|MadSci Network: Agricultural Sciences|
The main elements required for life on Earth are carbon, nitrogen, hydrogen, oxygen, sulfur, phosphorus, calcium, magnesium, potassium, iron, and chloride. Plants obtain carbon from the atmosphere, and microbes fix atmospheric nitrogen which plants then use. The other elements come from the soil. Soil is a mixture of broken down minerals, water, air, and organic matter. Though we can determine what minerals comprise a soil, we cannot definitively say whether those minerals alone will provide nutrients for plant growth. That is, there could be a variety of minerals that would support plant life. From the mineralogical standpoint, Earth and Mars are not so different that Martian soil wouldn't support plant life the same way Earth soil does. However, the question of whether Martian soils could support agricultural growth has not been answered experimentally yet. Work has been done on the growth potential of meteoritic soils, but the meteorites used in these experiments were not Martian.
The main problem with growing plants on Mars would be that the atmosphere is not the same as it is on Earth. There is a higher level of carbon dioxide on Mars, and not much oxygen. Seemingly, plants should be fine if they had more CO2, since they take CO2 in for growth. Experiments have indicated that this is not always the case, though. Some plants do not grow well in a high CO2 environment. Another consideration is that nitrogen fixation requires microbial action. Unless the right microbes were present and functioning, plants presumably would not get their nitrogen requirement. Also, the temperature of the Martian surface is very cold (-50 degrees Celsius on average) which would kill plants quickly if they were not kept warm artificially. Likewise, plants require liquid water. Unless the temperature were warmer, they could not possibly get this requirement.
The Mars Society is a group of people who want to colonize Mars. You might try their website for more information ( http://marssociety.org/). Also, the NASA Astrobiology website might be of interest to you ( http://astrobiology.arc.nasa.gov/). I know that I didn't answer your question directly, but that is partly because the answer is not yet known. It is a very interesting topic, though. I hope that this was helpful. Please write back if you want more information.
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