But how on earth does a spacecraft get all these farm-fresh juicy fruits and vegetables everyday?

The answer lies in a revolutionary new technique called soil-less agriculture or hydroponics which has recently been perfected. Hydroponics is a technique that uses nutrient-enriched water rather than soil as a growing medium in controlled conditions in a green house.

The term hydroponics is derived from the combination of two greek words, hudor (water) and ponos (working), and has been translated into numerous languages like hidroponia (Spanish), idroponica (Italian), panikheti (Hindi), and hydroponiques (French).

Whatever the name, the underlying formula is the same. Based on a combination of a series of scientificprinciples like plant physiology, chemistry, horticulture and agronomy, hydroponics is poised to change the whole concept of centuries old conventional method of crop cultivation.

Such are the amazing applications of hydroponics that many scientists feel that it is the answer to all food problems faced by the world today. It may be that soon some organisation will design a growth chamber for the home that will be about the size and shape of a refrigerator. You could pluck a head of lettuce, some radishes, some carrots or whatever and have a garden fresh salad without leaving your kitchen.

That chamber-in-the-kitchen vision may still be a few years into the future, but the very concept of getting fresh peaches in Alaska and ripe mangoes in the Sahara Desert is a tantalising one. It is bound to revolutionise farming. Many scientists predict that with the burgeoning population and growing scarcity of food, at least 25 per cent of the world's food production will come from this process in the 21stcentury.

As the name implies, crops cultivated by hydroponics are not sown in the ground, rather they are grown directly in a nutrient solution or another medium to which the solution is mixed with the aid of computers to control illumination, carbon dioxide concentration, nutrient levels, humidity and temperature.

In comparison to the regular soil agriculture, the advantages of hydroponics are manifold. For example, normal agriculture is affected by the chemical composition and mineral contents of soil and water, but hydroponics provides ecology with the means to establish footholds for exotic species in unfavourable surroundings.

Economically, the advantages of hydroponics are numerous compared to conventional cultivation. According to trials conducted, it has been deduced that expenses in hydroponics are 28 per cent less compared to soil culture, Labour wise, too, the process is far cheaper. It takes only 40 hours monthly to look after a hectare hydroponicum, against nearly 400 hours spent onconventional farms. Also, the fertiliser requirements are minimal since the whole nutrient supply is available to the plant without wastage. Even water requirements are much less since there is minimal loss because due to evaporation and seepage.

According to recent studies, the capital cost of installing a hydroponic unit can easily be recovered within one and a half to two years by operating profits. In India, for example, while maintenance and operating expenses account for total costs incurred, a farmer can easily make a profit of Rs 2.5 lakh per hectare per annum. In the west and Japan, however, the returns are higher. According to reports an American makes an annual profit of nearly $ 25,000. That is at least 40 per cent higher profit in comparison to conventional cultivation.

The greatest advantage of hydroponics lies in its ability to provide growers with means to raise high quality crops in areas where there may be shortages of suitable soil, water supply, space or other facilities. Deserts,waste or barren lands and sterile areas can be made cultivable by hydroponics. There are in existence today roughly two million small operative hydroponics units around the world maintained chiefly by housewives, flat owners and progressive farmers. And their number is growing.

Interestingly, though the technique may have caught the fancy of agronomists only recently, the science of hydroponics is ancient. There are references of it in the Rig Veda, the Hindu, scripture which dates back to the 12th century BC. Theophrastus (372-287 BC) has also made references to hydroponics. An early attempt at the culture of plants under artificial conditions was made by King Nebuchadrezzar when he built the famous Hanging Garden of Babylon. Emperor Tibercies of the Capri is known to have eaten cucumbers daily, which are some proofs of historical pedigree of this technique.

However, in the modern era it was Jukius Von Sachs who produced the first cultural solution in 1860 and was followed by W Knop who made anothersolution in 1865. Botanist believe that it was the work of Sachs and his pupils that actually laid the foundations for the eventful emergence of the modern technique of hydroponics.

In early 1983, W F Gericks of the University of California produced one tonne of tomatoes in an area of 9.2 sq mt and published a paper later. Though this achievement was ground-breaking, it was only two years later in 1938, when hydroponics made its commercial debut, albeit with limited success. The outbreak of the second world war generated considerable interest in hydroponics. But it was not before 1944 that the US army and the air force started using it. The first air force hydroponics installation was in Ascenscon Island in early 1954.

Hydroponics made it debut in India in 1945 when J Sholto Douglas set up an hydroponics centre in Kalimpong. By 1947, the Bengal method of hydroponics gained fame worldwide.