higher than the optimum temperature ranges for rice production, and this will have likely adverse effects on yield in the face of climate change with increasing temperatures. The results herein have practical implications for planning appropriate adaptation policies to ensure food security in the country.

Agro-Economic Productivity of Rice- Rabi Croprice Systems in Northwestern Drought-Prone Areas of Bangladesh

Productivity and economics of different rabi crop-based systems were evaluated at farmers’ field in Durgapur upazilla of Rajshahi district, Bangladesh to select the best rabi crop(s) for fitting in the T. Aman rice - rabi crop – DDS Aus rice pattern. Nine rabi crops namely, (1) Mustard, (2) Potato, (3) Lentil, (4) Field pea, (5) Radish, (6) Cabbage, (7) French bean, (8) Carrot and (9) Tomato were cultivated during the rabi season in between the two rice crops to form nine cropping patterns. The experiment used Randomized Complete Block Design (RCBD) with three replications. Aman rice variety BRRI dhan57 was transplanted on 12 July 2017 and harvested on 28 October 2017, while, Aus rice variety BRRI dhan28 was sown in the dry cultivated land on 16 March 2018 and harvested on 24 June 2018 while rabi crops were sown/transplanted on 28 November 2017. Proper agronomic management practices were adopted for all the crops in the patterns. Data on yield and related attributes of DDS Aus rice were recorded at harvest. In addition, the yield of Aman rice and all the rabi crops were recorded. In addition, rice equivalent yield of each rabi crop, system yield (total yield of all the crops in the sequence), cost of production, gross return and benefit cost ratios (BCR) of all the patterns were recorded. Results revealed that yield of dry direct seeded Aus rice cv. BRRI dhan28 did not differ significantly due to different rabi crops grown under the respective patterns. The system yield was the highest in T. Aman rice –tomato – DDS Aus rice pattern (19.62 t ha-1) and the lowest with T. Aman rice -mustard – Aus rice pattern (14.63 t ha-1). Since the market price of a rabi crop changes from year to year, the net profit of a pattern depends on the yield of a crop grown in rabi season. Therefore, any of the nine rabi crops under the trial can be successfully cultivated in between the two rice crops under Aman rice – rabi crop –Aus rice patterns. However, the present study concludes that any of the nine rabi crops can be grown in between the two rice crops but carrot, French bean, mustard, field pea, and tomato could be the most profitable ones for the T. Aman rice – rabi crops –DDS Aus rice patterns. SAARC J. Agric., 19(2): 85-94 (2021)

Influence of humic acid on morpho-physiology and yield of rice

A pot experiment was conducted to investigate the influence of soil organic amendments-cow dung and humic acid on morphology and yield of rice under drought stress at the net-house, Agricultural Botany Department at Sher-e-Bangla Agricultural University, during the period from July 2018 to November 2018. This single factorial experiment pots where arranged in a randomized complete block design with four replications. Four different levels of soil organic amendments viz. SM1 = Soil + inorganic fertilizer (control), SM2 = Soil + cow dung + inorganic fertilizer, SM3 = Soil + inorganic fertilizer + humic acid and SM4 = Soil + inorganic fertilizer + cow dung + humic acid. The results showed that morphological characters and yield of rice significantly increased with addition of cow dung and humic acid into the soil. In terms of morpho-physiology, the highest plant height 112.90 cm and number of tillers plant-1 11.25 were achieved from the treatment SM4 (Soil + inorganic fertilizer + cow dung + humic acid). In terms of the variables that contribute to the yield, the highest days to 1st flowering (72.75) and days to 1st maturity (122.05 days) were found from control treatment SM4 (Soil + inorganic fertilizer + humic acid + cow dung). Similarly, the highest panicle length (24.94 cm), number of filled grain panicle-1 (221.40), number of unfilled grain panicle-1 (42.25), root length (17.93 cm), number of grains panicle-1 (247.40), grain weight hill-1 (25.17 g), straw weight hill-1 (33.26 g) and harvest index (42.93%) were achieved from SM4 (Soil + inorganic fertilizer + cow dung + humic acid) . The highest soil moisture content (17.23 and 16.17% at 55 and 70 DAT, respectively) was also achieved from SM4 (Soil + inorganic fertilizer + cow dung + humic acid). This experimental results highlighted that together use of cow dung and humic acid increased the grain weight plants-1 more than 150% compared to controlled condition. Finally, it concluded that application of cow dung and humic acid as soil organic amendments increases the yield of aman rice.

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.

Row orientation and weeding time effect on yield of Aman rice

The effect of row orientation and weeding time on growth, yield and yield attributes of transplanted Aman (T. Aman) rice cv. BRRI dhan41 were tested in the agronomy field laboratory of the Bangladesh Agricultural University, Mymensingh. The experiment was carried out from July to December 2017. It comprised three row orientations viz. east-west, north-south and haphazard planting, and four weeding times viz. no weeding, weeding at 20 days after transplanting (DAT), weeding at 40 DAT and weeding at 60 DAT. Plant height, total tillers per hill, effective tillers per hill, grains per panicle, grain and straw yields were greater in east-west and north-south row orientation than in haphazard planting being the highest in east-west row orientation. But within east-west and north-south row orientation, there was no significant difference on plant characters. The highest performance in yield attributes and yield was observed in weeding at 40 DAT and the lowest one was recorded in no weeding. Among the treatment combinations, the highest yield was observed in east-west row orientation with weeding at 40 DAT for BRRI dhan41.
 Bangladesh J. Sci. Ind. Res.56(1), 47-52, 2021

Rain-Fed Rice Yield Fluctuation to Climatic Anomalies in Bangladesh

To examine the rain-fed Aman rice yield fluctuation due to climatic anomalies overtimes in Bangladesh, we used climate-induced yield index (CIYI), ensemble empirical mode decomposition (EEMD), step-wise multiple regression, isotopic signature, wavelet transform coherence (WTC) and random forest (RF) model. In this work, daily multiple source climatic data which were collected between 1980 and 2017, from 18 weather stations and five atmospheric circulation indices were used for this purpose. The key findings were as follows; by employing principal component analysis (PCA), six temporal variability modes were identified as six corresponding sub-regions with various Aman rice CIYI fluctuations. The Aman rice CIYI in different sub-regions represented a noteworthy 3–4-year quasi-oscillation using the EEMD. The key climate variables (KCVs) including the potential evapotranspiration and cloud cover in September, the minimum temperature in August, and precipitation in July, August, and October were the best rice yield prediction signals in these sub-regions. The results suggest that Aman rice yield could likely decline by 33.59%, and 3.37% in the southwestern and southeastern regions, respectively, if KCV increased by 1 °C or 1%. The RF model suggests that the Indian Ocean Dipole (IOD) significantly influenced the rice yield. Isotopic signatures were employed to confirm the fluctuation and anti-amount effect during the Aman rice-growing period in Bangladesh. The results obtained in this study could be used as a guideline for sustainable mitigation and adaptation measures in managing agro-meteorological hazards in Bangladesh.

Assessing Impact of BRRI Released Modern Rice Varieties Adoption on Farmers’ Welfare in Bangladesh: Application of Panel Treatment Effect Model

This study assesses the impact of Bangladesh Rice Research Institute (BRRI) released modern wet (Aman) season rice variety adoption on farmers‟ well-being in Bangladesh. Bangladesh Integrated Household Survey (BIHS) data collected by IFPRI were used for this study. The study applied difference-in-difference treatment effect and difference-in-difference quantile treatment effect models using unbalanced panel data to achieve the set objectives. Analysis revealed that BRRI released wet (Aman) season rice technology has a robust and positive effect on small farmers‟ welfare in Bangladesh as indicated by the level of increases in per capita household real income, increases in real aman rice income, and also increases in yield and decreases both in poverty gap and squared poverty gap over time. The marginal and near landless farmers have not gained significantly through adopting BRRI released modern variety over non-adopters in terms of all the indicators except aman rice yield. However, only yield of BRRI released modern wet (Aman) season rice technology has positive and significant impact on the marginal and near landless farmers. As such, BRRI variety adoption seemed to be conducive in increasing the level of yield of marginal and near-landless farms but it hardly helps them to overcome the poverty level, unless other equity-enhancing policy measures are undertaken. Overall, there was large scope for enhancing adoption of BRRI released rice variety in order to reduce the poverty level in rural areas. The current rice policy (rice self-sufficiency) appears to be supportive to help Bangladesh rice sector for achieving food security in the country.
 Bangladesh Rice j. 2019, 23(1): 1-11

Climate Change and Aman Rice Yield Nexus in the North-Western Part of Bangladesh: Using Quantile Regression

Aman is a rain-fed crop that is the second-largest rice crop in Bangladesh in general and in particular, in the study area with respect to the volume of production. It also carries significant value in the case of food security as well as livelihood options for many farmers. At this backdrop, the study focuses on exploring the relationship between climate change variables (Average Maximum Temperature, Average Minimum Temperature, Total rainfall, Average Relative Humidity) and Yield of Aman in Bogra and Joypurhat districts of Bangladesh. In this case, quantile regression at the median is used to examine climate change and Aman rice interrelations using time series data from 1969 to 2013. The findings of the study reveal that Average Maximum Temperature and Total Rainfall has a positive impact on the Aman yield production in the study area. Considering the future severe adverse effects of climate change on food security and nutrition, and employment aspects in the study area, the study, therefore, recommends the concerned authorities to strengthen their efforts to develop, and distribute of drought-tolerant HYV of Aman rice among the farmers at an affordable rate. Meanwhile, the farmers should be encouraged to cultivate drought-tolerant and less water-fed crops.

Exploring the Climate Change Impact on Major Food Crops of Bangladesh - A Time Series Analysis

This paper tries to explore the dynamic relationship between the yield of major crops in Bangladesh (aus, amas, boro, wheat and potato) and climate change (average rainfall, average maximum temperature and average minimum temperature). Graphical visualization shows that, there is increasing trend in average annual minimum temperature and average annual minimum rainfall, while there is decreasing trend of average annual maximum temperature. We applied autoregressive distributive lag (ARDL) cointegration method in order to study the dynamic relationship. The paper finds long run dynamic link between yield of aus rice and average rainfall and average minimum temperature. We have found short run dynamic relationship for yield of aman rice, boro rice and potato. However, we do not find any dynamic relationship has been found for yield of wheat with the variables of climate change. After estimation the dynamic relationship, we ensure there is no serial correlation among residuals using Breusch-Godfrey test and models are normally distributed using histogram and Jarque-Bera test. Finally, we ensure the stability of the models applying CUSUM test.

Performance of Pre- and Post-emergence herbicides in strip tillage Non-puddled transplanted Aman rice

A study was conducted on transplanted aman rice (cv. BINA dhan-7) in strip-tilled non-puddled field with some commonly used rice herbicides (pre-emergence: pyrazosulfuron-ethyl and butachlor, early post-emergence: orthosulfamuron and late post-emergence: acetochlor + bensulfuron methyl, butachlor + propanil and 2,4-D amine) applied singly or in sequences during 2013 and 2014 at field laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of those herbicides on weeds as well as growth and yield of aman rice in strip-tilled non-puddled condition. The study showed that herbicides significantly reduced weed density by 75-94% in 2013 and 46-98% in 2014 compared to the weedy check. Sole application of pre- or early post-emergence herbicide provided less weed control than sequential application of pre-, early post- and late post-emergence herbicides or application of pre- and late post-emergence herbicides. A wide range of sequential application of herbicide treatments has identified in the study that provided control on weed density and biomass by 49-98% and 56-95%, respectively. Application of pyrazosulfuron-ethyl followed by orthosulfamuron and butachlor + propanil was the most effective combination in this new rice establishment condition that controlled all types of weeds successfully and provided maximum grain yield (5.42 t ha-1 in 2013 and 6.18 t ha-1 in 2014) with highest economic return (Tk. 55930 ha-1 in 2013 and Tk. 69057 ha-1 in 2014). The study suggests economically beneficial some combinations of currently used herbicides for strip-tlled non-puddled transplanted aman rice that may help farmers to choose and rotate in the same land yearwise for obtaining optimum yield.Bangladesh J. Agril. Res. 42(4): 631-646, December 2017

Performance of rain-fed Aman rice yield in Bangladesh in the presence of climate change

AbstractThis paper uses the framework of the Just–Pope production function to evaluate the impacts of climate change on yields of the rainfed Aman rice crop in Bangladesh. It analyses disaggregated district-level data on climate variables and Aman rice yield over a 48 year time horizon. The results reveal that changes in maximum temperatures have had positive and negative effects on yield in the linear and quadratic functional forms, respectively. However, the elasticity values in the variance function confirm that maximum temperature is risk-increasing for Aman rice while minimum temperature is likely to decrease yield variability. Rainfall has become risk-increasing for Aman rice. Based on three climate change scenarios, this paper also reveals that future climate change is expected to increase the variability of Aman rice yields. Finally, statistically significant dummies for different in-country climate zones require zone-specific adaptation policies to reduce the adverse impacts of climate change.

Climatic Variability and Wet Season Rice (<i>Oryza sativa</i> L.) Production in North-West Bangladesh

Climate change is influencing rice (Oryza sativa L.) production in some agro-ecological regions of Bangladesh. The impact of seasonal climatic variability on rainfed lowland rice (transplanted aman or T. Aman) yield in north-west Bangladesh was analyzed based on historic weather data from 1971 to 2010. Wet season maximum and minimum temperatures were increasing by 0.0174 and 0.0083°C year-1, respectively. Sunshine hours for the same period have decreased by 0.0259-0.027 hr year-1. The representative concentration pathway (RCP) based projection showed increased maximum and minimum temperatures by 0.42-1.51 and 0.79-1.34°C, respectively in 2050. T. Aman rice yield could be reduced by 0.17-0.37 t ha-1 if temperature rises by 1°C. If sunshine hour decreases by 1 hr, yield reduction could be 0.20 t ha-1. Combined effect of increased minimum temperature and decreased sunshine hours will govern T. Aman rice yield in future.The Agriculturists 2017; 15(1) 68-80

Effect of transplanting times on pollen and spikelet sterility, growth and yield of aman rice

A field experiment was conducted to study the effect of planting dates on pollen/spikelet sterility, grain development and yield of hybrid rice in T. Aman season. The two varieties: Heera-4 (hybrid) and BINAdhan-7 (inbred) were transplanted on five consecutive dates at fifteen days interval viz. 15 July, 30 July, 15 August, 30 August and 15 September of 2011. The effect of variety and transplanting date showed significant variation in pollen sterility, grain growth & development, panicle length, filled grains panicle-1, spikelet sterility and grain yield. Pollen sterility was the highest in Heera-4 (>80%) consequently spikelet sterility for transplanting on 15 July while transplanting on 30 July low pollen sterility consequently spikelet sterility. Both early or late transplanting affected grain growth and development, enhanced pollen sterility as well as spikelet sterility and reduced grain yield. Late transplanting (30 August and 15 September) significantly reduced panicle length and filled grains panicle-1. Transplanting on 30 July gave low pollen sterility as well as spikelet sterility, high panicle length and high filled grains panicle-1 consequently greater grain yield in the varieties.Progressive Agriculture 27 (4): 400-408, 2016

Effect of Seedling Age and Method of Transplanting on the Yield of Aman Rice

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from June to December 2012 with a view to finding out the effect of seedling age and method of transplanting on the yield of Aman rice. Four seedling ages (10, 20, 30 and 40 days) and two transplanting methods (line and haphazard) were used as experimental treatments with four replications in a randomized complete block design. Seedling age, transplanting method and their interaction significantly influenced most of the yield components and yield of transplant Aman rice cv. BRRI dhan41. The highest total tillers, effective tillers hill-1, grains panicle-1, grain yield, straw yield and harvest index were obtained from 30-day-old seedlings. Line transplanting method produced the highest total tillers, effective tillers hill-1, grain yield and harvest index. The highest total tillers, effective tillers hill-1, grain yield and harvest index were obtained from 30-day-old seedlings with line transplanting method. Results revealed that 30-day-old seedlings under line transplanting method could be used to obtain maximum yield of transplant Aman rice cv. BRRI dhan41.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19092 Progress. Agric. 24(1&2): 9 - 16, 2013

Effect of Shrimp-Based Cropping Systems on Salinity and Soil Fertility in a Coastal Area of Bangladesh: A Village-Level Study

The present study analysed soil salinity and some essential soil nutrients for rice plant as affected by a shrimp-based cropping system in a coastal area of Bangladesh. The study was conducted in a village located in Satkhira district. Two main cropping systems, the shrimp-boro rice cropping system and the aman rice-boro rice cropping system, are mainly practised by local farmers in the study village. Soil and water samples were collected from the plots of these cropping systems and chemical analysis was done to measure the salinity level of the soil and water as well as to find out the nutrient status of the soil. The data was also collected for economic analysis and estimated rice and shrimp yield from the local farmers. The results revealed that the soil salinity level of the shrimp-boro rice cropping system was higher than that of aman rice-boro over the consecutive years of 2010, 2011 and 2012. The soil was found to be moderately saline. The organic matter content, potassium, calcium, magnesium and sulphur levels of the soil in the shrimp-boro rice system were increased, while the total nitrogen, phosphorus, boron and zinc availability decreased. It was also found that the yield of boro rice was 4,950 kg/ha whereas the aman rice yield was 3,020 kg/ha and that for shrimp the yield was calculated as 268 kg/ha for one growing season (six months). The total income from boro rice, aman rice and shrimp was calculated as 127,760 Tk, 87,118 Tk and 149,476 Tk, respectively. The paper concludes that although some nutrient elements were available in adequate amounts, salinity kept these nutrients from being taken up by the rice plants since salinity changes the osmotic pressure of the soil solution system. This may ultimately lead to a reduction in rice yield and threaten the sustainability of the local shrimp-boro rice cropping system.