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Winter rapeseed is one of the most important field crops in Germany. In comparison to other crops, nitrogen (N) surplus of rapeseed is usually high and increased values of mineral nitrogen are observed in soil after harvest. N losses via nitrate leaching or emissions of nitrous oxide (N 2 O) have a negative impact on the greenhouse gas (GHG) balance of biodiesel produced from rapeseed. So far, the effects of different post-harvest management options on these losses after rapeseed cultivation have not been assessed. The aim of this study was to investigate agronomic measures, such as different following main crops (wheat and barley) as well as different catch crops (mustard respectively ryegrass) and varied tillage intensity for their effectiveness in reducing high soil nitrate contents and the associated N 2 O emissions after rapeseed harvest. A field trial was conducted in Southern Germany at a site characterized by a silty loam soil, temperate climate and high precipitation. N 2 O fluxes were measured twice a week with the closed chamber method. In 2013/14 and 2014/15 the calculated N-balance (N input – N output) showed a surplus after rapeseed harvest of 61 kg N ha −1 and 117 kg N ha −1 , respectively. N 2 O-N emissions were relatively low from August to March in both years, remaining within a range of 0.3 and 2.0 kg ha −1 . The biomass N uptake of the succeeding crops increased significantly in both years and all treatments over winter with the exception of the mustard treatment which lost N due to freezing off. No clear relationship between N 2 O emissions and the course of soil mineral nitrogen (SMN) dynamics was observed. In both years, there were no significant differences in N 2 O emissions between all treatments. Our results indicate that as far as N 2 O emissions under well-managed soils in southern Germany are concerned, there is no need to change the established crop sequence of rapeseed – winter wheat. [ABSTRACT FROM AUTHOR]

Long-Term Field Experiments (LTEs) were implemented to study the long-term effects of different management practices, including tillage, fertilization and crop rotation under otherwise constant conditions. Climate change is expected to change these conditions, challenging interpretation of LTE data with regard to the distinction between climate change and management effects. The objective of the study was to quantify the expected, spatially differentiated changes of agroclimatic conditions for the German LTE sites as a precondition for modelling and LTE data interpretation. We developed a framework combining spatially distributed climate data and LTE metadata to identify the possible climatic changes at 247 LTE sites with experiments running for 20 years or more. The LTEs were classified using the following categories: fertilization, tillage, crop rotation, field crops or grassland, conventional or organic. We utilized climate variables (temperature, precipitation) and agroclimatic indicators (aridity, growing degree days, etc.) to compare a baseline (1971–2000) with future periods (2021−2100) under the IPCC's Shared Socio-economic Pathways (SSP). A comprehensive LTE risk assessment was conducted, based on changes in climate variables and agroclimatic indicators between baseline and future scenarios. Under the most extreme scenario (SSP585), 150 LTEs are expected to shift from humid and dry sub-humid to semi-arid conditions. Frost days in LTE areas are expected to decline by 81%, and the growing season to lengthen by up to 92%. The spatial differentiation of expected climate change also facilitates the identification of suitable sites for future agricultural practices and may inform the design of new LTEs. Our results may guide the interpretation of LTE data regarding the effect of climate change, facilitating future soil crop modelling studies with LTE data and providing information for planning new LTE sites to support future agricultural research and/or adapting management on existing LTE sites. The framework we developed can easily be transferred to LTE sites in agricultural regions worldwide to support LTE research on climate change impacts and adaptation. [Display omitted] • The effects of climate change on Long-Term Field Experiments (LTE) sites were assessed using Germany as a case study. • 150 LTEs were estimated to shift from humid and dry sub-humid to semi-arid conditions. • Frost days in LTE areas are expected to decline by 81%, and the growing season to lengthen by up to 92%. • No considerable correlation between soil quality and agroclimatic indicators were found on the LTE sites. [ABSTRACT FROM AUTHOR]

Agriculture is a major contributor to nitrate groundwater contamination. Hence, farmers are demanded to reduce the environmental impact but simultaneously must provide sufficient food products. One important building block for this "sustainable intensification" are appropriate cropping strategies. The potential of modified crop rotations was evaluated in a high-yielding environment in Northern Germany. Therefore, in five consecutive growing seasons (2016/2017 – 2020/2021) three crop rotations were grown in a field trial and compared with respect to agronomic (cereal unit), economic (gross margin) and environmental (N surplus) parameters. A standard crop rotation, typical for the region of the study, was compared with rearranged and augmented crop rotations. Therefore, crops with a high autumnal N uptake (winter oilseed rape and catch crops) were grown after crops with typically high soil mineral N (SMN) amounts after harvest (faba bean and winter oilseed rape). Due to the change of preceding and subsequent crops, an increased N transfer was supposed to prevent N from leaching and a lower N fertilizer demand of the subsequent crop was expected. On average, the modified crop rotations achieved significantly higher cereal units (9.3 and 10.8 t · ha−1) compared to the local crop rotation (8.5 t · ha−1). The gross margin of the local crop rotation was 1474 € · ha−1 and the other crop rotations maintained (1443 € · ha−1) or significantly increased (1572 € · ha−1) this value, respectively. The local crop rotation had a N surplus of 47 kg N · ha−1. In contrast, the N surplus of the modified crop rotations was significantly lower (10 and 28 kg N · ha−1). In summary, the results showed that a thoughtful rearrangement of crop rotations is an appropriate measure to simultaneously improve yields and gross margins with less unfavorable environmental impacts. • Field trial in five seasons fulfilling the principles of crop rotation experiments. • Modified crop rotations improve cereal units, gross margins, and nitrogen surpluses. • Thoughtful rearranged crop rotations can contribute to a sustainable intensification. [ABSTRACT FROM AUTHOR]

Avoiding soil compaction caused by agricultural management is a key aim of sustainable land management, and the soil compaction risk should be considered when assessing the environmental impacts of land use systems. Therefore this project compares different crop rotations in terms of soil structure and the soil compaction risk. It is based on a field trial in Germany, in which the crop rotations (i) silage maize (SM) monoculture, (ii) catch crop mustard (Mu)_sugar beet (SB)-winter wheat (WW)-WW, (iii) Mu_SM-WW-WW and (iv) SB-WW-Mu_SM are established since 2010. Based on the cultivation dates, the operation specific soil compaction risks and the soil compaction risk of the entire crop rotations are modelled at two soil depths (20 and 35 cm). To this end, based on assumptions of the equipment currently used in practice by a model farm, two scenarios are modelled (100 and 50% hopper load for SB and WW harvest). In addition, after one complete rotation, in 2013 and in 2014, the physical soil parameters saturated hydraulic conductivity (k S ) and air capacity (AC) were determined at soil depths 2–8, 12–18, 22–28 and 32–38 cm in order to quantify the soil structure. At both soil depths, the modelled soil compaction risks for the crop rotations including SB (Mu_SB-WW-WW, SB-WW-Mu_SM) are higher (20 cm: medium to very high risks; 35 cm: no to medium risks) than for those without SB (SM monoculture, Mu_SM-WW-WW; 20 cm: medium risks; 35 cm: no to low risks). This increased soil compaction risk is largely influenced by the SB harvest in years where soil water content is high. Halving the hopper load and adjusting the tyre inflation pressure reduces the soil compaction risk for the crop rotation as a whole. Under these conditions, there are no to low soil compaction risks for all variants in the subsoil (soil depth 35 cm). Soil structure is mainly influenced in the topsoil (2–8 cm) related to the cultivation of Mu as a catch crop and WW as a preceding crop. Concerning k S , Mu_SB-WW-WW (240 cm d −1 ) and Mu_SM-WW-WW (196 cm d −1 ) displayed significantly higher values than the SM monoculture (67 cm d −1 ), indicating better structural stability and infiltration capacity. At other soil depths, and for the parameter AC, there are no systematic differences in soil structure between the variants. Under the circumstances described, all crop rotations investigated are not associated with environmental impacts caused by soil compaction. [ABSTRACT FROM AUTHOR]

Crop cultivation intensifies globally, which can jeopardize biodiversity and the resilience of cropping systems. We investigate changes in crop rotations as one intensification metric for half of the croplands in Germany with annual field-level land-use data from 2005 to 2018. We proxy crop rotations with crop sequences and compare how these sequences changed among three seven-year periods. The results reveal an overall high diversity of crop sequences in Germany. Half of the cropland has crop sequences with four or more crops within a seven-year period, while continuous cultivation of the same crop is present on only 2% of the cropland. Larger farms tend to have more diverse crop sequences and organic farms have lower shares of cereal crops. In three federal states, crop rotations became less structurally diverse over time, i.e. the number of crops and the number of changes between crops decreased. In one state, structural diversity increased and the proportion of monocropping decreased. The functional diversity of the crop sequences, which measures the share of winter and spring crops as well as the share of leaf and cereal crops per sequence, remained largely stable. Trends towards cereal- or leaf-crop dominated sequences varied between the states, and no clear overall dynamic could be observed. However, the share of winter crops per sequence decreased in all four federal states. Quantifying the dynamics of crop sequences at the field level is an important metric of land-use intensity and can reveal the patterns of land-use intensification. [Display omitted] • First analysis of temporal trends in crop sequences on half of the German cropland. • Declining number of crops per sequence in three federal states. • Functional diversity of crop sequences remains stable. • High numbers of livestock often occur with less diverse crop sequences. • Organic farms use less cereal crops in their crop sequences. [ABSTRACT FROM AUTHOR]

Rye (Secale cereale L.) is primarily grown as an annual winter crop throughout the temperate zones of the northern hemisphere. Due to its high resource use efficiency, rather low input requirements and high resistance to frost and drought, it has good potential to support more sustainable crop production in the face of future climate change and rising food demand. Process-based dynamic crop models are cutting-edge tools in current agronomic research by simulating crop growth, development, and yield under diverse soil, climate, and management conditions. They enable to evaluate the impacts of climate variability and management practices on agricultural production beyond limited field experiments. We choose to adapt the widely applied CSM CERES-wheat as a starting point for the rye model development, as rye is similar to wheat in terms of its morphological and physiological proper-ties. We created large agronomic trial datasets of cultivar-specific data (rye cv. Palazzo and wheat cv. Winnetou) using value for cultivation and use (VCU) trial data from the Federal Plant Variety Office and state variety trials of Saxony-Anhalt (SVT). The datasets cover all relevant wheat and rye-growing regions in Germany, allowing us to scale up model calibration. We added in-season data from an N-regime trial in Kiel, Northern Germany, from 2008 to 2010, and the Julius Kuehn Institute in Braunschweig, Central Germany, from 2009 to 2010. Weather data for each experimental site were retrieved from the German weather service's climate data center (DWD), and soil data were derived from the European Soil Database (ESDB) v2.0, both data in 1km² grid scale. The CERES-rye model showed satisfactory simulation accuracy regarding phenology, LAI, aboveground biomass, and tiller m-2 at harvest, unit grain weight, grain m-2 at harvest, and grain yield. Simulation-observation comparisons resulted in an RMSE of 3.3 days for emergence, 7.2 days for anthesis, and 7.3 days for harvest maturity date for the calibration dataset from the phenology part. From the growth and yield simulation, RMSE of 1.61 for LAI, 2468.7 kg ha-1 for biomass, 169.6 for tiller m-2, 7708.0 for grain m-2, 3.6 mg for unit grain weight, and 2182.7 kg ha-1 for grain yield. CERES-rye is available to conduct various CSM-based analysis including the evaluation of crop management strategies, consideration in analyzing crop rotations in DSSAT, and assessing rye's suitability for cultivation in different growing environments. [ABSTRACT FROM AUTHOR]

Empirical data on energy performance (net-energy yield, energy efficiency, land demand) of biomass crop cultivation are needed for policy and agronomic decision making. Energy input and energy performance of the cultivation of silage maize (SM), sugar beet (SB), and winter wheat (WW) in crop rotations and continuous cultivation were evaluated on the basis of three field experiments on highly productive sites in Germany. Silage maize and SB root were considered as crops for biogas production and WW as a food crop. Even if SM cultivation needed the largest energy input across sites and years (19–22 GJ ha −1 a −1 ), the energy output compensated for it and largest net-energy yield (212–317 GJ ha −1 a −1 ), energy efficiency (11.4–17.1 GJ GJ −1 ), and smallest land demand (33–48 m 2 GJ −1 ) were observed. For SB cultivation, energy input (15–19 GJ ha −1 a −1 ) and energy performance were lower (119–266 GJ ha −1 a −1 , 9.1–14.7 GJ GJ −1 , 38–279 m 2 GJ −1 , respectively). Differences between both crops were significant (p ≤ 0.05), but not in all cases. Winter wheat cultivation required an energy input of 13–18 GJ ha −1 a −1 and showed the lowest energy performance (103–119 GJ ha −1 a −1 , 6.6–8.6 GJ GJ −1 , 84–102 m 2 GJ −1 , respectively). The net-energy yield and land demand values presented are among the largest and the lowest, respectively, for rainfed Central European conditions. As the preceding crops, SB induced a higher energy performance of the subsequent WW than SM. When taking such crop rotation effects into account for the overall evaluation, we concluded that SB root as a biomass crop is a suitable alternative to SM. [ABSTRACT FROM AUTHOR]

The reduction of pesticide use intensity is a societal and political ambition. Crop rotation is one important method to control pests and diseases in arable farming. We investigated the contribution of crop rotation to the variability of herbicide and fungicide use of 60 farms in four regions of Northern Germany. Our study aimed at answering the question: do diverse crop sequences lead to reduced herbicide and fungicide use in arable farming? Ten-year data on chemical plant protection measures and field management were examined for six field crops. We classified crop sequences (triplets of three succeeding crops) according to their susceptibility for weeds and diseases (= ’riskiness’). The Treatment Frequency Index (TFI) of the last crop in the triplet was set in relation to the crop triplet riskiness, additionally also in combination with tillage. In general, herbicide and fungicide use intensities were smaller in more diverse crop sequences. Diversified cereal sequences, involving roots and tubers, maize or spring cereals were less dependent on herbicides. Cultivation of maize in three subsequent years increased herbicide use. Crop sequences including high proportion of winter cereals increased fungicide use in cereals, while roots and tubers, winter oilseed rape and set-aside in the crop sequence decreased it. In winter oilseed rape, sequences with roots and tubers also increased fungicide use. In sugar beets, sequences with maize or a high concentration of sugar beets led to increasing fungicide use. If farmers chose riskier crop sequences tillage by plough decreased the need for herbicide and fungicide use. To reduce herbicide and fungicide use intensities we recommend increasing the diversity of crop rotations, including a higher number of crops per rotation together with ploughing. Simplifying both crop sequence diversity and tillage intensity implies higher use of herbicides and fungicides. Results will be useful for convincing farmers to diversify crop sequences. [ABSTRACT FROM AUTHOR]

The cultivation of short rotation coppices (SRC) on agricultural land represents an economically and environmentally promising option for sustainable provision of bioenergy. Not only the further development of efficient harvesting machinery, but also the development of harvest-optimised storage systems are necessary to implement cost-efficient cultivation and use strategies for SRC in practice. The storage of fine wood chips from poplar harvest with a forage harvester results in high dry matter losses of up to 25%. Tractor-mounted mower-chippers can harvest coarse wood chips that might possess more favourable storage and drying properties. The main objective of the current research project was to develop and perform a storage experiment in which the storage behaviour of fine and coarse wood chips could be examined and compared in detail over a period of nine months. In this experiment two covered storage piles (height 3.5 m), with over 500 m 3 fine and coarse wood chips respectively, were examined under practice scale conditions in Germany. After nine months of storage the fine chips in the core of the storage pile had dried to a moisture content of 34% with dry matter losses of 22%. Coarse chips, on the other hand, achieved a moisture content of 29% and dry matter losses of 21% in the same period. The maximum moisture content of 40% required by heating plants in practice is achieved by fine chips after 6.5 months and by the coarse chips already after 3.5 months. [ABSTRACT FROM AUTHOR]

Wheat is an important crop to meet the increasing demand for food and fodder. In Germany, it is the most common cereal crop, but only small area is cultivated with spring wheat. However, within the system of organic agriculture this acreage share is considerably higher. Diversified crop rotations with balanced proportions of summer and winter crops are an essential part of organic production systems. Thus, there is a need for varieties with potential under less intensive conditions. In a field trial, breeding progress among 7 European spring wheat varieties with different ages of approval (1949-2011) was investigated at two study sites in Germany and Russia. Newer varieties showed at both sites significant better yields (2 to 4 times higher) than the oldest one. Better lodging resistance as well as lower vulnerability to powdery mildew was observed at significant level for varieties released in the 2000er compared to 1949. Furthermore, individual yield-forming components like 1000-kernel weight, grains/ear and ears/m² were significantly higher among the newer than at the oldest variety. Overall, these results confirm breeding progress for the observed varieties over the entire period for their region of origin (Germany) and under other climatic conditions in Siberia, respectively. [ABSTRACT FROM AUTHOR]

Biomass provides two thirds of the total energy produced from renewables in Europe. The share of bioenergy from energy crops is growing rapidly. Given the environmental pressures arising from pesticide pollution from current agricultural food production, a substantial increase in energy crop cultivation might put additional pressure on biodiversity and soil and water resources. In the present study, we examine the potential of energy crops for pesticide contamination and develop general conclusions and recommendations for the future large-scale expansion of agricultural bioenergy. We base our analysis on the development of energy crop cultivation in Germany, the European country with the largest share of energy crops. Our findings reveal that there will not necessarily be an increase or decrease in the amounts of pesticides released into the environment. Due to the great variety of energy crops, the potential effects will depend rather on the future design of the agricultural systems. Possible risks are associated with the increased cultivation of pesticide-intensive energy crops, such as rapeseed, especially when grown in monocultures or on formerly set-aside land or converted grassland. Instead, energy crops should be integrated into the existing food production systems. Financial incentives and further education are needed to encourage the use of sustainable crop rotations, innovative cropping systems and perennial energy crops, which may add to crop diversity and generate lower pesticide demands than intensive food farming systems. Optimised cultivation systems with diverse crop rotations could help to improve monotonous agricultural landscapes, increase biodiversity and minimise pesticide exposure. [ABSTRACT FROM AUTHOR]

Abstract: Although there is a need for biomass and a potential for short rotation coppice (SRC), farmers hesitate to establish SRC, even on marginal agricultural land on which annual crops show low productivity. Probably the most important factor explaining this reluctance might be the uncertain economic prospects of the cultivation of SRC. Therefore, the aim of this study is to analyse the economy of a typical SRC supply chain by calculating the annuities which can be expected by German farmers who establish SRC on their marginal land. The result shows that the yearly annuity of a 20-year SRC cultivation is about 70 € y−1 ha−1 when poplar SRC is harvested every 4 years with a forage harvester (one-step system). The result includes the establishment, cultivation and transport of the fresh wood chips to a plant 50 km away. However, this result is not competitive with the result of annual crops (226–462 € y−1 ha−1) and is also lower than the CAP subsidy payments that farmers receive from the EU (300 € y−1 ha−1). To achieve higher annuities, four options were analysed possibly leading either to higher biomass yields or to higher market prices (extension of rotation cycle, implementation of irrigation, technical drying of fresh wood chips, using a two-step harvesting system). The implementation of drip irrigation to increase biomass yield turned out to be uneconomic. An extension of the rotation cycle from 4 to 5 years can be recommended as it leads to an annuity of 255 € y−1 ha−1 (instead of 69 € y−1 ha−1). Results also show that the technical drying of chips using (cheap) surplus heat can be very profitable if the added value is reflected in higher market prices. Furthermore, it is shown that the use of an alternative two-step harvesting system with natural interim drying of the rods can be an attractive option for farmers to increase the annuity of their SRC. [Copyright &y& Elsevier]

Integrating leys, cover crops, and animal manures constitute promising avenues to reach annual soil organic carbon changes (ΔSOC) >0.4% in forage and grain-based crop rotations, rates required to offset the increasing C emissions from fossil fuels ("4 per mille" initiative). How these practices and rotations perform in reaching this aim was object of analysis in this paper. Five cropping systems (CS), including three three-year forage and grain-based crop rotations containing annual grass-clover leys (FR and MR) or cover crops (GR), and two contrasting controls (continuous silage maize (CM), and permanent grassland (PG)) were compared for their impact on SOC stocks over eight years (2010–2018). The CS were unfertilized (N0) or fertilized using cattle slurry (N1) at a rate of 240 kg N ha−1 yr−1 applied in the non-leguminous crops. The ΔSOC of the top 30 cm soil layer and the annual carbon inputs (Cin) from slurry applications and plant residues were estimated, their relationship established, and the slurry-induced C retention coefficient was determined. The FR and MR SOC stocks remained stable at N1, while the GR and CM SOC decreased over time by tendency even at N1. Only the PG reached ΔSOC >0.4%. Differences in ΔSOC between CS and N rates were highly associated with the system-specific increase in belowground Cin, induced by slurry applications. Slurry-induced C retention coefficients differed strongly between CS: CM (3%) followed by GR (12%), and by FR and MR (20–15%), and lastly by PG (24%). Promoting belowground carbon inputs was identified as an efficient way to reach significant increases in ΔSOC. We conclude that a ley in only one out of three years is not sufficient to significantly increase SOC stocks in arable crop rotations of the study region. [ABSTRACT FROM AUTHOR]

Monitoring agricultural systems becomes increasingly important in the context of global challenges like climate change, biodiversity loss, population growth, and the rising demand for agricultural products. High-resolution, national-scale maps of agricultural land are needed to develop strategies for future sustainable agriculture. However, the characterization of agricultural land cover over large areas and for multiple years remains challenging due to the locally diverse and temporally variable characteristics of cultivated land. We here propose a workflow for generating national agricultural land cover maps on a yearly basis that accounts for varying environmental conditions. We tested the approach by mapping 24 agricultural land cover classes in Germany for the three years 2017, 2018, and 2019, in which the meteorological conditions strongly differed. We used a random forest classifier and dense time series data from Sentinel-2 and Landsat 8 in combination with monthly Sentinel-1 composites and environmental data and evaluated the relative importance of optical, radar, and environmental data. Our results show high overall accuracy and plausible class accuracies for the most dominant crop types across different years despite the strong inter-annual meteorological variability and the presence of drought and non-drought years. The maps show high spatial consistency and good delineation of field parcels. Combining optical, SAR, and environmental data increased overall accuracies by 6% to 10% compared to single sensor approaches, in which optical data outperformed SAR. Overall accuracy ranged between 78% and 80%, and the mapped areas aligned well with agricultural statistics at the regional and national level. Based on the multi-year dataset we mapped major crop sequences of cereals and leaf crops. Most crop sequences were dominated by winter cereals followed by summer cereals. Monocultures of summer cereals were mainly revealed in the Northwest of Germany. We showcased that high spatial and thematic detail in combination with annual mapping will stimulate research on crop cycles and studies to assess the impact of environmental policies on management decisions. Our results demonstrate the capabilities of integrated optical time series and SAR data in combination with variables describing local and seasonal environmental conditions for annual large-area crop type mapping. • Large-area crop type mapping without region−/class-specific feature selection. • Integration of data describing local and seasonal environmental conditions. • 24 agricultural land cover classes at national scale and for multiple years. • High accuracy despite strong inter-annual meteorological variability. • Combined crop type maps enable crop sequence analysis at national scale. [ABSTRACT FROM AUTHOR]

The demand for wood from short rotation coppice ( SRC) plantations as a renewable energy source is currently increasing and could affect biodiversity in agricultural areas. The objective was to evaluate the contribution of SRC plantations to phytodiversity in agricultural landscapes assessed as species richness, species-area relationships, Shannon indices, detrended correspondence analysis on species composition, Sørensen similarities, habitat preference proportions, and species proportions found in only one land use. Vegetation surveys were conducted on 12 willow ( Salix spp.) and three poplar ( Populus spp.) coppice sites as well as on surrounding arable lands, grasslands and forests in central Sweden and northern Germany. SRC plantations were richer in plant species (mean: 30 species per 100 m²) than arable land (10), coniferous forests (13) and mixed forests in Germany (12). Comparing SRC plantations with other land uses, we found lowest similarities in species composition with arable lands, coniferous forests and German mixed forests and highest similarities with marginal grassland strips, grasslands and Swedish mixed forests. Similarity depended on the SRC tree cover: at increased tree cover, SRC plantations became less similar to grasslands but more similar to forests. The SRC plantations were composed of a mixture of grassland (33%), ruderal (24%) and woodland (15%) species. Species abundance in SRC plantations was more heterogeneous than in arable lands. We conclude that SRC plantations form novel habitats leading to different plant species composition compared to conventional land uses. Their landscape-scale value for phytodiversity changes depending on harvest cycles and over time. As a structural landscape element, SRC plantations contribute positively to phytodiversity in rural areas, especially in land use mosaics where these plantations are admixed to other land uses with dissimilar plant species composition such as arable land, coniferous forest and, at the German sites, also mixed forest. [ABSTRACT FROM AUTHOR]

Abstract: Power based on biomass, in particular biogas, is increasing, with a concomitant increase in the need for energy crop production. The objective of this study was to determine the profitability of biogas substrate production on a marginal site in southwestern Germany. The effects of crop rotation and nitrogen fertilization level were evaluated in a three-year filed experiment. Production costs for supply of biogas substrates and sales of produced electricity were assessed using five crop rotations (CR1: annual monoculture maize; CR2: perennial monoculture perennial ryegrass; CR3: perennial monoculture Jerusalem artichoke; CR4: three-course crop rotation of sorghum – winter triticale – clover grass; CR5: four-course crop rotation of catch crop – maize – winter wheat – winter triticale) and three nitrogen fertilization levels (zero, middle and high levels of nitrogen). The variables were production costs, dry matter yield, substrate costs, energy output, biomass energy supply price, biomass energy sales price and sale/supply ratio. Production costs increased in the order CR4 (1252 € ha−1 a−1) < CR2 (1256 € ha−1 a−1) < CR5 (1404 € ha−1 a−1) < CR3 (1462 € ha−1 a−1) < CR1 (1649 € ha−1 a−1) due to differing mechanical cultivation needs. Dry matter yields ranged from 10.8 t ha−1 a−1 (CR3) to 4.0 t ha−1 a−1 (CR2) and showed significantly higher yields with increasing fertilization levels. Accounting for all variables, the lowest biomass energy supply price was achieved with CR3 (6.6 ct kWh−1), and increased in the order CR1 < CR5 < CR4 < CR2 (12.4 ct kWh−1). It was determined that only CR3 and CR1 were effective for the production of biogas substrates on marginal sites. The biogas substrate costs of the remaining crop rotations were not compensated for by the sale of electricity. [Copyright &y& Elsevier]

Abstract: The study provides information to more reliably estimate the value of conservation tillage in a temperate climate. Tillage effects on yield and weeds were evaluated in field experiments at two sites in SW Germany between 1999 and 2010. Tillage varied at site Ihinger Hof from mouldboard plough (P), chisel plough (CP), rototiller (RTT), varying P and CP (VAR), to no tillage (NT), partially combined with stubble tillage (S). Tillage at site Meiereihof was S/P, S/CP, and NT. Crop rotations included winter wheat (WW, Triticum aestivum), triticale (TR, Triticosecale), oat (OA, Avena sativa), silage maize (SM, Zea mays) and oilseed rape (OSR, Brassica napus) at Ihinger Hof, and winter wheat, spring barley (SB, Hordeum vulgare), silage maize, sugar beets (SBE, Beta vulgaris) and faba bean (FB, Vicia faba) at Meiereihof. At Ihinger Hof, tillage had an effect on yield (P > F =0.0049), but no effects were found on crop emergence and crop density. Tillage effects on yield were consistent across crops though differences between crops appeared to exist. The yield of S/P, the standard tillage, was 8.5 (WW), 7.7 (TR), 4.7 (OA), 18.3 (SM) and 4.1 (OSR)tDMha−1 at Ihinger Hof, with yield under NT always significantly lower than S/P by 7.3% on average for all crops. At Meiereihof, yields ranged from 7.2 to 8.0 (WW), 3.3 to 4.2 (SB), 19.8 to 21.5 (SM) and 3.1 to 3.2 (FB)tDMha−1, and 61.3 to 67.6 FM ha−1 for SBE. Yield was reduced by 4.5% from S/P to S/CP (P > F =0.0516), and by about 10% from S/P to NT (P > F =0.0009). Weed density ranged between 0.5 and 44plantsm−2 at Ihinger Hof and was higher in treatments without stubble tillage and under non-inversion tillage, though significance differed for the different classes of weeds. NT led to weed infestation about 2–20 times higher than S/P. The interaction crop×treatment indicated that factors other than tillage influenced weed infestation. It is unlikely that weed infestation and reduced yield will be problems in temperate climates if soil disturbance through tillage is reduced. Non-inversion tillage can easily replace inversion tillage, and stubble tillage can be added to primary tillage if needed to reduce weeds. Since no specific tillage method was unequivocally superior to another one, any method well suited to specific regional and farm conditions can be adopted successfully. [Copyright &y& Elsevier]

Over the past few years the number of biogas slurries, which are generally used as nitrogen fertilisers, have seen a steady increase in Germany. A mechanistic ammonia volatilisation model was developed to predict the ammonia losses of these slurries when applied to bare soil, maize, wheat and rye grass canopies. Data for model development were collected from several field measurements carried out at two locations in Northern Germany between the years of 2007 and 2008. Additionally, the behaviour of the slurries on and in the soil was investigated through the use of infiltration pot experiments. The model includes three main compartments: slurry, atmosphere and soil. The soil compartment model is relatively simple, as the slurry infiltration, nitrification and ploughing dislocation into the soil determined in the experiments showed quantitatively no significant differences between the tested slurries (mono-fermented, co-fermented and pig slurry) and soils (sand soil and loamy sand). Hence, instead of a complex soil model, stable reduction factors, as derived from the experiments, were implemented in the model. Simulated ammonia emissions were statistically compared (root mean square error (RMSE), modelling efficiency (ME), linear regression) to the observed emissions. All evaluations showed an acceptable model performance (RMSE = 1.80 kg N ha), although there were a few number of anomalies which could not be modelled in an adequate way. A model sensitivity analysis showed that temperature and slurry pH value are the main drivers of NH volatilization in the model. Following a change of +1°C or of +0.1 pH unit ammonia volatilization will increase by about 1% and 1.6% of the applied total ammoniacal nitrogen, respectively. We were able to show that a simple model approach could explain most factors of ammonia volatilization in biogas crop rotations. [ABSTRACT FROM AUTHOR]

Abstract: This study provides a risk analysis of long-term field experiments in Germany (Bavaria) on various field crops (potato, wheat and corn), grown in rotation, under a variety of different tillage and nitrogen management systems. The field experiment provided yield and input data for the analysis, and was combined with market data relevant to the case-study region. The emphasis of the analysis is on the interaction between risk and tillage and nitrogen strategies. Over the whole rotation (corn–wheat–potato–wheat), conventional tillage combined with conventional nitrogen rates is optimal, both for risk-neutral and risk-averse farmers. Although less intensive management practices involve lower risk, the decrease in risk premium is not sufficient to alter the ranking of strategies, even for farmers with higher levels of risk aversion. Reducing nitrogen rates would be costly to farmers, especially under reduced or shallow tillage. Decoupled farm subsidies within the expected utility model show that even for a scenario with no subsidies our conclusions do not change. [Copyright &y& Elsevier]

Abstract: Ten years of a long-term field experiment using different strategies of conventional and conservation tillage in SW Germany were evaluated for soil mineral nitrogen (SMN) and soil moisture content. Treatments analysed were combinations of stubble tillage (S) or no stubble tillage with primary tillage P: mouldboard plough, CP: chisel plough, RTT: rototiller, NT: no-till, and VAR: alternating S/P or S/CP. Best management practices were used for crop rotation, fertilisation and plant protection. CP, VAR and NT resulted in 18.7–19.0% gravimetric water content in spring. Partially significantly lower water content was observed in spring under S/P and CP with 18.2%; P and S/RTT resulted in 18.5%. Autumn soil moisture ranged from 15.3 to 15.8% and did not significantly differ between the treatments. Interactions between treatment and depth were not significant. There was no clear trend for spring soil moisture. No treatment showed a particular response to dry or wet season. Total SMN ranged between 8 and 49kgha−1 in spring and 5–26kgha−1 in autumn; significant effects of the treatments or interactions of treatment×depth did not occur. The effect of the season was most relevant for the amount of SMN, probably as a result of different conditions for mineralisation. Downward movement of nitrogen in spring was low in all treatments if catch crops were grown in the previous autumn. Overall, different soil tillage methods had little effect on soil moisture and soil SMN under temperate conditions. Seriously adverse effects of any tillage treatment in terms of nitrate leaching or reduced mineralisation seem unlikely. Similarly, the tillage systems did not exhibit obvious advantages or disadvantages in terms of soil water content. An exception may have been the higher water content in autumn in 0–30cm under high soil disturbance which provided more suitable conditions for germination of the following crop. The decision of whether or not to adopt conservation tillage in temperate climates seems not to be primarily dependent on soil moisture and nitrogen mineralisation or on nitrogen leaching. [Copyright &y& Elsevier]

The effect of various rotations and fallow periods on development of sugar beet, product quality and nematode infestation as well as soil physical parameters have been studied in the sugar beet rotation experiment Etzdorf, which had been started in 1970 on a Haplic Chernozem in the state Saxony-Anhalt, Germany. In 2006, for the first time various soil physical parameters have been analysed. The different rotations did not affect the parameters significantly. This does also apply to the total organic carbon content, which was 2.08 vol. % in sugar beet monoculture and thus only 0.16 vol. % in a rotation with only 20% sugar beet. Serious yield effects were measured if the proportion of sugar beet in the rotation was increased to 25% and more. The break in the rotation affected the yield and quality parameters. In situations with a substantial nematode infestation breaks of a minimum of three years are recommended. If this recommendation is exceeded a critical infestation with 500 eggs and larvae in 100 g soil causes yield decreases of a minimum of 5% on average, which might be higher in single years. This affects yield stability depending on seasonal weather conditions. In dem Fruchtfolgeversuch auf Loss-Schwarzerde in Etzdorf (Sachsen-Anhalt), angelegt 1970, wurden die Auswirkungen unterschiedlicher Anbaukonzentrationen und Anbaupausen bei Zuckerruben auf die Pflanzenentwicklung, Produktqualitat und den Nematodenbesatz als auch auf bodenphysikalische Parameter untersucht. Bei den 2006 erstmalig in Krume und Unterboden unter Zuckerruben ermittelten bodenphysikalischen Eigenschaften (Trockenrohdichte, Grobporenvolumen und Wasserleitfahigkeit) wurden zwischen den Anbaukonzentrationen nur geringe Differenzierungen festgestellt. Das trifft auch fur den TOC-Gehalt zu, der bei Rubendaueranbau (2,08 M.-%) gegenuber 20% Anteil in der Fruchtfolge nur um 0,16 M.-% abnahm. Deutliche Ertragseinbussen treten bei Zuckerrubenanteilen von mehr als 25% in der Fruchtfolge auf. Die Anbaupausen wirken sich auf den Korper- und Zuckerertrag stark differenzierend aus, besonders wenn mehrere Zuckerrubenfelder in die Rotation einbezogen werden. Auf den nematodenverseuchten Standorten sind deshalb Anbaupausen von mindestens 3 Jahren einzuhalten. Bei Uberschreitung dieser Empfehlung werden in Abhangigkeit vom Ausgangszustand die kritischen Nematoden-Verseuchungswerte von 500 Eier und Larven je 100 g Boden, die zu gesicherten Ertragsausfallen von mehr als 5% fuhren, in den Einzeljahren haufiger erreicht und teilweise auch wesentlich ubertroffen. Unter diesen Bedingungen wird in Abhangigkeit von jahresspezifischen Einflussen die Ertragssicherheit ungunstig beeinflusst. [ABSTRACT FROM AUTHOR]

As agricultural policies affect land use, they have effects on the amount of soil erosion in agricultural regions through changes of the economic conditions of agricultural production. Prices of inputs and outputs, regulations and incentives can change, forcing or encouraging farmers to adopt new crop rotations. This paper shows how a bio-economic model can be used to describe and estimate the effects of policies on agricultural production and the risk of soil erosion at the example of a region in North-Eastern Germany. The model uses both an assessment tool that is based on a fuzzy-logic approach for the estimation of soil erosion risk of cropping practices, and a linear programming model, that simulates farmers’ economic behaviour under the assumption of gross margin maximisation being the main goal of farmers’ actions. The analysed policy options were both a targeted and an untargeted incentive programme for reduced tillage, and a restriction option where high erosive crops are not allowed on high erodible field types. The results show that policy changes can have an impact on soil erosion. Furthermore, soil conservation policies are shown to have different levels of efficiency in terms of reduced soil erosion related to the costs of the policy. In the case of this study, a restriction option was more efficient than the incentive options. The results of such simulations can serve as a decision support for the development of soil conservation policies and help to foresee the effects of general changes of agricultural policies. [Copyright &y& Elsevier]

Abstract: Nitrogen inputs into surface waters from diffuse sources are still unduly high and the assessment of mitigation measures is associated with large uncertainties. The objective of this paper is to investigate selected agricultural management scenarios on nitrogen loads and to assess the impact of differing catchment characteristics in central Germany. A new modelling approach, which simulates spatially distributed N-transport and transformation processes in soil and groundwater, was applied to three meso scale catchments with strongly deviating climate, soil and topography conditions. The approach uses the integrated modelling framework JAMS to link an agro-ecosystem, a rainfall-runoff and a groundwater nitrogen transport model. Different agricultural management measures with deviating levels of acceptance were analysed in the three study catchments. N-leaching rates in all three catchments varied with soil type, the lowest leaching rates being obtained for loess soil catchment (18.5 kg nitrate N ha−1 yr−1) and the highest for the sandy soils catchment (41.2 kg nitrate N ha−1 yr−1). The simulated baseflow nitrogen concentrations varied between the catchments from 1 to 6 mg N l−1, reflecting the nitrogen reduction capacity of the subsurfaces. The management scenarios showed that the highest N leaching reduction could be achieved by good site-adapted agricultural management options. Nitrogen retention in the subsurface did not alter the ranking of the management scenarios calculated as losses from the soil zone. The reduction effect depended strongly on site specific conditions, especially climate, soil variety and the regional formation of the crop rotations. [Copyright &y& Elsevier]

Rhizoctonia solani (AG 2-2IIIB), causing root and crown rot in sugar beet, poses an increasing problem in Europe. Agronomic measures have to be optimized to control disease and minimize yield and quality loss, because no fungicides can be applied. Resistant sugar beet cultivars have been introduced to reduce disease occurrence. Furthermore, crop rotation can influence R. solani occurrence. In contrast to other cereals, maize serves as a host of the fungus. In order to study the combined effect of these factors, a series of four field trials was established with crop rotations varying in the proportion of maize and comparing a resistant with a susceptible sugar beet cultivar in 2001-02 in southern Germany. Within crop rotations, cultivation methods were varied in the form of soil tillage, intercrops, or both. Sugar beet cultivar and crop rotation had the main impact on disease severity and sugar yield. With increasing proportion of maize, sugar yield decreased, whereas cultivation method had only a minor impact. Plowing directly before sugar beet increased sugar yield only within the unfavorable maize-maize-sugar beet rotation compared with mulching. These results give strong evidence that crop rotation of sugar beet with nonhost plants and cultivation of resistant sugar beet cultivars are adequate means for integrated R. solani control. [ABSTRACT FROM AUTHOR]

Legume catch crops can enhance soil fertility and promote the N and P supply of the subsequent main crop, especially with low mineral fertilizer use. However, the specific impact of catch crops on arbuscular mycorrhiza formation of the following main crop is unknown. Therefore, the impact of serradella (Ornithopus sativus) vs. bare fallow was tested on mycorrhiza formation, potential soil enzyme activities and plant-available P under subsequently grown barley (Hordeum vulgare) and different fertilization treatments (P-unfertilized—P0; triple superphosphate—TSP; compost—COM; combined—COM + TSP) in a long-term field experiment in northeastern Germany. Catch cropping significantly increased mycorrhiza formation of barley up to 14% compared to bare fallow. The impact of serradella on mycorrhiza formation exceeded that of the fertilization treatment. Serradella led to increased phosphodiesterase activities and decreased ß-glucosidase activities in soil. Plant availability of P was not significantly affected by serradella. These findings provide initial evidence that even serradella as a non-host crop of mycorrhizal fungi can promote the mycorrhiza formation of the subsequent crop and P mobilization in soil. We conclude that the prolonged vegetation cover of arable soils by the use of catch crops can promote P mobilization and transfer from P pools to the following main crops. [ABSTRACT FROM AUTHOR]

Nitrogen fertilizers are the major source of nitrous oxide (N 2 O) emissions from arable land. The addition of nitrification inhibitors to fertilizers may improve the nitrogen (N) use efficiency and reduce N 2 O emissions. However, it is still unclear how crop rotations affect nitrification and urease inhibitors to reduce N 2 O emissions. We conducted a field experiment with two-year winter wheat and one-year oilseed rape cultivation in Germany from 2016 to 2017. We applied five different fertilizer treatments: (1) a control treatment without fertilization (N0); (2) calcium ammonium nitrate (CAN); (3) ammonium sulfate nitrate with the nitrification inhibitor 3,4-dimethylepyrazole phosphate (ENTEC); (4) urea; and (5) urea with the urease inhibitor N -(n -butyl) thiophosphoric triamide (UTEC). Crop yield, grain and straw N content, and N 2 O fluxes were measured to assess yield-scaled N 2 O emissions under different treatments. We found that in all fertilized treatments, the aboveground N uptake of wheat after wheat was 199–203 kg N ha−1, which was much lower than that of wheat after oilseed rape (252–271 kg N ha−1). The apparent N recovery of oilseed rape (13–23%) was much lower than in wheat after wheat (63–66%). The enhanced-efficiency fertilizers increased aboveground N uptake by 0–5% compared to fertilizers without inhibitors. The oilseed rape field had the highest yield-scaled N 2 O emissions (18.0, 15.1, 16.7 and 15.6 g N 2 O-N kg−1 aboveground N uptake in CAN, ENTEC, urea and UTEC, respectively). These results indicate that urease and nitrification inhibitors hold the potential to increase crop yield and reduce N 2 O emissions. Oilseed rape straw should be carefully managed to avoid high N 2 O emissions. Future research should be focused on different fertilizer level and optimized N application strategy to increase the efficiency of urease and nitrification inhibitors, for instance, by increasing the N application rate in wheat after wheat, but reducing it in oilseed rape. • Effect of NBPT and DMPP on grain yield is minor. • NBPT and DMPP hold the potential to reduce N 2 O emissions in winter wheat and oilseed rape fields. • In oilseed rape, N fertilization induced high post-harvest N 2 O emissions. [ABSTRACT FROM AUTHOR]

The advantages of using multispectral remotely sensed data instead of CORINE Land Cover for the modelling of nitrate concentrations in the leachate of the Rur catchment are presented and discussed in this paper. In this context it has been shown that the identification of main crops and annual crop rotation in the Rur catchment by SPOT, LANDSAT and ASTER imagery provides the key for a spatial and thematic enhancement of the model results. The spatial resolution of the nitrogen surplus data set which denotes the linkage between RAUMIS and GROWA is enhanced from district level to field/pixel level. In parallel, the empirical water balance model GROWA is enhanced to differentiate between agricultural crops in the real evapotranspiration calculation. It is calibrated by runoff data measured at gauging stations. Results indicate, e.g., an average nitrate concentration in the leachate of 42mg NO3/L in the relatively wet year of 2002 and almost 62mg NO3/L in the dry year of 2003. There is a 20mg NO3/L weather-induced difference which can be modelled in a more detailed way using self-processed remotely sensed data. The model results were compared to nitrate concentrations observed in the top parts of multi-level wells. In this way the related coefficient of determination has been improved from a value (R) of −0.50 using CORINE to 0.59 by using self-processed remotely sensed data, thus demonstrating the potential of the enhanced model system. [Copyright &y& Elsevier]

In 1937, K. Opitz founded an agricultural experimental station at Thyrow (Brandenburg County, Germany) where field experiments with a duration of 25 to 65 years still are being managed representing classical long-term field experiments. The location is characterized by low soil fertility, low silty sand soil and unstable water supply and represents arable land of low quality in the lowland of Northern Germany. The long-term collection of results of three different experiments lead to the following approaches for sustainable plant production on marginal sand soils: • In cereal cropping a well-balanced crop rotation is more important than high amounts of soil organic matter. • Sustainable reproduction of soil organic matter needs at least 10 t/ha and year farm yard manure or straw manure in every second year. • Irrigation is effective only if additional mineral N fertilizer is applied. [ABSTRACT FROM AUTHOR]

[Display omitted] • We propose summable C factors to enable easy assessment of water erosion. • Summable C factors were calculated for 57 crops instead of defined crop rotations. • Results for Central Europe also include estimation functions for additional crops. • Summable C factors have changed due to climate change. • Row crop C decreased and small grain C increased. Crop cultivation, crop stages and the seasonal distribution of rainfall erosivity are continuously changing in response to changes in climate and socio-economic conditions. Therefore, the crop and cover factor (C factor) of the (Revised) Universal Soil Loss Equation should also be adjusted continuously. Within the framework of the (R)USLE, C factors can only be calculated for crop rotations. However, for large-scale and regional modeling of soil erosion on arable land and targeted subsidy schemes for the implementation of soil protection measures, C factors are required that quantify the effect of individual crops and management options on the risk of soil erosion. We therefore develop a method for deriving summable C factors that can easily be combined to derive C factors for crop rotations. These summable C factors also account for carry-over effects that influence the risk of soil erosion in subsequent crops. Using the latest data on the temporal distribution of rain erosivity and approximately 3.5 million observations of crop stages, summable C factors were derived for 57 crops and crop management options, including double cropping, which is currently becoming more prevalent in temperate areas. These C factors apply for Germany. However, the regional variation of summable C factors within Germany was small and comparison with Swiss data indicated that our summable C factors will also apply in neighboring countries in Central Europe. Changes in the seasonal distribution of rain erosivity and in crop development due to climate change caused some convergence of the summable C factors for different crops, i.e. the C factors for crops where the risk of soil erosion potential had previously been low increased, while for those crops where the risk of erosion had previously been high the C factors decreased. Of the arable crops, potatoes had by far the highest summable C factor, whereas sod-forming crops had negative summable C factors, leading to low C factors for crop rotations. The sod crops seem to be largely responsible for the low level of soil erosion found on many organic farms and in Switzerland, where sod crops account for a large share of arable land. [ABSTRACT FROM AUTHOR]

Alopecurus myosuroides Huds. (blackgrass) frequently occurs in Western European cropping systems. It causes high yield losses in winter-cereals and winter-oil-seed rape. Several preventive measures to control blackgrass are available, however long-term studies with combinations of preventive and direct control methods are rare. In this seven-year study at two locations in Germany, three crop rotations with different proportions of winter-annual crops, four herbicide strategies and four tillage measures were combined and their interactions were analyzed. Aim was to investigate the effects on blackgrass densities, crop yields and contribution margins. Densities increased from 14 to 3098 heads m-2 and 201 to 3563 heads m-2 in the rotation containing only winter-annual crops without weed control and reduced tillage. Rotations with spring crops reduced densities by up to 98%. Inversion tillage with a moldboard plough and false seedbed preparation using a harrow (shallow) and a rotary harrow (deep) reduced blackgrass infestations by up to 70% compared to solely reduced conservation tillage with a chisel plough. Blackgrass densities were 23–99% (average 59%) lower, when herbicide Mode of Action (MOA) was rotated in every year compared to herbicide strategy continuously using the same MOA. Grain yield loss in the control plots due to blackgrass competition amounted up to 3.0 t ha-1 (41%). Contribution margins were highest in the cropping systems that combine crop rotation, inversion tillage, false seedbed preparation and herbicide MOA rotation. The results highlight the benefits of integrated weed management in regard to weed control and economic sustainability. The Graphical figure shows an aerial photo of the crop rotation experiment to suppress blackgrass. The image was taken in the fourth year of the experiment in April 2014 in oil-seed-rape (OSR) at time of flowering. The green parts/plots are the control plots without any control against blackgrass. WW = winter wheat, SB = spring barley. [Display omitted] • Blackgrass densities were in average 59% lower in rotations including spring crops. • Blackgrass densities were 23–99% lower, when herbicide Mode of Action was rotated. • Ploughing and false seedbed preparation reduced infestations by up to 70%. • Grain yield loss in winter wheat due to blackgrass competition amounted up to 3.0 t ha-1. • Contribution margins were highest in IWM systems. [ABSTRACT FROM AUTHOR]

Combining agriculture and photovoltaics on the same land area gains in attention and political support in a growing number of countries accompanied by notable research activities in France, USA and Korea, amongst others. This study assesses the technical feasibility of agrivoltaic (APV), while it gives insights on how to design an APV system. Furthermore, it analyses the electrical yield and the behavior and productivity of four crops grown in Germany's largest agrivoltaic research facility installed in 2016 near Lake Constance within the research project APV-RESOLA by Fraunhofer Institute for Solar Energy Systems ISE. The German design differs from most other agrivoltaic approaches by allowing for a wide range of machine employment, facilitated by a vertical clearance of 5 m and a width clearance of up to 19 m. Crops cultivated under the APV system and on the reference field under a crop rotation scheme include potato, celeriac, clover grass and winter wheat. The land use efficiency measured by the Land Equivalent Ratio (LER) indicated a rise between 56% and 70% in 2017 while the dry and hot summer in 2018 demonstrated that the agrivoltaic system could increase land productivity by nearly 90%. Radiation simulations showed that deviating from full south by around 30° resulted in equal distribution of radiation on ground level, representing the basis for the agrivoltaic design. Considering climate change and increasing land scarcity, our overall results suggest a high potential of agrivoltaics as a viable and efficient technology to address major challenges of the 21rst century. • Light distribution under the APV system simulated by Radiance software tool. • Assessment of different system orientations on the light availability. • The effect of different row distance on the biomass and electrical yield. • The technical feasibility and the design of APV in arable farming. • Promising results of Land Equivalent Ratios for the first two operational years. [ABSTRACT FROM AUTHOR]

Vegetation of arable fields has changed significantly over the past decades as indicated by a marked decline in the abundance and diversity of arable plants. Thus, beyond the preservation of remnant populations, introduction of autochthonous seeds is a necessary measure to promote threatened arable plants and to restore agro-ecosystems. However, there is a lack of knowledge on the most suitable agricultural methods for plant establishment. This topic was investigated for three winter annuals (Legousia speculum-veneris , Consolida regalis , Lithospermum arvense) in a three-year field experiment in southern Germany. We established 14 management treatments with five replicates in a completely randomized block design. In year 1, arable plants were sown in a mixture of 850 seeds m−2 either without crop or with cereal crops in different sowing densities (25 %, 100 %). After crop harvest different types of soil tillage were applied (rotary cultivator, mouldboard plough). In year 2, four different crop types (autumn-sown spelt, spring-sown triticale, pea, clover-grass) were sown, and in year 3, rye was cultivated. Establishment was measured yearly as seed production of the rare arable plants, and their overall population growth rates were calculated at the end of the study period. Highest population growth rates were observed in L. speculum-veneris, followed by C. regalis and L. arvense. Population growth of the target plants decreased significantly with crop and weed cover averaged over the study period. Initial crop sowing densities had a significant impact on first-year establishment, with persisting effects in years 2 and 3. Best results were obtained without cover crop compared to cereals sown with 25 or 100 % sowing density. The establishment of target plants was also affected by crop type in year 2 (spelt > pea > spring triticale > clover-grass). However, establishment was overall high in year 3, when all plots were cultivated with rye. Type of soil tillage had no effect within the crop rotation 'rye–clover-grass–rye', while rotary cultivation in 'without crop–rye–rye' was positive for the establishment of L. speculum-veneris and L. arvense. The results indicate good opportunities for the reintroduction of rare arable plants under different crop rotations with best results for extensively managed fields with low crop competition. [ABSTRACT FROM AUTHOR]

• Spatiotemporal variability of C value for various crop rotations was assessed. • Rotation involving sugar beet and maize increased C value. • Rotation including winter rape could reduce the risk of soil erosion. • Monoculture maize could elevate erosion risk by 72 % compared to winter rape. • The results can be useful for spatiotemporally explicit agroecosystem modelling. In arable land management, different crop rotation patterns and sequences, such as changing agricultural land use to erosion prone crops, or crops providing less ground cover, can greatly influence soil loss rate through their impact on soil cover status (C factor value). The influence of crop rotation on C value and on erosion rate is often determined on an experimental plot scale, so the results are often erroneous when extrapolated to large heterogeneous landscapes, where they fail to capture the spatiotemporal variability beyond the experimental sites. In the present study we have endeavored to investigate the impact of various crop rotation patterns on C value and on subsequent soil erosion rate, at a landscape level, by combining 28 time-series satellite images (from 2013 to 2016) along with annually updated land-use data, via the integrated administration and control system (IACS), from the Uckermark district of north eastern Germany. In total, 21 different crop sequences were investigated. Winter wheat (WW), winter rape (WR), and maize (Mz) were found to be the predominant arable crops grown in the study area. The highest average annual C values were estimated from crop sequences involving Mz and sugar beet (SB), both as pre-crops and succeeding crops. The highest value of 0.39 was computed from SB/Mz rotation. On the other hand, crop rotation involving WR gave significantly lower annual C values in all the years considered, with the lowest average annual C value of 0.07 calculated on WR parcels preceded by winter cereals. It was also apparent that crop rotation patterns influenced C value in a temporally variable manner. Among the self-sequencing patterns, WR/WR reduced the C value significantly compared with Mz/Mz and to a lesser extent compared with WW/WW. Continuous cultivation of Mz increased the potential soil loss rate by as much as 72 % compared to WR/WR and by 51 % compared to WW/WW. It was also possible to determine the spatial distribution of the impact of crop rotation on soil erosion risk within the study area. The results obtained agreed with the results of other international and regional studies. Overall, the output from this research could contribute towards further efficient investigation of the impact of agronomic practices on the environment in a large agricultural landscape, without the need to set up multi-location experimental plots. [ABSTRACT FROM AUTHOR]

• the superiority of arable conventional or organic crop rotations regarding N leaching depends on the functional unit used. • organic arable crop rotations reduced the nitrate leaching loads per area significantly. • production related N leaching was 50 % lower in the conventional system. • all crop rotations exceeded the critical N load with respect to the EU-Nitrate directive threshold. • integrated approaches, which include crops with high N uptake efficiency in late autumn are needed to fulfill EU standards. Sustainable intensive agriculture requires enhanced nitrogen use efficiency and reductions in nitrogen (N) leaching losses. To investigate if organic farming systems have potential to achieve this, a comparison between conventional and organic arable farming was carried out over a two-year period. Two differently managed specialized organic arable crop rotations (low N-intensive (Ol), semi -N- intensive (Os)), and a typical N-intensive conventional crop rotation (Ch) were studied. The study was done under commercial farm scale conditions covering close to 400 ha in total (5−23 ha field sizes) in a highly productive arable region on fertile soils in northern Germany. Nitrogen leaching losses were measured using ceramic suction cups. Two functional units were used as indicators for eco-efficiency: N losses per area and per unit of grain equivalent (GE) produced. Results revealed that organic arable crop rotations reduced the nitrate (NO 3 -N) leaching loads per area significantly, with losses (kg NO 3 −-N ha-1 a-1) of 22.0 in Ol, 24.4 in Os and 35.1 in Ch. In contrast, when using the functional unit 'nitrate leaching per grain equivalent' as an indicator for eco-efficiency the conventional system resulted in 50 % lower N leaching loads per GE. This was due to the much higher land use efficiency of the conventional system (115 GE ha-1 vs 36 GE ha-1 for Ol and 38 GE ha-1 for Os), which resulted in N leaching losses (kg NO 3 -N GE-1) of Ch 0.32 for Ch, 0.64 for Ol, and 0.66 for Os. Regarding EU-Nitrate directive threshold for drinking water of 11.3 mg NO 3 -N l-1, all crop rotations exceeded the critical load. For the various main crop/preceeding crop sequences, the soil mineral N content at the end of the vegetation period and the autumn N uptake were the best predictors for N leaching, whereas for the aggregated effect across the various crop rotations within a farm system the N balance was the best descriptor. Considering N leaching loads our results show that both, specialized arable conventional and organic farming systems fail to meet the requirements of given environmental standards for water protection in the EU. This suggests that integrated approaches beyond such specialised systems are necessary, which are based on a balanced combination of forages (with two year leys), catch crops and cash crops. [ABSTRACT FROM AUTHOR]

Lignocellulosic bioenergy crops are a potential option for climate mitigation and for meeting the targets of the Paris Agreement in Europe. The PopFor process-based model has been developed based on the earlier MiscanFor model and parameterised for poplar using data from a literature review in combination with experimental data on high performing clones Max 1, 3, 4 for extensively and intensively managed sites in Germany. PopFor needs comparatively few input data to provide accurate estimates of biomass yield. The parameters found allowed a good match to measured values. The best fit for bud emergence is 81 °days (base 5), with leaf emergence at 463 °days (base 5) and the temperature at which photosynthesis slows is 28 °C. Maximum radiation use efficiency was set to 2.9 gMJ−1. The air temperature threshold that kills crop was set at −37 °C with the number of days below this threshold that kills the crop set at 90 days. 30 days below wiltpoint was set as a threshold that kills the crop from drought. It was found that plant available water was the key explanatory variable in predicting yield and access to groundwater explained 97% of the yield variation between the sites. The results show that the model estimates the yield of poplar after the establishment phase with a mean difference of 0.27 DM t ha−1 y−1 (r2 0.99, n29, F = 4.18, p < 0.05 with RMSE = 19.68%). PopFor was shown to be an effective model for predicting yields under different soil conditions. Image 1 • New poplar model for predicting yield estimates on a local or larger scale. • PopFor needs only soil and weather data, no diameter or stem measurements. • PopFor accurately modelled yield for 2nd rotation and intensively managed 1st rotation poplar coppice. • PopFor parameters are widely applicable. • PopFor is a suitable tool for defining the most suitable areas for poplar bioenergy. [ABSTRACT FROM AUTHOR]

Fusarium species are common pathogens on maize and reduce the product quality through contamination with mycotoxins thus jeopardizing safety of both animal feed and human food products. Monitoring of Fusarium infected maize ears and stalks was conducted in Germany to determine the range of Fusarium species present in the field and to assess the impact of tillage, crop rotation, and weather conditions on the frequency of Fusarium species. From 2016 till 2018, a total of 387 infected ears and 190 stalk segments from 58 locations in Germany were collected. For each sample location, site-specific agronomic data on tillage and previous crops as well as meteorological data on precipitation, air temperature, and relative humidity during the vegetation period were recorded. The most frequent Fusarium species detected in maize ears were Fusariumgraminearum, F.verticillioides and F.temperatum, whereas, F.graminearum, F.equiseti, F.culmorum, and F.temperatum were the species prevailing on maize stalks. Differences in the local species composition were found to be primarily associated with weather variations between the years and the microclimate at the different locations. The results indicate that mean temperature and precipitation in July, during flowering, has the strongest impact on the local range of Fusarium spp. on ears, whereas the incidence of Fusarium species on stalks is mostly affected by weather conditions during September. Ploughing significantly reduced the infection with F.graminearum and F.temperatum, while crop rotation exerted only minor effects. [ABSTRACT FROM AUTHOR]

• A further legume can be integrated in the crop rotation by maize-bean intercropping. • The appropriate bean cultivar is crucial for the success of this system. • The intercropping yields are comparable to those of pure maize. • Maize-bean intercropping fits into organic farming systems. • Maize-bean intercropping can be adopted to moderate maritime climate. Maize-bean intercropping is currently gaining popularity among farmers in Germany, although there is hardly any data available on the yield potential under moderate maritime climate conditions in comparison to pure maize cultivation as well as on the choice of the bean cultivar. To assess the agronomic potential of maize-bean intercropping for organic farming, field-experiments over two growing seasons were conducted in Northern Germany (53°46′N, 10°30′E). A split-plot design with two sowing times of the beans as main-plot-factor and different bean species and cultivars (Phaseolus vulgaris , cv.: Cobra, Eva, Tarbais, P. coccineus , cv.: Preisgewinner, Weiße Riesen, Vicia faba cv.: Isabell) as subplot-factor was applied. In both years, the average intercropping yield (11 t ha−1 in 2011 and 14 t ha−1 in 2012) of the two sowing dates was comparable to that of maize-control, except for Maize-Eva in 2011. The highest intercropping yields in 2011 were shown by cv. Tarbais and Preisgewinner with bean shares ranging from 34% to 39%. By contrast, the late-sown beans in 2012 had a share of 6–12% only, reflecting the overall higher maize yield level. Compared to maize control, the intercropping with Tarbais and Preisgewinner, which achieved the highest leaf mass scores, led to a significant improvement in crude protein yield by 36% and 18% in 2011, respectively. Earlier ripening bean cultivars (e.g. cv. Eva and Cobra) tend to lose their leaves before harvest. So cultivars with a longer growth period (e.g. cv. Tarbais), similar to maize, should be used to achieve high bean and crude protein yields. Our results demonstrate the importance of cultivar choice for achieving high bean yields that have the potential to improve feed quality. Tarbais and Preisgewinner were the most suitable cultivars for maize-bean intercropping, as they achieved the highest bean yields and improved the crude protein yield in 2011. Even though further optimization is indispensable, we have shown that maize-bean intercropping can fit into organic farming systems under moderate maritime climate. [ABSTRACT FROM AUTHOR]

Introducing agro-ecological techniques such as no-tillage systems with cover crops in rotations with soybean (Glycine max (L.) Merr.) could provide more resilience to changing climatic conditions and, at the same time, reduce soil erosion, nitrate leaching, and weed density in the main crop. However, there are challenges in introducing no-tillage techniques in crop systems in Europe as there is little quantitative knowledge about the agro-economic impact. The objectives of this study were to evaluate the agronomic and economic impacts of three soybean cropping systems involving a rye (Secale cereal L.) cover crop prior to soybean, i.e., two no-tillage systems; either herbicide-free with crimping the rye or herbicide-based without rye crimping and one plough-based in which rye was cut as green silage. The impacts of these cropping strategies were compared in a three-year cropping system experiment at a research station in north-eastern Germany with and without irrigation. The following parameters were measured: (1) cover crop biomass; (2) weed biomass; (3) soybean plant density; (4) soybean grain yield; and (5) gross margin of the cropping system. The results showed that all three soybean cropping systems can effectively suppress weeds. System (C), the no-tillage herbicide-based system, produced the lowest rye biomass and highest soybean yield; system (B), the no-tillage herbicide-free/crimped rye system, produced the highest rye biomass and lowest soybean yield compared to system (A), the standard cutting/plough-based system. The differences in rye biomass and soybean yield observed between the three systems could be mainly attributed to the timing of the cover crop termination and the soybean sowing date. The gross margin was highest in system (C), due to the high soybean grain yield. The low soybean grain yield in system (B) resulted in lower revenues and gross margins compared to systems (A) and (C), although system (B) could be economically attractive in organic farming with higher prices for organic soybean. In the particularly dry year 2016, gross margins were higher when soybean was irrigated compared to the rainfed cultivation, due to significantly higher grain yields. Before recommending the application of the no-tillage with cover crop technique for the conditions tested in north-eastern Germany, more investigations on the benefits and risks of this technique are needed. Further research needs to focus on maintaining a high rye biomass as well as on ensuring an early soybean planting date. Optimizing the crimping and drilling equipment is still required in order to develop good management practices for no-tillage herbicide-free systems in European conditions. [ABSTRACT FROM AUTHOR]

• No-tillage gains lower yield than plow tillage with sandy soil and low precipitation. • No-tillage signigicantly nagatively influences silage maize yield after 3 years. • Achieving approximate double yield by irrigation in extreme drought years. • Irrigation is the most important factor as compared to tillage and crop rotation. • Giving highest and stable yield under plowed, irrigated and crop rotation combination. To analyze the effects of tillage (no-tillage , plow tillage), irrigation (rainfed , irrigated), and crop rotation (continuous maize , 4-year crop rotation) and their development, we conducted a field experiment over 9 years under sandy soil conditions in northeastern Germany. The generalized linear model showed that tillage, irrigation and crop rotation jointly explained approximately 35% of the total variance. Irrigation and crop rotation significantly positively influenced maize biomass yield started immediately in the first years in 2008 and 2011 respectively, while tillage started to significantly positively affect yield starting from the fourth year. In general, irrigation had the most relative importance as a management factor compared to the importance of tillage and crop rotation. Crop rotation with legumes increased soil nitrogen and carbon content and led to a higher yield than continuous maize 11.1 dt ha−1 y−1 in average. Furthermore, the significant effect of crop rotation on the yield of the following crop (maize) continued after 2 cycles of a 4-year crop rotation. A significant influence of the 2-way interactions between rotation, tillage and irrigation was only found in extremely dry years. It can be concluded that (i) the negative influence of no-tillage becomes noticeable after 3 years, leading to significantly lower yield compared to plow tillage; (ii) under the sandy soil and dry conditions, irrigation significantly increases yields and is the most important factor compared to tillage and crop rotation; and (iii) crop rotation significantly increases and maintains maize yield under both plowed and irrigated conditions. [ABSTRACT FROM AUTHOR]

Based on plot scale experiments and simulations we develop and parameterize the new Agro-Forest Crop Atmosphere Soil System model (AFCASS) within the ecosystem modelling framework Expert-N that combines tree growth and crop respectively grass growth models assuming three different field areas: (i) tree strip area, (ii) transition area between trees and crop/grass and (iii) crop/grass land area to simulate the complete field scale agro-forestry system.The model structure of the new model is presented and discussed. Simulations include light attenuation and plant internal water flow, leaf photosynthesis, plant growth and nutrient uptake for the three different agroforest areas for which also soil organic matter turnover and specific crop residue management is modelled by using the models SOILN and CENTURY and the Expert-N surface litter turnover model adapted to include tree litter: twigs, branches and specific fruits.The model is parameterized and tested using experimental data obtained by sub-projects of the BONARES SIGNAL Project that investigates agro-forestry systems at five different sites within different regions of Germany. It is the aim to study scenarios to analyse possible impacts of various management options (tree & crop area, tree & crop species, crop rotations, harvesting intervals, exposition) on soil and ecosystem properties (biodiversity, C-sequestration, nitrate leaching, soil erosion, plant water availability). [ABSTRACT FROM AUTHOR]

Crop rotation is known from millenia as the one of the best agronomical practice in plant cultivation. Rotation of plant crops is beneficial due to erosion prevention, nutrients retention, and many other factors for soil quality and improvement. Mostly, single catch crops are applied, but the benefits of diverse mixtures of catch crops are not yet clear. A long-term field experiment of the CATCHY project (Catch-cropping as an agrarian tool for continuing soil health and yield-increase) with two contrasting crop rotations was established in two different locations in Northern (Asendorf) and Southern (Triesdorf) Germany. Single catch crops (white mustard, Egyptian clover, phacelia and bristle oat), catch crop mixtures (a mixture of the above and a commercial mixture) and main crops (wheat and maize) have been grown. To investigate how catch crops can affect the microbial diversity and community composition, we were studying first the short-term effect of different catch crop mixtures on the microbiomes associated with soils and roots of the next main crop, maize. Roots, rhizosphere and bulk soils were collected from representative samples of triplicate field plots, including fallow treatments. Changes of the bacterial populations in the bulk soil, rhizosphere soil and root microbiomes of maize were investigated by Illumina Miseq amplicon sequencing of the targeted rRNA, and protein encoding nifH genes. Effects of the cover crop cultivation were compared with fallow soil treatment as control, relative abundance, alpha and beta diversity analyses were performed. [ABSTRACT FROM AUTHOR]