(2019 Archived) - Argument XII: Agriculture on Venus vs. Agriculture on Mars

Having written this in 2019, and originally published in 2021.. when I was 15 and 17, there would be inaccuracies that I would correct here. Having removed it, I'm publishing  again, for sake of completion so that the efforts wouldn't have gone to vain: While many things stand through, both are incredibly hectic, and having to import soil from Earth is just as unviable. Besides, with hydroponics and newer tech, by then, we would have the ability to viably grow on both worlds.

For a great part of humanity’s lifetime, we’ve been hunters and scavengers. For most of ancient human history; we’ve lived quite a nomadic lifestyle, fed ourselves with the day’s kill, went hungry until our next meal, survived on available plant-based food in the meanwhile. That was until, we found how to intentionally germinate and grow the plants we need – initially as a small experiment, and then as a mass-scale industry.

The agricultural revolution is one of the greatest things that have ever happened to us, and it was one of the foundations for primary human civilization. It isn’t every time in our cosmos; that a form of organic intelligence gets to exploit a lower autotrophic life-form, via mass-scale harvesting through repetitive seasonal cycle, in order to fulfil their nutritional needs.

Considering that – we are quite lucky – with agriculture still being a quintessential industry at present; and it will be so, for many centuries to come. Agriculture survived this long, because it had been an effective and efficient way of extinguishing the fire of our nutritional demands. It is so effective and efficient, that it is quite a feasible mode of nutrition in our extraterrestrial colonies and voyages to infinity. As for the purpose of this argument; we’re currently taking agriculture to our colonies on Mars and Venus.

The primary requirements of agriculture are the seeds, soil, water, and sunlight – meaning that if we were to have an extraterrestrial colony with soil, water, sunlight, and seeds; we can run an agricultural industry there. Let’s take Mars as our first example: it has dim sunlight, hardly extracted and recycled water, brought seeds but unfortunately toxic soil. It would be shameful to have a world of dust and soil, but being unable to use any of it! Still, we might be able to find solutions if we were to have a good idea of our problems. Why isn’t Martian soil good for agriculture?

First and Foremost, it is due to the high concentrations of Perchlorates in the Martian soil: The perchlorates are not too damaging to the crops, but are highly toxic to humans. A terrestrial study in 2013 found that plants grown in Mars-like concentrations of Perchlorates have had ^[34];

·         A significant decline in the chlorophyll content in plant leaves.

·         Reduction in the oxidizing power of plant roots.

·         Reduction in the size of the plant both above and below ground

·         An accumulation of concentrated perchlorates in the leaves.

A significant decline in photosynthesis of chlorophyll means that there would be a significant decline in photosynthesis – which in turn, would mean less energy to grow and develop food. That is bad! Reduction of root oxidizing power would result in the crops taking-in fewer nutrients from the soil, which would also be devastating for the harvest. Last, but certainly not least, the accumulation of concentrated Perchlorates in leaves would imply the same for the food it produces – which could lead to Martian food poisoning that could lead to fatalities and deaths. Similarly, the Perchlorates give Martian soil its gnarly basic pH of 8.3, which isn’t an ideal pH for plants to grow in. Similarly, the toxic heavy metals in Martian soil like Hexavalent Chromium would also find their way into Martian crops and lead to food-poisoning.

Solving this would require the usage of purification methodologies that would give Martian soil a neutral pH and removal of Perchlorate salts. This could turn out to be quite an expensive operation, and the composition of the soil wouldn’t be Earth-like with possible traces of heavy metals. Assume that such an expensive purification methodology was used; would the resultant processed alien-soil still be good enough for agriculture?

I can’t give a definite answer for that – but hopefully, the Food for Mars project would: The Food for Mars project – led by Dr. Wieger Wamelink; the Senior Ecologist of the Wageningen Environmental Science, at the Wageningen University – aims “to provide initiatives like Mars One information necessary to plan for sufficient food production for future human Martians” ^[45]. Dr. Wamelink successfully managed to grow ten varieties of crop – green bean, radish, rucola, garden cress, spinach, pea, rye, carrot, tomato, and potato – in Mars soil simulant ^[46], which would represent the purified Martian soil. Out of the ten grown crops, the green beans and tomatoes were the best harvested.

Still, the potatoes tended to form new shoots halfway in the season, which is quite a bad sign ^[46]. To make matters worse, the heavy metals still found their way into some of the harvest, with Radish having the highest amount of metals overall – the Radishes had relatively high amounts of Aluminium, Iron and Nickel ^[47].

Another problem Dr. Wamelink encountered was that the Martian soil simulant had very little specific fertilizer. Legumes were grown with the crops in order to increase the Nitrogen content in the soil simulant. But, I believe his most ingenious measure of dealing with this, was to ally with Earthworms. But, how is that helpful? You see, Earthworms had always been a fundamental part in agriculture, by playing a major role in breaking-down and recycling organic matter in the soil ^[48]. They feed on dead plant-remains and excrete nutrients back into the soil – which is fundamental in cycling Nitrogen, Phosphorous and Potassium (NPK: The major nutrients needed by plants) in agricultural soil. Earthworms also dig burrows, which aerate and improve the structure of the soil – thus making watering effective ^[48].

But, that is on Earth-soil. How did the Earthworms do in the Mars soil simulant? They were observed do just fine: They were quite active in their Earthly lifestyle and were even able to reproduce ^[48]. So far, except for the heavy metal issues; Martian agriculture seems to go just fine. But, how is the Venusian agriculture? The Venusians would have the seeds, sunlight and produced water; but, there is a serious issue – there isn’t any soil! The Venusian surface, which lies 50-55km below the cloud-city altitude, is mainly comprised of Basalt rocks. Thereby, any soil available would not be any good for agriculture. This would mean that the Venusians would have to import soil from the Earth. Soil would mostly be a major part of supplies for initial colonies, and would be a valuable imported commodity for future interplanetary trade. But it comes with a catch – the Venusians would have to master the art of self-sufficiency, with regard to soil fertility. The fertility of soil would be maintained by many means of sustainable development; such as using legumes and nitrifying bacteria to increase Nitrogen content in the soil, and as we’ve learnt from the Food for Mars project: bring Earthworms to Venus. Yeah, Earthworms would also be an interplanetary species, thriving in the soils of a trio of worlds.

But, the ability of the Martians to use their own filtered and purified soil; is quite an advantage. In order to prove Venus as better or even equal in terms of agriculture; a healthy counter-argument would be required, which I believe to be as sunlight: You see, plants love sunlight and depend on it to synthesize their food. But, plants require sunlight at the right amount – not too much, not too less. On Mars, agriculture wouldn’t be done directly with the sunlight received from the sun; it is simply too dim. It is for this reason, along with the Martians living metres underground, that agricultural activities have to be done with the assistance of artificial lighting – that is, artificial lighting which works on the electricity generated by the solar panel arrays, from the solar energy received by the dim Martian sunlight.

To put this into perspective, let’s take a 250W solar panel on Earth as an example: It would generate a power of 1kWh once exposed to 4 hours of persistent sunlight. That is enough power to light-up a fine LED bulb for 100 hours – which is roughly four days. But, the efficiency of this system would lower once on Mars, which receives ~ 35%, less sunlight than the Earth. The same LED bulb, powered by the same 250W solar panel would only light-up for 65 hours (~2.6 days) for a similar 4 hour exposure to undisturbed Martian sunlight. That is, powering anything including artificial lighting on Mars, using Martian sunlight – is 35% less efficient than powering such a system on the Earth.

Such a measure would be redundant on Venus, as crops could be grown quite well in Venusian sunlight alone – Even if Venusian agriculture were to be done under artificial lighting, the system would be 218% more efficient than that on Mars! But, the ability to use natural Venusian sunlight is a perk in itself: The expense needed for purification and filtration of the Martian soil – to get rid of its gnarly basic pH, Perchlorates and most heavy metals – along with separately allocating separate solar panel arrays to power artificial lighting required for Martian agriculture; is more overwhelming than just using cycled Earth-soil and natural sunlight for Venusian agriculture. Simply, what Venus lacks in natural soil, it makes-up with its natural sunlight.

Because of the (1) Purification and Filtration of Martian soil is costly, (2) artificial lighting for Martian agriculture using low Martian sunlight makes the system inefficient, (3) the ability to use safe and ideal Earth soil in Venusian agriculture, and (4) the Ability to use natural sunlight in Venusian agriculture: we can conclude that Venusian Agriculture is as Successful as Martian Agriculture, and perhaps even more Successful and Easier.

34.        He, H.&Gao, H.&Chen, G.&Li, H.&Lin, H.&Shu, Z. (2013, May 15). "Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues". Retrieved from Environmental Science and Pollution Research International, Volume 20, Issue 10, pp 7301–7308. [Retrieved fromhttps://link.springer.com/article/10.1007%2Fs11356-013-1744-4].

45.        Mars One. (Retrieved at 2019 February). Dr.ir. Wieger Wamelink (NL). Retrieved from (https://www.mars-one.com/about-mars-one/advisers/dr.-ir.-wieger-wamelink-nl).

46.        Wageningen University. (2016, September 2). Dinner of Mars and Moon vegetables well received. [Retrieved from https://www.wur.nl/en/newsarticle/dinner-of-mars-and-moon-vegitables-well-recieved].

47.        Wageningen University. (2016, July 26). The Martian becomes reality: at least four crops grown on simulated Mars soil are edible. [Retrieved from https://www.wur.nl/en/news article/the-Martian-becomes-reality-at-least-four-crops-grown-on-simulated-Mars-soil-are-edible.htm].

48.        Wageningen University. (2017, November 27). Earthworms can reproduce in Mars soil stimulant. [Retrieved from https://www.wur.nl/en/newsarticle/Earthworms-can-reproduce-in-Mars-soil-simulant.htm].

Achinthya Nanayakkara (31.03.2025)

Originally written - 2019