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The purpose of the StaPlaRes project was to evaluate two innovative techniques of urea fertiliser application and to quantify greenhouse gas (GHG) emissions. All GHG emissions, as well as other gaseous emissions, agronomic and environmental variables were collected for three years (2016/2017–2018/2019) at three experimental field sites in Germany. All management activities were consistently documented. Multi-variable data sets of gas fluxes (N2O and NH3), crop parameters (grain and straw yield, N content, etc.), soil characteristics (NH4-N, NO3-N, etc.), continuously recorded meteorological variables (air and soil temperatures, radiation, precipitation, etc.), management activities (sowing, harvest, soil tillage, fertilization, etc.), were documented and metadata (methods, further information about variables, etc.) described. Additionally, process-related tests were carried out using lab (N2 emissions), pot and lysimeter experiments (nitrate leaching). In total, 2.5 million records have been stored in a Microsoft Access database (StaPlaRes-DB-Thuenen). The database is freely available for (re)use by others (scientists, stakeholders, etc.) on the publication server and data repository OpenAgrar for meta-analyses, process modelling and other environmental studies. Measurement(s) air temperature • air humidity • air pressure • global radiation • precipitation • Grain yield • nitrous oxide concentrations (gas field measurements) • emissions of NH3 • soil moisture • ammonium in soil • nitrate in soil Technology Type(s) weather station • Weighing • static closed chamber technique • method of calibrated Passive sampling • SENTEK sensor • Extraction with 0.0125 M CaCl2 solution or 0.1 M KCl (VDLUFA method handbook I A 6.1.4.1) Factor Type(s) Fertilizer Sample Characteristic - Environment gaseous field emissions Sample Characteristic - Location Germany [ABSTRACT FROM AUTHOR]

In organic farming the control of perennial weed species, in particular Cirsium arvense, can be a major concern for farmers, especially if there is no regulation through perennial forage production. To test whether the stubble cleaner (SC), an enhanced skim plow (PL), is as effective in the control of C. arvense and other weeds as conventional ploughing and perennial forage production, an organic field experiment was established. Three different tillage/crop rotation systems were compared: an SC system and a PL system, both in a cereal-based crop rotation and an additional PL system in a crop rotation that included a perennial alfalfa–grass mixture (PLALF). In the SC system, tillage was carried out solely with the SC, while in the PL and PLALF systems, ploughing was alternated with chiseling. In the fifth year, each main plot was divided into subplots, and seven different cover crop treatments were integrated into each of the three systems. The effects of the three systems and the cover crop treatments on weed cover and density, weed biomass, and weed diversity in the sixth and seventh year of the experiment are the subjects of this paper. The choice of cover crop species was of minor importance for weed control. The PLALF system was generally more effective in controlling C. arvense than the PL and SC systems. No significant differences between the PL and SC systems regarding the control of C. arvense could be identified in four of five assessments. The SC system had significantly higher total weed density than the PLALF and PL systems in both years. However, the differences in weed emergence between the PL and SC systems diminished until the assessment of weed cover and biomass in the main crops, when no significant differences between these two systems (2012) or no differences at all (2013) could be identified. Species richness was not significantly influenced by the tillage/crop rotation system in both years. Evenness and Shannon–Wiener index were significantly higher in the PLALF and PL systems than in the SC system on most assessment dates in 2012. In 2013 there was no clear trend regarding evenness and Shannon-Wiener index probably due to a hoeing operation.. In conclusion, for weed control, the choice of crop rotation was more important than the choice of tillage method, while for the diversity of the weed community, the choice of tillage method was more important than the crop rotation. [ABSTRACT FROM AUTHOR]

Perennial energy crop production methods such as short rotation coppice (SRC) have gained interest among farmers and policy makers. SRC is characterised by rapid biomass production, low inputs, and high managerial flexibility. SRC plantations also provide environmental advantages relative to annual crop production and contribute to the transition towards renewable energy. Yet, the combination of high sunk costs and high uncertainty hampers SRC adoption among farmers. Policy instruments currently implemented to foster SRC adoption exhibit limited success. In this paper we assess the performance of different policy measures intended to stimulate SRC adoption in terms of efficiency and farm-level effects, taking into account related uncertainty. We use a combination of stochastic programming and the real options approach in our model featuring SRC poplar cultivation in Germany. We analyse four policy measures intended to foster SRC adoption: an establishment subsidy, a price floor, a guaranteed price, and increasing the “Ecological Focus Area” (EFA) value for SRC systems within the European Union Common Agricultural Policy. Our results indicate that a guaranteed price can stimulate immediate SRC adoption; however, it is inferior to the other instruments in other dimensions. An establishment subsidy as recently implemented in the study area might incentivise farmers to adopt SRC by contributing substantially to farm income, but should be modified because it may encourage postponement of SRC adoption. Increasing the EFA coefficient and a price floor are more efficient measures in terms of governmental expenditures, while having limited positive effects on bioenergy produced. [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]

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]

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]

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]

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]

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]

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]

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]

• 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]

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]