Raphaël Wittwer

• PhD in Plant Sciences
• Researcher at Agroscope

Understanding the effects of agricultural soil management on the soil system and its functions is crucial to ensure the sustainable use of soil. Due to the countless ways in which soil can be managed, it is not an easy task to compare soil management practices across different locations and over time. One approach to making soil management comparab...

Soil structure is important for plant growth and ecosystem functioning, and provides habitat for a wide range of soil biota. So far, very few studies directly compared the effects of three main farming practices (conventional, organic and conservation agriculture) on soil structure and soil physical properties. Here, we collected undisturbed soil c...

Investigating plant responses to climate change is key to develop suitable adaptation strategies. However, whether changes in land management can alleviate increasing drought threats to crops in the future is still unclear. We conducted a management × drought experiment with winter wheat (Triticum aestivum L.) to study plant water and vegetative tr...

Litter decomposition is a fundamental process in soil carbon dynamics and nutrient turnover. However, litter decomposition in arable systems remains poorly explored, and it is unclear whether different management practices, such as organic farming, conservation agriculture can mitigate drought effects on litter decomposition. Thus, we examined the...

Agricultural production is under threat of water scarcity due to increasingly frequent and severe drought events under climate change. Whether a change in cropping systems can be used as an effective adaptation strategy against drought is still unclear. We investigated how plant water uptake patterns of a field-grown pea–barley (Pisum sativum L. an...

For decades, conservation tillage has been promoted as a measure to increase carbon stocks in arable soils. Since organic farming improves soil quality and soil carbon storage, reduced tillage under organic farming conditions may further enhance this potential. Therefore, we assessed soil organic carbon (SOC) stocks of reduced tillage compared with...

CONTEXT Crop phenology integrates information of how environmental drivers and management practices affect plant performance and crop yield. However, little is known about the impact of cropping systems (CS) on crop phenology and how this relates to differences in yield. OBJECTIVES We assessed the applicability of PhenoCams to track crop phenology...

Agricultural production is under threat of water scarcity due to increasingly frequent and severe drought events under climate change. Whether a change in cropping systems can be used as an effective adaptation strategy against drought is still unclear. We investigated how plant water uptake patterns of a field-grown pea-barley (Pisum sativum L. an...

Ecosystems provide multiple services to humans. However, agricultural systems are usually evaluated on their productivity and economic performance, and a systematic and quantitative assessment of the multifunctionality of agroecosystems including environmental services is missing. Using a long-term farming system experiment, we evaluated and compar...

In recent years there has been an upsurge of studies on ecosystem multifunctionality (EMF), or the ability of ecosystems to simultaneously provide multiple functions and/or services. The concept of EMF itself, the analytical approaches used to calculate it, and its implications depending on the spatial scale and field of study have been discussed i...

An amendment to this paper has been published and can be accessed via the original article.

Cover crops are often recommended as a valuable practice to develop more sustainable cropping systems but, despite many benefits, their adoption in practice is still limited mainly because the effects on productivity and economic return are variable. Furthermore, it is still unclear under which combinations with other management practices (e.g. til...

The impact of organic and conventional crop management together with two variations of conservation tillage was evaluated on N supply and losses at the end of a 4-year Swiss crop rotation. Soil samples were taken from four cropping systems: conventional intensive tillage (C-IT), conventional no tillage (C-NT), organic intensive tillage (O-IT) and o...

Reducing soil tillage can lead to many benefits, but this practice often increases weed abundance and thus the need for herbicides, especially during the transition phase from inversion tillage to non-inversion tillage. We evaluated if subsidiary crops (SCs, e.g., cover crops) can mitigate the effects of non-inversion tillage on weed abundance. Two...

The impact of different arable farming practices on soil erosion is only partly resolved, and the effect of conservation tillage practices in organic agriculture on sediment loss has rarely been tested in the field. This study investigated rainfall-induced interrill sediment loss in a long-term replicated arable farming system and tillage experimen...

We aimed to understand how crop practices such as tillage, crop management and cover crop use affect aggregate microhabitats for nitrogen (N)-cycling microorganisms. We quantified the abundance of five N-cycling functional genes: two genes related to ammonia oxygenation (amoA from archaea and bacteria), two nitrite reducers (nirS and nirK) and one...

There is an urgent need to identify and evaluate management practices for their biophysical potential to maintain productivity under climate change while mitigating greenhouse gas (GHG) emissions from individual cropping systems under specific pedo-climatic conditions. Here, we examined, through DayCent modeling, the long-term impact of soil manage...

Highlights • Subsidiary crops cultivation affects soil quality enhancing biochemical activity. • Subsidiary crops short-term effect on soil were similar in the mild pedo-climatic zones. • High rainfall and low temperature may reduce the effect of subsidiary crops growth on soil. • The Mediterranean north was the most suitable climate to promote...

Conservation tillage and organic farming are strategies used worldwide to preserve the stability and fertility of soils. While positive effects on soil structure have been extensively reported, the effects on specific root- and soil-associated microorganisms are less known. The aim of this study was to investigate how conservation tillage and organ...

Following publication of the original article [1], the authors reported that while the ordination graphs are all correct, the symbols in the legend are wrong.

Intercropping has been proposed as a useful strategy for reducing external inputs in cereal-based cropping systems, while maintaining adequate crop yield. Intercropping of wheat and subclover, implemented as living mulch, is recommended, but there is limited experimental proof for its suitability in different environments. The main objective of thi...

Leguminous cover crop and living mulch species show not only great potential for providing multiple beneficial services to agro-ecosystems, but may also present pathological risks for other crops in rotations through shared pathogens, especially those of the genus Fusarium. Disease severity on roots of subterranean clover, white clover, winter and...

Root rot disease assessment of field plants. (XLSX)

Aggressiveness of Fusarium spp. in greenhouse. (XLSX)

Number of Fusarium isolates recovered. (XLSX)

Background: Harnessing beneficial microbes presents a promising strategy to optimize plant growth and agricultural sustainability. Little is known to which extent and how specifically soil and plant microbiomes can be manipulated through different cropping practices. Here, we investigated soil and wheat root microbial communities in a cropping sys...

Fusarium head blight, caused by fungi from the genus Fusarium, is one of the most harmful cereal diseases, resulting not only in severe yield losses but also in mycotoxin contaminated and health-threatening grains. Fusarium head blight is caused by a diverse set of species that have different host ranges, mycotoxin profiles and responses to agricul...

The overall goal in nematode management is to develop sustainable systems where nematode populations are kept under the economic damage threshold. Conservation tillage and subsidiary crops, applied as cover crops and living mulches, generally improve soil health by increasing soil organic matter content and stimulating soil microbial activity. Howe...

To reduce environmental impacts of cropping systems, various management strategies are being discussed. Long-term field experiments are particularly suitable to directly compare different management strategies and to perform a comprehensive impact assessment. To identify the key drivers of several environmental impacts, we analysed a six year crop...

There is an urgent need to identify and evaluate management practices for their bio-physical potential to mitigate greenhouse gas (GHG) emissions from agriculture. The cost and time required for direct management-specific GHG measurements limit the spatial and temporal resolution and the extent of data that can be collected. Biogeo-chemical process...

A major challenge for agriculture is to enhance productivity with minimum impact on the environment. Several studies indicate that cover crops could replace anthropogenic inputs and enhance crop productivity. However, so far, it is unclear if cover crop effects vary between different cropping systems, and direct comparisons among major arable produ...

Reduced tillage is increasingly promoted to improve sustainability and productivity of agricultural systems. Nonetheless, adoption of reduced tillage by organic farmers has been slow due to concerns about nutrient supply, soil structure, and weeds that may limit yields. Here, we compiled the results from both published and unpublished research comp...

A network of experimental fields in northern and western Switzerland was used to better understand the behavior of various cover crops in diversified environmental conditions. Several species were oriented towards soil cover in autumn (e.g. brown mustard). Others produced an important aerial biomass (e.g. sunflower). Some, with intermediate perform...

Soil erosion is a major environmental problem of our time and negatively affects soil organic matter (SOM), aggregate stability or nutrient availability for instance. It is well known that agricultural practices have a severe influence on soil erosion by water. Several long-term field trials show that the use of low input strategies (e.g. organic f...

Within the CORE ORGANIC II project, TILMAN-ORG, we have compiled data from ongoing trials and the published literature to conduct a meta-analysis on the effects of reduced tillage on yields, weed pressure and oil C in organic farming. The results indicate that replacing deep inversion tillage with some form of reduced tillage intensity results in y...

There is great scientific and societal interest in the ecology and functioning of the immense diversity of microorganisms associated with plant roots (Mendes et al., 2011; Porras-Alfaro & Bayman, 2011). In particular, research into plant–soil interactions has unveiled a pivotal role of root-associated fungi in influencing plant growth and community...

More and more farmers consider to switch from conventional to organic production. What effect, then, does this have on yield and environmental performance? In particular, the question of how the duration of organic management affects plant yield, weed populations, biodiversity and soil fertility has rarely been investigated. To investigate this que...

Induction of plant resistance by herbivory is a complex process, which follows a temporal dynamic and varies spatially at the within-plant scale. This study aimed at improving the understanding of the induction process in terms of time scale and within-plant allocation, using apple tree seedlings (Malus × domestica) as plant model. Feeding preferen...