The Imperial College in London is going to investigate if bacteria will survive in the Mars and Moon soil simulant in cooperation with Wageningen University & Research in March 2017. To be able to live on Mars or the Moon, humans will need to grow their own food. One of the key factors in plant growth and recycling of dead plant parts are bacteria. They break down the dead leaves, roots and stems and thus make nutrients, manure, available again for plant growth. Completing this cycle is essential for sustainable crop growth on Mars.
“With this next step we are moving from just growing crops to building a small but sustainable ecosystem”, says Dr. ir. Wieger Wamelink of Wageningen University & Research. The experimental work will be carried out by Dr. Maaike van Agtmaal, a Postdoctoral Research Associate at the Division of Ecology and Evolution of the Imperial College in London. Soon she will start her first measurements. First, the Mars and Moon soil simulant is sterilised to make sure no bacteria are present. Then the simulant soil will be inoculated with bacteria from different agricultural soils and placed in microcosms. The activity of the bacteria will be monitored. “My aim is to study the process of terraforming of soils, the process of making soil habitable. We will therefore also compare the results from the simulants with Sahara sand and Arctic soil and with sterilised soil simulant without bacteria”, Van Agtmaal said. The experiment will last one month during which samples will be taken every week to observe which bacteria can enter the soil, see if they survive and test which essential soil functions they can bring.
One of the essentials for plant growth are nutrients as nitrogen, phosphorous potassium or calcium. These nutrients will be taken up by plants, resulting in growth. However, this will deplete the nutrient stock in the soil. For this reason, dead plant parts that are not eaten have to be returned to the soil, just like the faeces and urine of the humans. The nutrients in the dead plant parts will not be released to the soil, unless bacteria break down the dead plant material first. They feed from the dead plants, meanwhile releasing the nutrients for the plants. “We have been growing crops on Mars and Moon soil simulant for several years now”, Wamelink explains, “and we have demonstrated that it is possible to harvest over a dozen different crops including tomatoes, green beans, potatoes, carrots and radishes. These are important ingredients for a healthy and tasty diet for future Mars settlers. However, the harvest is still less than from crops grown on earth potting soil. This could be due to a lower bacterial activity and this experiment may reveal this.”