Earth Day is on April 21
The biodiversity that people made
John Tuxill

The intricate genetic diversity of the world’s crops is largely a human invention, and it remains essential for human sustenance. The complex landscape of traditional farmland is also a human invention, and it is now essential natural habitat. Traditional farmers really know what they are doing, and there are good reasons why they aren’t doing monoculture.

Snaking along the border of Minnesota and the Dakotas, the Red River Valley has long been one of North America’s leading rain-producing regions. Blessed with fertile prairie soils deep enough "to bury a man standing," Red River farmers have intensified their production in recent decades, and planted more and more of their land to just two crops, wheat and barley.

Such specialisation is supposed to be the key to success in the brave new world of multinational agribusiness. Yet the last few years have been anything but bountiful for most Red River farmers. In the early 1990s, following several years of abnormally cool, wet weather, their fields were hit with unprecedented outbreaks of a fungal disease called "wheat scab."

But according to Brian DeVore of the Minnesota-based Land Stewardship Project, the fungus is benefiting from more than just the weather. Many of the region’s farmers have recently adopted a "no till" cultivation System that is designed to conserve soil. Standard cultivation prepares the soil for planting by plowing, but as the soil is broken up it becomes vulnerable to erosion. "No till" reduces erosion by leaving the previous year’s broken stalks in place and planting through them. Unfortunately, however, those crop residues are a perfect home for the fungus in between growing seasons.

A few decades ago, one solution would have been to let cattle graze down the residue, but there are few cattle in the region any more. Cattle production has grown increasingly specialised too; few of the valley’s farmers can compete with the enormous livestock operations elsewhere. So the fungus has its way with these vast, monotonous expanses of wheat, one field after another, year in and year out: that must be the wheat scab version of heaven.

The bottom line is that disease and record low grain prices have cost Red River farmers over $4.2 billion (thousand million) since 1992. Nearly half of that loss is directly attributable to the scab. On the Minnesota side of the river, wheat and barley plantings in 1999 were down some 35 percent compared to their levels at the start of the decade. One-fifth of the region’s farmers went out of business in 1997 alone.

Such problems are usually debated in economic terms, but they are related just as fundamentally to the loss of biological diversity in agriculture. Biodiversity refers to the variety inherent in life — both the genetic variety within single species and the "species variety" within ecosystems. For most people, the term probably evokes Nature with a capital "N", tropical rain forests, coral reefs, mountain wildernesses, and other untrammeled corners of our planet. Not surprisingly, most of our efforts to protect biodiversity have focused on such places.

Yet there is another side to biodiversity, one that is very much a part of human history. As agriculture developed over the past eight millennia, farmers domesticated several hundred different crop species, and developed hundreds of thousands of different varieties within those crops. In the hands of early European farmers, for instance, an inconspicuous herb of coastal Mediterranean hillsides gradually became cabbage, kale, cauliflower, broccoli, and somewhat more recently, kohlrabi and brussel sprouts. Native American farmers took five shrub species with small, bright fruit originally adapted to attract birds, and diversified them into hundreds of eye-catching and tongue-searing varieties of Chile pepper. This ancient form of "cooperation" between people and plants has produced a vast wealth of genetic diversity within crop species.

Traditional agriculture fosters diversity in another dimension too, particularly on land used, not for commercial production, but primarily For "subsistence production" — that is, land that farmers cultivate for their own households. In just about any part of the world, subsistence production results in a highly diverse agricultural landscape. You’ll find intensively cropped fields for staples such as wheat, corn, rice, or potatoes;fallow fields covered in more unkempt vegetation, where the soil is "resting" to regenerate its fertility; an orchard or garden plot for fruits, vegetables, and herbs; a woodlot for fuelwood and other forest products. This kind of land use, replicated on farm after farm, creates substantial ecological diversity.

Today, both forms of agricultural biodiversity are receding in the face of commercial production, which usually demands a high degree of uniformity. The economic and political pressure on farms to grow for the mass market is a pervasive effect of the globalisation of agriculture, and in many places, farmers are forsaking the practices that have long fostered biodiversity practices that have sustained farming for millennia. But it’s becoming increasingly obvious that the current agricultural paradigm will be far less sustainable. Intensive monoculture farming is exacting a heavy ecological toll in the form of pesticide and fertiliser pollution, erosion, freshwater depletion, and the destruction of wildlife habitat. And as farmers in such places as the Red River Valley have found, the social costs can be very steep as well. The message from such places is now very plain: we’ve no hope of achieving a sustainable agricultural system unless we can find ways to restore what scientists now call "agrodiversity."

The author is a research fellow with the Worldwatch Institute.

Mission to the Red Planet
D. P. Singh

Mars has always been the subject of a very special human fascination. The tantalising possibility that life exists — or once existed — there has exercised an all pervasive influence on the studies of the Red Planet. A procession of increasingly sophisticated probes has been dispatched to the planet, beginning with Mariner 4 in 1964, Viking mission in 1976 and culminating in the landings of the Mars Pathfinder in July 1997.

Other than our own moon, Mars has attracted more spacecraft exploration attempts than any other object in the solar system, and no other planet has proved as daunting to success. Of the 30 missions sent to Mars by the three countries over 40 years, less than one-third have been successful. Despite the wealth of information from previous missions, exactly what Mars is made of is not fully known.

To get a basic understanding about the chemistry and mineralogy of the Martian surface, NASA has launched a $ 400 million 2001 Mars Odyssey on Saturday (April 7). The Mars Odyssey lifted off at 11:02 am EDT from the Cape Canaveral Air Force Station on Florida’s Atlantic seaboard. The orbiter carries a suite of scientific instruments designed to tell us what makes up the Martian surface, and provide vital information about potential radiation hazards for future human explorers. The mission will seek out underground water-ice and explore space weather around the Red Planet.

The 2001 Mars Odyssey, named in tribute to science fiction author Arthur C Clarke, will travel 460 million km before arriving at Mars in the late October, tightening its orbit to begin its work in January, 2002. Odyssey is carrying three scientific instruments to map the chemical and mineralogical makeup of Mars: a thermal-emission imaging system (THEMIS), a gamma ray spectrometer (GRS) and a Martian radiation environment experiment (MARIE).

THEMIS will map the planet with high-resolution thermal images. These images will help us to understand the relation between the landforms of the planet and its mineralogy. Odyssey’s GRS will allow us to peer into the upper few centimetres of Mars’s crust to measure the abundance and distribution of about 20 primary elements of the periodic table, including the amount of hydrogen that exists therein. The spectrometer will also be able to measure permanent ground ice and how that changes with the seasons.

Since space radiation presents an extreme hazard to crews of interplanetary missions, MARIE will attempt to predict anticipated radiation doses that would be experienced by future astronauts and help determine possible effects of Martian radiation on human beings. The experiment will take data on the way to Mars and in orbit around the red planet.

The Odyssey mission will also set up a communication relay for future Mars Landers, including NASA’s Mars Exploration Rovers, scheduled for launch in 2003.

NASA has also planned the Mars reconnaissance project for 2005. The project will take close-range photos of smaller objects some 20-30 cm across to follow the water trails, the first clues leading to signs of life there. NASA has planned some 10 missions to Mars over the next 20 years. It has already devoted to the project a whopping $ 1.6 billion over the next four years. NASA has also a plan up its sleeve to send manned missions to Mars.

"The launch of 2001 Mars Odyssey represents a milestone in our exploration of Mars — the first launch in our restructured Mars Exploration Programme, said Ed Weiler, Associate Administrator for Space Science At NASA Headquarters. "Mars continues to surprise us at every turn. We expect Odyssey to remove some of the uncertainties and help us plan where we must go with future missions."

Space scientists believe that if primitive life does exist or had existed on Mars, it might be similar to the primitive life on earth. 2001 Mars Odyssey is likely to provide the answer to our never-ending curiosity to the possibility of life on Mars and could open up the possibility of colonising this planet in the none too distant future.

NEW PRODUCTS & DISCOVERIES

High-quality pump for lab use

Scientists have designed special, high-quality, light weight pumps for laboratories for routine handling of acids and alkalis in small quantities.

The pumps-F303 PP and F-304 PP-weighed only 2 kg and can be used with ease by all laboratory personnel. They offer a high safety factor by virtue of a double insulated motor, and have built in overload cut-out switches and a two pole on/off switch, a report in World Pumps has said.

Manufactured by Flux Pumps International, the pumps have resistance to corrosive fluids and, for short periods, highly corrosive fluids such as chromic acid, hydrofluonic acid, nitric acid upto 40 per cent, hydrochloric acid and sulphuric acid due to their polypropylene construction.

With outer tube diameters of 25 or 32 mm, the pumps are suitable for emptying containers with narrow necks. They come in standard lengths 700 and 1000 mm, and in a shorter 500 mm version suitable for pumping liquids from carboys. Versions of the pump are available with delivery rates up to 471 min., at delivery heads up to 6 m. PTI

In view of the fact that the actual output of solar cell panel turns out to be less than expected, researchers in Germany have developed a system to predict the exact output of solar powers systems.

Many users in Germany are disappointed to discover that the actual output of the solar panels on the roof of their home is less than the figures quoted by the manufacturer or installer — up to 20 per cent less in some cases. This put the manufacturing and installation companies in an awkward situation, because it means that they have to either over-estimate the size of every system or risk paying a considerable fine for breach of contract, a report in Fraunbofer Gesellschafi says.

Solar cells produce different amounts of electricity from different wavelengths of light. In the system developed by scientists of the Fraunhofer Institute for Solar Energy systems, the solar cell is placed under a light source that imitates sunlight, together with a suitable reference cell. The current flowing through each cell is measured, and the two results compared. The manufacturer then knows how much power the cell can output.

Reference cells are simply solar cells that have been tested to extremely strict standards. To perform the tests, the researchers have to simulate the Sun — not an easy task, because as a rule, artificial light and natural sunlight do not behave in the same way, according to the report.

Another important factor in the dimensioning of solar power systems is to ascertain their efficiency in outdoor tests. This can deviate considerably from the values obtained in the laboratory. Acceptance tests and in-service tests provide further confirmation of the systems performance. PTI

SCIENCE QUIZ
J. P. GARG tests your IQ

 1. This American scientist is known for his kite experiment by which he linked lightning to electricity at the risk of his own and his son’s life. His inventions include lightning rod, bifocal lenses, a musical instrument called harmonica, and an efficient stove. Whom are we talking about?

10. After the failure of its earlier two missions Mars Climate orbiter and Mars Polar Lander, NASA launched on April 7 another spacecraft to search Mars for water with the goal of determining if life ever existed there. Can you name this spacecraft which will also study Mars’ environment to assess the risk to human explorers? When will it reach Mars?

Answers

1. Benjamin Franklin 
2. Helium and neon 
3. Ears 
4. Spinach 
5. Biological magnification 
6. Thermocouple; for measuring temperature 
7. Relative humidity of air 
8. Astrochemistry or exochemistry 
9. US inventor Almon Strowger in 1905 
10. Mars Odyssey; in October this year.