Catch Crops Research Articles

Optimal use of agricultural robot in arable crop rotation: A case study from the Netherlands

Acute shortages and rising costs of labour in the food and farming sector across Europe exhibit the fragility of agrifood systems. Agricultural robots present an opportunity to strengthen agrifood systems by addressing labour shortages and reduce CO2 emissions. This study proposes a method to investigate the potential use of an autonomous robotic system based on a case study on a typical high-tech Dutch farm that implements both an agricultural robot (AGR) and a conventional tractor (TRC) on a farm of 200 hectares in the region of Oldambt. To demonstrate the optimal use of an AGR, five farming operations (seeding, catch crop seeding, tine weeding, harrowing, inter-row hoeing, and spot spraying) in a crop rotation system of five crops (sugar beets, pumpkins, onions, spring barley and winter wheat) was chosen. The agricultural robot is here considered as a supplement (not substitute) to the farms overall cropping capability. It is found that price of fuel and labour are critical factors where higher fuel and labour price increases the benefit and use of the robot. Besides, time needed for remote supervision of the robot plays an important role.

Twin-Screw Extrusion Mechanical Pretreatment for Enhancing Biomethane Production from Agro-Industrial, Agricultural and Catch Crop Biomasses

This study aimed to evaluate the effects of mechanical treatment through twin-screw extrusion for the enhancement of biomethane production. Four lignocellulosic biomasses (i.e., sweetcorn by-products, whole triticale, corn stover and wheat straw) were evaluated, and two different shear stress screw profiles were tested. Chemical composition, particle size reduction, tapped density and cellulose crystallinity were assessed to show the effect of extrusion pretreatment on substrate physico-chemical properties and their biochemical methane production (BMP) capacities. Both mechanical pretreatments allowed an increase in the proportion of particles with a diameter size less than 1 mm (from 3.7% to 72.7%). The most restrictive profile also allowed a significant solubilization of water soluble coumpounds, from 5.5% to 13%. This high-shear extrusion also revealed a reduction in cellulose crystallinity for corn stover (i.e., 8.6% reduction). Sweetcorn by-products revealed the highest BMP values (338–345 NmL/gVS), followed by corn stover (264–286 NmL/gVS), wheat straw (247–270 NmL/gVS) and whole triticale (233–247 NmL/gVS). However, no statistical improvement in maximal BMP production was provided by twin-screw extrusion. Nevertheless, BMP kinetic analysis proved that both extrusion pretreatments were able to increase the specific rate constant (from 13% to 56% for soft extrusion and from 66% to 107% for the high-shear one).

Strategies of Climate Change Mitigation in Agriculture Plant Production—A Critical Review

Agriculture is the second-highest, after energy use, source of greenhouse gas emissions, which are released from soils and animal digestion processes and as a result of energy consumption at various stages of agricultural production. However, changes in the management of agricultural systems may mitigate the negative impact of this sector on the atmosphere and climate. This paper presents a literature review on energy consumption in agriculture and the potential of agricultural crop production to assist in mitigation of global warming by increasing absorption of CO2 from the atmosphere. The issue was considered in the context of managing the cultivation of main, catch and cover crops. The potential of carbon sequestration in the above- and below-ground biomass of selected crops was analyzed. It was stated that, depending on the species, main crops can sequester up to 113 CO2 ha−1 yr−1 in whole biomass, while catch or cover crops can sequester up to 14.80 CO2 ha−1 yr−1 and 0.17 CO2 ha−1 yr−1 in the above- and below-ground biomass, respectively. The benefits of the spread of catch or cover crops, such as improvement of soil quality (leading to an increase in primary crop yield by even as much as 65%) and a phytosanitary effect, as well as the barriers that limit the use of catch crops, including the problems with matching crop species to climate and soil conditions and the risk of reducing farmers’ income, were considered. The results of the review show that catch crops can assimilate an additional amount of 4 to 6 tonnes CO2 ha−1 yr−1, and thus, spreading of catch crops is an effective way to reduce the climate impact of agriculture.

Assessing the Role of Crop Rotation in Shaping Foliage Characteristics and Leaf Gas Exchange Parameters for Winter Wheat

Properly designed crop rotation enriches the diversity of the agroecosystem, which has a favorable effect on the environmental properties and crop yield. The experiment assessed winter wheat cultivated under the following crop rotations: A. winter rape + catch crop − spring barley − field pea − winter wheat; B. winter rape − winter wheat + catch crop − field pea − winter wheat; C. winter rape + catch crop − field pea − winter wheat − winter wheat; D. winter rape − winter wheat + catch crop − spring barley − winter wheat. The aim of the study was to investigate: (i) whether the cultivation of wheat in crop rotations following forecrops of rape, pea, barley, and wheat will affect its foliage and photosynthesis; (ii) how the photosynthetic process will affect the wheat yield. At the stem elongation stage (BBCH 36) and at the heading stage (BBCH 58), the following were investigated: foliage features, photosynthetic parameters, and the above-ground biomass; while at the BBCH 89 stage, the grain yield was investigated. It was demonstrated that photosynthesis was most intense under crop rotation A (the highest stomatal conductance, transpiration, intercellular CO2 concentration, and net assimilation rate ranged from 13.1–29.7 μmol CO2∙m−2·s−1). This was reflected in the above-ground biomass volume (1245–1634 g m−2) and grain yield (4.58–7.65 t ha−1). The cultivation of wheat following wheat under crop rotation C and following barley under D had a negative effect on both the foliage and photosynthetic parameters.

Consortia of Plant Growth-Promoting Rhizobacteria and Selected Catch Crops for Increasing Microbial Activity in Soil under Spring Barley Grown as an Organic Farming System

In order to protect and remediate soils, organic farming methods have grown in popularity. The aim of the study was to evaluate the effect of rhizobacteria (Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens) and catch crops (undersown red clover alone, undersown Italian ryegrass alone and a mixture of clover and ryegrass) on the microbiological activity of the soil under organic spring barley. In 2019–2021, a field experiment was carried out on an organic farm, randomly in eight variants, each in three repetitions. The following parameters were analyzed: enzymatic activity of dehydrogenases (DHA), acid phosphatase (PAC) and catalase (CAT), soil fertility index (BIF), and a number of selected physiological groups of microorganisms (molds, bacteria, and actinomycetes). Compared to the control variant (without catch crops and bacteria), the values of DHA, CAT, and BIF increased significantly in the variant in which rhizobacteria and catch crops were used simultaneously. The highest BIF, of 32, was obtained in 2019, after the application of red clover catch crop + Italian ryegrass + rhizobacteria. PAC activity dropped significantly after the application of the bacterial consortium alone and was lower than the control by an average of 30%.

Effect of anaerobic digestion on odor and ammonia emission from land-applied cattle manure

High ammonia (NH3) and odor emission can occur after land application of liquid animal manure. This study was aimed at evaluating NH3 loss and odor nuisance after field application of cattle manure and how it is affected by two anaerobic digestion strategies: i) digestion of cattle manure alone and ii) digestion with catch crops and dilution by water. A system of dynamic chambers with online measurements of NH3 and odorous compounds (summarized as odor activity value, OAV) was used. Two experiments were conducted under different temperature conditions. The results demonstrated that anaerobic digestion did not affect NH3 loss but did decrease OAV. Addition of catch crops and water to the digestion process reduced both NH3 loss and OAV. Cool temperature in one of the experiments had a large effect on both NH3 and odor emissions, and at high temperature the differences between treatments increased.

Estimated nutrient leakage from arable land in different bioeconomy scenarios for two areas in central Sweden, determined using a leaching coefficient method

Knowledge of future developments in agriculture and how these will affect nutrient leakage from arable land is important in efforts to achieve good ecological status of surface waters. This study assessed the impact of five scenarios for a bioresource-based economy, involving use of renewable biological resources from land and sea, on nitrogen (N) and phosphorus (P) leakage from arable land to surface-waters and groundwater. The scenarios (developed in an earlier study) were applied to two areas in central Sweden, leaching region LR-6 (5350 km2) and catchment C6 (19 km2). Using the NLeCCS calculation system to produce leakage coefficients, we evaluated the changes in total N and total P leakage from arable soil. The leakage coefficients described agricultural management practices and climate conditions representing the leaching region LR-6 in Sweden and the baseline year was 2016. The scenarios varied from a baseline in terms of crop combination (relative area of different crops) and extent of mitigation measures (e.g. delayed tillage date, buffer zone width and relative area, and catch crop). Expected consumption of meat varied in the scenarios, with lower consumption meaning fewer cattle and consequently less grass ley. The scenarios was supplemented with calculations of introducing mitigation measures up to their maximum potential.In leaching region LR-6, calculated baseline leakages was 10.5 kg N ha−1 year−1 and 0.87 kg P ha−1 year−1, values that varied in the scenarios by −4% to 5% (N) and −6% to 19% (P). In catchment C6 calculated baseline leakages was 7.1 kg N ha−1 year−1 and 1.11 kg P ha−1 year−1, and the values in the scenarios varied by −15% to 2% (N) and −5% to 5% (P). Assuming maximum potential of the mitigation measures decreased leakage further, by up to −19%.Crop combination had a major impact on total N and P leakage in the scenarios. Leakage increased when the amount of grass ley in the rotation decreased, but remained relatively unchanged when the crop combination change only involved annual crops. Frequency of the mitigation measures increased in all scenarios, with associated decreases in N and P leakage that counteracted the increased leakage caused by changes in crop combination. The most effective mitigation measure was catch crop for N leakage and delayed soil tillage for P leakage.

Intensifying dryland wheat systems by integrating guar increased production and profitability

Guar [Cyamopsis tetragonoloba (L.) Taub.], is a summer legume with heat- and drought-tolerance properties that is produced in the U.S. Southern Great Plains, but is often restricted to a catch crop or substitute crop following cotton failures. This is despite the large domestic market for guar gum and the opportunity to diversify regional cropping systems with guar, potentially adding ecosystem benefits like biological N fixation (BNF). To address this, a systems research study was conducted near Chillicothe, TX from 2018 to 2021 to evaluate the integration of guar into no-till dryland winter wheat (Triticum aestivum L.) systems. Treatments included integrated wheat-guar systems differing in cropping intensity, 1.33 crops yr−1 (WG1.3) and 2 crops yr−1 (WG2), plus guar (G1) and wheat (W1) monocrop systems with 1.0 crop yr−1. Results showed that crop rotation sequence influenced seasonal guar yields, with negative yield impacts when guar immediately followed wheat. Consequently, the average seasonal guar yield was greatest in G1 and WG1.3 (1.01 and 0.96 Mg ha−1, respectively), followed by WG2 (0.64 Mg ha−1). Seasonal wheat yield averaged 2.31 Mg ha−1 across years, with no differences among systems. Across years, cumulative system yield was greatest for WG2, followed by W1 and WG1.3, then G1. Similarly, average annual net income followed the trend of G1 < W1 < WG1.3 < WG2, with values ranging from US$ 62.7–213.0 ha−1 year−1. Although overall production and net income were somewhat greater for WG2 than WG1.3, seasonal risks of crop failure and economic loss were lower for the WG1.3 system under the regional climate. There was no direct evidence of guar BNF benefits on subsequent wheat yield and quality, though inclusion of guar enhanced soil NO3-N at varying levels among systems, particularly following wet growing seasons and in less intensive systems.

Effects of frequency of the stale seedbed after autumn or spring ploughing on weed density and composition in sown lemon balm

AbstractWeed management in organic farming needs to integrate a wide range of preventive tools. Here we tested the stale seed bed technique in field experiments with organic lemon balm. In a two‐factorial trial, four intensities of stale seedbed after either autumn or spring ploughing were tested in 2019/2020 and 2020/2021 on alluvial loams of the research farm Wiesengut in the Rhineland, Germany. Increasing the number of stale seedbed passes did not promote weed emergence before sowing in 2020 due to serious spring drought; in 2021 only the two last stale seedbed passes in later spring caused extra weed flushes, while cold weather conditions in early spring prevented weed response to the earlier passes. Despite the differences in the number of germinating weeds in 2021 before sowing, intensification of the stale seedbed had no decreasing effect on weed density in lemon balm after sowing. However, weed species‐specific periods were identified in which the stale seedbed selectively promoted emergence. Autumn ploughing followed by a superficial incorporation of the catch crop in spring resulted in a lower weed emergence than complete residue incorporation by spring ploughing. Seedbank size differed greatly between fields, probably due to crop rotation. The overall weed reducing effect of the tested tillage treatments was low, probably due to high weed pressure on the organic farm. To increase the efficacy of the stale seed bed technique, sufficient soil moisture as well as temperature requirements of the dominating weed flora need to be considered.

More extreme and frequent drought periods reduced crop production and altered stable isotope ratios of C and N in plants

Summary Climate change scenarios predict more frequent and intense drought periods for 2071–2100 in the most important and intensively used agricultural region of Austria, the Marchfeld. Current and predicted lower precipitation scenarios were simulated at a lysimeter station for 9 years. Plant biomass, nitrogen (N) and carbon (C) content, and δ13C and δ15N values of plant compartments were monitored in years 7–9. Aboveground biomass of cereals and grain yield decreased under the predicted scenario, while the quality of grain (% N) was unaffected. Weed and catch crops grown in winter were not affected or were even positively affected, possibly due to the accumulation of nutrients in the soil following the lower plant uptake in summer. Accordingly, low plant δ15N values were mainly attributed to the presence of higher proportion of mineral fertilizer in the predicted precipitation scenario. As expected, water stress significantly increased δ13C values in plants grown over summer, while this was not seen for plants growing over winter. Fertile agricultural soil might ameliorate but cannot outbalance the negative impact of more frequent and intense drought periods.

Domestication effects on nitrogen allocation, internal recycling and nitrogen use efficiency in the perennial new crop Silphium integrifolium (Asteraceae)

AbstractImprovements in seed yield during domestication and breeding are frequently achieved moving plants from the conservative syndrome of the plant economic spectrum towards the more acquisitive side, changing how plants acquire, allocate, use and store C and nutrients in relation to their wild relatives. The aims were to evaluate if domestication changed the N allocation, the internal plant N recycling (N resorption efficiency and proficiency, and N storage) and N‐use‐efficiency, in the perennial new crop Silphium integrifolium. We compared in a field experiment repeated in two locations (Kansas and Patagonia), a Wild (W) and two improved accessions, with high‐ (HYI) and low‐seed yield improved (LYI) accessions. HYI accessions produced more than twice the biomass and acquired twofold more N than LYI and Wild accessions. Changes in proportional N allocation were similar in both improved accessions (HYI and LYI) and locations: higher allocation to leaves and lower to the crown at pre‐anthesis (growth‐storage trade‐off) and higher allocation to seeds and lower to the crown at maturity (reproduction‐storage trade‐off). HYI and LYI allocated 50% more N to seeds in average, reducing a 31% the N allocated to the crown in relation to the Wild. Nitrogen use efficiency (NUE) and mean residence time (MRT) of N were reduced in both improved accessions. In HYI, the lower MRT was related to the lower storage of N in the crown and N removal through seed production, and in LYI was the result of the N lost through leaf senescence. HYI produced litter with lower N concentration (more proficient) that the wild accession. These could decrease the net N mineralization rate and soil N availability at long term. HYI plants should require higher external N inputs to the soil to sustain their N uptake requirements. LYI and Wild accessions, had lower resorption efficiency, but N recycled was allocated to the crown for future remobilization and uses (better internal cycling). The leaf litter type of these accessions with higher N content should sustain faster N‐cycles rates and N release to the soil. If the focus is on the ecosystem services, HYI accessions could help achieve a reduction in nitrate leaching by maximizing N uptake, N resorption and N removal through seed (i.e. nitrate catch crop), and also produce crop residues that slow down biogeochemical cycling and soil nutrient retention.

Temporal Dynamics of CO2 Fluxes Measured with Eddy Covariance System in Maize, Winter Oilseed Rape and Winter Wheat Fields

The full understanding of variation and temporal changes in carbon dioxide (CO2) fluxes in cropland may contribute to a reduction in CO2 emissions from agriculture. The aim of this study was to determine the CO2 exchange intensity in the three most popular crops in Poland. The CO2 fluxes in summer maize, winter oilseed rape and winter wheat fields were measured using the eddy covariance system. The seasonal dynamics of CO2 fluxes for all studied crops varied from each other due to individual dynamics in atmospheric CO2 assimilation of each species through the growing season. The weighted average values of CO2 fluxes calculated for the entire vegetation period were −22.22 µmol CO2 m−2 s−1, −14.27 µmol CO2 m−2 s−1 and −11.95 µmol CO2 m−2 s−1 for maize, oilseed rape and wheat, respectively. All the studied agro-ecosystems were carbon sinks during the growing season. The highest negative values of CO2 fluxes (−36.31 µmol CO2 m−2 s−1 and −33.56 µmol CO2 m−2 s−1) were observed in the maize field due to the high production of biomass. However, the maize field was also the most significant carbon source due to slow growth of plants at the beginning of the growing season, and due to leaving the field fallow after harvest until the next sowing. In these two periods, the CO2 fluxes ranged from 0.59 µmol CO2 m−2 s−1 to 3.72 µmol CO2 m−2 s−1. CO2 exchange over wheat and oilseed rape fields was less intense, but more even throughout the growing season. In the wheat field, the CO2 fluxes ranged from −1.70 µmol CO2 m−2 s−1 to −23.49 µmol CO2 m−2 s−1 and in the oilseed rape field they ranged from −1.40 µmol CO2 m−2 s−1 to −22.08 µmol CO2 m−2 s−1. In addition, the catch crop in the oilseed rape field contributed to the intensive absorption of CO2 after harvesting the main crop.

Is sorghum a promising summer catch crop for reducing nitrate accumulation and enhancing eggplant yield in intensive greenhouse vegetable systems?

Is sorghum a promising summer catch crop for reducing nitrate accumulation and enhancing eggplant yield in intensive greenhouse vegetable systems?

Effect of Different Tillage Systems and Soil Biostimulants on Agrochemical Properties and Intensity of Soil CO2 Emission in Wheat Crop

In this study, a field experiment was performed at the Experimental Station of Vytautas Magnus University Agriculture Academy in Lithuania from 2018 to 2020. The researched soil comprised carbonate deeper gleyic leachate (IDg4-k) (Calc(ar)i Endohypogleyic Luvisol) (LVg-n-w-cc). A two-factor field experiment was performed on spring and winter wheat. Factor A was soil tillage technology; factor B was the use of biostimulants and their mixtures (Ruinex, Penergetic, Azofix). The experimental fields were arranged randomly in four replicates. The aim of the work was to assess the soil CO2 emissions, soil carbon, soil nitrogen, humus, and humic substances using two different soil tillage management methods (no till—wheat straw left on the soil surface; and reduced till—soil incorporation of the wheat straw) and different biostimulants or nitrogen fertilization. The humus content of the soil remained sufficiently stable or slightly decreased when the straw was retained and the single-component biostimulators Azofix, Ruinex, and Penergetic were used. In contrast, when continuous straw application was combined with two- or three-component mixtures of these biological preparations or with compensatory nitrogen the humus content increased. Compared with the initial state, it increased by 1.4–12.8 % due to the improved complexity of extra conditions for microbiological biodiversity. Meanwhile, after three years of investigation, the soil tillage technology did not significantly impact the humus content, total nitrogen, and CO2 emissions. Tillage technologies had a significant impact on the content of water-soluble soil carbon. Under no-till, the carbon content increased by an average of 9.0%, and under reduced tillage, the carbon content increased by only 2.3%. It is likely that the combination of no-till with catch crops increased the stocks of soluble C in the soil. Compared to the use of compensatory nitrogen, this indicator was increased by all biostimulants, especially when using all three preparations in the mixture (Ruinex, Penergetic, Azofix). The effect of the two-preparation mixtures was also more pronounced than that of the single component. The results over three years show that biostimulants promote the release of mobile humic substances and mobile humic acids better than compensatory nitrogen for straw decomposition. The effect was the same for the organic carbon content.

Response of Field Pea and Common Vetch, Grown as a Catch Crop, on the Sowing Method

In temperate climate zones, long periods without rainfall or with excessive rainfall are common during sowing and the initial vegetation of a catch crop. These periods can result in poor emergence and/or low yields. The study aimed to determine the influence of the depth of furrow sowing of catch crops on the soil moisture in the immediate vicinity of the seeds sown (1), dynamics of germination and plant emergence (2), and the biomass yield (3). Three furrow sowing depths (4–5 cm FS-S, 6–7 cm FS-M, and 8–9 cm FS-D) were tested and compared with traditional sowing (TS) in the cultivation of field pea and spring vetch catch crops. High amounts of precipitation were stated in the study period, especially in years 2016 and 2017. Furrow sowing enabled placing seeds in soil layers characterized by higher moisture content than traditional sowing. The sowing method did not significantly affect the plant density in any of the three years of the study. Field pea turned out to be a more valuable species for cultivation in catch crops in conditions with excessive precipitation. This plant produced a significantly greater yield of above-ground dry matter and total biomass than spring vetch. The sowing method did not affect the yield of catch crop biomass in study conditions.

Evaluating the Effectiveness of Catch Crops and Tillage Systems for Carbon Farming

In modern agriculture, it is necessary to identify strategic steps that will reduce greenhouse gas emissions: on the one hand, reducing emissions by cutting down fuel consumption, reducing soil interference, limiting nitrogen losses when using fertilisers, and on the other hand – increasing the efficiency of carbon extraction from the atmosphere through plant photosynthesis and sequestration as organic matter of the soil. The purpose of this study is to figure out the influence on the carbon balance of such elements of the agricultural system as the system of tillage and the use of intermediate cover crops in a model 4-field crop rotation in the Steppe zone of Ukraine. This work was performed using the method of empirical calculations based on the online calculator of greenhouse gas emissions Cool Farm Tool. The influence of intermediate crops in two fields of crop rotation (after the early grain predecessors – wheat and winter barley) and tillage systems (traditional, reduced, and no-till) on the balance of carbon emissions and sequestration in the model 4-field crop rotation was analysed. According to the results, it was found that during the model 4-field crop rotation under the conditions of the classical system of tillage for sunflower and maize without intermediate crops and reduced processing for wheat and barley, the total greenhouse gas emissions amount to 4015 kg/ha of CO2 -eq. in 4 years. Switching to a reduced tillage system has been shown to reduce emissions by 30.1%. The addition of two intermediate crops in two crop rotation fields before spring crops allows obtaining a negative balance of greenhouse gas emissions of -377 kg/ha of CO2 -eq. during this period, and when switching to no-till for all crops -1221 kg/ha of CO2 -eq. for a 4-year rotation period. This study will help identify strategic steps and their potential contribution to the development and implementation of agricultural systems with minimal greenhouse gas emissions

The effect of catch crops in spring barley on nitrate leaching and their fertilizer replacement value

Catch crops have been proven effective in reducing nitrogen leaching in cropping systems due to their uptake of post-harvest soil mineral N prior to the main percolation season in winter. Information on the residual effect of catch crops, and their nitrogen fertilizer replacement value is scarce. To determine nitrogen fertilizer replacement values for different catch crops a field experiment was conducted over a four-year period on a sandy soil in Denmark, involving different catch crops and catch crop mixtures with non-legume and legume species. The residual effect of the catch crops was measured in spring barley grown in the residual year. For comparison, winter rye was also included. Over the four-year period the spring barley/fodder radish showed significantly lower leaching compared with the other catch crops, and the winter rye had the highest leaching. Regarding the residual effect, fodder radish and ryegrass, were most valuable, with nitrogen fertilizer replacement values ranging from 13 to 41 kg ha-1, based on fertilizer recovery efficiency of 50%. The process based APSIM (Agricultural Production Systems sIMulator) model was used to simulate the spring barley/catch crop rotations and the winter rye, and showed good model performance regarding N leaching and, crop yield and N uptake. The model was then run over a period of 20 years, to determine variations in N leaching and residual effects due to environmental conditions. The simulations showed that catch crops reduced N leaching by 38–64% when grown every year, and by 21–39% when grown only every second year. Nitrogen fertilizer replacement values ranged on average from 28 to 44 kg N ha-1, but showed high inter-annual variability. The nitrogen fertilizer replacement values showed only a weak relationship with the N uptake of the catch crop prior to termination, likely due to long term effects of N mineralisation from catch crop residues and pre-emptive competition for N by the catch crop.

Evaluation of the Environmental Performance of Cropping Systems under Different Nitrogen Management Scenarios Considering Regional Nitrogen Resilience

The agricultural sector is a primary driver of nitrogen (N) pollution. Several European and German policy measures exist regulating N inputs and fostering mitigation measures in crop management. Life cycle assessment (LCA) is an established tool for assessing environmental impacts which are also broadly applied for crop production systems and evaluation of N management strategies. However, due to the multiple spatial and temporal pathways of N losses from crop production, assessing N-related impacts in LCA is not straightforward. Consequently, this study further developed and applied a novel distance-to-target approach including regional carrying capacity based normalization references for N assessment in LCA. The overall aim was to prove its applicability as regional decision support for the assessment of N management strategies in cropping systems considering environmental interventions with regional N resiliencies. Therefore, environmental interventions were evaluated within a case study for four different N management scenarios for rapeseed cropping systems in five German NUTS-3 regions. Regional carrying capacity based normalization references were derived for two N-related impact categories: terrestrial eutrophication and terrestrial acidification. The regional normalization references also included background interventions of non-crop producing sectors and were provided for all German NUTS-3 regions applicable as distance-to-target values in LCA. Overall results showed that environmental interventions and exceedance of N resilience were lowest in the N-management scenario applying catch crops for both impact categories. The case study demonstrated that considering absolute sustainability references as regional N resilience in LCA is a valuable tool for agricultural decision-makers to evaluate N management strategies for crop production systems.

Effect of common vetch (Vicia sativa L.) seeds in organic diets for broiler chickens: Acceptance and precaecal digestibility of crude protein and amino acids from raw, germinated and ensiled vetches

The common vetch (Vicia sativa L.) is a hardy legume mostly used as a catch crop, but it also produces seeds with high protein content. Due to anti-nutritional factors present in the seeds, their use in diets for monogastric animals is limited. In order to improve the usability of common vetch seeds (CVS) as a protein-rich component with a suitable amino acid profile in organic diets for broiler chicken, we compared raw CVS (cultivar Slovena) with a digestibility of 0.860 of crude protein and 0.960 of methionine with germinated and ensiled CVS in a digestibility trial and a feeding trial. We used a slow-growing genotype (Hubbard/Isa-JA-757) in both trials. In the digestibility trial, raw, ensiled and germinated CVS were fed at three inclusion levels: 0, 100 and 200 g CVS/kg of diet (as fed basis). A total of 972 day-old mixed-sex broiler chicks were used. During the experimental period of the feeding trial, a total of 640 mixed-sex birds were offered raw, ensiled and germinated CVS separately.The voluntary intake of raw CVS was 57 g/kg of total dry matter intake, and fattening performance did not differ from the vetch-free control diet. While germination did improve the digestibility of crude protein and almost all amino acids in CVS, this change did not translate into equally improved performance of the birds in the feeding trial. High voluntary intake of the separately offered germinated CVS (132 g/kg of total dry matter intake) resulted in an inferior feed conversion ratio in comparison to the vetch-free control diet. We can therefore state that germinated CVS are a very attractive feed for broilers that is eagerly consumed, but comes at the cost of decreased feeding efficiency, at least at the inclusion level applied in our study. Ensiling, on the other hand, resulted in a markedly decreased digestibility of crude protein and all amino acids compared to the unprocessed CVS. Moreover, the ensiled CVS were consumed at a much lower rate than germinated CVS (77 g/kg of total dry matter intake). Therefore, ensiling of CVS prior to feeding cannot be recommended. We conclude that feeding raw CVS at low inclusion levels is more recommendable than germination or ensiling, because of the observed disadvantages of the treatments.

Modified crop rotations for a sustainable intensification? A case study in a high-yielding environment with recurrent nitrogen surplus

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.