Use of digestate from Swedish biogas production in organic agriculture – possibilities for efficient plant nutrient recycling

We have conducted an extensive review of current knowledge and experiences regarding the possibilities for use of digestate from biogas production on organic farms in Sweden to improve plant nutrient recycling. The main findings of this review are presented below

Winter Runoff of Nitrogen and Phosphorus from a Rotational Pen Design with Suckler Cows

Keeping beef cattle outdoors during winter reduces costs and improves animal welfare, but increases the risk of nitrogen (N) and phosphorus (P) runoff losses. This study evaluated a rotational pen design on grassland with two groups of suckler cows given access to an expanding staying area and a new feeding area each week (72 cattle ha−1), with one month’s stay per pen. The spatial distribution of excreta and effects on N and P surface runoff was evaluated during six months. The total excreta loads corresponded to 500 kg·N·ha−1 and 50 kg·P·ha−1. New feeding areas did not distribute excretions evenly, which resulted in the highest proportion of excretions (31%) occurring in the first week’s sub-area. The topsoil had significantly higher amounts of mineral-N, mainly as NH4-N (29 - 81 kg·ha−1), than an unaffected area (13 kg·ha−1). Mean total runoff losses were similar for both groups (1.4 kg·P·ha−1 and 9.0 kg·N·ha−1). Around 78% of N and 70% of P runoff losses occurred during the month with cattle present. During the first two weeks with heavy rain, N and P runoff losses were 50% higher from an area with suckler cows than a corresponding vegetated sub-area without cows. The study design did not provide a sufficient distribution of excretions and a high animal density in combination with trampling resulted in unacceptable N and P run-off losses. An environmentally friendly design would need to include frequent moving of all equipment and access to larger areas

Environmental consequences of pig production scenarios using biomass from rotational grass-clover leys as feed

Production of pork based on monoculture cereal-based cropping systems causes substantial environmental pressures and feed-food competition. This study evaluated the environmental consequences of five different scenarios involving inclusion of rotational grass-clover leys and incorporation of grass-clover biomass in pig diets: (1) a conventional reference scenario without grass-clover biomass; (2) a conventional scenario with replacement of feed with grass-clover silage in a total mixed ration, i.e., with grass-clover biomass replacing other feed; (3) an organic scenario using grass-clover silage for enrichment purposes only; (4) an organic scenario using grass-clover silage for enrichment purposes and additional grass-clover leys for green manuring; and (5) an organic scenario using grass-clover silage and pasture to replace feed. The functional unit was 1 kg of pork slaughter weight and the system boundary was from cradle to farm gate. We used life cycle assessment, the introductory carbon balance method and human edible feed conversion efficiency to assess the performance of the pig production system. Introducing grass-clover biomass as a total mixed ration in conventional pig diets, reduced the climate impact (-17%), eutrophication (-7.1%), marine eutrophication (-15%), energy use (-13%), and feed-food competition (-20%) per kg of pork meat, while acidification (+2.7%) and land use (+1.5%) were slightly increased compared with the reference. The lower climate impact (without considering soil carbon change) was attributable to reduced fertilizer and diesel needs due to pre-crop effects. Overall, feeding grass-clover biomass decreased several environmental impact categories, feed-food competition and improved cereal-based cropping systems by the introduction of grass-clover leys

Developing an organic research agenda with stakeholder involvement promotes increased relevance in research

A Swedish organic research agenda was developed by EPOK, Centre for Organic Food and Farming, in an open process together with interested parties in the food chain. The main aim of the research agenda was to provide a well-supported document which would enable decision makers and research funding bodies prioritise future research calls. The agenda took on the most important future challenges and knowledge needs of the organic food chain on the road towards increased sustainability, efficiency and environmental and social benefits. Three cross-cutting themes were identified to describe the overall challenges that face organic agriculture and the organic food chain: Robust systems, Added value for the environment and society and Competitiveness and thriving rural communities. Based of the three overarching themes five prioritised focal areas were pointed out in the research agenda: 1) High productivity with maintained sustainability, 2) Innovative production systems with many functions, 3) Closed-loop cycles and renewable resources, 4) Sustainable enterprises and market development, 5) Healthy food with added value. Involving stakeholders in forming the research agenda promoted early interactions and cooperation between actors within organic agricultural research. Furthermore the involvement of numerous stakeholders enabled a broad view of the need for new knowledge in the organic food chain, from primary production and marketing questions to the performance of organic agriculture in respect of beneficial contribution to environment and society. A dialogue with researchers and agricultural research funding bodies was an important part of the process forming the agenda. The consequence of this cooperation was that the agenda has been used as a basis of a number of research calls

Improved concrete outdoor runs in housing systems for growing-finishing pigs: automatic manure scrapers

This factsheet provides knowledge-based strategies for the installation of automatic manure scrapers in concrete outdoor runs for organic pigs. Additionally, it presents the results of the Core Organic Cofund project POWER on automatic manure scrapers’ relevance for animal welfare and their environmental impact

Rötrest från biogasanläggningar

En viktig utmaning för det ekologiska lantbruket är att utveckla hållbara lösningar för effektiva kretslopp av växtnäring, såväl inom gården, mellan gårdar som mellan stad och land. Det finns många hinder att överbrygga. Det handlar bland annat om att kretsloppsprodukter som genereras i urbana samhällen inte innehåller skadliga halter av främmande ämnen, såsom tungmetaller eller kemiska ämnen. Det handlar också om att restprodukterna innehåller växtnäringsämnen i för växterna rätt proportioner och i tillräckligt höga halter för att vara ekonomiskt intressanta som gödselmedel. Kunskap behöver byggas upp och kommuniceras om hur olika typer av restprodukter ska hanteras på bästa sätt för att undvika negativ miljöbelastning. även gödslingsrekommendationer behöver tas fram för att nå ett högt resursutnyttjande. Under senare år har utbyggnaden av biogasanläggningar tagit fart och det finns idag även ett antal anläggningar från vilka rötresten är godkänd att användas i ekologisk produktion. Syftet med denna skrift är att bidra till att kunskap kommer ut kring möjligheter att förbättra hushållningen med växtnäring vid användning av rötrest från biogasproduktion på ekologiska gårdar. I skriften sammanställs dagsaktuell kunskap och även praktiska erfarenheter kring användning av rötrest. Blandannat presenteras förslag till rekommendationer om hur rötresten ska hanteras och användas för att nå hög avkastning och minimal miljöpåverkan. Skriften vänder sig till växtnärings- och energiråd - givare samt myndigheter som har miljötillsyn inom jordbrukssektorn och andra intresserade av växtnäring, kretslopp och miljö

Hur förebygga att kor trampar sönder betet?

Upptrampade och leriga ytor på kornas bete kan påverka kotrafik, djurhälsa och mjölkkvalitet. En lösning kan vara att använda tramptåliga vallfröblandningar. En annan lösning kan vara att stabilisera markytan på särskilt hårt belastade ytor, exempelvis vid grindhål. Här rapporteras preliminära resultat från ett forskningssamarbete mellan SLU och RISE