Periodic Reporting for period 3 - Circular Agronomics (CIRCULAR AGRONOMICS - Efficient Carbon, Nitrogen and Phosphorus cycling in the European Agri-food System and related up- and down-stream processes to mitigate emissions)
Période du rapport: 2021-09-01 au 2023-02-28
By applying different innovative strategies it is possible to reduce nutrient surplus up to 20% and increase nutrient efficiency and carbon stocks in soil both directly (fertilization strategies, genotypic species, nitrification inhibitors, etc.) and indirectly (by reducing/recovering N and P from manure and food waste(water)). A reduction of GHG and ammonia emissions by more than 15% can be achieved by applying strategies such feeding strategies, acidification or fertigation while promoting the use of bio-based fertilizers that have been efficiently produced by the 5 innovative technologies developed (The solar drying (TRL7), Microfiltered digestate fertigation (TRL8), Vacuum degasification (TRL6), Struvite recovery (TRL6), Membrane Treatment (TRL6)).
The solar-dried fertilizers and the fertilization with microfiltered digestate are the most promising technologies from the environmental point of view, with the lowest impact, while the precision feeding systems is the most cost-effective technology, with farm net income 21% higher than the conventional system.
From a social perspective, farmers with ecocentric attitudes are more likely to adopt technologies that have demonstrated a potential economic benefit. If farmers adopt these circular and more sustainable agricultural practices, consumers are willing to pay a premium for these sustainably produced food products.
The solar-dried fertilizers and the fertilization with microfiltered digestate are the most promising technologies from the environmental point of view, with the lowest impact, while the precision feeding systems is the most cost-effective technology, with farm net income 21% higher than the conventional system.
From a social perspective, farmers with ecocentric attitudes are more likely to adopt technologies that have demonstrated a potential economic benefit. If farmers adopt these circular and more sustainable agricultural practices, consumers are willing to pay a premium for these sustainably produced food products.
Within WP2 and WP3, five innovative technologies have been developed to produce bio-based products and recover nutrients and carbon from different agri-food waste (water), while minimizing GHG and ammonia emissions (solar drying, microfiltration and fertigation, vacuum degasification, k-struvite recovery and membrane treatment). Some of them have achieved high TRLs (up to 7) and are now ready for exploitation. An exploitation brochure and an approximation to other sites have been delivered. Up to 6 bio-based products compiling the new European Fertilizing Regulation or struvite application requirements have been obtained. We have been able to recover more than 83% of P in the form of struvite from soybean wastewater, and up to 62% of N from manure digestate that remain in the fertilizer product in a more stable form. Ammonia emissions have been reduced with fertigation by 86% compared to business as usual, and during manure storage by 23% when using manure coming from precision feeding vs conventional, while acidification step during the solar drying process allowed to reduce ammonia emissions up to 90%. To close the cycles, the products generated in WP2 and WP3 have been tested in several agronomical/horticultural trials within WP1, and different strategies have been implemented to reduce nutrient surplus and increase nutrient use and C stocks (fertilization strategies, genotypic species, nitrification inhibitors, etc.). Some of the main outcomes are: In the long-term fertilization trials after seven years of organic fertilizers’ application, SOC stocks are >20% higher in the first 10 cm of the soil compared with mineral fertilizer. Vacuum-degasification of digestate limits N losses at a small cost to yield. Good potential for micro-filtered digestate and dried acidified digestate to replace mineral fertilizer while reducing ammonia emissions. In mixed farming systems, the dairy slurry from precision feeding is not a fertilizer as efficient as the slurry from conventional feeding but crop protein content is higher. Under phosphorus limitation, combining ryegrass and fescue enables a considerable increase of yield compared to their respective monoculture while struvite as P (and N) fertilizer maintains crop yield while strongly mitigating nitrous oxide emissions.
Within CA a ground-breaking new approach (hyperspectral imagery) has been used for ultra-high resolution (~60 μm per pixel) assessment of various soil chemical properties in an undisturbed state, without mixing, enabling a more sensitive analysis of change in the soil profile. This has strongly increased the understanding of soil amendments in relation to carbon sequestration. CA has developed a novel approach of combining an application of organic fertilizer after seeding (of maize, between rows) with nitrification inhibitors. This combination has allowed for a cost-effective adjustment of nutrient availability and plant demand. The microfiltered digestate for fertigation (MDF) has been tested as a promising prototype for direct use of liquid digestate for fertigation with drip irrigation lines increasing the nutrient use efficiency, reducing emissions and minimizing water consumption. MDF has lower energy demand, lower cost than membrane filtration. A new solar drying system to produce bio-based fertilizers has been developed. For intensive dairy farming, CA has promoted the use of precision feeding systems in dairy cows to adjust nutrients to animal requirements and therefore reduce N excretion in the manure and GHG emission by improving their feed efficiency. Additionally, as a part of CA’s research approach, isolation of potential bacteriophages to control the amount high-ammonia producing bacteria in dairy cows rumen has been investigated. For extensive dairy farms, CA focus on the physiology of the cows and comparing different feeding strategies via the respiration chamber has brought the possibility to combine not only feeding with nutrient cycles, but also with GHG gases and emissions, studying the whole nutrient flow. Whey has been separated at the innovative electrospun nanofibrous membranes in comparison with recently used technologies (ultrafiltration, reverse osmosis) with further concentrate treatment (polishing, drying) for food industry of sweet and acid whey. Acid whey products will be no longer wasted but reused in livestock and crop farming. We have developed a novel N-recovery technology, which can be integrated into existing biogas plants via side-stream treatment. Vacuum degasification can handle mixed phases (solids + liquids; no filtration or other excessive pre-treatment required), does not require extra heat and thus is more economic compared to stripping. A novel treatment by usage of commodity enzymes has been used to stimulate phosphate release from phytic acid is developed. The process is flexible adjustable for waste and wastewater treatment of soybean processing factory.
The project has a direct impact at Political/legal, environmental, social, technological and economic level. CA has contributed to the development of effective joined up policy making by providing clear evidence-based policy recommendations that will support policy makers to identify policy barriers to closing nutrient loops. In addition, the project has provided fresh input to CAP improvement debates as our leading-edge research has fostered new thinking in policy making e.g. on the perception of the important role of carbon in agriculture as well as on risk vs. chances debates related to the use of bio-based residues. CA has developed affordable technical solutions which fit within the current structures of European agriculture, minimising the economic pressure on producers within the European agricultural sector so that food production costs remain stable. The social analysis within WP4 has led to develop non-technical measures such as policy actions, towards more sufficiency in agriculture, food consumption and waste management.
The project has a direct impact at Political/legal, environmental, social, technological and economic level. CA has contributed to the development of effective joined up policy making by providing clear evidence-based policy recommendations that will support policy makers to identify policy barriers to closing nutrient loops. In addition, the project has provided fresh input to CAP improvement debates as our leading-edge research has fostered new thinking in policy making e.g. on the perception of the important role of carbon in agriculture as well as on risk vs. chances debates related to the use of bio-based residues. CA has developed affordable technical solutions which fit within the current structures of European agriculture, minimising the economic pressure on producers within the European agricultural sector so that food production costs remain stable. The social analysis within WP4 has led to develop non-technical measures such as policy actions, towards more sufficiency in agriculture, food consumption and waste management.