Periodic Reporting for period 3 - LEX4BIO (Optimizing Bio-based Fertilisers in Agriculture – Knowledgebase for New Policies)
Período documentado: 2023-06-01 hasta 2024-05-31
World food production relies heavily on agricultural productivity to feed the increasing world population. In recent decades, crop yield increases have been achieved with mineral fertilisers, especially those containing nitrogen (N) and phosphorus (P). Regional excessive use has caused vast environmental problems that have become even more severe due to disintegration of crop and animal production and urbanisation.
Currently, nutrient-rich side-streams (NRSS), such as manure, anaerobic digestate, sewage sludge, municipal biowaste and food industry by-products, are poorly used sources of nutrients for agriculture. They are often geographically concentrated: manure, due to the segregation of livestock and crop production, and municipal sewage sludge and biowaste due to urbanisation. This has led to great variations in nutrient balances, e.g. for P (applied P amount minus P export in crops), balances (EU27) varied from -2.8 (Eastern) to +23.2 kg/ha (Western Europe) in 2005 (van Dijk et al., 2016). High nutrient balances also often indicate low actual need for further P inputs in agricultural soils and large losses to the environment.
Application of synthetic, mineral fertilisers have remained prevalent in agriculture mainly due to the logistic challenges of NRSS as well as potential risks related to organic pollutants, heavy metals and nutrient losses to the environment. Therefore, to replace mineral fertilisers with bio-based fertilisers (BBF), produced from NRSS, better stabilised and more transportable fertiliser products with reduced water content, high nutrient content and quality assurance must be produced and become market available.
The overall objective of optimising bio-based fertilisers in agriculture – providing a knowledge basis for new policies (LEX4BIO) is to realise the potential of BBFs and consequently decrease European dependency on finite and imported, apatite-based P fertilisers and energy-intensive mineral N fertilisers.
Comprehensive evaluation of BBFs showed that they can be efficiently utilized as replacement for mineral fertilisers, and they do not pose risks for the environment, food and feed safety nor human health as long as recommendations provided by LEX4BIO are followed.
Currently, nutrient-rich side-streams (NRSS), such as manure, anaerobic digestate, sewage sludge, municipal biowaste and food industry by-products, are poorly used sources of nutrients for agriculture. They are often geographically concentrated: manure, due to the segregation of livestock and crop production, and municipal sewage sludge and biowaste due to urbanisation. This has led to great variations in nutrient balances, e.g. for P (applied P amount minus P export in crops), balances (EU27) varied from -2.8 (Eastern) to +23.2 kg/ha (Western Europe) in 2005 (van Dijk et al., 2016). High nutrient balances also often indicate low actual need for further P inputs in agricultural soils and large losses to the environment.
Application of synthetic, mineral fertilisers have remained prevalent in agriculture mainly due to the logistic challenges of NRSS as well as potential risks related to organic pollutants, heavy metals and nutrient losses to the environment. Therefore, to replace mineral fertilisers with bio-based fertilisers (BBF), produced from NRSS, better stabilised and more transportable fertiliser products with reduced water content, high nutrient content and quality assurance must be produced and become market available.
The overall objective of optimising bio-based fertilisers in agriculture – providing a knowledge basis for new policies (LEX4BIO) is to realise the potential of BBFs and consequently decrease European dependency on finite and imported, apatite-based P fertilisers and energy-intensive mineral N fertilisers.
Comprehensive evaluation of BBFs showed that they can be efficiently utilized as replacement for mineral fertilisers, and they do not pose risks for the environment, food and feed safety nor human health as long as recommendations provided by LEX4BIO are followed.
Selection of different types of both N- and P-BBFs were screened for their effect on crop growth and agronomic efficiency in different climatic conditions. Potential risks related to their use, including environmental N and P losses, organic contaminants, heavy metals and dissemination of antibiotic resistance genes were assessed. Socio-economic impacts were analyzed and finally policy recommendations for replacing mineral fertilisers with BBFs were derived.
Two-year field trials conducted across Europe showed that both N- and P-BBFs can efficiently replace mineral counterparts. Average N fertiliser replacement value of N-BBFs was 71% across the experimental sites. The agronomic mineral replacement value of P-BBFs showed a larger variation compared to N-BBFs, but many of the P-BBFs are as efficient as common mineral P fertilisers. Production technologies had a major impact on the agronomic efficiency of the investigated BBFs, especially for P-BBFs. Considering these aspects, production technologies should potentially be adjusted accordingly to maximize the nutrient utilization from BBFs. European soils were found to have a high P status and majority of the agricultural lands are not P-responsive and up to 86% of the P requirement could be covered with BBFs.
A literature review and meta-analysis showed that solid and carbon rich BBFs had a positive effect on soil organic carbon content as compared to mineral fertilisers. Both climatic conditions and soil properties need to be considered when selecting the most beneficial BBFs. Furthermore, carbon depleting steps during BBF processing should be applied with caution and only if needed to eliminate organic pollutants and pathogens.
Content of harmful substances in the wide range of BBFs investigated were generally far below national EU member state benchmarks (pharmaceuticals, pesticides, PCBs, phthalates, dioxines, furans, PFAS, PAHs, plastics, heavy metals). Also, BBFs studied generally do not pose a risk of disseminating antibiotic resistance in the soil. BBFs are produced with a wide range of technologies, having different efficiencies for removing harmful substances. Therefore, the chemical composition of nutrient-rich side-streams needs to be known for targeting proper processing technologies for producing safe BBFs.
Due to the variable composition of P- and N-rich BBFs they may potentially induce very different losses (higher or lower) of N and P to the environment relative to their synthetic counterparts. For P leaching, P-BBFs are likely to cause lower P leaching losses than mineral P fertilisers, but soil and BBF properties need to be known for minimising P loss risk. For ammonia loss, some BBFs have very low risk, while others have a relatively high risk; for the latter, immediate soil incorporation should be recommended. For N leaching, BBF application rate (as determined by expected N fertiliser replacement value) is the major determinant factor - farmers should therefore not apply much higher total N rates with BBF to compensate for low N fertiliser value.
Replacing conventional mineral fertilisers with BBFs requires policy measures, as BBFs are typically not economically competitive without policy support. Applying investment support, subsidies for BBFs and gate fees on the potential biomasses to decrease the production costs of BBFs will enhance the competitiveness of BBFs. Targeting the policy instruments for regions with a high nutrient surplus may support the redistribution of BBFs to regions with high demand for nutrients.
Two-year field trials conducted across Europe showed that both N- and P-BBFs can efficiently replace mineral counterparts. Average N fertiliser replacement value of N-BBFs was 71% across the experimental sites. The agronomic mineral replacement value of P-BBFs showed a larger variation compared to N-BBFs, but many of the P-BBFs are as efficient as common mineral P fertilisers. Production technologies had a major impact on the agronomic efficiency of the investigated BBFs, especially for P-BBFs. Considering these aspects, production technologies should potentially be adjusted accordingly to maximize the nutrient utilization from BBFs. European soils were found to have a high P status and majority of the agricultural lands are not P-responsive and up to 86% of the P requirement could be covered with BBFs.
A literature review and meta-analysis showed that solid and carbon rich BBFs had a positive effect on soil organic carbon content as compared to mineral fertilisers. Both climatic conditions and soil properties need to be considered when selecting the most beneficial BBFs. Furthermore, carbon depleting steps during BBF processing should be applied with caution and only if needed to eliminate organic pollutants and pathogens.
Content of harmful substances in the wide range of BBFs investigated were generally far below national EU member state benchmarks (pharmaceuticals, pesticides, PCBs, phthalates, dioxines, furans, PFAS, PAHs, plastics, heavy metals). Also, BBFs studied generally do not pose a risk of disseminating antibiotic resistance in the soil. BBFs are produced with a wide range of technologies, having different efficiencies for removing harmful substances. Therefore, the chemical composition of nutrient-rich side-streams needs to be known for targeting proper processing technologies for producing safe BBFs.
Due to the variable composition of P- and N-rich BBFs they may potentially induce very different losses (higher or lower) of N and P to the environment relative to their synthetic counterparts. For P leaching, P-BBFs are likely to cause lower P leaching losses than mineral P fertilisers, but soil and BBF properties need to be known for minimising P loss risk. For ammonia loss, some BBFs have very low risk, while others have a relatively high risk; for the latter, immediate soil incorporation should be recommended. For N leaching, BBF application rate (as determined by expected N fertiliser replacement value) is the major determinant factor - farmers should therefore not apply much higher total N rates with BBF to compensate for low N fertiliser value.
Replacing conventional mineral fertilisers with BBFs requires policy measures, as BBFs are typically not economically competitive without policy support. Applying investment support, subsidies for BBFs and gate fees on the potential biomasses to decrease the production costs of BBFs will enhance the competitiveness of BBFs. Targeting the policy instruments for regions with a high nutrient surplus may support the redistribution of BBFs to regions with high demand for nutrients.
The selected BBFs (84 in total) included a wide range of available BBFs, including those already on the market as well as potential future BBFs, covering a wide selection of PFC/CMC categories of FPR. This ensured evaluation of different technologies for producing safe and efficient BBFs in different climatic conditions in the EU, focusing on environmental protection, food and feed safety and human health. Compliance methods for both N- and P-BBFs were evaluated, ensuring improved utilisation of BBFs and minimising potential losses to the environment.
LEX4BIO has provided information on required technologies for producing regionally safe BBFs. Analysis of LUCAS soil samples provided knowledge on bioavailable nutrient and harmful heavy metal concentrations in agricultural soils in the EU. This information can be used for targeting BBFs to ensure food and feed safety, having a direct impact on human health. Better BBF utilization also ensures reduced dependency on imported, apatite-based P fertilisers and energy intensive mineral N fertilisers, providing tools for reaching the goals of the Paris agreement on climate change.
LEX4BIO has provided information on required technologies for producing regionally safe BBFs. Analysis of LUCAS soil samples provided knowledge on bioavailable nutrient and harmful heavy metal concentrations in agricultural soils in the EU. This information can be used for targeting BBFs to ensure food and feed safety, having a direct impact on human health. Better BBF utilization also ensures reduced dependency on imported, apatite-based P fertilisers and energy intensive mineral N fertilisers, providing tools for reaching the goals of the Paris agreement on climate change.