Category Science

ARE CROP CIRCLES CAUSED BY WEIRD WEATHER?

          There are many theories about the origin of mysterious patterns that appear in fields of corn around the world – commonly known as crop circles. While some people believe they are the work of alien spacecraft, many of them are known to be man-made. Unusual weather, such as small tornadoes or electrical storms, is thought to be the cause of some of the patterns.

          George Meaden, a meteorologist and physicist, explained crop circles in terms of atmospheric physics, as the effect of a plasma-vortex. Meaden likened the phenomenon to ball-lightning, but larger and longer-lasting. He expanded his theories in later research to include ionisation and electromagnetism. Physicist Stephen Hawking appeared to give credence to this view, writing in 1991 that corn circles are either hoaxes or formed by vortex movement of air.

           Meaden’s ideas were taken up by Ralph Noyes, a senior Ministry of Defence official and an expert in UFO phenomena, who wrote as follows:

          If Meaden is right, our atmosphere is sometimes able to produce a short-lived but vigorously swirling disturbance with strong electrical properties. A layman grasps after the analogy of something between ball-lightning and a mini-tornado. Depending on conditions, this transient energy-form can manifest as a globe of light, often with associated sounds. It may be able to interfere with the ignition system of automobiles and perhaps to affect close witnesses. Descending to earth, it can make a cropfield circle. Acting more vigorously it may well cause more violent circular damage at ground level. In short, a good meteorologist whose sole concern has been to investigate cropfield circles has ended by describing much of the UFO phenomenon!

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WHAT ARE THE EFFECTS OF EL NINO?

            IN an El Nino year, weather systems around the world become very unpredictable. This is most noticeable in the Pacific region. In the El Nino of 1997-98, massive floods caused widespread devastation in many parts of South America, making many thou-sands of people homeless. It also triggered a hurricane, bringing torrential rain to the deserts of California and Nevada. In the west of the region, El Nino brings hot, dry weather in what ought to be a rainy season. In the past, this has caused forest fires in Australia and Indonesia.

            The 1997–98 El Niño was regarded as one of the most powerful El Niño–Southern Oscillation events in recorded history, resulting in widespread droughts, flooding and other natural disasters across the globe. It caused an estimated 16% of the world’s reef systems to die, and temporarily warmed air temperature by 1.5 °C, compared to the usual increase of 0.25 °C associated with El Niño events.

            It led to a severe outbreak of Rift Valley fever after extreme rainfall in north-eastern Kenya and southern Somalia. It also led to record rainfalls in California during the water season of 1997–98 and one of Indonesia’s worst droughts on record. 1998 ultimately became the warmest year in recorded history (up until then).

            The 1997–98 El Nino Event had various effects on tropical cyclone activity around the world, with more tropical cyclones than average occurring in the Pacific basins. This included the Southern Pacific basin between 160°E and 120°W, where 16 tropical cyclones in the South Pacific were observed during the 1997–98 season compared to an average of around 8 The area where most of the tropical cyclones developed was shifted eastwards, with parts of the Cook Islands and French Polynesia impacted as a result. In the West Pacific basin, the season saw a record of 11 super typhoons, with 10 of them reaching Category 5 intensity. In the east Pacific basin, the 1997 Season featured two Category 5 hurricanes, Guillermo and Linda, the latter of which was the strongest on record before Patricia took that title during the 2015 season. The North Pacific basin broke the record for having the most tropical cyclones reaching Category 4 and 5 intensities with 17 that season. However, the 2015 season surpassed it with 21 tropical cyclones during the 2014–16 El Niño event.

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WHAT DOES EL NINO MEAN?

            El Nino is Spanish for “Boy Child” — a reference to Jesus. It was named in the 17th century by Spanish-speaking fishermen who lived in Peru, South America. It was given this name because the unusual weather associated with El Nino began around Christmas.

            El Niño Spanish is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the International Date Line and 120°W), including the area off the Pacific coast of South America. The ENSO is the cycle of warm and cold sea surface temperature (SST) of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. El Niño phases are known to occur close to four years, however, records demonstrate that the cycles have lasted between two and seven years. During the development of El Niño, rainfall develops between September–November. The cool phase of ENSO is La Niña, with SSTs in the eastern Pacific below average, and air pressure high in the eastern Pacific and low in the western Pacific. The ENSO cycle, including both El Niño and La Niña, causes global changes in temperature and rainfall.

            Developing countries that depend on their own agriculture and fishing, particularly those bordering the Pacific Ocean, are usually most affected. In American Spanish, the capitalized term El Niño means “the boy”. In this phase of the Oscillation, the pool of warm water in the Pacific near South America is often at its warmest about Christmas. The original name of the phase, El Niño de Navidad, arose centuries ago, when Peruvian fishermen named the weather phenomenon after the newborn Christ. La Niña, chosen as the “opposite” of El Niño, is American Spanish for “the girl”.

            Originally, the term El Niño applied to an annual weak warm ocean current that ran southwards along the coast of Peru and Ecuador at about Christmas time. However, over time the term has evolved and now refers to the warm and negative phase of the El Niño–Southern Oscillation and is the warming of the ocean surface or above-average sea surface temperatures in either the central and eastern tropical Pacific Ocean. This warming causes a shift in the atmospheric circulation with rainfall becoming reduced over Indonesia and Australia, while rainfall and tropical cyclone formation increases over the tropical Pacific Ocean. The low-level surface trade winds, which normally blow from east to west along the equator, either weaken or start blowing from the other direction.

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Why don’t farmers take up alternative options to stubble burning?

  • Even with capital subsidy, machines like Happy Seeder are not considered economical, as their demand is seasonal. The high cost of the machines and the rising price of diesel put pressure on farmers. For them, stubble burning is a cheaper option. A Happy Seeder machine is priced at Rs 1.5 lakhs. Though the government offers a 50% subsidy on the purchase of Happy Seeders to individual farmers, the machine still remains unaffordable. Also not all tractors are capable of pulling a happy seeder along, only those with a capacity of 65 horsepower would be able to drag an additional device mounted on it.
  • Farmers remain sceptical about the efficiency of these machines. They fear the machines will affect productivity and damage the soil. Besides, they feel using machinery is time-consuming.
  • The farmers have expressed that the number of machines provided is extremely inadequate.

How can stubble burning problem be solved?

  • The equipment has to be supplied quickly and in good numbers. There are reports that subsidized agromachines being provided by the government have not reached many villages and whenever given, the number is too low.
  • It is important to find other uses for stubble such as biomass, which may encourage farmers to look for alternative sources of income.

 

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What are the alternative options available for stubble burning?

Farmers can use devices such as mulchers (that cut up grass, leaves, etc., for use as mulch), rotavators (a machine with rotating blades for breaking up or tilling the soil), Happy Seeders and straw management system to manage and utilise stubble.

Happy Seeder is nothing but a tractor-mounted device which can cut and lift the previous crop (in this case the rice straw) and sow a new (wheat) crop in its place simultaneously. It also deposits the straw over the sown area as mulch. Mulch enriches and insulates the soil.

The straw management system involves the use of a machine attached to a harvester chopper, which spreads loose straw uniformly. Here, the straw serves as mulch.

Straw could also be used as feeder.

(However, farmers in these regions report a lower preference for paddy straw because of the comparatively high silica content in it. There are also reports of wheat straw rejection due to fuel spillover during harvesting by machines.)

 

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Why do farmers resort to stubble burning?

Farmers have to clear the stubble soon after harvest so as to prepare the field for sowing the next crop.

For clearing the farm waste, they usually have a short span of 10 to 15 days during which they prefer burning the stubble to other methods as it is considered the cheapest and least time-consuming solution. The residue and stubble are an important source of organic matter for the soil. Burning off this organic matter will gradually reduce soil organic matter levels. Burning can made the soil hotter and drier on the surface, creating a hard seedbed. Burning can temporarily seal the soil surface to some extent. Burning will result in the loss of some of the volatile nutrients, such as nitrogen, in the residue. Phosphorus and other minerals are not volatilized by burning and will remain on the field in the ash, unless the ash is blown away.

 

Picture Credit : Google