133 research outputs found
Strategies for weed suppression in aerobic rice cultivation
No full textAerobic rice, a promising water-wise rice production system, is highly vulnerable to weed
invasion which demands an effective weed management strategy. This study was,
therefore, initiated aimed at developing a more comprehensive integrated weed
management system for aerobic rice. Thirteen rice varieties were evaluated for their weed
suppressive ability and productivity under aerobic soil conditions. Rice varieties differed
widely in their weed suppressive ability and yield. AERON 1 exhibited very strong weed
suppressive ability and highest yield potential closely followed by AERON 4. Two
seeding methods and three seeding rates were tested to identify suitable method and
seeding rate in terms of weed suppression and yield of AERON 1. Weed density and dry
weight decreased gradually with increased seeding rate but were independent of seeding
methods. Row seeding produced higher grain yield compared to broadcast seeding.
Increasing seeding rate up to 300 seeds/m2 was found worthwhile to reduce weed pressure
without sacrificing rice yield. An attempt was made to explore the possibility of adopting seed priming technique as a tool for weed management. Seed priming considerably
improved germination attributes, weed suppressive ability and yield of AERON 1.
Zappa® priming was the best in terms of weed suppression and yield. In herbicide
screening trial, eight herbicide formulations were applied in different combinations. Most
of the herbicides provided excellent weed control. In terms of weed control efficacy and
cost effectiveness, Cyhalofop-butyl + Bensulfuron followed by (fb) Bentazon/MCPA
performed the best. Among others, Bispyribac-sodium fb Bentazon/MCPA and
Pretilachlor/safener fb Propanil/Thiobencarb also exhibited high weed control efficacy and
net benefit. All the herbicides showed high selectivity to rice plant. An attempt was made
to identify the critical period of weed control (CPWC) of AERON 1 in two different
seasons. The CPWC varied between seasons. Based on the 5% yield loss level, the CPWC
in main and off seasons were 7 to 49 and 7 to 53 days after seeding (DAS), respectively,
while at 10% yield loss level, the same were 23 to 40 and 21 to 43 DAS, respectively. To
develop an integrated weed management package, weed competitive rice variety AERON
1, higher seeding rate of 300 seeds/m2 and seed priming by Zappa® were incorporated. As a
consequence of integrating different agronomic practices, lower weed pressure and higher
weed control efficacy were evident in this study compared to the previous study. Weed
management through Cyhalofop-butyl + Bensulfuron or Bispyribac-sodium or
Propanil/Thiobencarb fb Bentazon/MCPA emerge as highly effective and most economic
package. Application of Pretilachlor/safener fb Propanil/Thiobencarb fb Bentazon/MCPA
also may be considered. Despite being less remunerative, spraying with any of the
aforesaid early-post emergence herbicides in rotation followed by a manual weeding may
be recommended for long-term sustainability of aerobic rice system
Systematic investigation of gas assisted injection molding
No full textThis thesis presents a systematic investigation of the GAIM process integrating the effects of process variables, gas channel geometries and material properties on gas penetration length, fingering formation, residual wall thickness (RWT), and mechanical properties of gas-assisted injection molded parts.Master of Engineering (MPE
Experimental investigation of the ternary Mg-Al-Sr system
No full textIn this work, the ternary Mg-Al-Sr system was investigated experimentally by differential scanning calorimeter (DSC), X-ray Diffraction (XRD) and metallography. The experimental work focused on the critical regions after reviewing the phase diagrams developed by thermodynamic modeling. DSC has permitted real-time measurement of the temperature and enthalpy of the phase transformations. The experimental results were compared with the pertinent thermodynamic findings as well as with the literature data. The thermodynamic calculations are consistent with experimental results in few samples especially in the liquidus temperature, whereas discrepancy was observed in several cases especially in the solid phase transformation temperature that suggests this system should be remodeled. Two ternary eutectic transformations have been observed. XRD was used to identify the phases in the studied samples where Al 4 Sr and (Mg) were found to be the dominating phases. Distinct unknown peaks were observed in the investigated samples. In this investigation, four new phase fields have been tentatively identified. The new phase may be ternary intermetallics or ternary or binary solid solutions. Thermodynamic calculations were also utilized to understand the microstructures and the phase relationships. The microstructural evolution in two post-DSC samples has also been investigated and compared with the as-cast condition
Exploring the possibility of using Agroplus Biodecomposer for boosting up rice productivity under Bangladesh condition
No full textOver dependence on chemical fertilizers is a threat to the sustainability of rice ecosystem. Application of organic and biofertilizers might reduce reliance on chemical fertilizers and thus can play a vital role to boost up rice productivity in an eco-friendly way. An experiment was conducted at Mymensingh (24°10'0'' N latitude and 90°25'0" E longitude at 15 m above the sea level), Bangladesh during November 2015 to April 2016 to evaluate the effect of different dosages of Agroplus Biodecomposer, an organic biofertilizer containing Streptomycetes bacteria, on the growth and yield performance of some rice. The experiment included four winter rice varieties viz. (i) Hybrid rice Hira and (ii) Hybrid rice Tej (iii) BRRI dhan28 and (iv) BRRI dhan29; and four concentrations of Agroplus Biodecomposer viz. (i) no Agroplus Biodecomposer (Control), (ii) 2% Agroplus Biodecomposer (iii) 3% Agroplus Biodecomposer and (iv) 4% Agroplus Biodecomposer. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Agroplus Biodecomposer positively influenced growth and productivity of winter rice. It was evident that both plant height and tillering ability of winter rice were increased gradually with increased concentration of Agroplus Biodecomposer at all the growth stages of rice. All the yield contributing characters of rice were enhanced due to Agroplus Biodecomposer application which resulted in increased grain yield. Compared to control, rice grain yield was increased by 14, 20 and 28%, respectively due to application of Agroplus Biodecomposer at 2, 3 and 4% concentration. Rice variety also differed significantly in terms of growth and yield performance among themselves. Hybrid varieties performed better than inbred ones. Hybrid variety Hira appeared as the best performer followed by another hybrid Tej. Hybrid variety Hira interacted favorably with 4% Agroplus Biodecomposer to produce the highest grain yield of rice (7 t ha-1). Therefore, biofertilizer Agroplus Biodecomposer can be introduced to Bangladesh and foliar spray with 4% Agroplus Biodecomposer at 30, 45 and 60 DAT can be recommended for boosting up winter rice yield in a sustainable way. [Fundam Appl Agric 2018; 3(1.000): 372-381
Growth and yield of transplanted Aman rice cv. Binadhan-16 as influenced by seedling age and nitrogen fertilization at staggered transplanting
No full textAn experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during July to December 2016 to find out the effect of age of seedlings and level of nitrogen on the growth and yield of transplant Aman rice cv. Binadhan-16. The experiment comprised four ages of seedlings viz. 15, 20, 25 and 30-day old and four levels of nitrogen viz. 0, 50, 70 and 90 kg N ha-1. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The results revealed that the effect of age of seedlings and level of nitrogen and their interaction was significant on yield and yield contributing characters of transplant Aman rice. The highest plant height and total dry matter production hill-1 were recorded in the treatment of 15-day old seedlings with 70 kg N ha-1. Grain yield gradually increased with the use of relatively younger seedlings and with 15-day old seedlings produced the highest values of effective tillers hill-1 (8.583), grains panicle-1 (122.7), grain yield (4.265 t ha-1) and straw yield (5.392 t ha-1). In case of level of nitrogen, 70 kg N ha-1 produced the highest grains panicle-1 (114.1), grain yield (4.539 t ha-1) and straw yield (5.623 t ha-1). In interaction, 15-day old seedlings with 70 kg N ha-1 produced the highest effective tillers hill-1 (9.71), grain yield (5.17 t ha-1) and straw yield (6.20 t ha-1). Therefore, 15-day old seedlings with 70 kg N ha-1 appeared as the promising technique to obtain the highest grain yield [Fundam Appl Agric 2019; 4(2.000): 785-791
Agronomic manipulation for adaptation of black rice cultivars in plain land environment to eliminate hidden hunger
No full textTwo field experiemtns were conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from July 2016 to December 2016 to study the effect of cultivars, date of transplanting and fertilizer dose on the yield and quality of few hilly black rice cultivars. The experiment one consisted of two factors. Factor A: Varieties, viz., i) Galong se and ii) Gelong ni and Factor B: Planting date, viz., i) July 20, ii) August 5, iii) August 20, iv) September 5, v) September 20 and vi) October 5. The experiment two also consisted with two factors. Factor A: varieties, viz., i) Kongnam ene ii) Gelong se and iii) Nazirshail rice and Factor B: Fertilizer management viz., i) No fertilizer ii) 50% of recommended dose (RD) of fertilizers of a local aman rice variety, iii) 75% of RD of fertilizers of a local aman rice variety, iv) 100% of RD of fertilizers of a local aman rice variety, v) 125% of RD of fertilizers of a local aman rice variety and vi) 150% of RD of fertilizers of a local aman rice variety. Results revealed that among varieties, the black rice cultivar Gelong se was best grain yielding potential variety than three other rice varieties, of which two are black rice cultivars (Kongnam ene and Gelong ne) and another one is plain land white rice cultivar (Nizershail). Regarding time of transplanting it has been found that all the varieties gave higher yield when they were transplanted either on July 20 or August 05. The worst transplanting time was October 5 when lowest grain yield was obtained. From the nutritional view point, it has been found that all the three black rice cultivars got higher crude protein (%), crude fibre (%), ash (%), crude fat (%), Fe (ppm) and Zn (ppm) content over white rice cultivar. Therefore, it can be concluded that black rice could be incorporated in human diet and it would be a way of eliminating hidden hunger
Plant density influence on yield and nutritional quality of soyabean seed.
No full textPlant density is an important factor affecting soybean seed yield and but information regarding plant density effects on seed quality is highly scarce. The present study examines the relationship of seed yield and quality of two soybean varieties viz., PB-1 and G-2 with plant densities. The experiments were conducted in three consecutive seasons viz., Rabi 2004-05, Kharif 2005 and Rabi 2005-06 at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh, Bangladesh. Six plant densities viz., 20, 40, 60, 80, 100 and 120 plants m -2 were established using an equidistant planting pattern having spacings of 22.4×22.4 cm, 15.8×15.8 cm, 12.9×12.9 cm, 10.0×10.0 cm and 9.1×9.1 cm, respectively. A split-plot design was used having variety as main plot and density as sub-plot with three replicates. The results revealed that soybean seed yield increased with increase of plant density and the highest yield was obtained at 80 to 100 plants m -2 depending on variety and season. The further increase in plant density reduced the seed yield. The seed yield, seed protein and mineral contents such as phosphorus, calcium, potassium, sulphur and zinc showed a quadratic relation with plant density. Seed protein content decreased with increase in plant density up to 80 or 100 plants m -2 and then increased with further increase in plant density while reverse occurred for seed yield and different minerals. The results also showed that seed protein content was inversely related with seed yield and mineral contents in seed
Growth, yield and quality of faba bean (Vicia faba L.) in response to sowing date and phosphorus fertilization
No full textAn experiment was carried out to study the effect of date of sowing and level of phosphorus on the yield, yield components and seed protein content of faba bean (Vicia faba L.) at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during November 2018 to March 2019 to study the influence of sowing date and phosphorous fertilization on the growth, yield and quality of faba bean (V. faba). Three date of sowing viz. 25 November, 5 December, 15 December and five levels of phosphorus viz., 0, 10, 20, 30, 40 kg P ha-1 were used in this experiment laid out in a randomized complete block design with three replications. At 60 DAS, 25 November sowing fertilized with 40 kg P ha-1 showed significant influence on all characters except dry matter production. Early sowing on 25 November produced the tallest plant (42.95 cm), highest number of branches plant-1 (8.31), number of pods plant-1 (49.87), 1000-seed weight (97.55 g), seed yield (1.21 t ha-1), stover yield (1.98 t ha-1) and seed protein content (31.54%) while the corresponding lowest values were recorded from late sowing on 15 December. The crop fertilized with 40 kg P ha-1 produced the highest number of branches plant-1 (8.33), number of pods plant-1 (49.05), 1000-seed weight (97.40 g), seed yield (1.33 t ha-1), stover yield (2.28 t ha-1) and seed protein content (38.17%) while control treatment (0 kg P ha-1) produced the lowest values of all parameters. In case of interaction, the highest number of pods plant-1 (58.42), seed yield (1.59 t ha-1), stover yield (2.44 t ha-1) and protein content in seeds (39.60) were recorded with 25 November sowing fertilized with 40 kg P ha-1 whereas the lowest seed yield (0.54 t ha-1), stover yield (1.32 t ha-1) and seed protein content (25.90%) were obtained from 15 December sowing along with control treatment. Therefore, early sowing (25 November) with 40 kg P ha-1 appears as the promising combination for higher yield and seed protein content of faba bean
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