We review the recent development of Conservation Agriculture (CA) for rice-based smallholder farms in the Eastern Gangetic Plain (EGP) and the underpinning research on agronomy, weed control, soil properties and greenhouse gas emissions being tested to accelerate its adoption in Bangladesh. The studies are based mostly on minimum soil disturbance planting in strip planting (SP) mode, using the Versatile Multi-crop Planter (VMP), powered by a two-wheel tractor (2WT). One-pass SP with the VMP decreased fuel costs for crop establishment by up to 85% and labour requirements by up to 50%. We developed strip-based non-puddled rice (Oryza sativa) transplanting (NPT) in minimally-disturbed soil and found that rice grain yield increased (by up to 12%) in longer-term practice of CA. On farms, 75% of NPT crops increased gross margin. For non-rice crops, relative yield increases ranged from 28% for lentil (Lens culinaris) to 6% for wheat (Triticum aestivum) on farms that adopted CA planting. Equivalent profit increases were from 47% for lentil to 560% for mustard (Brassica juncea). Moreover, VMP and CA adopting farms saved 34% of labour costs and lowered total cost by up to 10% for production of lentil, mustard, maize (Zea mays) and wheat. Effective weed control was obtained from the use of a range of pre-emergent and post-emergence herbicides and retention of increased crop residue. In summary, a substantial body of research has demonstrated the benefits of CA and mechanized planting for cost savings, yield increases in many cases, increased profit in most cases and substantial labour saving. Improvement in soil quality has been demonstrated in long-term experiments together with reduced greenhouse gas emissions.
The results of the present study implies that the analyzed plants possess varying degree of antioxidant capacity and, therefore, the antioxidant potency of these underused plants may be utilized to prevent oxidative damage and oxidative stress related disorders.
The seed bank is the resting place of weed seeds and is an important component of the life cycle of weeds. Seed banks are the sole source of future weed populations of the weed species both annuals and perennials that reproduce only by seeds. For this reason, understanding fate of seeds in the seed bank can be an important component of overall weed control. When weed seeds enter the seed bank, several factors influence the duration for which seeds persist. Seeds can sense the surrounding environment in the seed bank and use these stimuli to become dormant or initiate germination. Soil and crop management practices can directly influence the environment of seeds in the soil weed seed bank and can thus be used to manage seed longevity and germination behavior of weed seeds.
Glasshouse experiments were conducted from March to July 2003 to determine the effects of sowing depth, and the time, duration, and depth of flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl. The treatments that were evaluated in the first experiment were three seeding depths (0, 0.5, and 1.0 cm), while in the second experiment, three flooding depths (saturated soil with no standing water and soil with water depths of 5 and 10 cm) and three flooding durations (7, 14, and 21 days from sowing) were evaluated. In the third experiment, three flooding depths (saturated soil with no standing water, and soil with water depths of 5 and 10 cm) and four flooding regimes (7, 14, 21 or 28 days after sowing [DAS]) were evaluated. Surface seeding gave the highest emergence rate compared to the 0.5 cm and 1.0 cm soil depths. A significantly higher emergence rate was recorded with the saturated conditions than with the flooded conditions. A flooding duration of ≥ 14 days showed a clear trend of reduced emergence with increasing flooding depth. A significantly higher survival rate, plant height, root length, number of leaves, and dry matter were recorded at soil saturation followed by the 5 cm and 10 cm flooding depths when flooding was simulated at 7 and 14 DAS. When the flooding was delayed to 21 and 28 DAS, the 10 cm flooding depth was required to suppress this weed. The results provide sufficient evidence to confirm that from deeper seed burial (1 cm sowing depth), flooding depths of ≥ 5 cm of durations of 14 and 21 days and at the onset of flooding within 14 DAS were effective in suppressing the emergence and growth of F. miliacea. 1995;Begum et al. 1999) and one of the principal weeds in the Philippines, Mashhor
The present study provides a characterization of water quality and plankton samples in earthen fish pond in Rajshahi, Bangladesh. Sampling was done over a period of six months, running from October, 2004 through March, 2005. All the water quality parameters were within the optimal ranges for plankton productivity. Temperatures varied from 19.75 to 27.25 degrees C; transparency, 24.75-29.50 cm; pH, 6.62-7.85; Dissolved Oxygen (DO), 3.87-5.85 mg L(-1); free CO2 5.25-7.25 mg L(-1) and bicarbonate (HCO3) alkalinity, 81.25-147.5 mg L(-1). Analyses of plankton samples recorded a total of 5 classes phytoplankton viz.; Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae and 2 classes of zooplankton; Crustacea and Rotifera. The phytoplankton population was comprised of 17 genera belonging to Cyanophyceae (5 classes, 34.47%), Bacillariophyceae (3, 13.87%), Cyanophyceae (3, 34.48%), Euglenophyceae (3, 10.68%) and 1 to Dinophyceae (6.50%). The zooplankton population consisted of 10 genera belonging to Rotifera (4, 40.13%) and Crustacea (6, 59.87%). Phytoplankton and zooplankton abundance varied from 60800 to 239400 units/l and 7620 to 12160 units/l, respectively. It is concluded that the phytoplankton groups provide the main support for earthen pond aquaculture in the pond compared to zooplankton classes. The information provides for more research to compare water quality and pond plankton characteristics in earthen aquaculture systems with and without fish stocking. Further studies on the seasonal changes of water quality parameters and its effects on plankton production in the fish ponds and all year extended monitoring is recommended in future studies.
A study was conducted to compare the survival, production and economics of mud crab fattening in cage with fattening in encircled earthen brackishwater pond. Thirty cages of 1m (L) × 1m (W) × 0.3m (H) partitioned into 16 compartments (each 25 × 25 × 30 cm) were set in a 40 m 2 pond and another pond with same area was encircled with bamboo fence. Mud crab fattening in cage and in encircled earthen area were considered as Treatment-1 and Treatment-2, respectively with three replications each to compare the fattening system. Single adult non-gravid female crab (204.42 ± 2.58g) was stocked into each compartment of the cages and 80 crabs (204.42± 2.58g) were also stocked into earthen pond @ 2 indiv./ m 2 . The crabs were fed with chopped tilapia @ 8% of body weight twice daily. Survival rate of crab was found 93.75 ± 6.25% and 86.12 ± 2.16% respectively in cages and encircled earthen area. Significantly (P<0.05) higher total production of crab from cages (3.30±0.08 kg/m 2 ) was recorded than the encircled earthen area (0.37±0.01 kg/m 2 ). Comparative benefit-cost analysis showed that bamboo cage fattening attained higher net profit (Tk 91,630.00) than crab fattening in encircled earthen area (Tk 9,345.00) from 12 crops (12-16 days per crop) fattening period. The present study revealed that mud crab fattening using bamboo cage might be better than encircled earthen area with fencing in Bangladesh.
A total of 263 angiosperm species under 210 genera and 79 families have been recorded from Dhamrai Upazila of Dhaka district. Of these, Magnoliopsida is represented by 200 species under 154 genera and 62 families while Liliopsida is represented by 63 species under 56 genera and 17 families. Asteraceae is the largest family in Magnoliopsida represented by 17 species, and Poaceae is the largest family in Liliopsida represented by 20 species. Habit analysis shows that herbs, shrubs and trees are represented by 166, 23 and 74 species, respectively. Sixty two medicinal plants have been documented with their uses for the cure of more than 30 diseases, and some of these are diabetes, jaundice, diarrhoea, dysentery, spleen and liver complaints, chronic ulcers, bronchitis, rheumatism, irregular menstruation, piles, urinary problems and heart diseases. Threats to the species have also been assessed and appropriate conservation measures suggested.
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