Mechanization of dairy farming in Bangladesh

The mechanization status of dairy farming in Bangladesh is not mentionable. In every steps of the farming operation, indigenous systems have been practiced in most of the farms. This study has been conducted to assess mechanization status in dairy farming. The selected areas of this study were Bangladesh Agricultural University (BAU) dairy farm, Mymensingh, Rural Development Academy (RDA) dairy farm, Bogra and four small, four medium and two large farms in Sirajganj district. Most mechanized RDA dairy farm and rest of the non-mechanized farms were selected for this study. The field survey was conducted by interviewing identified sample respondents with pre-determined interview schedules to cover all selected locations. Most of the farms have no specific designed farm building with specific space per animal, feeding alley, manger, gutter and drainage system, ventilation system. Even the manure management system in study area was very poor. A biogas plant can utilize manure properly. Milking machine and chopper machine were only found in BAU and RDA dairy farms. Spacing per animal for dairy cow was 3.65 m2, for pregnant cow was 9.30 m2, for dry cow or heifer was 1.37 m2, and for calf was 1.31 m2 respectively. Mangers in a pen barn were about 0.5-1.25 m wide and 0.5-1 m depth which varies for dairy cow, heifer, calf, and bull individually. All farms in study areas found natural ventilation system. Concentrates require per day for dairy cow, dry cow, heifer, bull calf, cow calf and mature bull were 3.4, 2.2, 1.2, 0.5, 1.01 and 5.2 kg respectively. The amount of maize for bull is 2.4 kg, for dairy cow is 1.4 kg and lowest amount for bull calf is 140 g per head. Due to lack of knowledge and unfamiliarity farmers do not accept machinery like milking machine, chopper machine etc. Installation of partial mechanization can contribute to convert indigenous into modernization with gross productivity of dairy farming systems in Bangladesh

FIELD PERFORMANCE OF BAU-STR DRYER IN RURAL AREA OF BANGLADESH

Paddy drying after harvest is important for reducing loss and storing long term. High moisture promotes the development of insects and molds that are harmful to the grain. It is necessary to adapt technology for drying paddy at small scale traders and farmers’ level as an alternative to traditional sun drying. The low cost BAU-STR dryer would be one of the alternative effective drying technologies. Therefore, the objective of this study was to investigate technical and financial performance of BAU-STR dryer at the field level. The study of BAU-STR dryer was conducted during Boro Season, 2016 at selected areas of Mymensingh and Jessore districts. Air temperature inside grain bin was recorded using 3 ACR Smart Button data logger. Ambient air temperature was recorded using TRH-1000 sensor. Moisture content of the grain was measured at five locations in the BAU-STR dryer during drying operation. The dryer was evaluated with three verities: T1-SL 8, T2-Hybrid Taj, T3-BRRI dhan28 which consider as three treatments. The dryer capacity was 500 kg per batch. The results showed that the temperature and moisture distributions in BAU-STR dryer were uniform. Paddy was dried from moisture content 22.8 to 12.2% uniformly in between 2.5 to 4.8 hours for 500 kg dryer capacity in different treatments. The drying time for larger grain (T1-SL8) was less compared to other two varieties. The drying efficiency was about 52%, 65% and 52% for T1, T2, and T3, respectively. The operating cost of drying was found Tk. 0.87 per kg (diesel engine operated blower) for BAU-STR dryer. The benefit-cost ratio and payback period were found 1.9 and 0.28 yr for diesel engine operated BAU-STR dryer from the experiments at field level of Bangladesh

Opening Size Effects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building-A CFD Study

Airflow inside naturally ventilated dairy (NVD) buildings is highly variable and difficult to understand due to the lack of precious measuring techniques with the existing methods. Computational fluid dynamics (CFD) was applied to investigate the effect of different seasonal opening combinations of an NVD building on airflow patterns and airflow rate inside the NVD building as an alternative to full scale and scale model experiments. ANSYS 2019R2 was used for creating model geometry, meshing, and simulation. Eight ventilation opening combinations and 10 different reference air velocities were used for the series of simulation. The data measured in a large boundary layer wind tunnel using a 1:100 scale model of the NVD building was used for CFD model validation. The results show that CFD using standardk-epsilon turbulence model was capable of simulating airflow in and outside of the NVD building. Airflow patterns were different for different opening scenarios at the same external wind speed, which may affect cow comfort and gaseous emissions. Guiding inlet air by controlling openings may ensure animal comfort and minimize emissions. Non-isothermal and transient simulations of NVD buildings should be carried out for better understanding of airflow patterns

Opening Size E ects on Airflow Pattern and Airflow Rate of a Naturally Ventilated Dairy Building : A CFD Study

Airflow inside naturally ventilated dairy (NVD) buildings is highly variable and difficult to understand due to the lack of precious measuring techniques with the existing methods. Computational fluid dynamics (CFD) was applied to investigate the effect of different seasonal opening combinations of an NVD building on airflow patterns and airflow rate inside the NVD building as an alternative to full scale and scale model experiments. ANSYS 2019R2 was used for creating model geometry, meshing, and simulation. Eight ventilation opening combinations and 10 different reference air velocities were used for the series of simulation. The data measured in a large boundary layer wind tunnel using a 1:100 scale model of the NVD building was used for CFD model validation. The results show that CFD using standard k-ε turbulence model was capable of simulating airflow in and outside of the NVD building. Airflow patterns were different for different opening scenarios at the same external wind speed, which may affect cow comfort and gaseous emissions. Guiding inlet air by controlling openings may ensure animal comfort and minimize emissions. Non-isothermal and transient simulations of NVD buildings should be carried out for better understanding of airflow patterns

Non-linear temperature dependency of ammonia and methane emissions from a naturally ventilated dairy barn

Ammonia (NH3) and methane (CH4) emissions from naturally ventilated dairy barns affect the environment and the wellbeing of humans and animals. Our study improves the understanding of the dependency of emission rates on climatic conditions with a particular focus on temperature. Previous investigations of the relation between gas emission and temperature mainly rely on linear regression or correlation analysis. We take up a preceding study presenting a multilinear regressionmodel based onNH3 and CH4 concentration and temperaturemeasurements between 2010 and 2012 in a dairy barn for 360 cows inNorthern Germany.We study scatter plots and non-linear regressionmodels for a subset of these data and show that the linear approximation comes to its limits when large temperature ranges are considered. The functional dependency of the emission rates on temperature differs among the gases. For NH3, the exponential dependency assumed in previous studies was proven. For methane, a parabolic relation was found. The emissions show large daily and annual variations and environmental impact factors like wind and humidity superimpose the temperature dependency but the functional shape in general persists. Complementary to the former insight that high temperature increases emissions, we found that in the case of CH4, also temperatures below 10 C lead to an increase in emissions from ruminal fermentation which is likely to be due to a change in animal activity. The improved prediction of emissions by the novel non-linear model may support more accurate economic and ecological assessments of smart barn concepts

Manufacturing of agricultural machinery in Bangladesh: opportunities and constraints

Despite numerous limitations, agricultural machinery (AM) manufacturing sub-sector inBangladeshis growing quite satisfactorily and has potential to make substantial contribution to much needed non-farm economic growth, employment generation, mechanization of on and off-farm agricultural activities, and as a whole orientation in the national development.  This study made an attempt to take account of AM manufacturers, importers, traders/wholesalers and retailers, their associations, assess market potential and identify serious bottlenecks associated with this sub-sector.  Stratified random sampling technique was used for identifying respondents in quantitative survey, while focus group discussions (FGDs) and Key Informant Interviews (KIIs) were conducted for qualitative investigation.  In recent years, there are about 70 foundries, 800 agricultural machinery manufacturing industries and workshops, 1,500 spare parts manufacturing workshops, and about 20,000 repair and maintenance workshops are engaged in AM sub-sector of the country.  The annual estimated market size of AM and spare parts in the country is about US$802.3 million with an US$ 105.2 million annual repair and maintenance service market, estimating an annual total AM market size of about US$907.5 million of which local production market share is about     US$ 402.7 million.  The spare parts market size in the country is about US$309.3 million of which domestic production of spare parts is estimated US$ 237.9 million.  The significant shift in the supply of spare parts in the country underlines the growth potential of the local spare parts manufacturing sub-sector and potential for substitution of imported spare parts.  Bogra has emerged as the center of manufacturing AM and spare parts especially for irrigation pumps, threshers, maize shellers, piston, liner and numerous spare parts of small diesel engines and machines, casting of machine components etc. and contributing about 80% of the local production in the country.  However, infrastructures for production of AM and spare parts in Bogra and elsewhere in the country are still inadequate. The study recommends declaration of Borga and Jessore as ‘Agri-machinery districts’ and establishment of special ‘Agri-machinery Production Zones (APZ)’ in these areas.  To promote export market to Indian subcontinent and other developing countries, tariff and non-tariff restrictions would be waved on AM through bilateral negotiations and border markets (hats) withIndiato be allowed for AM sales. 

EVALUATION OF SOLAR TUNNEL DRYER FOR DRYING OF CABBAGE

Drying is an effective means of reducing moisture content of perishable fruit and vegetables to a safe storage level and reduce post harvest loss. This study was conducted to evaluate a solar tunnel dryer for drying cabbage in comparison to traditional open sun drying at the advanced drying lab of the Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh. Salt pre-treated cabbage was used for drying inside the dryer and open sun drying. The parameters like solar radiation, temperature, relative humidity, and moisture content were measured using standard instruments during the experiments. The results showed that the maximum peak temperature inside the drying chamber was 45 °C during mid-day (12 pm) when solar radiation was 600 w/m2 and in an average inside temperature was approximately 30°C to 40°C in a full sunny day (9:00 AM to 04:00 PM) when average solar radiation was 321±115 W/m2. The moisture content of sliced cabbage was reduced initially 94.42, 90.18, and 92.24 % (w.b.) to 4.85, 15.84, and 15.71% (w.b.), and drying time of the dryer was 28, 21, and 19 hours in 1st, 2nd, and 3rd trials, respectively. The drying rate and drying efficiency were found 0.15 kg/hr. and 8.22 %, respectively in tunnel dryer and 0.02 kg/hr. and 3.38 %, respectively in open sun drying. The color and texture of the solar tunnel dried cabbage were better than the open sun drying method. Further experiments are required for estimating drying capacity with the operating cost of the solar tunnel dryer when the dryer will be used with its full capacity. [J Bangladesh Agril Univ 2022; 20(3.000): 267-279