The biorefinery technology aiming at protein extraction is rising and identification of suitable plant biomass input with valuable protein compounds for extraction is needed. Forage crops have been ...evaluated by the Cornell Net Carbohydrate and Protein System (CNCPS), and the result used as proxy of extractable protein in a biorefinery process. This serves as a helpful link between crop production and refinery output; however, the method has never been validated. Such validation is the main aim of this study. Five forage species—white clover, red clover, lucerne, perennial ryegrass, and tall fescue—were cut at four dates during spring and processed in a lab-scale refinery (screw press and subsequent protein precipitation from the green juice). The pulp fraction and the precipitated protein concentrate were both CNCPS analyzed to follow the initial crude protein (CP) plant input into these two fractions. Total recovery in concentrate was highest for the legumes, which points to an advantage of these species in protein extraction setups. High recovery of B1 and B2 (50% or higher for the grasses) in the pulp demonstrated a large proportion of soluble protein ending up in the fibrous pulp and shed light on the reason behind high feed quality of the pulp fraction. In conclusion, the existing tentative assumption of extractable protein being equal to CNCPS fractions of B1 and B2 and partly B3 was shown to be too simplified. The presented findings can improve crop species screening in terms of expected extractable protein yield.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Aims Application of carbon (C) and nitrogen (N) isotopes is an essential tool to study C and Í flows in plant-soil-microorganisms systems. When targeting single plants in a community the tracers need ...to be added via e.g., leaf-labeling or stem-feeding approaches. In this study we: (i) investigated if bicarbonate can be used to introduce ¹⁴C (or ¹³C) into white clover and ryegrass, and (ii) compared the patterns of ¹⁴C and ¹⁵N allocation in white clover and ryegrass to evaluate the homogeneity of tracer distribution after two alternative labeling approaches. Methods Perennial ryegrass and white clover were pulse labeled with ¹⁵N urea via leaf-labeling and ¹⁴C either via a ¹⁴CO₂ atm or with ¹⁴C bicarbonate through leaflabeling. Plants were sampled 4 days after labeling and prepared for bulk isotope analysis and for ¹⁴C imaging to identify plant parts with high and low ¹⁴C activity. Subsequently, plant parts with high and low ¹⁴C activity were separated and analyzed for ¹⁵N enrichment. Results Bicarbonate applied by leaf-labeling efficiently introduced ¹⁴C into both white clover and ryegrass, although the ¹⁴C activity in particular for white clover was found predominantly in the labeled leaf. Using ¹⁴C imaging for identification of areas with high (hotspots) and low ¹⁴C activity showed that ¹⁴C was incorporated very heterogeneously both when using bicarbonate and CO₂ as expected when using pulse labeling. Subsequent analysis of ¹⁵N enrichment in plant parts with high and low ¹⁴C activity showed that ¹⁵N also had a heterogeneous distribution (up to two orders of magnitude). Conclusion Bicarbonate can efficiently be used to introduce ¹⁴C or ¹³C into plant via the leaf-labeling method. Both ¹⁴C and ¹⁵N showed heterogeneous distribution in the plant, although the distribution of ¹⁵N was more even than that of ¹⁴C.
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BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Long‐term agricultural field experiments are essential for quantifying changes in soil properties and associated crop productivity that occur slowly but continue over long periods. Initiated in 1894 ...in the South of Denmark, the Askov long‐term experiment (LTE) is among the few LTEs in the world that continued for more than 125 years. The experiment compares different rates of nitrogen, phosphorus, and potassium applied in mineral fertilizers or animal manure with abundant treatment replicates. With well‐managed treatments, detailed yield records, and a soil archive dating back to 1923, today the Askov‐LTE represents a unique platform for research not envisioned at the start of experiments. Here, we provide a short description of site characteristics and experimental layout, examples of historic crop yields and changes in soil carbon (C) content. We provide short overviews of some of the studies that have used the Askov‐LTE as a research platform. These include crop yield‐related research; models simulating changes in soil C; availability of soil P reserves; indicators of biological, chemical, and physical soil quality; and studies related to prehistoric archaeology. Finally, we offer some reflections on long‐term field experimentation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Adding the forb (Plantago lanceolata) to a grass-clover mixture further enhanced yield.•Yield gain was due to positive forb-grass-clover interactions and high yield potential of the forb.•Adding ...selected forbs to a grass-clover mixture maintained short-term weed suppression.•Yield gain and weed suppression were robust over a wide range of forb proportions and two N levels.
Grass-legume mixtures characterized by high productivity, efficient nitrogen (N) use and strong weed suppression were proposed to increase sustainability of grassland production. Adding competitive forbs to grass-clover mixtures can be expected to further enhance the high productivity of grass-clover mixtures. This study investigates whether and to what extent adding forbs to a grass-clover mixture results in yield gains, and estimates the contributions of forb species (identity effect) and interactions with the grass-clover mixture (diversity effect) to these gains. It further examines the effectiveness of weed suppression in forb-containing grass-clover mixtures. Fifteen pure and mixed stands, all comprising the grass Lolium perenne L. and the legume Trifolium pratense L., and one or three competitive forb species (Cichorium intybus L., Carum carvi L., Plantago lanceolata L.) were established in a two-year field experiment and fertilised at two levels of N application. The diversity effect between P. lanceolata and the L. perenne-T. pratense mixture and a strong identity effect of P. lanceolata jointly contributed to yield gains of 10–21% over the binary L. perenne-T. pratense reference mixture for a wide range of P. lanceolata proportions across years and N fertilisation levels. In contrast, comparably smaller diversity and/or identity effects of C. intybus and C. carvi resulted in maximal yield gains of 5% and 7%, respectively, occurring at a narrower proportional range, but also in yield losses at high forb proportion. Including up to 80% forb in the L. perenne-T. pratense mixture effectively maintained weed suppression, but the degree of weed suppression decreased with increasing forb proportion in the following year. Including selected forbs, especially P. lanceolata, in productive grass-clover mixtures is promising for further enhancing productivity, meanwhile effectively suppressing short-term weed growth in intensively managed grasslands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract Background Crop‐ and site‐specific quantification of non‐harvestable aboveground residues and root biomass is essential for predicting management‐induced changes in soil C storage. Aims The ...aim of this study was to quantify stubble and root biomass C from productive grass–clover leys used for cutting as affected by fertilization and sward age. Methods Based on an organic long‐term dairy crop rotations experiment with 4 years of grass–clover in a six‐course rotation, we examined the effects of fertilization (unfertilized and 300 kg total‐N ha −1 in cattle slurry) and sward age (1–4‐year‐old) on herbage yield and composition, stubble biomass, and composition and root biomass of grass–clover ley. Results Ley duration and fertilization altered plant community composition and aboveground productivity but did not affect stubble and root biomass C. Conclusions The results question the use of yield‐dependent allometric functions for grass–clover ley used in simulation models and life cycle assessments for C accounting in agricultural systems. For predictions of soil C changes, we recommend the use of a fixed stubble‐derived C input from grass–clover ley regardless of sward age and fertilization‐induced differences in species composition, and herbage yield. Likewise, a fixed root‐derived C input for 1‐year‐old grass–clover, irrespective of fertilization, may be implemented. However, the contribution of continuous rhizodeposition and fine root turnover to root‐derived C input need to be accounted for.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Plant species and harvest time affect DM and N content of biorefined fractions.•High plant DM content results in low N recovery in the protein concentrate.•Nitrogen recovery in the protein ...concentrate is positively correlated to plant N.•A high proportion of nitrogen is recovered in legume protein concentrates.•High recovery in the protein concentrate is at the expense of recovery in the pulp.
Biorefining is a promising method for sustainable feed production through conversion of biomass into a protein concentrate for monogastrics and fibrous pulp for ruminants. Nitrogen (N) content and recovery in pulp and protein concentrate from lucerne, red clover, white clover, perennial ryegrass and tall fescue harvested at different spring cut harvest times were analysed to assess the effect of plant species, developmental stage and number of screw press processing.
Plant species and spring cut harvest time affected N content of pulps and protein concentrates (P < 0.01). The N contents of the legume pulps and protein concentrates (22.0–43.2 g/kg dry matter (DM) and 52.1–68.9 g/kg DM, respectively) were higher than corresponding values of the grasses (16.4–31.2 and 38.1–58.9 g/kg DM, respectively) and lowest in late harvested pulps (16.4–29.2 g/kg DM). The proportion of N retained in pulp increased with spring cut harvest time (P < 0.01) and was higher in grasses compared to legumes (544.5–715.1 and 334.0–565.2 g/kg plant N, respectively). Plant species and spring cut harvest time affected N recovery in protein concentrate (P < 0.01) and correlated positively with the plant N content (P < 0.01) and negatively with the plant DM (P < 0.01). The legumes had a higher recovery than grasses (160.2–556.2 g/kg plant N and 160.2–335.6 g/kg plant N, respectively). Regardless of plant species, late spring cut harvests reduced the total N extractability, i.e. recovery after application of a two-step extraction procedure, to 342.8–490.9 g/kg plant N (P < 0.01). The largest proportion of N was extracted from the three legumes (458.4–653.8 g/kg plant N), with the lowest extractability in the late spring cut harvest.
The N content and recovery in fractions produced in the biorefining process were dynamic variables influenced by plant species, spring cut harvest time and number of screw press processings. More N was retained in the pulp from late cut grasses whereas the N recovery in protein concentrate was highest in early and intermediate cuts from legumes. The dynamics of N distribution between pulp and protein concentrate highlight the importance of considering input plant species, time of harvest and processing technique in order to enhance recovery and secure efficient utilisation of the biomass as feed for monogastrics and ruminants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Green manure mixtures including legumes and forbs can help to increase N availability in organic arable systems. Anaerobic digestion of green manures may provide ammonium rich digestate, which can be ...redistributed as fertilizer. The aim of this study was to investigate the effect of plant species composition, cutting strategy and anaerobic digestion on the N fertilizer replacement value (NFRV) of different green manures. Digestates obtained from silages of pure stand lucerne (four cuts/year) and a mixture including lucerne, grass and forbs (two or four cuts/year) were used to fertilize winter wheat (surface banding) and spring barley (injection). In general, NFRV was 46–173% higher in spring barley than winter wheat, due to the different application method and timing, which reflect the common practices in Denmark. NFRV of digestates were 25–63% higher than the corresponding silages, with the largest increase with the most fibrous material (mixture at two cuts/year). Total N concentration (DM based) in the silages largely explained NFRV of the digestates. To obtain NFRV above 60%, total N concentration of silage should exceed 3.5 g 100 g
−1
DM, achievable with silages from four-cut strategies. Silages of plant materials with different composition and N content may be similar in terms of biomethane production, but the fertilizer value of the digestates varies considerably depending on total N concentration.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Slurry acidification before storage is known to reduce NH3 emissions, but recent observations have indicated that CH4 emissions are also reduced. We investigated the evolution of CH4 from fresh and ...aged cattle slurry during 3 mo of storage as influenced by pH adjustment to 5.5 with sulfuric acid. In a third storage experiment, cattle slurry acidified with commercial equipment on two farms was incubated. In the manipulation experiments, effects of acid and sulfate were distinguished by adding hydrochloric acid and potassium sulfate separately or in combination, rather than sulfuric acid. In one experiment sulfur was also added to slurry as the amino acid methionine in separate treatments. In each treatment 20‐kg portions of slurry (n = 4) were stored for 95 d. All samples were subsampled nine to 10 times for determination of NH3 and CH4 evolution rates using a 2‐L flow‐through system. In all experiments, the pH of acidified cattle slurry increased gradually to between 6.5 and 7. Acidification of slurry reduced the evolution of CH4 by 67 to 87%. The greatest reduction was observed with aged cattle slurry, which had a much higher potential for CH4 production than fresh slurry. Sulfate and methionine amendment to cattle slurry without pH adjustment also significantly inhibited methanogenesis, probably as a result of sulfide production. The study suggests that complex microbial interactions involving sulfur transformations and pH determine the potential for CH4 emission during storage of cattle slurry, and that slurry acidification may be a cost‐effective greenhouse gas mitigation option.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The aim of this paper is to elaborate on the phenomenological approach to expertise as proposed by Dreyfus and Dreyfus and to give an account of the extent to which their approach may contribute to a ...better understanding of how athletes may use their cognitive capacities during high-level skill execution. Dreyfus and Dreyfus's non-representational view of experience-based expertise implies that, given enough relevant experience, the skill learner, when expert, will respond intuitively to immediate situations with no recourse to deliberate actions or mental representations. The paper will subsequently outline some implications and consequences of such an approach and will also examine to what extent Dreyfus and Dreyfus's skill model is capable to resist different attacks that have been made against their view, and in particular regarding the practical application of their approach to the skill domain of competitive sport.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
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