| 1. |
- de Toro, Alfredo, et al.
(författare)
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Effects of variable weather conditions on baled proportion of varied amounts of harvestable cereal straw, based on simulations
- 2021
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- All harvestable cereal straw cannot be collected every year in regions where wet periods are probable during the baling season, so some Swedish studies have used 'recovery coefficients’ to estimate potential harvestable amounts. Current Swedish recovery coefficients were first formu-lated by researchers in the early 1990s, after discussions with crop advisors, but there are no recent Swedish publications on available baling times and recovery proportions. Therefore, this study evaluated baling operations over a series of years for representative virtual farms and machine systems in four Swedish regions, to determine the available time for baling, baled straw ratio and annual variation in both. The hourly grain moisture content of pre-harvested cereals and swathed straw was estimated using moisture models and real weather data for 22/23 years, and the results were used as input to a model for simulating harvesting and baling operations. Expected available baling time during August and September was estimated to be 39–49%, depending on region, with large annual variation (standard deviation 22%). The average baling coefficient was estimated to be 80– 86%, with 1400 t·year−1 harvestable straw and 15 t·h−1 baling capacity, and the annual variation was also considerable (s.d. 20%). © 2021 by the authors.
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| 2. |
- Agenäs, Sigrid, et al.
(författare)
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Gårdar anses för små – men gör stor nytta
- 2020
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Ingår i: Svenska Dagbladet Debatt. - 1101-2412.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- De små gårdarna är allvarligt hotade och därmed också mosaiklandskapet och den gastronomiska mångfalden. Det skriver flera debattörer.
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| 3. |
- Suardi, Allessandro, et al.
(författare)
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Admixing chaff with straw increased the residues collected without compromising machinery efficiencies
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- The collection of residues from staple crop may contribute to meet EU regulations in renewable energy production without harming soil quality. At a global scale, chaff may have great potential to be used as a bioenergy source. However, chaff is not usually collected, and its loss can consist of up to one-fifth of the residual biomass harvestable. In the present work, a spreader able to manage the chaff (either spreading [SPR] on the soil aside to the straw swath or admixed [ADM] with the straw) at varying threshing conditions (with either 1 or 2 threshing rotors [1R and 2R, respectively] in the combine, which affects the mean length of the straw pieces). The fractions of the biomass available in field (grain, chaff, straw, and stubble) were measured, along with the performances of both grain harvesting and baling operations. Admixing chaff allowed for a slightly higher amount of straw fresh weight baled compared to SPR (+336 kg straw ha−1), but such result was not evident on a dry weight basis. At the one time, admixing chaff reduced the material capacity of the combine by 12.9%. Using 2R compared to 1R strongly reduced the length of the straw pieces, and increased the bale unit weight; however, it reduced the field efficiency of the grain harvesting operations by 11.9%. On average, the straw loss did not vary by the treatments applied and was 44% of the total residues available (computed excluding the stubble). In conclusion, admixing of chaff with straw is an option to increase the residues collected without compromising grain harvesting and straw baling efficiencies; in addition, it can reduce the energy needs for the bale logistics. According to the present data, improving the chaff collection can allow halving the loss of residues. However, further studies are needed to optimise both the chaff and the straw recoveries. © 2020 by the authors.
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| 4. |
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| 5. |
- De Toro, Alfredo, et al.
(författare)
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Cereal harvesting : Strategies and costs under variable weather conditions
- 2012
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 111:4, s. 429-439
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Tidskriftsartikel (refereegranskat)abstract
- This study simulated 30 years of harvesting operations on an hourly basis with a harvesting model linked to a grain moisture model capable of predicting the moisture content of standing ripe wheat using historical weather data from Stockholm, Sweden, as input, in order to assess the effects of weather on cereal harvesting costs. Several combinations of harvester size and grain moisture ceiling were assessed on three cereal areas in terms of overall costs (machine + labour + timeliness + drying) and their annual variations.The main findings obtained by simulation and valid for regions with similar climate and agricultural conditions to the studied region were that: (a) available combining time was highly dependent on grain moisture ceiling, which showed large annual variation, e.g. a moisture ceiling of 21% (w.b.) was related to a potential harvesting time of 65% and a standard deviation of 24% (n = 30 years); (b) in order to complete harvesting operations in most years, it was necessary to operate at a moisture ceiling of 22-24% (w.b.), however, the average moisture content of the harvested grain was much lower, about 17-18%; (c) overall harvesting costs were estimated at approx €140 ha -1 for those systems performing relatively well, i.e. with a daily harvesting capacity of 4-5% of the cereal area and operating at a moisture ceiling of 22-24% (w.b.); and (d) the main sources of annual cost variation were firstly the timeliness costs and secondly the drying costs. © 2012 IAgrE.
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| 6. |
- Spörndly, Rolf, et al.
(författare)
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A method of estimating timeliness costs in forage harvesting illustrated using harvesting systems in Sweden
- 2009
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Ingår i: Grass and Forage Science. - : Wiley. - 0142-5242 .- 1365-2494. ; 64, s. 276-291
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Tidskriftsartikel (refereegranskat)abstract
- A method for estimating timeliness costs, depending on dry-matter yield and nutritive value of forage is presented, and used to estimate timeliness costs, to examine different harvesting systems and to present conclusions on machinery selection when harvesting silage for dairy cows in Sweden. Timeliness costs (in euro ha(-1) d(-1)) of forage for silage were significantly higher for the first cut compared with the second or third cuts in the season. It is, therefore, important to avoid delaying the first cut. The timeliness costs also varied greatly between years. Harvesting costs decreased with increasing forage area up to a certain threshold area beyond which decreasing machinery costs were outweighed by increasing timeliness costs due to a longer duration of harvest. At increasing transport distances, the difference in cost between different harvesting systems and different sizes of machinery increased. Harvesting of forage by contractors decreased harvesting costs, particularly for small forage areas, since increased annual use of the machinery lowered the machinery costs and enabled larger machines with higher capacity to be used. To avoid high timeliness costs it is important to avoid delays in harvesting.
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| 7. |
- Gunnarsson, Carina, et al.
(författare)
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Logistics for forage harvest to biogas production : Timeliness, capacities and costs in a Swedish case study
- 2008
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 32:12, s. 1263-1273
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Tidskriftsartikel (refereegranskat)abstract
- Production of biogas from energy crops of agricultural origin is regarded as a promising alternative to decrease dependence on non-renewable energy sources. A model was built to evaluate the handling system comprising harvest, transport and ensiling of forage intended for production of CH4-enriched biogas for vehicle fuel. The model was applied to a full-scale plant in Sweden producing biogas from organic household waste and forage. Timeliness, capacity and harvesting costs were studied by varying transport system design, transport distance, field size and dry matter (DM) yield. Matching harvest and transport capacity is essential in minimising the time required for harvesting and the resultant costs. However, this study showed that keeping the harvest and transport capacity sufficiently high to avoid idle time did not necessarily result in the lowest costs. By adapting the transport system, it was possible to reduce costs by 30% when the average transport distance was decreased from 17 to 8.5 km. The study showed that with forage for biogas production, it was optimal to harvest later than the normal dates for harvesting forage for milk production, since the lower biogas production per kg DM was compensated for by higher DM yield. As long as the harvest started on the days calculated as being optimal with respect to the value of the harvest, timeliness costs made up less than 4% of total costs depending on the transport system chosen. When the start of harvest deviated from the optimal, timeliness costs increased substantially. Delayed harvest had even larger impact on the total harvest costs. © 2008 Elsevier Ltd. All rights reserved.
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