Nahar first proposed to cultivate a non-foodbioenergy crop, Jatropha curcas L. in Bangladesh, as it did not need arable land and does not compete with food. Her work focused on the increasing water deficit conditions due to global climate change and its relationship to fruit yield, particularly in combating world hunger. Her publications also center around bioenergy and food production in both the cyclical water deficit lands and the highly flooded plains of Bangladesh.[5] Emphasizing land use patterns and possible cultivation areas of Bangladesh, she stressed the uses and socioeconomic benefits of the plant, citing minimal production costs and ease for the production of biodiesel and other useful byproducts compared to conventional fossil fuel. Carbon sequestration was also implied in the national scheme.[6][7]
Soil fertility and water deficiency
In the early 1980s, Nahar began analysing the soils of different areas of the country. Twenty soil samples belonging to four pedons from Bhola District were analysed for their profile morphology, particle-size distribution, and mineral composition in the clay fraction. Fine to medium-sized mottles with distinct contrast were present in almost all the horizons. Structural B (cambic) horizon has developed in all the pedons where clay content ranged from 17 to 42%. The texture of the soils ranged from siltloam to silty clay loam. Mica and kaolinite were the two other minerals whose abundance was nearly equal. The occcurrence of small quantities of mica-vermiculite intergrades and some interstratified clay minerals was suspected. A small portion of smectites was considered to be formed authigenically in the soils from Bhola.[8]
Later, a total of twenty-one soil samples belonging to five representative soil series were collected on a horizon basis from the three distinct vegetative zones of Raojan Rubber Garden, Chittagong and analysed for their different properties. The different horizons of the profiles studied were truly pedogenetic. Sand was the dominant fraction of the soil, which might indicate that the parent materials were arenaceous in nature. The texture of the soil ranged from loamy sand to sandy loam at the surface and sandy loam to sandy clay loam at the subsurface. The sand/silt ratio indicated that the studied profiles did not form on uniform parent materials. Moisture percentage of air dry soils ranged from 0.3 to 2.6. A positive correlation existed between percent clay and hygroscopic moisture of the soils.[9]
Drought-resistant plants and crop yield
Since then, Nahar's research has focused on increasing water deficit conditions due to global climate change and its relationship to fruit yield, particularly in combating world hunger. Her publications also center around bioenergy and food production in both the cyclical water deficit lands and the highly flooded plains of Bangladesh. The influence of water stress on tomato plants and fruit quality was investigated in a pot experiment. The uptake of nitrogen, sodium, potassium, sulphur, calcium and magnesium was significantly reduced by water stress in the plants. Significant increases in glucose, fructose, sucrose in fruits and proline content in leaves showed some tendency of this crop to adjust osmotically to water stress. Water stress increased the sugar and acid contents (ascorbic, malic and citric acid) of the tomato fruits and thus improved the fruit quality.[10] This study investigates the effects of water stress on moisture content distribution at different soil layers (pot) and on the morphological characters of tomato plants. Moisture content distribution was higher at the surface and decreased with increasing stress at all growth stages. Yield and related morphological characters responded better at certain of the field capacity compared when with other treatments.[11] A study was conducted in the experimental field of Sher-e-Bangla Agricultural University in Dhaka, Bangladesh, to study the effect of water stress on fruit quality and osmotic adjustment in different types. The plants had a tendency to adjust against a drop in potential in the soil by producing organic solutes such as glucose, fructose, sucrose and proline. The quality of fruits was improved as a result of the synthesis of ascorbic acid, citric acid and malic acid. No physical damage due to stress was observed in fruits, which were over 90% red.[citation needed] Another such test conducted studied the effect of water stress on the height, dry matter and yield of a few cultivars where it was noticed that the yield was reduced due to stress but no significant difference was observed.
Second-generation bioenergy crops
Nahar also worked on energy crops, especially their adaptability in different soil types of Bangladesh, especially wastelands choosing second generation energy crops not in high demand in the global food market and thus has little impact on food prices and food security thereby negating the food-fuel dilemma. She explored the potential of biofuel production on a limited land space for sustaining a growing population like Bangladesh. With rapidly growing urban and national population growth rate, Bangladesh's growing demand for energy with urban expansion has led to deforestation and a steady loss of arable lands, which may result in future food shortages, where she proposes a simple required land use per capita model [note 1] for establishing a relationship between the biomass production,[note 2] associated crop yields, the biomass to biofuel conversion methods and the overall fuel demand, as a plan to meet the national energy and habitable land demands while considering the looming environmental effects related to energy usage.
↑ , is the total number of people using this source of energy, is the average driving distance per vehicle and: is the total distance to be traveled, is the average , hence,
↑ Where the current planned theoretical production is given by, and optimal production by ; with , , and ; where with , (after pretreatment conversion) and .
↑ Nahar, Kamrun (July 1989). "A Morphological and clay mineralogical study of some soils from Bhola District in Bangladesh". Dhaka University Studies Part B. 4 (2). Dhaka: 93–104.
↑ Nahar, Kamrun (1993). "A Study of some morphological and physical properties of soils from Raojan Rubber Plantation of Chittagong". Journal of Soil Science. 24 (1&2): 31–39.
Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface into the atmosphere. It covers both water evaporation and transpiration. Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in water resource management agricultural irrigation.
Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricultural, domestic or industrial bio waste. Biofuels are mostly used for transportation, but can also be used for heating and electricity. Biofuels are regarded as a renewable energy source. The use of biofuel has been subject to criticism regarding the "food vs fuel" debate, varied assessments of their sustainability, and ongoing deforestation and biodiversity loss as a result of biofuel production.
Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.
A renewable resource is a natural resource which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes in a finite amount of time in a human time scale. When the recovery rate of resources is unlikely to ever exceed a human time scale, these are called perpetual resources. Renewable resources are a part of Earth's natural environment and the largest components of its ecosphere. A positive life-cycle assessment is a key indicator of a resource's sustainability.
Panicum virgatum, commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55°N latitude in Canada southwards into the United States and Mexico. Switchgrass is one of the dominant species of the central North American tallgrass prairie and can be found in remnant prairies, in native grass pastures, and naturalized along roadsides. It is used primarily for soil conservation, forage production, game cover, as an ornamental grass, in phytoremediation projects, fiber, electricity, heat production, for biosequestration of atmospheric carbon dioxide, and more recently as a biomass crop for the production of ethanol and butanol.
Loam is soil composed mostly of sand, silt, and a smaller amount of clay. By weight, its mineral composition is about 40–40–20% concentration of sand–silt–clay, respectively. These proportions can vary to a degree, however, and result in different types of loam soils: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, and loam.
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids and particles but soil may also contain organic solids and other matter. Along with rock mechanics, soil mechanics provides the theoretical basis for analysis in geotechnical engineering, a subdiscipline of civil engineering, and engineering geology, a subdiscipline of geology. Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils. Example applications are building and bridge foundations, retaining walls, dams, and buried pipeline systems. Principles of soil mechanics are also used in related disciplines such as geophysical engineering, coastal engineering, agricultural engineering, and hydrology.
Soil moisture is the water content of the soil. It can be expressed in terms of volume or weight. Soil moisture measurement can be based on in situ probes or remote sensing methods.
This is an index of articles relating to soil.
Arundo donax is a tall perennial cane. It is one of several so-called reed species. It has several common names including giant cane, elephant grass, carrizo, arundo, Spanish cane, Colorado river reed, wild cane, and giant reed. Arundo and donax are respectively the old Latin and Greek names for reed.
Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.
Energy crops are low-cost and low-maintenance crops grown solely for renewable bioenergy production. The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to generate electrical power or heat.
Miscanthus sinensis, the eulalia or Chinese silver grass, is a species of flowering plant in the grass family Poaceae, native to eastern Asia throughout most of China, Japan, Taiwan and Korea.
Miscanthus × giganteus, also known as the giant miscanthus, is a sterile hybrid of Miscanthus sinensis and Miscanthus sacchariflorus. It is a perennial grass with bamboo-like stems that can grow to heights of 3–4 metres (13 ft) in one season. Just like Pennisetum purpureum, Arundo donax and Saccharum ravennae, it is also called elephant grass.
Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading countries in area planted for energy generation are Sweden and the UK.
Jatropha curcas is a species of flowering plant in the spurge family, Euphorbiaceae, that is native to the American tropics, most likely Mexico and Central America. It is originally native to the tropical areas of the Americas from Mexico to Argentina, and has been spread throughout the world in tropical and subtropical regions around the world, becoming naturalized or invasive in many areas. The specific epithet, "curcas", was first used by Portuguese doc Garcia de Orta more than 400 years ago. Common names in English include physic nut, Barbados nut, poison nut, bubble bush or purging nut. In parts of Africa and areas in Asia such as India it is often known as "castor oil plant" or "hedge castor oil plant", but it is not the same as the usual castor oil plant, Ricinus communis.
Second-generation biofuels, also known as advanced biofuels, are fuels that can be manufactured from various types of non-food biomass. Biomass in this context means plant materials and animal waste used especially as a source of fuel.
Algae fuel, algal biofuel, or algal oil is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Also, algae fuels are an alternative to commonly known biofuel sources, such as corn and sugarcane. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil. These fuels have no practical significance but remain an aspirational target in the biofuels research area.
Issues relating to biofuel are social, economic, environmental and technical problems that may arise from biofuel production and use. Social and economic issues include the "food vs fuel" debate and the need to develop responsible policies and economic instruments to ensure sustainable biofuel production. Farming for biofuels feedstock can be detrimental to the environment if not done sustainably. Environmental concerns include deforestation, biodiversity loss and soil erosion as a result of land clearing for biofuels agriculture. While biofuels can contribute to reduction in global carbon emissions, indirect land use change for biofuel production can have the inverse effect. Technical issues include possible modifications necessary to run the engine on biofuel, as well as energy balance and efficiency.
In fluid dynamics, the radiation stress is the depth-integrated – and thereafter phase-averaged – excess momentum flux caused by the presence of the surface gravity waves, which is exerted on the mean flow. The radiation stresses behave as a second-order tensor.
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