Abstract:In this study, the interferometric coherence calculated from 12-day Sentinel-1 image pairs was analysed in relation to mowing events on agricultural grasslands. Results showed that after a mowing event, median VH (vertical transmit, horizontal receive) and VV (vertical transmit, vertical receive) polarisation coherence values were statistically significantly higher than those from before the event. The shorter the time interval after the mowing event and the first interferometric acquisition, the higher the coherence. The coherence tended to stay higher, even 24 to 36 days after a mowing event. Precipitation caused the coherence to decrease, impeding the detection of a mowing event. Given the three analysed acquisition geometries, it was concluded that afternoon acquisitions and steeper incidence angles were more useful in the context of this study. In the case of morning acquisitions, dew might have caused a decrease of coherence for mowed and unmowed grasslands. Additionally, an increase of coherence after a mowing event was not evident during the rapid growth phase, due to the 12-day separation between the interferometric acquisitions. In future studies, six-day pairs utilising Sentinel-1A and 1B acquisitions should be considered.

The trials were carried out in the Estonian University of Life Sciences (58°23'N, 26°44'E), and studied to what extent green manure crops bind nutrients and the effect and stability of biologically fixed nitrogen (N). Our research covered more species than most of the earlier studies in the Nordic countries. Compared with biomass from unfertilized barley, legume undersowing, straws plus roots added up to 4 times more N, 2.8 times more phosphorus (P) and 2.5 times more potassium (K) returning to the soil. Red clover, hybrid lucerne and white melilot as pure sows produced the highest biomass, amounts of N, P, and K being up to 206, 24 and 144 kg/ha, respectively. The effect of additional N in soil was measured by weighing successive grain yields. In the first test year, 1 kg of N from green manure had the effect of producing 8.6 kg grain and this relation did not change even for higher N amounts. Green manure had a significant effect even in the third year after the green manure was ploughed into soil.

Purpose To clarify needs and requests of the young generation to the contemporary and future education on food systems, this paper aims to examine the following issues: students’ background knowledge, students’ behaviour as consumers and food citizenship, most interesting topics of SFS for students and students’ preferences and expectations in developing different skills, topics and preferences in teaching/learning methods. Design/methodology/approach This study was performed as an online-survey amongst eight European Universities in seven European Union (EU) countries to which 1,122 students responded. Data was analysed with descriptive and multivariate statistical analyses. Findings Taste and Health are the most important values and motives that influence students’ food buying and consumption decisions, but significant differences were found amongst students from different universities and countries. The most important topics for students for future teaching courses are “organic food”, “fair trade”, “organic agriculture” and most important skills to learn are “ability to make a judgement and justify decisions” and the “ability to create and innovate”. Excursions and field trips as teaching methods was given the highest ranks. Research limitations/implications Different study programmes and cultural backgrounds of the participating students in the different universities could be a limiting factor for the interpretation of some results. Originality/value These results provide a basis for improvement of higher education in the EU towards sustainable food systems based on experiential learning/teaching methods.

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