Management of vegetable crop residues for reducing nitrate leaching losses in intensive vegetable rotations

Crop residues of field vegetables are often characterized by large amounts of biomass with a high N-content. Despite low soil temperatures during autumn, high rates of N mineralization and nitrification still occur causing important N-losses through leaching1. Crop residues pose a possible threat to maintaining water quality objectives, while at the same time being a vital link in closing the nutrient and organic matter cycle of soils. Appropriate and sustainable management is needed to obtain the full potential of crop residues. In this research some novel strategies for vegetable crop residue management are being investigated. The outcome of this work will help in defining the best practices in vegetable production in order to better meet the requirements set by the nitrate directive, whilst making best use of a valuable organic material. Vegetable crop residues constitute an important link in the soil nutrient and organic carbon cycle and aid in maintaining soil quality and fertility. However during autumn large amounts of N are released by vegetable crop residues causing important N-losses through leaching. Appropriate and sustainable management is needed to obtain the full potential of crop residues while meeting water quality objectives. In this research the potential of removal and valorisation of vegetable crop residues by means of ensilage or composting was evaluated

Utility of proximal plant sensors to support nitrogen fertilization in Chrysanthemum

Chrysanthemum morifolium Ramat. is a commonly grown ornamental worldwide. A proper timing of nitrogen (N) supply is essential for a qualitative crop and the return on investment for growers. Sub-optimal nitrogen nutrition negatively influences the commercial plant quality, while supra-optimal N has an environmental impact due to nitrate leaching. Therefore, (a) reliable indicator(s) of plant nitrogen status is/are needed. Two field-grown potted Chrysanthemum cultivars, 'Maya' and 'Orlando' were studied for three consecutive years (2016-2018). Three different N treatments were applied in order to obtain a variation in N content. Plant quality measurements consisted of plant height, diameter, leaf mass per area (2017 and 2018 only), biomass and foliar and plant N content analysis. Optical measurements were performed with a SPAD sensor (2016 and 2017) and a Dualex Scientific sensor (2017 and 2018) on leaf level and with a GreenSeeker NDVI meter on canopy level. Biomass, height and diameter tended to be smaller in the minimal fertilizer treatments. Leaf mass per area did influence the relation between N and chlorophyll measured with SPAD and Dualex. Epidermal polyphenolics measured with Dualex correlated better with foliar nitrogen than non-destructive chlorophyll measurements and the nitrogen balance index. Since abaxial epidermal polyphenolics were highly correlated with foliar nitrogen and convenient to measure in-field, we propose this measurement for decision support in Chrysanthemum fertilization. Because of cultivar and sometimes year-to-year variability, reference plots can be of help for growers and advisors. NDVI was found to be more susceptible for yearly variation, but very high correlation with several quality parameters and convenience in use make this vegetation index useful for detecting the extent of spatial quality variability and thus support site dependent N requirements to reach the desired plant diameter at the end of the growing season

Application of proximal optical sensors to fine-tune nitrogen fertilization : opportunities for woody ornamentals

Today, high amounts of residual nitrogen are regularly being reported in the open field production of hardy nursery stock. In some cases, excessive fertilizers or side-dressings are applied when circumstances are not favorable for uptake. Aquatic as well as terrestrial ecosystems are sensitive to enrichment with nutrients, but growers also benefit when losses are avoided. In this study, the potential of proximal optical sensors to optimize nitrogen fertilization was investigated in four woody species: Acer pseudoplatanus L., Ligustrum ovalifolium Hassk., Prunus laurocerasus 'Rotundifolia' L. and Tilia cordata Mill. For three consecutive growing seasons, plants were grown under three different fertilization levels to generate different nitrogen contents. Plant growth and nitrogen uptake were monitored regularly and combined with sensor measurements including Soil Plant Analysis Development (SPAD), Dualex and GreenSeeker. Here, we show that optical sensors at the leaf level have good potential for assisting growers in the sustainable management of their nursery fields, especially if leaf mass per area is included. Nevertheless, care should be taken when plants with different leaf characteristics (e.g., wax-layer, color, and leaf thickness) are measured. When all measuring years were considered, high correlations (R-2 >= 0.80) were found between area-based foliar nitrogen content and its non-destructive proxy (i.e., chlorophyll)measured by Dualex or SPAD. Based on our results, we recommend a relative rather than absolute approach at the nursery level, as the number of species and cultivars produced is very diverse. Hence, knowledge of absolute threshold values is scarce. In this relative approach, a saturation index was calculated based on the sensor measurements of plants grown in a reference plot with an ample nitrogen supply

Impact of agricultural management on soil aggregates and associated organic carbon fractions: analysis of long-term experiments in Europe

Inversion tillage is a commonly applied soil cultivation practice in Europe, which often has been blamed for deteriorating topsoil stability and organic carbon (OC) content. In this study, the potential to reverse these negative effects in the topsoil by alternative agricultural management practices are evaluated in seven long-term experiments (running from 8 to 54 years the moment of sampling) in five European countries (Belgium, Czech Republic, Hungary, Italy and UK). Topsoil samples (0–15 cm) were collected and analysed to evaluate the effects of conservation tillage (reduced and no tillage) and increased organic inputs of different origin (farmyard manure, compost, crop residues) combined with inversion tillage on topsoil stability, soil aggregates and, within these, OC distribution using wet sieving after slaking. Effects from the treatments on the two main components of organic matter, i.e. particulate (POM) and mineral associated (MAOM), were also evaluated using dispersion and size fractionation. Reduced and no-tillage practices, as well as the additions of manure or compost, increased the aggregates mean weight diameter (MWD) (up to 49 % at the Belgian study site) and topsoil OC (up to 51 % at the Belgian study site), as well as the OC corresponding to the different aggregate size fractions. The incorporation of crop residues had a positive impact on the MWD but a less profound effect both on total OC and on OC associated with the different aggregates. A negative relationship between the mass and the OC content of the microaggregates (53–250 µm) was identified in all experiments. There was no effect on the mass of the macroaggregates and the occluded microaggregates (mM) within these macroaggregates, while the corresponding OC contents increased with less tillage and more organic inputs. Inversion tillage led to less POM within the mM, whereas the different organic inputs did not affect it. In all experiments where the total POM increased, the total soil organic carbon (SOC) was also affected positively. We concluded that the negative effects of inversion tillage on topsoil can be mitigated by reducing the tillage intensity or adding organic materials, optimally combined with non-inversion tillage methods.</p

Soil-Improving Cropping Systems for Sustainable and Profitable Farming in Europe

Soils form the basis for agricultural production and other ecosystem services, and soil management should aim at improving their quality and resilience. Within the SoilCare project, the concept of soil-improving cropping systems (SICS) was developed as a holistic approach to facilitate the adoption of soil management that is sustainable and profitable. SICS selected with stakeholders were monitored and evaluated for environmental, sociocultural, and economic effects to determine profitability and sustainability. Monitoring results were upscaled to European level using modelling and Europe-wide data, and a mapping tool was developed to assist in selection of appropriate SICS across Europe. Furthermore, biophysical, sociocultural, economic, and policy reasons for (non)adoption were studied. Results at the plot/farm scale showed a small positive impact of SICS on environment and soil, no effect on sustainability, and small negative impacts on economic and sociocultural dimensions. Modelling showed that different SICS had different impacts across Europe-indicating the importance of understanding local dynamics in Europe-wide assessments. Work on adoption of SICS confirmed the role economic considerations play in the uptake of SICS, but also highlighted social factors such as trust. The project's results underlined the need for policies that support and enable a transition to more sustainable agricultural practices in a coherent way

Do Agricultural Advisory Services in Europe have the Capacity to Support the Transition to Healthy Soils?

The need to provide appropriate information, technical advice and facilitation to support farmers in transitioning towards healthy soils is increasingly clear, and the role of the Agricultural Advisory Services (AAS) in this is critical. However, the transformation of AAS (plurality, commercialisation, fragmentation, decentralisation) brings new challenges for delivering advice to support soil health management. This paper asks: To what extent do agricultural advisory services have the capacity to support the transition to healthy soils across Europe? Using the ‘best fit’ framework, analytical characteristics of the AAS relevant to the research question (governance structures, management, organisational and individual capacities) were identified. Analysis of 18 semi-structured expert interviews across 6 case study countries in Europe, selected to represent a range of contexts, was undertaken. Capacities to provide soil health management (SHM) advice are constrained by funding arrangements, limited adviser training and professional development, adviser motivations and professional cultures, all determined by institutional conditions. This has resulted in a narrowing down of access and content of soil advice and a reduced capacity to support the transition in farming to healthy soils. The extent to which emerging policy and market drivers incentivise enhanced capacities in AAS is an important area for future research

Soil-Improving Cropping Systems for Sustainable and Profitable Farming in Europe

Soils form the basis for agricultural production and other ecosystem services, and soil management should aim at improving their quality and resilience. Within the SoilCare project, the concept of soil-improving cropping systems (SICS) was developed as a holistic approach to facilitate the adoption of soil management that is sustainable and profitable. SICS selected with stakeholders were monitored and evaluated for environmental, sociocultural, and economic effects to determine profitability and sustainability. Monitoring results were upscaled to European level using modelling and Europe-wide data, and a mapping tool was developed to assist in selection of appropriate SICS across Europe. Furthermore, biophysical, sociocultural, economic, and policy reasons for (non)adoption were studied. Results at the plot/farm scale showed a small positive impact of SICS on environment and soil, no effect on sustainability, and small negative impacts on economic and sociocultural dimensions. Modelling showed that different SICS had different impacts across Europe—indicating the importance of understanding local dynamics in Europe-wide assessments. Work on adoption of SICS confirmed the role economic considerations play in the uptake of SICS, but also highlighted social factors such as trust. The project’s results underlined the need for policies that support and enable a transition to more sustainable agricultural practices in a coherent way

Use of Root Organ Cultures To Investigate the Interaction between Glomus intraradices and Pratylenchus coffeae

The interaction between Glomus intraradices and Pratylenchus coffeae on transformed carrot roots was studied in root organ culture. G. intraradices provided the roots with increased protection against P. coffeae by suppressing nematode reproduction in the roots. The internal and external mycorrhizal development was not influenced by the presence of the nematodes