PETRICHOR: THE SWEET EARTHY SMELL CAUSED BY RAIN ON DRY SURFACE

When the first light rain falls on the parched soil surface after dry spell of weather, the soil releases an fragrant aroma which is like magic to humans. This magical aroma has been described by many writers. So much for the feeling and aroma. But what is actually happening to create this magic.
Scientists have a explanation for it. Two Australian scientists in 1964 coined the term “PETRICHOR” for it. The word is made by shortening the two words “PETRA” meaning “ROCK” and “ICHOR” the fluid which flows in the veins of gods.

In fact soil which is mainly clay has many chemical compounds which are released by many tiny plants trapped in its lattice. These are volatile oils predominately stearic acid and palmitic acids which are fatty acids with long chain carbon structure with acid group on one end and methyl group on the other.

Also there is a chemical called “GEOSMIN” released by a soil bacteria called “ACTINOMYCETES”. Geosmin is a organic cyclic compounds with sweet smell and human nose can detect its smell down to 5 parts per trillion concentration in the air.

IMG_3352IMG_3351

If the rains are accompanied by lightening and thunder, oxygen and nitrogen molecules in the air are broken down to oxygen and nitrogen radicals and recombine to form NITROUS OXIDE and OZONE. Ozone also contributes to the aroma.

So in nutshell the substances which are responsible for the aromatic earthy smell are vegetable volatile oils, geosmin and ozone.

When the rain water seeps through the soil, it enters the lattice spaces and displaces these substances out. The smells are stronger when rain is not heavy.

 

Note: These images are taken from Wikipedia.

Advertisements

Land Stories 

Land used to be like one’s mother in India as more than 70% people were connected to land. Before the introduction of modern agricultural equipment like tractors, bullocks were used virtually for agricultural jobs like tilling the land, pulling the cart which the farmer used for bringing the produce and fodder home for cattle. Agriculture was completely manual and commerce was not in force. Farmer produced only enough for his family needs. Agriculture was dependent on the surface water available through rivers and rains.

Now the story is different. Even small farmers own the tractors which is economically not viable for small pieces of land. But it is a rat race. Many of them take the loans which become difficult to repay. A tractor can do many days work in a few hours. Need for manual labor arises only during the sowing of the crops. Bullocks have been faced out and are facing the same fate as the girls faced: they have become unwelcome.

Land is so much precious to the owner that hawks are on the outlook to grab any piece of it by hook or crook. Wars had been fought over the land. Most prominent example is the epic story of Mahabharata in which cause of the biggest battle between cousins was about the possession of land and women.

But as the cities are expanding at a furious rate, the value of the land is increasing. What the land can do to its owners will be illustrated by three scenarios.

Scenario No.1

State of Haryana was carved out from Punjab. It is a fact that people of Haryana were neglected by Punjab and so the state was separated from Punjab. But city of Chandigarh, which was the capital of Punjab was not given to any one of these states but made a union territory. It was also made the capital of both the states. The reality now is that the capital of both these sites is located nor in the centre but in one corner of the states.

As Chandigarh could not be expanded more, both Haryana and Punjab decided to construct the extensions of it on their own sides. Haryana thus acquired the agricultural land adjacent to Chandigarh. There were many villages in the area with farmers having small land holdings. All were given a meagre compensation. Overnight they become lost what they were dependent on. Being conversant with agriculture only, they faced difficulty to carry on their lives. They migrated here and there and on their lands mushrooms the concrete buildings with their owners being outsiders who could afford to buy them.

Scenario No.2

This one is a really interesting and shows how in same country but at different time points, the fortunes can turn for some. District of Mohali in Punjab was carved in such a way that it’s one side touched Panchkula district of Haryana. So some villages which though were very near to Panchkula became part of Punjab and their lands were not acquired by government.

These villages are situated near the ghaggar river and land is very poor for manual farming. The reason is that where the land is situated, the river flowed once and thus has left huge amounts of pebbles and sand covered with alluvial. Thus it is full of pebbles and bullocks were unable to till it.  Additionally there were uneven land surfaces which again posed challenges for farming.

Thus the land owners eked out a pathetic life. They lived hand to mouth. But somehow, barring a few they didn’t part off with their land which in any case no other farmer will buy due to poor quality.

But the demon of city expansion and opening of information technology parks and some pharmaceutical companies resulted in the large influx of people from interiors of Haryana, Himachal Pradesh,and so on resulted in the construction frenzy. There was no scope for expansion of Panchkula. So these adjoining areas became the focal points of building activity. Overnight, the land which was useless became the gold mine for the owners. They sold portions for a windfall. The farmers who have not seen money were dazed and it took them days to come back to reality from dream.

They constructed palaces for living. They became educated suddenly. As the money came, so we’re associations with powerful people like politicians. Some of them even began to grab the unoccupied or reserved lands. With a part of money bought tractors and modern equipment for remainder of land and procured cheaper land in the nearby districts. The elderly still can be identified to have done back breaking work but new generation is all like managers and leaders.

Scenario No.3

This story is similar to previous one but with small difference. It is from Sanand district in Gujarat. As the Tata nano car factory relocated here, the villagers nearby had windfall. Their used to be working as labors, peon and other lower rung jobs in the future Factories and manufacturing units for monthly wages like rupees 6000 to 15000 as their land was not fertile or due to lack of resources was not providing them with enough. Suddenly the arrival of entrepreneurs they became millionaires overnight by selling their land. After the initial excitement, Many of them have decided to carry on with those peanut wages jobs to keep themselves busy. More than hundreds of millionaires are working as helping hands in the factories there. The interest on their fixed deposits is enough for their requirements.

Thus as the Mark Twain once advised someone who came to him for investing the money to “invest in the land because they don’t make it anymore”, land can catapult your future.