When developing various technologies designed for biomass conversion into biofuels, it is important to establish the suitability of raw material of lignocellulotic, non-food plants such as Miscanthus, whose biomass has a good energy potential. Biomass productivity, quality and its suitability for processing under more northern climatic conditions are important factors to be considered. Experiments were aimed to estimate quality and technological parameters of Miscanthus growing, harvesting and processing into synthetic diesel, to evaluate chemical, physical and mechanical properties of biomass and to determine energy consumption necessary for biomass preparation for conversion into synthetic diesel. The study object was biomass of Miscanthus (Miscanthus × giganteus Greef et Deu) produced under Lithuanian and German climate conditions. Miscanthus harvested in the autumn produced up to 9.42 t ha -1 dry matter (DM) yield, which was significantly higher in the treatments fertilised with a higher nitrogen rate. The content of cellulose (413-456 g kg -1 DM) and hemicellulose (204-236 g kg -1 DM) was very similar at all fertilisation levels. The highest content of lignin (117 g kg -1 DM) was established in the treatments fertilised with 120 kg ha -1 N. The spring-harvested Miscanthus biomass had significantly lower moisture content and the yield was significantly lower, too. While preparing the biomass as feedstock for synthetic diesel the greatest reduction in moisture content (to 8.59 ± 1.38%) occurred when Miscanthus biomass was chopped, pre-dried and milled, and particles larger than 2 mm accounted for the largest share. The energy use for chopping of autumn-harvested biomass was lower and chopping efficiency was higher compared with the spring-harvested biomass. The composition of major components of synthetic fuel from Miscanthus biomass was very similar to that of mineral diesel.
Climate change, new varieties, better technological abilities, and increased demand for local resources provide significant reasons to introduce soybeans in northern regions, above the typical soybean distribution area in Europe. This research examined the effects of two delayed sowing times, wide 25 cm and 50 cm row spacings, seed inoculation with Bradyrhizobium japonicum, and the interaction of all these factors on soybean development and productivity in an organic farming system. Length of soybean vegetation varied from 142 to 161 days at latitude 55° N. Yield varied from 673 to 3154 kg ha−1 in response to management factors. In the dry 2015 year, the combination of later sowing dates and wide 50-cm row spacing significantly (p < 0.01) increased the number of pods per plant by 28%, aboveground dry biomass by two times, and seed yield by 36% plant−1. In the wet 2016, yield components reached their highest values of 16.8 g dry biomass, 19.9 pods plant−1 and 7.9 g seeds plant−1 when inoculated soybeans were sown earlier, with 50-cm row spacings. Protein content significantly varied from 27.4 to 35.3%, and fat content 17.4–21.5%. This study suggests that regular soybean development could be maintained in organically managed locations above the present northern soybean distributional region, but its development, productivity, and production quality significantly depends on management practices.
There have been few long-term field studies on greenhouse gases measurement in organic crop rotations under temperate climatic conditions. Little is known about the extent to which the share of legumes in a crop rotation of organic farming affects the potentials for CO 2 emission and soil organic carbon sequestration. The current study was aimed to investigate soil physicochemical state and soil net CO 2 exchange rate in diverse organic crop rotations with different crop species and proportions of legumes. Four 5-year duration crop rotations were investigated. The best soil sustainability of the arable layer was found in a crop rotation enriched with red clover (Trifolium pratense L.). This rotation resulted in the highest soil mesoporosity and the lowest microporosity, ensured the best supply of plant-available water and revealed high soil resistance to dry conditions. Red clover secured the highest soil organic C sequestration, caused the increase in reserves of total N and available K, and slackened the decrease of soil-available P sources. Red clover-based cropping system exhibited the highest soil net CO 2 exchange rate during five experimental years. The effect of crop rotation, consisting of phacelia (Phacelia tanacetifolia Benth.), peas (Pisum sativum L.) and yellow lupin (Lupinus luteus L.), on soil sustainability was weaker than the effect of rotation with red clover. Non-legume rotations, i.e. binary (two-crop) rotation and the crop rotation involving four spring and one winter species, can be regarded as miners of soil nutrient resources rather than contributors. These rotations did not promote soil sustainability because the soil lost large amounts of macronutrients and caused 26-33% lower soil net CO 2 exchange rate, compared with leguminous rotations. For future, it could be recommended for ecological farming to rely more on crop rotations with red clover to improve ecosystems functioning.
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