Weed suppressive ability of BRRI released popular monsoon rice varieties

Develoment of weed competitive crop cultivars is an attractive low-cost strategy of integrated weed management program that can reduce the heavy dependence of crop cultivation to chemical herbicides. Hence, to evaluate the weed competitiveness Bangladesh Rice Research Institute (BRRI) released selected monsoon rice varieties, a field experiment was conducted during July to December 2018 at the Agronomy Field Laboratory of Bangladesh Agricultural University. Thirty-three rice varieties were grown under season long weedy and weed-free conditions. Plots without rice plants were also maintained to investigate the natural growth of weed in absence of rice. The experiment was conducted following randomized complete block design with three replicates. The results showed that rice varieties varied widely in yielding ability and weed competitiveness. Among rice varieties, BRRI dhan31 allowed the minimum weed growth (32.5 g m-2) while BRRI dhan51 allowed the maximum weed growth (155.3 g m-2). Grain yield ranged between 3.6 t ha-1 (BRRI dhan49) and 7.5 t ha-1 (BR10) under weed-free condition and between 2.2 t ha-1 (BRRI dhan70) and 3.9 t ha-1 (BRRI dhan34) under weedy condition. Weed imposed relative yield loss ranged from 10.2 to 66.9% among the rice varieties. BRRI dhan34 allowed the least yield penalty (10.2%) while BRRI dhan70 had the maximum yield penalty (66.9%) due to competition with weeds. Although BR10 appear as the most productive variety (7.5 t ha-1) its weed imposed relative yield loss was higher (51.3%) than many other varieties with low yield potential. On the other hand, BRRI dhan34 appeared as the most weed competitive variety (only 10.2% relative yield loss) with productivity of 3.9 t ha-1. Considering the yield, BR10 was the best but for weed suppressive ability BRRI dhan34 performed well

Application of moringa leaf extract improves growth and yield of Tomato (Solanum lycopersicum) and Indian Spinach (Basella alba)

Moringa (Moringa oleifera L.) leaf extract is a natural plant growth stimulant that is well-known for its ability to improve plant growth and development. A field study was conducted to evaluate the influence of MLE (Moringa Leaf Extract) on the growth, yield and nutritional improvement in two vegetable crops [Tomato (Solanum lycopersicum) and Indian Spinach (Basella alba)]. The extract was applied at two weeks interval with different frequencies. The crops were fertilized with chemical fertilizers and MLE application was done as per treatment @ 25 ml/plant. For each of the crops, this bio-stimulant had a significant boosting effect on growth, yield and nutrient uptake whereas the maximum frequency in the application i.e. T4 (foliar application of MLE at 2 weeks after transplanting and application at every 2 weeks thereafter) showed the highest influence. Indian Spinach responded proportionally more to foliar-applied MLE in terms of plant growth and nutrient uptake compared to tomato. The effect of MLE on the yield parameters was more pronounced in tomato that showed a 25% (averaged across all the growth parameters) increase over control, but Indian Spinach showed ~20% increase in yield parameters compared to control. Therefore, applying MLE to the foliage may assist in increasing the yield by improving plant growth across the different vegetable species (e.g., Tomato and Indian Spinach)

Agricultural livelihoods in coastal Bangladesh under climate and environmental change - A model framework

We describe a novel integrated modelling system aiming to approximate the impact of environmental change on farmers' livelihoods in Bangladesh.</p

ゼロ価鉄粉を用いた地下水中のヒ素の浄化 : メカニズムの解明とその利用

京都大学0048新制・課程博士博士(地球環境学)甲第16248号地環博第77号新制||地環||15(附属図書館)28827京都大学大学院地球環境学舎地球環境学専攻(主査)教授 勝見 武, 教授 藤井 滋穂, 准教授 乾 徹学位規則第4条第1項該当Doctor of Global Environmental StudiesKyoto UniversityDA

Climate Change, Water Scarcity, and Health Adaptation in Southwestern Coastal Bangladesh

Climate change may affect human health through multiple and interactive pathways that include safe water scarcity. However, impacts of climate change-induced water scarcity on health and well-being are complex. About 80% of illnesses in developing countries are attributed to unsafe drinking water and waterborne diseases. In Southwestern Bangladesh, lack of safe drinking water is a severe crisis due to climate change. The study investigated the impacts of climate change on water resources and human health in a coastal area. A questionnaire survey was carried out in two villages of Shymnagar upazila on the southwestern coast to investigate the present status of safe water sources and health care facilities and their impacts on the local community. The results show that the local community believes that climate change is having substantial impacts on freshwater sources and health. More than 70% of the respondents identified diarrhea, dysentery, and skin diseases as the prime waterborne health risks that occur through climate-related safe water scarcity. By synthesizing the ground data, we suggest pathways to health adaptation to climate change effects and safe water scarcity through locally available adaptive practices such as the use of pond sand filters, rainwater harvesting, and importing potable water with the active participation of the government, nongovernmental organizations, and communities

Combined Effect of Salicylic Acid and Proline Mitigates Drought Stress in Rice (Oryza sativa L.) through the Modulation of Physiological Attributes and Antioxidant Enzymes

Salicylic acid (SA) and proline exhibit protective effects against a wide range of stresses. However, the combined impact of SA and proline on rice under drought stress is still unknown. Therefore, we investigated the protective roles of SA and/or proline in conferring drought tolerance in rice. There were eight treatments comprising the control (T1; 95-100% FC), 1.5 mM SA (T2), 2 mM proline (T3), 0.75 mM SA + 1 mM proline (T4), 45-50% FC (T5, drought stress), T5 + 1.5 mM SA (T6), T5 + 2 mM proline (T7), and T5 + 0.75 mM SA + 1 mM proline (T8), and two rice varieties: BRRI dhan66 and BRRI dhan75. Drought stress significantly decreased the plant growth, biomass, yield attributes, photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), photosynthetic pigments (chlorophyll and carotenoids content), relative water content (RWC), membrane stability index (MSI), soluble sugar and starch content, and uptake of N, P and K+ in roots and shoots. Drought-induced oxidative stress in the form of increased hydrogen peroxide (H2O2) production and lipid peroxidation (MDA) was observed. The combined application of SA (0.75 mM) + proline (1 mM) was found to be more effective than the single application of either for drought stress mitigation in rice. A combined dose of SA + proline alleviated oxidative stress through boosting antioxidant enzymatic activity in contrast to their separate application. The application of SA + proline also enhanced proline, soluble sugar and starch content, which resulted in the amelioration of osmotic stress. Consequently, the combined application of SA and proline significantly increased the gas exchange characteristics, photosynthetic pigments, RWC, MSI, nutrient uptake, plant growth, biomass and yield of rice. Therefore, the combined application of SA and proline alleviated the detrimental impacts of drought stress more pronouncedly than their separate application did by increasing osmoprotectants, improving nutrient transport, up-regulating antioxidant enzyme activity and inhibiting oxidative stress

Determination of Critical Limit of Zinc for Rice (<i>Oryza sativa</i> L.) and Potato (<i>Solanum tuberosum</i> L.) Cultivation in Floodplain Soils of Bangladesh

The critical limit for zinc (Zn) varies from 0.38 to 2 µg/g soil depending on the crop and soil type. However, the critical limit for Zn was not explored recently for rice and potato cultivation in the floodplain soils of Bangladesh. A pot experiment was conducted to determine the critical limits of Zn in soil and plants for rice and potato cultivation in two agro-ecological zones (AEZs) of Bangladesh. The soil samples were collected from 20 different locations of Old Brahmaputra and Active Ganges Floodplains with low (1.80 µg/g) Zn status. The experiment was laid out in a factorial and completely randomized design with two levels of Zn (Zn0 and Zn1 (0 and 4.87 kg/ha as Zn sulphate)) applied to 20 different soil samples for rice and potato cultivation using three replications. The critical limit of Zn was determined through a graphical and statistical approach and crops were harvested at the stem elongation (for rice) and tuber filling (for potato) stage. The critical limit of Zn in soil for rice was found to be 0.8 and 0.85 µg/g by graphical and statistical methods, respectively, and both methods revealed the same value (0.73 µg/g) for potato. The critical limit of Zn in rice plants was 23.9 and 24.32 µg/g, whereas in potato plants it was 27.1 and 26.61 µg/g, determined by graphical and statistical methods, respectively. The added Zn supply in soil significantly increased the dry matter accumulation in rice (by 5.6%) and potato (by 10%) compared to no Zn supply. Therefore, a significant positive response to added Zn could be observed on crop growth and yield when the Zn concentration remained below the mentioned critical level for rice and potato cultivation in floodplain soils of Bangladesh

Determination of Critical Limit of Zinc for Rice (Oryza sativa L.) and Potato (Solanum tuberosum L.) Cultivation in Floodplain Soils of Bangladesh

The critical limit for zinc (Zn) varies from 0.38 to 2 &micro;g/g soil depending on the crop and soil type. However, the critical limit for Zn was not explored recently for rice and potato cultivation in the floodplain soils of Bangladesh. A pot experiment was conducted to determine the critical limits of Zn in soil and plants for rice and potato cultivation in two agro-ecological zones (AEZs) of Bangladesh. The soil samples were collected from 20 different locations of Old Brahmaputra and Active Ganges Floodplains with low (&lt;0.9 &micro;g/g), medium (0.91&ndash;1.80 &micro;g/g) and high (&gt;1.80 &micro;g/g) Zn status. The experiment was laid out in a factorial and completely randomized design with two levels of Zn (Zn0 and Zn1 (0 and 4.87 kg/ha as Zn sulphate)) applied to 20 different soil samples for rice and potato cultivation using three replications. The critical limit of Zn was determined through a graphical and statistical approach and crops were harvested at the stem elongation (for rice) and tuber filling (for potato) stage. The critical limit of Zn in soil for rice was found to be 0.8 and 0.85 &micro;g/g by graphical and statistical methods, respectively, and both methods revealed the same value (0.73 &micro;g/g) for potato. The critical limit of Zn in rice plants was 23.9 and 24.32 &micro;g/g, whereas in potato plants it was 27.1 and 26.61 &micro;g/g, determined by graphical and statistical methods, respectively. The added Zn supply in soil significantly increased the dry matter accumulation in rice (by 5.6%) and potato (by 10%) compared to no Zn supply. Therefore, a significant positive response to added Zn could be observed on crop growth and yield when the Zn concentration remained below the mentioned critical level for rice and potato cultivation in floodplain soils of Bangladesh

Nitrogen, phosphorus and sulphur mineralization in soil treated with amended municipal solid waste compost under aerobic and anaerobic conditions

Purpose Our study had considered some organic amendments to enhance nutrient level of marketed municipal solid waste (MSW) compost for its potential use as fertilizer for growing crops in alluvial soils. Method We prepared three types of amended compost by mixing 20% mustard oil cake (MOC), and 30% poultry manure (PM) or cowdung (CD) or sugarcane press mud (SPM) with 50% MSW compost. The nitrogen (N), phosphorus (P) and sulphur (S) mineralization study was done in soil treated with three amended and one unamended composts with three replications through an incubation experiment at a temperature of 25 ± 1°C for 82 days under aerobic (field capacity) and anaerobic (submerged) conditions. The mineralization data were fitted to the first-order kinetic model. Results The soil NO3--N content was 2-3 times higher in aerobic condition than in anaerobic condition, while the NH4+-N was higher in anaerobic soils. The kinetic model reveals that poultry manure and sugarcane press mud had higher capability to supply N for use by the crops. The P release was the highest at day 15 with three-time higher availability in anaerobic condition. The S mineralization in soil was higher in field capacity than in submerged condition. ConclusionThe compost mixture comprising MSW, MOC and SPM in a ratio of 5:2:3 demonstrated the highest cumulative N, P and S mineralization in both aerobic and anaerobic conditions. The N and S availability decreased while the P availability increased in submerged soils which result has fertilizer management implications for wet  land rice crop

ICT Uses, Constraints, and Challenges in Flash Flood Risk Management: A Case Study in North-Eastern Haor Areas of Bangladesh

This study intends to explore the extent of the use of information and communication technology (ICT) in flash-flood-prone haor (wetland ecosystem) areas of north-eastern Bangladesh. Addressing the situation of severe flash floods in 2017 at the community level, this study aims to examine the constraints and challenges in using ICT for flash flood risk management. An empirical study was conducted in two upazilas (administrative sub-districts) within the Sunamganj, the most affected district. A total of 120 household heads were interviewed using a semi-structured questionnaire. Focused group discussions (FGD) and key informant interviews (KII) were also used. Results reveal that people in these areas do not use computers or Internet. However, the use of mobile phones is common for communication during disasters. Illiteracy, poor quality of life, poor social capital, poor infrastructure, and poor communication with institutions are highlighted as the main constraints and challenges in the effective application of ICT in flash flood management. The results showed that the local community people of the study area receive early warning and hazards preparedness-related information through mobile phones, television, radio, and Facebook. However, the results also highlighted the constraints and challenges in applying ICT in DRR at the community level. By addressing a remote region and a relatively less focused disaster (flash flood), this study contributes to boosting the application of ICT in DRR, especially in remote, disadvantaged communities