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Treatment of plants with mineral-organic concentrates has developed intensively in recent years. Fertilizers containing, among others, humus, L-amino acids, vitamins, chelates and metal complexes, macro-, micro- and meso-elements, organic matter and humic acids from the top organic layer of leonardite coal have a positive effect on plant growth and quality and seed yield. An experiment was conducted between 2019 and 2022 at the University of Agriculture in Kraków, in which the impact of mineral-organic concentrate on the seed yield and quality of perennial ryegrass (Lolium perenne L.) 2N Bokser (Hodowla Roślin Grunwald Ltd. Grupa IHAR, Grunwa, Poland) was determined. As part of the experiment, plants were sprayed with a mineral-organic product in three different doses: 1.0, 2.0 and 3.0 L·ha−1. The following parameters were examined: the number of generative shoots, the length of the flag leaf, seed yield, germination capacity and the weight of one thousand seeds. It turned out that the application of the concentrate with 3 L·ha−1 and 2 L·ha−1 led to a significant increase in the number of generative shoots and in seed yield, compared to control. In addition, seed germination capacity of fertilized plants was higher, with the greatest increase after the application of 3 L·ha−1. Moreover, the average weight of one thousand seeds was significantly higher in fertilized plants, compared to the control, and the largest increase was recorded in response to the highest dose. The results indicated a positive effect of the organic-mineral concentrate on perennial ryegrass development parameters and seed quality.

The ongoing fragmentation of ash populations due to ash dieback requires an effective gene flow between individuals; thus, investigations on ash pollen transport are essential. In this study, comprehensive aerobiological field experiments at two seed plantations in Baden-Württemberg were conducted in 2019 and 2020 in order to study the influence of phenology and meteorology (especially wind) on pollen transport using self-constructed gravimetric pollen traps located 1.5 and 5 m a.g.l. Our main objectives were to investigate the local scale dispersion of ash pollen and to evaluate the recommended distance (i.e., 400 m) from seed plantations to other ash trees according to the German Forest Reproduction Act. Our results showed a link between pollen transport and meteorology, the onset of phenological development, and the topography of the plantation. The plantation at Schorndorf was characterized by a slope and associated cold air flows, suggesting that this could be a factor contributing to higher pollen levels at the downslope traps. In addition, in many cases, the cardinal direction associated with the highest pollen impaction was also identical with the predominant wind direction. Analyzing pollen data for single traps in detail, we found that the highest total pollen catch (31%) was measured outside the plantations in 2019, a year with very low flower development. In contrast, most pollen (33%) was caught within the plantation in 2020, which presented a much stronger pollen year than 2019 (with a factor of 11 regarding total sums). This indicates, in the lower pollen year, a potential higher contribution of trees from outside the plantation, and thus it can be recommended that seed harvesting of ash trees in the plantations should preferentially take place in full mast years. Interestingly, the total pollen deposition in Emmendingen at 5 m height showed little difference compared to the traps at 1.5 m height, but there was a large temporal difference pointing to vertical variations in pollen availability. In general, we found that ash pollen was transported for a larger distance than 400 m, but the amount of pollen decreased substantially with increasing distance. At a distance of 200 m, there was already approx. 50% less pollen captured from the air. However, even at a distance of 500 m, more than 10% of the pollen was still captured. In order to ensure cross-pollination of healthy ash trees, the distance of ash individuals or stands should not be too large, and there should be no spatial separation (e.g., by conifer stands).