TILMAN-ORG - Reduced tillage and green manures for sustainable organic cropping systems

• Forschungsstelle: BLW
• Projektnummer: 07.12_4
• Projekttitel Englisch: TILMAN-ORG - Reduced tillage and green manures for sustainable organic cropping systems

Kurzbeschreibung (Englisch)

Organic farming systems contribute to ecosystem services such as the maintenance of soil quality and biodiversity. Reduced tillage and green manures are efficient conservation agriculture tools that can be adapted to further improve organic crop production systems. The TILMAN-ORG project’s overall goals are to design improved organic cropping systems with: (a) enhanced productivity and nutrient use efficiency, (b) more efficient weed management and (c) increased biodiversity, but (d) lower carbon footprints (in particular increased carbon sequestration and lower GHG emissions from soils). These goals will be achieved by adapting and integrating conservation agriculture techniques (in particular reduced tillage and improved use of green manures) into organic farming systems to intensify biological soil functions like nutrient cycling, soil carbon build-up, and biological nitrogen fixation, while at the same time optimising management protocols for weeds (which are the main challenge when introducing minimum tillage systems). Optimum techniques for organic systems will be identified using an integrated approach:

i. Farmers’ experiences and perceptions about reduced tillage and green manures will be assessed in semi-structured interviews. Existing data from medium and long-term trials on reduced tillage and green manures provided by the consortium and the published existing peer reviewed and grey literature, will be evaluated with respect to yield stabilisation, soil quality and biodiversity (WP1 and WP2).

ii. Experimental Case Studies on soil quality and greenhouse gas emissions, weed management and functional biodiversity, and improved nutrient management will be carried out, and carbon stocks under reduced tillage compared to ploughing will be measured (WPs3-5). Data from long-term tillage trials across Europe will be exploited to calibrate NDICEA, a decision support tool to predict soil organic carbon and nitrogen fluxes in the soil - plant system.

iii. Design of optimised cropping systems by modelling approaches based on results from the literature and case studies (WP6). This will also involve the preparation of guidelines focused on helping farmers to address weed management challenges, and temporary shortages of nitrogen supply in order to improve yields and yield stability, thus improving both the environmental and economic sustainability of organic farming systems.

The project’s dissemination activities will target farmers, advisors, and the scientific community, but also the agricultural support industries and policy makers. The main innovative strategy of the project is to adapt conservation agriculture approaches to organic farming drawing on existing field experiments across Europe.

Umsetzung und Anwendungen (Englisch)

No-Till and Reduced Tillage are conservation tillage practices with a high potential to restore or improve essential soil functions and mitigate climate change through carbon sequestration and reduced fuel use. While No-Till systems are widely used in conventional farming, these techniques are challenging to adapt to organic farming due to weed pressure and frequent nitrogen deficiency in early spring. A potential answer may be reduced tillage, such as shallow inversion ploughing, or non-inversion tillage. The project goals are to design improved organic cropping systems that integrate conservation tillage and result in enhanced productivity and nutrient use efficiency, more efficient weed management, but lower carbon footprints.

Most of the research activities were based on 20 replicated field trials that were classified in three categories according starting time: older than seven years, three to seven years, and younger than two years. Additionally, a meta-analysis on existing literature was conducted. The main parameters of investigation were crop yield, soil quality and weed pressure.

Kunden/Berichterstattung (Deutsch)

Schlussbericht und FiBL-Merkblatt zum Thema reduzierte Bodenbearbeitung liegen dem BLW vor.

Webseite: http://www.tilman-org.net

Diverse Publikationen, Tagungen und Informationsveranstaltungen für Landwirte

Publikationen / Ergebnisse (Deutsch)

Das im Rahmen des Projektes verfasste FiBL-Merkblatt erläutert die verschiedenen Verfahren sowie die Vor-und Nachteile der reduzierten Bodenbearbeitung. Gemäss den Forschenden können die Empfehlungen auch von konventionellen Landwirten befolgt werden, um ihren Dünger- und Pflanzenschutzmittelverbrauch zu senken.

Publikationen / Ergebnisse (Englisch)

The main findings are as follows:

• Yield: In 62% of the cases, there was no significant difference between plough and reduced tillage. As an average, yields were 7% lower as compared to plough when reduced tillage was applied, which is well supported by the findings of the literature review.
  
  
• Soil quality: Reduced tillage increased soil organic carbon content in top soil, resulting in a better erosion control and increased plant available water. Moreover, reduced and no-tillage systems had more fertile top soil layers and different microbial communities than plough systems. Contrasting to non-inversion reduced tillage practices, the reduction in ploughing depth increased soil organic carbon without increasing weed density or reducing yields. This shows that reducing the ploughing depth is a practice which can easily be implemented without yield losses. In addition, the lower fuel consumption and fewer labor and tractor hours in reduced tillage systems may compensate for yield reductions if they occur at all.
  
  
• Weed pressure: Weeds were more abundant with reduced tillage, but did not necessarily affect yields. Site-specific weed management strategies are needed, and green manures can be useful in that context. However, in the majority of field trials having tillage as the only factor, weed abundance in various reduced tillage treatments and ploughing were not significantly different. Twelve trials had significantly higher weed abundance under reduced tillage, whereas two had higher abundance under ploughing. Weeds can be controlled in organic reduced tillage systems without jeopardizing crop yield. This is a relevant finding because ploughing has been considered a ‘must’ to control weeds in organic systems.
  
  
• In the last part of the project, innovative cropping systems were designed by the researchers. After defining the objectives for prototyping farms, crop rotations were designed according to the defined strategy and management factors were included step by step. Subsequently, the prototypes were evaluated by multi-criteria assessment models. Multi-criteria assessment revealed that the strength of reduced tillage is a positive influence on biodiversity and the macro-fauna in particular and that weed control is a major challenge in the long-term perspective. The results were used to define management guidelines.
  In the oceanic and the Mediterranean climate, reduced soil tillage performs well with respect to yield. Shallow ploughing is recommended, showing positive effects on soil organic carbon, without increasing weeds.
  In the humid continental climate, reduced soil tillage alone cannot be recommended. Here the use of green manures has advantages. A hybrid system with mostly reduced tillage but occasional ploughing is promising.