Replacing Mineral Fertilizer with Nitrified Human Urine in Hydroponic Lettuce (Lactuca sativa L.) Production

Source-separated, nitrified, and decontaminated human urine constitutes a promising plant fertilizer that contains a large share of the nitrogen and phosphorus in household wastewater, and other plant nutrients. However, human urine contains high levels of sodium and chloride that can affect salt-sensitive greenhouse crops. Replacing mineral fertilizer with nitrified urine fertilizer could reduce the environmental impact of lettuce production in hydroponic systems, if marketable yield, appearance, and produce quality are not affected. In the present study, a treatment combination of a nitrified urine fertilizer and mineral fertilizers was used to grow lettuce through the nutrient film technique. This was compared to a conventionally fertilized control treatment. No significant differences were observed regarding yield, phenotype, and contents of nitrate, heavy metals, phenolic acids, and chlorophyll in leaf tissue. Calcium content was significantly reduced and sodium was elevated in nitrified urine treatment. For the elements nitrogen, phosphorous, and potassium, a saving of 48%, 13%, and 15% was calculated, respectively. The calculated carbon footprint from the total fertilizer production was reduced by 34.25%, caused by the nitrified urine treatment. Based on these results, a nutrient solution composed of nitrified urine fertilizer combined with mineral fertilizer may be a promising alternative for growers to produce lettuce with a reduced environmental impact without loss of plant quantity and quality.city of BerlinPeer Reviewe

Initial survey on fresh fruit and vegetable preferences of Neumayer Station crew members: Input to crop selection and psychological benefits of space-based plant production systems

The inclusion of higher plants in bio-regenerative life support systems has been suggested to contribute to a nutritious menu, increase food acceptability and provide psychological benefits to the crew. In 2017, the EDEN ISS project will deploy a greenhouse module to the Neumayer Station III in Antarctica. This system will be used to advance bio-regenerative life support system technologies and operations. An initial survey was conducted to improve crop selection for the EDEN ISS greenhouse module by further investigating the aspects of food acceptability and psychological benefits of crop cultivation. Former members of the overwintering crews of the three Neumayer stations were asked about their fresh food and vegetable preferences and about further aspects concerning Antarctic plant production. Results confirm the benefits of growing higher plants in isolated and confined environments and offer insight on the importance of crop selection aspects like taste, texture, pungency and colour