SiEUGreen - D2.2 Evaluation of crop techniques
Creators: name: Jiangsan Zhao
name: Verheul, Michel
name: Skar, Siv Lene Gangenes
name: Van Leeuwen, Geo
name: Qiao, Fen
name: Robert, Charlotte
name: Hvoslef-Eide, Trine
name: Remberg, Siv Fagertun
name: Aurdal, Siv Mari
Publisher: name: Zenodo
Year: 2021

description: The SiEUGreen project aims to enhance the EU-China cooperation in promoting urban agriculture for food security, resource efficiency and smart, resilient cities. Plant cultivation technology is one of the main components of urban farming. This report presents WP2, D2.2- Evaluation of crop techniques. During the first 18-month project period, we have evaluated four main crop-cultivating techniques; (1) paper based balcony garden (microgreen technique), (2) hydroponics, (3) aquaponics and (4) soil (compost or peat) based systems. Detailed descriptions of the completed experiments, the validated protocols and recommendations for the implementation of these technologies in SiEuGreen showcases are provided in this report. With each crop cultivation system, we have tested key factors (e.g. LED light, deep learning for rapid evaluation of biomass, compost compared with peat) affecting plant growth and yield (biomass). In order to develop a protocol for the paper-based balcony garden (i.e. microgreen technique) which shall be implemented in showcases including Fredrikstad in Norway, we tested more than 10 vegetable cultivars/seeds in the completed experiments. Our data suggest that the paper based microgreen technique is easy and can be adopted in showcases where this technique is desirable. The validated protocol and key recommendations are (1) to keep constant moisture and (2) to water the germinated seeds 2-3 times a day to achieve optimal conditions for a paper-based balcony garden and produce fresh and healthy microgreens. For the second crop cultivation technique, hydroponics (soilless plant cultivation system), we have selected two vegetable cultivars, lettuce and cucumber, with the focus on rapid biomass evaluation using a deep learning technique and investigation of the effect of various light spectra on vegetable growth. Results showed that ‘Crispy’ lettuce was grown healthily in a simple nutrient film technique (NFT) setup; its fresh biomass could be very well predicted using the UNET deep learning method through automatic segmentation, which permits the vegetable yield to be easily evaluated and the hydroponic plant growth system to be utilized in Fredrikstad and other showcases in the future. Red light was more effective in stimulating lettuce growth compared with plants treated by white light, despite plants having lower chlorophyll content when subjected to red light. For cucumber production, we have tested a floating hydroponic crop production system. Our data indicate that the floating system promoted significant vegetative growth whereas the yield of cucumber was similar to that of cucumber plants grown in a rock wool system. For the future implementation of the hydroponic crop production system in the showcases like Fredrikstad, the floating system is preferable for cucumber production. The third tested crop cultivation technique was aquaponics, meaning combined fish and vegetable production. We focused on the green crop production and chose lettuce as our vegetable crop. The experimental data showed that lettuce acquired sufficient nutrients, which was produced by the fish fingerlings from Setesdalen, Norway, and biomass of lettuce was comparable with that produced in hydroponics. However, lettuce plants grown in hydroponics were generally higher in photosynthetic activities and final yield compared with aquaponics, which was probably due to a more optimal nutrient supply. This comparison of hydroponics and aquaponics provides valuable data for the implementation of these plant growth systems in the showcases in the SiEUGreen project, in particular the Fredrikstad showcase. The fourth important crop production system is the recycled compost-based system, important for circular economy. The “Den Lille Gartner” Maxi system with a water/nutrient reservoir has been tested and showed that it is very suitable for cultivating small vegetables 4 like herbs and greens in the kitchen. Using this system we have also concluded that compost made from a mixture of waste from the garden and food (vermicompost) is as suitable for herbs and greens as peat based compost. For tomato production on balconies, compost was able to produce a similar yield and higher quality tomatoes with less cracking fruits, compared with peat in a hot summer. Roof top gardens with blackberries grown in the best compost (85:15 household:vermicompost) had twice the amount of Vitamin C, compared with ones in peat. Our preliminary conclusion for all crops tested is that compost gives equal yields, and improved plant quality compared to peat. Urine-based recycling fertilizer, Aurin, with lower NO3/NH4 ratio, promoted biomass accumulation of maize plants grown in soil. The biomass and height of Chinese cabbage increased with the increase in kitchen compost added in coconut shaft from zero to 60 kg/m-3 while the ones with the best quality, the highest vitamin C and sugar, were produced in coconut shaft with 45 kg/m-3 kitchen compost. Taken together, this technical report documents the evaluation of four different plant growing techniques providing protocols, recommendations and guidelines for future implementation of each crop production technique in different showcases within the framework of the SiEUGreen project.